Question 1

A 31-year-old woman, gravida 1 para 0, at 14 weeks gestation comes to the office to establish prenatal care. She has had some nausea but no vomiting, abdominal pain, or vaginal bleeding. The patient contracted HIV through intravenous heroin use. She was diagnosed 3 years ago while hospitalized for drug rehabilitation. The patient is on triple-combination antiretroviral therapy with no significant side effects. She has no other chronic medical conditions and has had no previous surgeries. In addition to her HIV medications, the patient takes a daily prenatal vitamin. She does not use tobacco or alcohol and has not used illicit drugs since rehabilitation. Temperature is 36.7 C (98.1 F), blood pressure is 110/60 mm Hg, and pulse is 65/min. BMI is 24 kg/m². Pelvic examination reveals a 14-week-sized nontender uterus with no adnexal masses. Laboratory results are as follows: Bedside ultrasound reveals a 14-week intrauterine pregnancy with a normal heart rate. The patient is compliant with highly active antiretroviral therapy (HAART) throughout pregnancy. She continues to abstain from tobacco, alcohol, and illicit drugs. The patient has an uncomplicated delivery at 38 weeks gestation and indicates that she would like to breastfeed her child. Which of the following is the most appropriate recommendation?

Accepted Answer

Explanation: 11ec2b69_bf88_8c01_8f63_b34a8d43b5f3_MD0005_00 Breast milk is the optimal form of infant nutrition due to its immunologic properties; however, breastfed infants are at risk of postnatal HIV acquisition. In the United States and other industrialized countries with access to clean water for formula, women with HIV are advised to formula-feed their infants. In resource-poor countries, formula feeding is associated with an increased risk of water-borne infectious disease (eg, diarrhea). In these countries, breastfeeding decreases infant morbidity and mortality rates by providing protective maternal antibodies and minimizing exposure to water-borne pathogens. In addition, most antiretroviral drugs are excreted in breast milk in significant enough quantities to provide passive infant protection and decrease the risk of postnatal HIV transmission. (Choices A, B, C, and D) In all countries, infants born to HIV-positive mothers should receive zidovudine prophylaxis for >6 weeks while the mother continues highly active antiretroviral therapy for indefinite viral suppression. Educational objective: HIV-positive women in resource-rich countries are advised to feed their infants with formula rather than breast milk, regardless of maternal or infant antiretroviral therapy. In contrast, women in resource-poor countries are recommended to breastfeed due to high rates of infant morbidity and mortality from water-borne infectious diseases associated with formula feeding. References: Guidelines on HIV and infant feeding 2010: principles and recommendations for infant feeding in the context of HIV and a summary of evidence. (http://www.ncbi.nlm.nih.gov/pubmed/24501786) Triple antiretroviral compared with zidovudine and single-dose nevirapine prophylaxis during pregnancy and breastfeeding for prevention of mother-to-child transmission of HIV-1 (Kesho Bora study): a randomised controlled trial. (http://www.ncbi.nlm.nih.gov/pubmed/21237718) Antiretroviral regimens in pregnancy and breast-feeding in Botswana. (http://www.ncbi.nlm.nih.gov/pubmed/20554983)

Question 2

A 43-year-old woman comes to the office due to 2 days of frequent "runny stools." She has not noticed blood or mucus in her stool but has had nausea, abdominal cramping, and malaise. Yesterday, the patient returned from a week-long vacation in Honduras, where she saw notable sights, snorkeled in the Caribbean Sea, and ate food from street vendors. Her medical history is significant for obesity, hypercholesterolemia, and gastroesophageal reflux disease. The patient takes atorvastatin and omeprazole and has not recently used antibiotics. She does not smoke tobacco or drink alcohol. Temperature is 37.8 C (100 F), blood pressure is 130/80 mm Hg, pulse is 80/min, and respirations are 12/min. BMI is 31 kg/m². The patient appears uncomfortable. The abdomen is soft and mildly tender but no guarding, rigidity, or rebound tenderness is present. The remainder of the physical examination is normal. Laboratory results are as follows: Which of the following pathogens is the most likely cause of this patient's symptoms?

Accepted Answer

Explanation: 11ec2b69_bf85_3099_8f63_13bb5ef4883b_MD0005_00 Travelers' diarrhea is common in those who travel from resource-rich to resource-limited countries, occurring at rates as high as 50%. The vast majority of cases are bacterial in etiology, and the leading cause is enterotoxigenic Escherichia coli (ETEC). ETEC is transmitted via contaminated water or food and releases enterotoxins in the intestine that cause watery diarrhea and crampy abdominal pain 1-3 days after inoculation. Fever, nausea, vomiting, and myalgias may also occur. Infections are typically self-limited and resolve with supportive therapy in 3-4 days. Travelers to developing countries can reduce their risk of ETEC infection by avoiding peeled, uncooked fruits and vegetables; unpasteurized dairy products; food from street vendors; and untreated water (including ice). (Choice B) Giardia lamblia is a common protozoal cause of travelers' diarrhea that can manifest with watery diarrhea, malaise, and abdominal cramps. However, stools are typically foul-smelling or fatty, and symptoms almost always arise >1 week after exposure. (Choice C) Rotavirus is the most common viral cause of travelers' diarrhea and typically manifests with vomiting, nonbloody diarrhea, and fever. Bacterial causes are far more common, and this patient has no vomiting or significant fever. (Choice D) Shigella is a bacterial cause of travelers' diarrhea that typically results in dysentery (bloody, mucoid diarrhea) and high fever (unlike this patient). (Choice E) Vibrio parahaemolyticus is a bacterial cause of seafood-associated diarrhea that can manifest with watery or bloody diarrhea, abdominal cramps, nausea, vomiting, and fever. This patient has no fever, vomiting, or bloody stools. Educational objective: Enterotoxigenic Escherichia coli is the most common cause of travelers' diarrhea and typically manifests 1-3 days after exposure with watery diarrhea and crampy abdominal pain. Symptoms are usually self-limited and resolve spontaneously within 3-4 days.

Question 3

An 82-year-old woman with dementia and insulin-dependent diabetes mellitus is evaluated at her nursing home due to a urine culture result showing Escherichia coli.  Two days ago, the patient was taken to the emergency department due to increased confusion from her baseline that was noted shortly following breakfast.  Evaluation revealed mild hypoglycemia and dehydration but normal blood cell counts, serum chemistry studies, chest x-ray, and brain imaging.  Urinalysis showed 10-15 leukocytes/hpf and occasional bacteria; a clean catch urine culture specimen was obtained.  The patient's confusion resolved with intravenous hydration and normalization of her glucose levels; her medication regimen was reviewed, and she was sent back to the nursing home.  A staff member from the emergency department contacts the nursing home as the urine culture grew >100,000 cfu/mL of Escherichia coli sensitive to trimethoprim-sulfamethoxazole and ciprofloxacin.  The patient has had no fever, abdominal pain, dysuria, hematuria, or hypoglycemia.  Her other medical issues include hypertension, hyperlipidemia, and osteoarthritis.  Vital signs are within normal limits.  The patient is at her baseline neurocognitive function with orientation to place and person only.  Lungs are clear to auscultation and heart sounds are normal.  Abdominal examination reveals no suprapubic or flank tenderness.  Which of the following is the most appropriate next step in management of this patient's urinary abnormalities?

Accepted Answer

Explanation: This elderly patient with a history of diabetes mellitus and dementia had a transient episode of confusion, possibly due to mild dehydration excerbating hypoglycemia in the setting of insulin use before breakfast. Although her urinary studies were abnormal, including a urine culture result showing Escherichia coli, she has had no manifestations of a urinary tract infection (UTI) such as fever, abdominal pain, hematuria, dysuria, suprapubic/flank tenderness, or continued confusion. As a result, her urinary abnormalities are most likely due to asymptomatic bacteriuria. Asymptomatic bacteriuria is common in women, particularly as they age (prevalence is ~20% in women age >80). Diagnosis is made when a patient with no manifestations of UTI has a clean catch urine culture that reveals >100,000 cfu/mL of a single organism. Some guidelines recommend 2 clean catch urine cultures for diagnosis; however, a second specimen typically confirms the initial result (in >80% of patients). Most cases of asymptomatic bacteriuria are transient and resolve within 2 weeks. Repeat testing or treatment is rarely required; patients can be reassured and observed. Treatment is generally recommended only for those who are pregnant, undergoing urologic procedures, or within 3 months of renal transplantation. (Choice A) Three days of oral trimethoprim-sulfamethoxazole is often used to treat acute, uncomplicated cystitis. This patient has no symptoms of a UTI and does not require antimicrobial treatment. (Choice B) Seven days of oral ciprofloxacin is often used to treat acute pyelonephritis in the outpatient setting. This patient has no manifestations of acute pyelonephritis such as flank pain/tenderness, fever, nausea, and vomiting. (Choices D and E) Even if repeat urine studies showed >100,000 cfu/mL E coli, no treatment would be required in this patient with asymptomatic bacteriuria. If she developed urinary tract symptoms or recurrent confusion, additional testing or treatment could be undertaken. Educational objective: Asymptomatic bacteriuria is common in elderly women. As most cases resolve spontaneously within weeks, no additional testing or treatment is usually required. References: Infectious Diseases Society of America guidelines for the diagnosis and treatment of asymptomatic bacteriuria in adults. (http://www.ncbi.nlm.nih.gov/pubmed/15714408) "Urinary tract infection"-requiem for a heavyweight. (http://www.ncbi.nlm.nih.gov/pubmed/28542707)

Question 4

A 19-year-old man comes to the student health center due to 2 days of burning pain during urination.  He has also had itching of the urethral meatus but no urinary discharge, fever, chills, or rash.  The patient has no chronic medical conditions and takes no medications.  He had unprotected sexual intercourse with a new female partner a week ago.  The patient has smoked a pack of cigarettes daily since age 14.  He drinks alcohol on weekends and does not use illicit drugs.  Vital signs are within normal limits.  There is scant, watery urethral discharge at the urethral meatus.  There are no genital ulcers, rashes, erythema, or inguinal lymphadenopathy.  Urethral swab is performed, and Gram stain of the urethral fluid reveals many neutrophils but no organisms.  Nucleic acid amplification tests of the urine are sent for Chlamydia trachomatis and Neisseria gonorrhoeae.
This patient's symptoms are most likely to respond to which of the following?

Accepted Answer

Explanation: 11ec2b69_bf8c_d1c9_8f63_0b7ea55a9c2f_MD0005_00 This young patient had a new, unprotected sexual partner and subsequently developed dysuria and watery urethral discharge, indicating infectious urethritis. Most cases are due to sexually transmitted infection with Neisseria gonorrhoeae, Chlamydia trachomatis, or Mycoplasma genitalium. Gonorrhea tends to cause profuse, thick discharge, while nongonococcal infections tend to cause scant, watery discharge; however, the underlying organism cannot be diagnosed by symptoms alone. Nucleic acid amplification testing (NAAT) of urethral, vaginal, or anal samples provides definitive diagnosis, but Gram stain can quickly identify the presence of N gonorrhoeae. Gonococcal urethritis is diagnosed when Gram stain shows leukocytes with intracellular gram-negative diplococci. In contrast, nongonococcal urethritis (NGU) is marked by leukocytes with no visible organisms because C trachomatis and M genitalium do not have significant peptidoglycan in their cell wall. Therefore, patients with symptoms of infectious urethritis who have negative Gram stain for N gonorrhoeae (ie, no visible organisms) and are awaiting NAAT results should receive empiric treatment for NGU with azithromycin or doxycycline. Empiric azithromycin adequately treats most cases of C trachomatis, but treatment failure can occur due to antibiotic resistance or to infection with an alternate organism (eg, M genitalium, Trichomonas vaginalis). (Choice B) Gonococcal urethritis is treated empirically with ceftriaxone monotherapy. However, patients with gonorrhea and uncertain or positive C trachomatis testing should also receive empiric doxycycline to treat potential coinfection. This patient with an aseptic Gram stain has nongonococcal, not gonococcal, urethritis and should be treated with azithromycin or doxycycline monotherapy. (Choice C) T vaginalis can cause NGU and is treated with metronidazole. However, metronidazole is not used for empiric treatment of infectious urethritis in men because T vaginalis is much less common than other causes. (Choice D) Coliform organisms (eg, Escherichia coli) can cause infectious urethritis in older men with enlarged prostates. These individuals are often treated with fluoroquinolones (eg, ofloxacin). Young, sexually active men with infectious urethritis usually have sexually transmitted infection, not infection with coliform organism. (Choice E) Valacyclovir treats herpes simplex virus infection, which typically causes painful genital vesicles/ulcerations. Educational objective: Infectious urethritis in young male patients is typically due to sexually transmitted infection with Neisseria gonorrhoeae, Chlamydia trachomatis, or Mycoplasma genitalium. Diagnosis is made with nucleic acid amplification testing, but urethral fluid Gram stain can quickly differentiate gonococcal (intracellular diplococci) from nongonococcal (aseptic) urethritis. Nongonococcal urethritis is treated empirically with azithromycin or doxycycline.

Question 5

A 3-year-old girl is brought to the clinic for evaluation of a lump on her left axilla.  Her parents first noticed the lump 3 days ago; they placed cold compresses on the mass with no relief.  The mass is now tender to the touch but has not changed in size or had any discharge.  The patient had a fever a few weeks ago but it resolved after several days; she is otherwise healthy.  Immunizations are up to date.  She attends day care and has 2 dogs and a kitten at home.  Temperature is 37.8 C (100 F).  The child is alert and appears in no acute distress.  Examination of the axilla shows a warm, tender, mobile left axillary lymph node that is approximately 2 cm (0.8 in) in diameter.  Cardiac examination reveals no murmurs.  The lungs are clear to auscultation bilaterally.  The abdomen is soft, nontender, and without hepatosplenomegaly.  The left index finger has a small erythematous, painless papule on the dorsal aspect.  Both hands and arms have several superficial linear abrasions.  In addition to clindamycin, which of the following is the most appropriate pharmacotherapy for this patient?

Accepted Answer

Explanation: 11ec2b69_bf87_efbe_8f63_fb0a6d5a1b04_MD0005_00 This patient's localized papule and regional lymphadenopathy following cat exposure are consistent with cat-scratch disease (CSD). CSD is caused by Bartonella henselae, a fastidious gram-negative bacillus carried by the majority of cats, especially kittens. B henselae can be transmitted by a scratch or bite, or (rarely) by a flea. In many cases, patients do not recall a specific scratch or bite. Patients typically have a skin lesion that can be erythematous, papular, or nodular. Fever is present in <50% of cases. Regional lymphadenopathy follows within 1-2 weeks; it is the hallmark of CSD and can be the presenting sign if the skin lesion goes unnoticed. Affected lymph nodes are tender and erythematous; suppuration is less common. Cat exposure and symptoms consistent with CSD are usually sufficient to make a clinical diagnosis. Mild cases in healthy patients often self-resolve within 1-4 months; however, azithromycin is effective against B henselae and has been shown to decrease the length and severity of symptoms. In unclear cases, antistaphylococcal and streptococcal coverage (eg, clindamycin) may be added to empirically treat the most common organisms causing lymphadenitis. (Choices A and C) Several antibiotics have in vitro activity against Bartonella, including penicillins (eg, amoxicillin) and third-generation cephalosporins (eg, cefdinir), but are not proven to improve clinical outcomes. (Choice D) Cephalexin is a first-generation cephalosporin that treats staphylococcal and streptococcal skin infections but has no activity against most gram-negative pathogens, including Bartonella. (Choice E) Doxycycline (plus rifampin) treats neurologic manifestations of CSD in patients age >8. However, prolonged doxycycline is avoided in young children due to the risk of dental staining, and this patient has no neurologic findings. Educational objective: Cat-scratch disease generally presents with a cutaneous lesion and regional lymphadenopathy following a cat scratch or bite. Azithromycin treatment can reduce the length and severity of symptoms. References: Cat-scratch disease. (http://www.ncbi.nlm.nih.gov/pubmed/21243990)

Question 6

A 74-year-old woman is brought to the emergency department from a skilled nursing facility due to a positive stool PCR test for Clostridioides difficile. The patient was discharged from the hospital to the nursing facility 10 days ago after treatment for urinary tract infection and septic shock. She developed C difficile-associated diarrhea during the hospitalization and completed a course of oral fidaxomicin therapy 3 days ago. This treatment resolved the diarrhea, nausea, and abdominal pain; yesterday, the patient had an episode of bloating, nausea, and loose stool after a meal at the nursing facility, prompting repeat stool testing. Since then, she has had no additional abdominal pain, nausea, vomiting, or diarrhea. Other medical conditions include hypertension, hyperlipidemia, ischemic stroke with residual left hemiparesis, and gastroesophageal reflux. Temperature is 37 C (98.6 F), blood pressure is 130/68 mm Hg, and pulse is 84/min. The abdomen is soft, nondistended, and nontender, with normoactive bowel sounds in all quadrants. Rectal examination shows soft, brown stool negative for occult blood. Leukocyte count is 7,100/mm³. Which of the following is the most appropriate course of action in management of this patient's symptoms?

Accepted Answer

Explanation: Clostridioides difficile is a gram-positive, spore-forming bacterium transmitted via the fecal-oral route. Nontoxigenic strains are typically benign, but toxigenic strains can cause colitis in susceptible patients (eg, hospitalized, elderly, recent antibiotic users). The diagnosis of C difficile-associated diarrhea (CDAD) requires both of the following: Characteristic symptoms: Watery diarrhea (≥3 loose stools in 24 hr) is the hallmark symptom of C difficile infection; other classic symptoms include lower abdominal pain, low-grade fever, and leukocytosis. Positive stool testing for toxigenic C difficile: When characteristic symptoms are present, a positive test generally represents active infection (vs carrier status). Treatment with 10 days of oral fidaxomicin or vancomycin is generally curative, but recurrence occurs within 30 days of antibiotic cessation in approximately 25% of patients. Recurrence is marked by the reemergence of characteristic symptoms with positive C difficile stool testing. This patient's single episode of loose stool does not qualify as a CDAD symptom (≥3 loose stools in 24 hr) and could have many causes (eg, food intolerance). Although PCR testing for C difficile was positive, stool testing may remain positive for days to weeks after treatment; this is particularly true for PCR, which tests for the toxin-producing gene, not the toxin itself. A positive PCR alone is insufficient to diagnose recurrence. Therefore, this patient should be observed; antibiotic therapy is not indicated at this time (Choice E). (Choice B) Enzyme immunoassays for toxins A and B detect active toxin production and can therefore be more specific than PCR for detecting active infection (vs carrier status). However, further stool testing is not indicated in this patient given the absence of characteristic CDAD symptoms. (Choice C) Sigmoidoscopy with biopsy is an invasive procedure and is not indicated in this patient for a single episode of loose stool. In patients with ongoing CDAD, sigmoidoscopy is generally avoided due to the risk for perforation but is sometimes used to aid in the diagnosis of fulminant colitis when diarrhea is absent. (Choice D) With drug-resistant strains of C difficile, symptoms are likely to worsen or continue during treatment. This patient's condition clinically improved with fidaxomicin, making drug resistance unlikely. When CDAD recurs, it is commonly due to the persistence of spores or reinfection by exogenous C difficile rather than drug resistance. Educational objective: The diagnosis of Clostridioides difficile-associated diarrhea requires the presence of characteristic symptoms (eg, watery diarrhea, abdominal pain, leukocytosis) in addition to positive stool testing for C difficile. References: ACG clinical guidelines: prevention, diagnosis, and treatment of Clostridioides difficile infections. (http://www.ncbi.nlm.nih.gov/pubmed/34003176) Current knowledge on the laboratory diagnosis of Clostridium difficile infection. (http://www.ncbi.nlm.nih.gov/pubmed/28321156)

Question 7

A 74-year-old woman is brought to the emergency department from a skilled nursing facility due to a positive stool PCR test for Clostridioides difficile. The patient was discharged from the hospital to the nursing facility 10 days ago after treatment for urinary tract infection and septic shock. She developed C difficile-associated diarrhea during the hospitalization and completed a course of oral fidaxomicin therapy 3 days ago. This treatment resolved the diarrhea, nausea, and abdominal pain; yesterday, the patient had an episode of bloating, nausea, and loose stool after a meal at the nursing facility, prompting repeat stool testing. Since then, she has had no additional abdominal pain, nausea, vomiting, or diarrhea. Other medical conditions include hypertension, hyperlipidemia, ischemic stroke with residual left hemiparesis, and gastroesophageal reflux. Temperature is 37 C (98.6 F), blood pressure is 130/68 mm Hg, and pulse is 84/min. The abdomen is soft, nondistended, and nontender, with normoactive bowel sounds in all quadrants. Rectal examination shows soft, brown stool negative for occult blood. Leukocyte count is 7,100/mm³. The patient has no diarrhea or other gastrointestinal symptoms while in the emergency department. Prior to discharge, she asks if there is any way to prevent Clostridioides difficile-associated diarrhea in the future. In addition to minimizing antibiotic use, which of the following is most likely to prevent recurrent episodes of the disease in this patient?

Accepted Answer

Explanation: Clostridioides difficile is a common commensal species in normal gut flora, although growth is typically suppressed by more populous anaerobes. Most people are asymptomatic carriers; however, C difficile-associated diarrhea (CDAD) can occur in patients with alterations in the gut microbiome, which allows for C difficile proliferation, or in those inoculated with a new, toxigenic isolate. The risk for developing CDAD is increased in those with the following: Antibiotic use: Antibiotics disrupt the barrier function of normal colonic flora. Fluoroquinolones, clindamycin, and broad-spectrum penicillins/cephalosporins are most likely to cause CDAD. Gastric acid suppression: C difficile spores are acid resistant, but proton pump inhibitors and H₂ blockers are thought to alter the colonic microbiome, which increases the risk for C difficile proliferation. Hospitalization: Nosocomial exposure accounts for most C difficile transmissions. Advanced age (>65): Older individuals often have diminished colonic immunity and greater exposure to antibiotics, proton pump inhibitors, and hospital environments. Minimizing antibiotic use is the most important way of reducing the risk for recurrent CDAD in this patient, but avoiding gastric acid suppression is also an important risk-reduction strategy. (Choice B) Chlorhexidine bathing can help prevent recurrences of methicillin-resistant Staphylococcus aureus, but it has not been conclusively shown to reduce the risk for CDAD. (Choice C) Physical inactivity is not a prominent risk factor for the development of CDAD. (Choice D) Probiotic-rich yogurt contains live microorganisms that, in theory, may repopulate the gut microbiome and reduce the proliferation of pathogenic bacteria. However, recent guidelines have not supported the use of probiotics for either primary or secondary prevention of C difficile infection because of insufficient evidence. (Choice E) Asymptomatic C difficile carriage rates are lower among health care workers (~0%-10%) than among adults who are hospitalized or residing in long-term care facilities (~20%-50%). The screening of asymptomatic carriers has not been shown to affect nosocomial transmission rates; hand hygiene and infection-control measures (eg, sporicidal disinfectants, contact isolation) are the most important means for preventing C difficile transmission. Educational objective: Minimizing the use of antibiotics and reducing gastric acid suppression can reduce the risk for recurrent Clostridioides difficile-associated diarrhea. References: Recurrent Clostridium difficile infection: risk factors, treatment, and prevention. (http://www.ncbi.nlm.nih.gov/pubmed/30400734) Association of gastric acid suppression with recurrent Clostridium difficile infection: a systematic review and meta-analysis. (http://www.ncbi.nlm.nih.gov/pubmed/28346595)

Question 8

A 25-year-old woman, gravida 1 para 1, comes to the office for evaluation of fever and right breast pain.  The patient is 2 weeks postpartum after an uncomplicated pregnancy and vaginal delivery.  She has been breastfeeding every 2-3 hours; however, the infant has had difficulty with latching due to the mother's inverted nipples.  Yesterday, the patient developed constant sharp pain in the side of her right breast as well as fever, chills, nausea, and body aches.  The pain is worsening, especially during breastfeeding.  She has been taking acetaminophen and ibuprofen with minimal relief.  The patient has no chronic medical conditions.  She is on maternity leave from her engineering job.  The patient has no drug allergies and is taking a daily prenatal vitamin.  Temperature is 38.9 C (102 F), blood pressure is 110/70 mm Hg, and pulse is 100/min.  Examination reveals the upper outer quadrant of the right breast to be erythematous, tender, and swollen but without fluctuance.  The left breast has no erythema or tenderness. 
Which of the following is the best next step in management of this patient?

Accepted Answer

Explanation: 11ec2b69_bf89_0132_8f63_83a26d5ec53b_MD0005_00 This patient has fever, breast pain, and focal inflammation, which are classic for lactational mastitis. Women are at greatest risk of developing mastitis during the first 3 months postpartum, when breastfeeding is still becoming established. Difficulties with breastfeeding (eg, poor latching) can lead to prolonged engorgement, inadequate milk drainage, and clogged milk ducts (tender, palpable lump or "cord"). Bacteria from the skin can enter the milk ducts and proliferate in stagnant milk, resulting in infection. The most common organism is Staphylococcus aureus. Diagnosis is clinical and no further workup is indicated. First-line antibiotics include oral dicloxacillin (antistaphylococcal penicillin) and cephalexin (first-generation cephalosporin); both are safe during breastfeeding. (Choice A) Intravenous ampicillin is a second-generation penicillin used for intrapartum prophylaxis of Group B Streptococcus colonization. Ampicillin has no activity against S aureus. (Choice B) Intravenous vancomycin is the treatment of choice for suspected methicillin-resistant S aureus (MRSA). It is indicated in the treatment of lactational mastitis in patients who have MRSA risk factors (eg, recurrent hospitalizations/antibiotics, incarceration), hemodynamic instability, or failed outpatient therapy. (Choice D) Cold compresses, nonsteroidal anti-inflammatory medication, and breast pumping are first-line treatments of breast engorgement, which typically presents with diffuse, bilateral breast tenderness. (Choice E) Trimethoprim-sulfamethoxazole is effective against S aureus. However, it is avoided during breastfeeding as it is excreted in breast milk and is associated with a risk of neonatal kernicterus. Educational objective: Lactational mastitis typically occurs during the first 3 months postpartum and presents with fever, breast pain, and focal inflammation. First-line antibiotics include oral dicloxacillin and cephalexin. References: Breast pain: engorgement, nipple pain, and mastitis. (http://www.ncbi.nlm.nih.gov/pubmed/26512442) Management of mastitis in breastfeeding women. (http://www.ncbi.nlm.nih.gov/pubmed/18819238)

Question 9

A 62-year-old man comes to the office for follow-up after recent hospitalization. Two weeks ago, the patient went to the emergency department due to a 3-day history of fever, chills, dysuria, urinary frequency, and low back pain. Evaluation showed a tender and swollen prostate, leukocytosis, pyuria, and bacteriuria. Treatment for acute bacterial prostatitis was begun with intravenous antibiotics. Blood and urine cultures returned positive for Escherichia coli sensitive to all tested antibiotics. The patient was discharged after clinical improvement and was prescribed oral ciprofloxacin. He has had no fever, and urinary symptoms have resolved, but over the last 2 days, he has had mild abdominal cramps and 4 or 5 watery bowel movements per day with no blood or mucus. Other medical conditions include hypertension and type 2 diabetes mellitus. On examination, the patient is afebrile, and other vital signs are within normal limits. There is mild periumbilical tenderness, but physical examination is otherwise unremarkable. Laboratory studies show a leukocyte count of 14,500/mm³ and serum creatinine level of 0.9 mg/dL. Stool testing is positive for Clostridioides difficile. The patient returns to the office 3 weeks later and says that he took oral fidaxomicin as prescribed but stopped a week ago after the abdominal cramps and diarrhea improved. Since yesterday, he has had intermittent lower abdominal discomfort and several episodes of watery bowel movements. The patient reports no urinary symptoms and continues to take trimethoprim-sulfamethoxazole for the prostatitis. Temperature is 37.2 C (99 F), blood pressure is 122/80 mm Hg, and pulse is 85/min. Physical examination shows mild tenderness in the left lower quadrant with no guarding or rebound tenderness and normal bowel sounds. Laboratory studies show a leukocyte count of 14,300/mm³. Which of the following is the most likely cause of this patient's symptoms?

Accepted Answer

Explanation: This patient most likely has recurrent Clostridioides difficileinfection (CDI). Recurrence of CDI is common, affecting approximately 15%-30% of patients whose infection initially responds to antimicrobial therapy. The risk is particularly increased in patients taking prolonged antibiotics for other conditions, such as this patient taking continued therapy (eg, trimethoprim-sulfamethoxazole) for prostatitis. When CDI recurs, it is usually due to persistent spores from the initial infection rather than from drug resistance or infection with a new strain (Choice D). C difficile spores are hardy and antibiotic resistant. Spores that survive the initial course of antimicrobial therapy can germinate into fully functional bacilli in the colon and proliferate. Especially when normal colonic flora is continuously disrupted (eg, continued antibiotic use), the C difficile bacilli can overgrow, leading to recurrent symptoms. To reduce the risk of recurrence, treatment for CDI is often extended throughout the course of other antibiotic therapies. (Choice A) Acute sigmoid diverticulitis can present with left lower quadrant tenderness and diarrhea; however, it also commonly causes fever, nausea, and/or vomiting. In addition, diverticulitis is less likely because of this patient's recent use of antibiotics, including trimethoprim-sulfamethoxazole, which is often used (typically with metronidazole) in the outpatient treatment of diverticulitis. (Choice B) Postinfectious irritable bowel syndrome (IBS), which can occur after gastrointestinal infection, affects up to 10% of patients following successful treatment of CDI. It can present with changes in stool frequency or consistency (eg, diarrhea) and abdominal discomfort, but leukocytosis is much less common than in CDI. In addition, relief of pain with defecation is commonly reported and abdominal examination is usually normal. (Choice E) Small intestinal bacterial overgrowth (SIBO) can cause abdominal discomfort and watery diarrhea. However, bloating and flatulence are also commonly present, and leukocytosis is unexpected. In addition, abdominal examination is usually normal in patients with SIBO (vs left lower quadrant tenderness in this patient). Educational objective: Recurrence of Clostridioides difficile infection is common, especially in patients on prolonged antibiotics for other conditions. Recurrence is typically due to germination of persistent spores from the initial infection. To reduce the risk of recurrence, treatment for CDI is often extended throughout the course of other antibiotic therapies. References: ACG clinical treatment guidelines: prevention, diagnosis, and treatment of Clostridioides difficile infections. (http://www.ncbi.nlm.nih.gov/pubmed/34003176) Recurrent Clostridium difficile infection: risk factors, treatment, and prevention. (http://www.ncbi.nlm.nih.gov/pubmed/30400734)

Question 10

A 26-year-old man is brought to the emergency department by his roommate, who found him lethargic in his apartment an hour ago.  Earlier that day, the patient complained of headache and asked for aspirin.  He also has felt weak and "exhausted" for the last 10 days.  His past history is notable for intravenous heroin abuse, but periodic HIV screening has been negative.  His temperature is 38.3 C (101 F), blood pressure is 112/70 mm Hg, and pulse is 102/min.  The patient appears somnolent but follows simple commands.  Needle tracks are seen on both arms.  Pupils are symmetric and reactive.  There are a few palatal petechiae on oral examination.  The patient's neck is stiff.  A 3/6 holosystolic murmur is heard at the apex.  Lungs are clear to auscultation and the abdomen is nontender.  He moves all extremities, and deep-tendon reflexes are symmetric.  Which of the following is the most likely diagnosis in this patient?

Accepted Answer

Explanation: 11ec2b69_bf8b_9946_8f63_b3657d6ed98f_MD0005_00 This patient's clinical presentation, with fever, petechiae, history of intravenous drug abuse, and holosystolic murmur at the apex, is suggestive of infective endocarditis (IE) involving the mitral valve. The headache, lethargy, and neck stiffness suggest subarachnoid hemorrhage secondary to rupture of a mycotic aneurysm. Mycotic or infected arterial aneurysms can develop due to metastatic infection from IE, with septic embolization and localized vessel wall destruction in the cerebral (or systemic) circulation. Intracerebral mycotic aneurysms can present as an expanding mass with focal neurologic findings or may not be apparent until aneurysm rupture with stroke or subarachnoid hemorrhage. The diagnosis of mycotic cerebral aneurysm can usually be confirmed with computed tomography angiography. Management includes broad-spectrum antibiotics (tailored to blood culture results) and surgical intervention (open or endovascular). (Choice A) Patients with basilar artery occlusion present with motor weakness, ataxia or incoordination, altered level of consciousness, facial weakness, dysphagia and/or dysarthria, and unilateral or bilateral gaze paralysis. The presence of neck stiffness is more suggestive of subarachnoid hemorrhage. (Choice B) Herpes simplex encephalitis is characterized by acute-onset (<1 week) fever, headaches, seizures, altered mental status, and focal neurologic findings such as hemiparesis or cranial nerve deficits. This patient's weakness/fatigue for >1 week, heart murmur, history of drug abuse, and absence of focal neurologic deficits make endocarditis with mycotic aneurysm more likely than herpes encephalitis. (Choice C) Progressive multifocal leukoencephalopathy is a demyelinating illness of the central nervous system that typically occurs in immunosuppressed patients, especially those with AIDS. It is caused by reactivation of the polyomavirus JC (JC virus) and presents with neurologic deficits including hemiparesis, gait ataxia, visual symptoms, and altered mental status. It is not seen in non-immunosuppressed patients, and fever is not typical. (Choice E) Valvular insufficiency in IE is due primarily to destruction of valve leaflets; papillary muscle rupture is rare. Papillary muscle rupture leads to acute and severe mitral regurgitation with sudden onset of hypotension, pulmonary edema, and cardiogenic shock. Educational objective: Mycotic aneurysms can occur in the cerebral or systemic circulation due to septic embolization and localized vessel wall destruction as a complication of infective endocarditis. Intracerebral mycotic aneurysms can present as an expanding mass with focal neurologic findings or with aneurysm rupture and subarachnoid hemorrhage. References: Mycotic aneurysm: a rare and dreaded complication of infective endocarditis. (http://www.ncbi.nlm.nih.gov/pubmed/23814229) Infectious endocarditis: diagnosis and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/22612050)

Question 11

A 12-month-old boy is brought to the office for a routine checkup.  The patient had an upper respiratory tract infection and otitis media a month ago and was treated with antibiotics.  He completed the full course of antibiotics and has been well.  The patient has no other past medical history and has met all developmental milestones.  He takes no medications, and his immunizations are up-to-date.  The patient is allergic to penicillin, which causes a rash.  His older sister was diagnosed with infantile-type polycystic kidney disease and underwent kidney transplantation 2 months ago.  She is receiving immunosuppressive therapy.  The patient is scheduled to receive the varicella vaccine today.  Which of the following is the most accurate statement regarding varicella vaccination in this patient?

Accepted Answer

Explanation: 11ec2b69_bf8c_5c97_8f63_63c130badedc_MD0005_00 The varicella-zoster virus (VZV) vaccine is a live-attenuated vaccine that is administered typically in 2 doses: the first at age 12-15 months and the second at age 4-6 years. VZV vaccination is recommended in all children without absolute contraindications (Table). However, vaccinating household contacts of transplant recipients is safe and recommended currently by the American Academy of Pediatrics and the Infectious Diseases Society of America. These organizations also recommend that pretransplant patients receive 2 doses of the VZV vaccine at least 4 weeks prior to transplantation. Household contacts who receive the VZV vaccine should be monitored closely for a vaccine-associated VZV rash, which occurs in <10% of children who receive the vaccine and is potentially contagious to immunocompromised individuals. (Choices A and E) If this patient develops a rash, he should be isolated from his sibling until all of the lesions have crusted over. Varicella immunoglobulin (VariZIG) should be administered to varicella-seronegative transplant recipients who have been exposed to VZV. If this patient's sister becomes exposed to VZV or a vaccine-related rash, she should receive VariZIG as soon as possible (within 10 days of initial exposure). (Choice B) Live virus vaccines, including VZV, should not be administered to this patient's sister as she is status post renal transplant and on immunosuppressive therapy. (Choice D) This patient has no contraindications and should receive the VZV vaccine. Educational objective: The varicella-zoster virus (VZV) vaccine can be administered safely to immunocompetent patients with household contacts who are immunocompromised. Although transmission of VZV by a vaccine-related rash is rare, vaccinated individuals should be monitored for a rash and isolated if one develops. References: Vaccinations for adult solid organ transplant recipient: current recommendations. (http://www.ncbi.nlm.nih.gov/pubmed/16182821) Updated recommendations for use of VariZIG--United States, 2013. (http://www.ncbi.nlm.nih.gov/pubmed/23863705)

Question 12

A 31-year-old woman, gravida 1 para 0, at 14 weeks gestation comes to the office to establish prenatal care. She has had some nausea but no vomiting, abdominal pain, or vaginal bleeding. The patient contracted HIV through intravenous heroin use. She was diagnosed 3 years ago while hospitalized for drug rehabilitation. The patient is on triple-combination antiretroviral therapy with no significant side effects. She has no other chronic medical conditions and has had no previous surgeries. In addition to her HIV medications, the patient takes a daily prenatal vitamin. She does not use tobacco or alcohol and has not used illicit drugs since rehabilitation. Temperature is 36.7 C (98.1 F), blood pressure is 110/60 mm Hg, and pulse is 65/min. BMI is 24 kg/m². Pelvic examination reveals a 14-week-sized nontender uterus with no adnexal masses. Laboratory results are as follows: Bedside ultrasound reveals a 14-week intrauterine pregnancy with a normal heart rate. Which of the following is the most appropriate recommendation for this patient?

Accepted Answer

Explanation: 11ec2b69_bf85_a5cc_8f63_e99259e8f304_MD0005_00 The risk of perinatal HIV transmission directly correlates with maternal HIV viral load. Antiretroviral therapy (typically, highly active antiretroviral therapy [HAART]) is continued throughout pregnancy as it is safe, treats maternal disease, and prevents perinatal transmission by suppressing viral replication and decreasing the maternal viral load. Modification of an effective antiretroviral regimen is generally avoided due to the risk of emerging drug resistance, loss of viral suppression, and during pregnancy, perinatal transmission (Choices C and D). However, changes are indicated if significant side effects or inadequate viral suppression is present. During pregnancy, alterations in drug metabolism and distribution volume often necessitate changes in dosing or medication to maintain a low viral load. Therefore, viral loads and CD4 counts are evaluated every 3 months. (Choice A) Adequate virologic control is important during pregnancy as the delivery modality (eg, cesarean, vaginal) is based on the third-trimester viral load. In women with a viral load of <1,000 copies/mL, the risk of perinatal transmission is low irrespective of delivery modality, so a vaginal delivery is preferred. In contrast, when the viral load is >1,000 copies/mL, cesarean delivery is indicated as there is a higher risk for perinatal transmission with vaginal delivery.(Choice B) Intrapartum antiretroviral therapy is indicated to further decrease the risk of perinatal HIV transmission. Patients with a viral load of <1,000 copies/mL continue HAART. In contrast, patients with a viral load of >1,000 copies/mL receive intrapartum intravenous zidovudine in addition to the HAART regimen.Educational objective: Highly active antiretroviral therapy is continued during pregnancy to treat maternal disease, maintain viral suppression, and reduce the risk of perinatal HIV transmission. Modifying an effective regimen can cause drug resistance and loss of virological control. Vaginal delivery is safe for patients who have a viral load of <1,000 copies/mL. References: Management of HIV infection during pregnancy in the United States: updated evidence-based recommendations and future potential practices. (http://www.ncbi.nlm.nih.gov/pubmed/27504071) Cesarean section for HIV-infected women in the combination antiretroviral therapies era, 2000-2010. (http://www.ncbi.nlm.nih.gov/pubmed/23791563) When should HAART be initiated in pregnancy to achieve an undetectable HIV viral load by delivery? (http://www.ncbi.nlm.nih.gov/pubmed/22441248)

Question 13

A 25-year-old woman, gravida 1 para 1, comes to the office for evaluation of fever and right breast pain.  The patient is 2 weeks postpartum after an uncomplicated pregnancy and vaginal delivery.  She has been breastfeeding every 2-3 hours; however, the infant has had difficulty with latching due to the mother's inverted nipples.  Yesterday, the patient developed constant sharp pain in the side of her right breast as well as fever, chills, nausea, and body aches.  The pain is worsening, especially during breastfeeding.  She has been taking acetaminophen and ibuprofen with minimal relief.  The patient has no chronic medical conditions.  She is on maternity leave from her engineering job.  The patient has no drug allergies and is taking a daily prenatal vitamin.  Temperature is 38.9 C (102 F), blood pressure is 110/70 mm Hg, and pulse is 100/min.  Examination reveals the upper outer quadrant of the right breast to be erythematous, tender, and swollen but without fluctuance.  The left breast has no erythema or tenderness. The patient had planned to breastfeed her infant exclusively for the first year of life but is now discouraged by the infection and the discomfort that occurs during latching.  Which of the following is the most appropriate advice for this patient?

Accepted Answer

Explanation: 11ec2b69_bf89_9d73_8f63_dfe6cac2e627_MD0005_00 In addition to antibiotics and analgesia, treatment of lactational mastitis requires effective and frequent milk drainage. Milk ducts are most effectively drained by direct breastfeeding. However, many women cease breastfeeding due to breast pain associated with or independent of mastitis. Rather than discontinuation of breastfeeding, the first step in management of breast pain is to assess breastfeeding technique and positioning; this is best achieved with an evaluation by a lactation consultant. The correct position for optimal milk intake involves the infant forming a tight seal around most of the areola. However, a common cause of severe pain during latching occurs when the infant suckles on only the nipple. This improper position can cause nipple blistering. (Choices B and E) Breastfeeding using both the infected and uninfected breasts is safe during treatment for lactational mastitis, and formula supplementation is not required if the milk supply is adequate. In addition, emptying of the breast via breastfeeding may decrease the pain associated with mastitis and prevent recurrence. Interruption of breastfeeding can decrease maternal milk production and should be avoided. (Choice C) Formula supplementation is indicated for an inadequate maternal milk supply as evidenced by newborn weight loss or dehydration. A reduction in the frequency of breastfeeding and/or breast emptying can decrease maternal milk production and should therefore be avoided. Pain during breastfeeding is not an indication for formula feeding but rather an indication to evaluate for infection or improper technique. (Choice D) Pumping after completion of feeding can alleviate pain associated with incomplete emptying. This patient experiences discomfort during latching and would not benefit from both breastfeeding and pumping. Educational objective: Breast pain and mastitis are common reasons for early discontinuation of breastfeeding. Pain during breastfeeding is frequently due to poor positioning or latching, which can be evaluated by a lactation consultant. References: Breast pain: engorgement, nipple pain, and mastitis. (http://www.ncbi.nlm.nih.gov/pubmed/26512442)

Question 14

A 25-year-old woman, gravida 1 para 1, comes to the office for evaluation of fever and right breast pain.  The patient is 2 weeks postpartum after an uncomplicated pregnancy and vaginal delivery.  She has been breastfeeding every 2-3 hours; however, the infant has had difficulty with latching due to the mother's inverted nipples.  Yesterday, the patient developed constant sharp pain in the side of her right breast as well as fever, chills, nausea, and body aches.  The pain is worsening, especially during breastfeeding.  She has been taking acetaminophen and ibuprofen with minimal relief.  The patient has no chronic medical conditions.  She is on maternity leave from her engineering job.  The patient has no drug allergies and is taking a daily prenatal vitamin.  Temperature is 38.9 C (102 F), blood pressure is 110/70 mm Hg, and pulse is 100/min.  Examination reveals the upper outer quadrant of the right breast to be erythematous, tender, and swollen but without fluctuance.  The left breast has no erythema or tenderness. The patient returns to the office the next day with worsening symptoms.  She has a family history of breast cancer and is very concerned about the pain.  Temperature is 39.4 C (103 F), blood pressure is 100/70 mm Hg, and pulse is 114/min.  Examination shows persistent swelling and erythema in the upper outer quadrant of the right breast in addition to a palpable area of induration.  Which of the following is the best next step in management of this patient?

Accepted Answer

Explanation: 11ec2b69_bf8a_39b4_8f63_7984d3692c6e_MD0005_00 Breast abscess development is an uncommon complication of lactational mastitis but should be suspected in patients whose symptoms do not improve or worsen despite antibiotic therapy. The characteristic finding of an abscess is a focal area of fluctuance (wavelike motion on palpation, indicating pus collection). Induration (skin thickening from edema and inflammation) can occur in both mastitis and abscess. Ultrasound is the gold-standard modality for differentiating these conditions; it is quick, safe, inexpensive, and widely available, and it diagnoses abscess more accurately than physical examination. If an abscess is identified, ultrasound is also used to guide fine-needle aspiration under local anesthesia. (Choices A, D, and E) A breast infection that is refractory to treatment should prompt investigation for inflammatory breast cancer. A malignant mass is a rare but possible obstacle to milk drainage. On examination, accompanying clinical features include skin thickening, peau d'orange, and axillary lymphadenopathy. MRI is the imaging method of choice. Mammogram is not recommended for women age <30 as younger women tend to have denser breasts, which make this test more difficult to interpret. In addition, breast cancer is uncommon in women age <30, and mammography is associated with a higher rate of false-positive results. Palpation-guided, percutaneous fine-needle aspiration is the usual biopsy method for suspected cancer. (Choice C) Incision with drainage is the preferred treatment for most skin abscesses. However, this treatment for a breast abscess has increased risk of complications (eg, milk fistulas), slower recovery time, and a less desirable cosmetic outcome. Therefore, incision and drainage are reserved for abscesses that do not improve with antibiotics and fine-needle aspiration. Educational objective: Inadequately treated mastitis can progress to breast abscess. Induration and fluctuance on examination are evaluated by ultrasound to distinguish mastitis from an abscess. Treatment includes antibiotics and aspiration of fluid. References: Breast abscess: evidence based management recommendations. (http://www.ncbi.nlm.nih.gov/pubmed/24791941) Breast abscesses: evidence-based algorithms for diagnosis, management, and follow-up. (http://www.ncbi.nlm.nih.gov/pubmed/21997989)

Question 15

A 6-year-old girl is brought to the office by her parents due to swelling on the right side of her neck.  Two weeks ago, the patient's mother first noticed a mass on her daughter's neck; although the mass size remains unchanged, it has become more painful.  Initially, her parents tried to treat the pain with ibuprofen and warm compresses, but with minimal relief.  A 7-day course of oral clindamycin resulted in no improvement.  The mass has become so painful that the patient is unable to fall asleep and tries not to turn her head.  Today, she reports a foreign body sensation in her eyes and increased tearing.  She has had increased fatigue and decreased appetite but no fever, weight loss, or difficulty swallowing.  The patient has environmental allergies and seborrhea.  She has a kitten and 2 hamsters.  Temperature is 37.2 C (99 F).  Examination of the right eye shows injected conjunctivae and scant clear discharge.  The left eye is unaffected.  Tympanic membranes are clear bilaterally.  The posterior oropharynx is clear and without erythema or exudates.  There is a 3-cm (1.2-in), tender, indurated, mobile cervical lymph node and a smaller 1-cm, tender, preauricular lymph node, both on the right side of the neck.  Which of the following complications is most likely to develop in this patient?

Accepted Answer

Explanation: 11ec2b69_bf87_2c6d_8f63_eb6f107f3fb7_MD0005_00 This patient has cervical and preauricular adenopathy as well as unilateral conjunctivitis. Given the history of kitten exposure, she most likely has oculoglandular syndrome (Parinaud oculoglandular syndrome), a specific manifestation of cat-scratch disease (CSD). CSD is caused by infection due to Bartonella henselae, a small gram-negative rod carried by cats, especially kittens. Human transmission most commonly occurs through a cat bite or scratch, although many patients do not remember the exact point of contact. CSD typically presents with lymphadenitis and is the most common cause of chronic (>2 weeks), unilateral adenitis in children. Since bites and scratches usually occur on the extremities, ipsilateral axillary or inguinal node involvement is most common. However, when the inoculation is near the face, adenopathy of the preauricular or cervical nodes is seen. Involvement of the conjunctivae (as in this case) is an uncommon but characteristic presentation of CSD. Symptoms typically self-resolve within a couple of months; however, in some cases, lymph nodes will suppurate and drain onto the skin. Treatment with azithromycin can help accelerate recovery, and needle aspiration may prevent overt rupture and relieve symptoms; lymph node excision is not indicated. (Choice A) Coronary artery aneurysms are a serious complication of Kawasaki disease (KD), which can also present with cervical adenitis. However, fever, mucous membrane changes, and rash are other common features of KD that are not present in this patient. In addition, conjunctivitis associated with KD is bilateral and limbic-sparing, not unilateral. (Choice B) Adenovirus can cause cervical adenopathy and severe conjunctivitis, which may progress to overt keratitis and visual impairment. However, presentation usually also includes pharyngitis and fever (not present in this patient), and symptoms typically last less than a week. (Choice D) Mycobacterium tuberculosis can present as chronic, unilateral cervical lymphadenopathy (ie, scrofula) and, if left untreated, will progress to lower respiratory tract disease including pneumonia, hilar adenopathy, and pleural effusions. However, tuberculosis does not cause preauricular adenopathy or conjunctivitis, and this patient has no fever, cough, or weight loss. (Choice E) Splenic rupture is an uncommon but serious sequela of infectious mononucleosis due to Epstein-Barr virus infection. Mononucleosis may present with chronic bilateral cervical adenopathy, but patients usually have pharyngitis, fever, and splenomegaly, none of which are present in this patient. Educational objective: Oculoglandular syndrome is a specific presentation of cat-scratch disease characterized by conjunctivitis and ipsilateral preauricular and cervical adenopathy. The most common complication of cat scratch disease is lymph node suppuration. References: Cat-scratch disease. (http://www.ncbi.nlm.nih.gov/pubmed/21243990) Ocular manifestations of bartonella infection. (http://www.ncbi.nlm.nih.gov/pubmed/28984726)

Question 16

A 64-year-old man comes to the emergency department after developing fever and chills during hemodialysis. He still feels feverish but has no sore throat, cough, abdominal pain, nausea, or diarrhea. Temperature was 38.9 C (102 F) at the dialysis center. The patient has a history of poorly controlled type 2 diabetes mellitus and hypertension, which led to end-stage renal disease. He was initiated on long-term intermittent hemodialysis 2 months ago. The patient has no known drug allergies. He does not use tobacco, alcohol, or illicit drugs. Temperature is 38 C (100.4 F), blood pressure is 120/62 mm Hg, pulse is 105/min, and respirations are 22/min. Oxygen saturation is 96% on room air. There is a tunneled central venous catheter in the right internal jugular vein, and the skin around the insertion site is not erythematous or tender. Cardiopulmonary auscultation reveals clear lung fields and normal heart sounds. The abdomen is soft and nontender. No skin rash or neck stiffness is present. Leukocyte count is 14,000/mm³ with 90% neutrophils. Chest-x ray reveals no infiltrate or consolidation. Two sets of blood cultures, one from a peripheral vein and the other from the central venous catheter, are obtained. Which of the following is the most appropriate immediate next step in management of this patient?

Accepted Answer

Explanation: This patient who has a tunneled hemodialysis catheter developed a fever with no localizing symptoms, raising suspicion for a catheter-related bloodstream infection (CRBSI). Tunneled hemodialysis catheters are associated with much higher rates of bacteremia (up to 2 episodes a year) than arteriovenous fistula. Most cases are caused by coagulase-negative staphylococci or Staphylococcus aureus, but infections with gram-negative bacilli are also common. Initial workup includes 2 sets of blood cultures, ideally one from a peripheral site and one from the central catheter. Empiric antibiotic therapy should then be initiated with vancomycin plus cefepime (or gentamicin). Catheter removal is indicated if any of the following are present: Severe sepsis Hemodynamic instability Evidence of metastatic infection (eg, endocarditis) Pus at the exit site of the catheter Continued symptoms after 72 hours of empiric antibiotics Long-term catheters (in place >14 days) should be removed if there is blood culture evidence of S aureus, Pseudomonas aeruginosa, or fungi (eg, Candida). Patients who do not require catheter removal should have the catheter changed over a guidewire (once afebrile and clinically stable if there is no evidence of tunnel tract involvement) or antibiotic lock therapy after each hemodialysis session. These measures are required to prevent recurrent infection. (Choices A and C) This patient requires the urgent initiation of empiric antibiotics to prevent morbidity and death. He has no indications for immediate catheter removal (eg, severe sepsis, hemodynamic instability, pus from the catheter site, evidence of metastatic infection). (Choice D) Vancomycin alone would not provide adequate coverage against gram-negative bacilli, and catheter change over a guidewire should be considered only once he is afebrile and clinically stable. (Choice E) The addition of empiric caspofungin is typically recommended for patients with CRBSI-related sepsis who have any of the following risk factors: Total parenteral nutrition, prolonged use of broad-spectrum antibiotics, hematological malignancy, solid organ transplant, femoral catheterization, or Candida colonization at multiple sites. Patients undergoing hemodialysis who develop CRBSI do not typically require empiric caspofungin coverage. Educational objective: Patients undergoing hemodialysis through a tunneled catheter have high rates of catheter-related bloodstream infection. Empiric treatment typically includes vancomycin plus cefepime (or gentamicin). Catheter removal is indicated for those with severe sepsis, hemodynamic instability, pus from the catheter site, evidence of metastatic infection, or symptoms that do not improve within 72 hours of antibiotic administration.

Question 17

A 62-year-old man comes to the office for follow-up after recent hospitalization. Two weeks ago, the patient went to the emergency department due to a 3-day history of fever, chills, dysuria, urinary frequency, and low back pain. Evaluation showed a tender and swollen prostate, leukocytosis, pyuria, and bacteriuria. Treatment for acute bacterial prostatitis was begun with intravenous antibiotics. Blood and urine cultures returned positive for Escherichia coli sensitive to all tested antibiotics. The patient was discharged after clinical improvement and was prescribed oral ciprofloxacin. He has had no fever, and urinary symptoms have resolved, but over the last 2 days, he has had mild abdominal cramps and 4 or 5 watery bowel movements per day with no blood or mucus. Other medical conditions include hypertension and type 2 diabetes mellitus. On examination, the patient is afebrile, and other vital signs are within normal limits. There is mild periumbilical tenderness, but physical examination is otherwise unremarkable. Laboratory studies show a leukocyte count of 14,500/mm³ and serum creatinine level of 0.9 mg/dL. Stool testing is positive for Clostridioides difficile. In addition to oral fidaxomicin therapy, which of the following is the most appropriate next step in management of this patient?

Accepted Answer

Explanation: 11ec2b69_bf91_1791_8f63_b7726b3f8594_MD0005_00 This patient who was recently hospitalized and has been on antibiotics for acute bacterial prostatitis (ABP) now has symptoms (eg, abdominal cramping, watery diarrhea) and stool testing consistent with Clostridioides difficileinfection (CDI). Risk factors for CDI include recent hospitalization, advanced age, and recent antibiotic use (most commonly fluoroquinolones, cephalosporins, and clindamycin). Oral fidaxomicin is appropriate treatment for primary CDI in most patients, including those with nonsevere disease, such as this patient, or severe disease; the distinction is typically based on the degree of leukocytosis (severe: >15,000/mm³) or the serum creatinine elevation (severe: >1.5 mg/dL). In addition to the initiation of fidaxomicin therapy, the inciting antibiotic (eg, ciprofloxacin) should be discontinued as soon as possible because its continued use is associated with prolonged diarrhea and increased likelihood of treatment failure (Choice A). If antibiotic therapy is still required to treat the primary infection (eg, ABP), then the inciting medication should be replaced by a lower-risk antibiotic. In this patient with pansensitive Escherichia coli, trimethoprim-sulfamethoxazole is an excellent alternative for the treatment of ABP; a prolonged course (up to 6 weeks) of antibiotics is frequently prescribed to ensure eradication of the organism and prevent complications such as prostatic abscess or chronic prostatitis. treatment of ABP (Choice B) Imaging of the abdomen is indicated in patients with evidence of severe (ie, leukocytes >15,000/mm³, serum creatinine >1.5 mg/dL) or fulminant (eg, septic shock, apparent ileus, megacolon) disease or in those with severe abdominal pain. This patient has only mild disease, so imaging is not required. (Choice C) Ciprofloxacin is a fluoroquinolone associated with the development of CDI, and it should be switched to another antibiotic. However, trimethoprim-sulfamethoxazole is a better choice than amoxicillin-clavulanate because it is a lower-risk antibiotic in patients with CDI and a first-line treatment for ABP. (Choice D) Oral metronidazole is no longer a first-line agent for the treatment of CDI because it is less effective than other agents (eg, fidaxomicin) for achieving a symptomatic cure. In addition, it is not typically used to treat ABP, unlike trimethoprim-sulfamethoxazole, which is a first-line agent with good prostatic penetration. Educational objective: In patients who develop Clostridioides difficile infection (CDI) while taking antibiotics, the inciting antibiotic should be replaced by a lower-risk antibiotic; in addition, appropriate antimicrobial therapy should be started for the CDI. References: Clinical practice guidelines by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA): 2021 focused update guidelines on management of Clostridioides difficile infection in adults. (http://www.ncbi.nlm.nih.gov/pubmed/34164674) ACG clinical guidelines: prevention, diagnosis, and treatment of Clostridioides difficile infections. (http://www.ncbi.nlm.nih.gov/pubmed/34003176)

Question 18

A 67-year-old man comes to the emergency department due to abdominal cramps, diarrhea, and fever that started 3 days ago. The patient initially had 3 or 4 stools per day for 2 days but, today, had 7 watery stools; the stools have not had gross blood or mucus or black discoloration. The patient has also had generalized weakness and malaise. Two weeks ago, he was treated with oral antibiotics for acute cellulitis. Since then, the patient's appetite has decreased, and he has had mild bloating. He has no history of recent travel, unusual foods, or sick contacts with similar symptoms. Other medical conditions include type 2 diabetes mellitus, hypertension, and hyperlipidemia. Temperature is 38.7 C (101.7 F), blood pressure is 110/70 mm Hg, and pulse is 95/min. Physical examination shows moderate abdominal tenderness. The cellulitis has resolved. Leukocytes are 26,000/mm³, serum creatinine is 1.9 mg/dL (increased from 1.2 mg/dL 2 months ago), and serum albumin is 2.9 g/dL. The patient does not want to be admitted to the hospital and would like to be treated as an outpatient. Stool PCR testing for Clostridioides difficile PCR is positive. The patient is adamant about going home. He is given a prescription for oral fidaxomicin and discharged home against medical advice. The patient returns 2 days later feeling much worse. He says, "I just got the pills today and have taken only one dose." Temperature is 38.9 C (102 F), blood pressure is 90/60 mm Hg, pulse is 114/min, and respirations are 24/min. The patient appears uncomfortable. The abdomen is distended, and bowel sounds are decreased; there is tenderness and guarding to palpation. CT scan of the abdomen shows diffuse colonic wall thickening and dilation. In addition to the appropriate oral pharmacotherapy, what is the most appropriate next step in management of this patient?

Accepted Answer

Explanation: 11ec2b69_bf90_2d2f_8f63_d9358770af6c_MD0005_00 This patient with PCR-confirmed Clostridioides difficileinfection (CDI) had evidence of severe infection (ie, leukocytes >15,000/mm³and serum creatinine >1.5 mg/dL) prior to leaving the hospital against medical advice. Now, after inadequate treatment (eg, only a single dose of oral antimicrobial therapy), he has findings (eg, hypotension, colonic dilation) concerning for progression to fulminant infection with possible toxic megacolon. A minority of patients with CDI develop severe complications such as toxic megacolon, which is characterized by nonobstructive colonic dilation. Toxic megacolon generally presents with the following: Severe systemic toxicity (eg, fever, hypotension, tachycardia) Abdominal distension and pain (diarrhea may cease due to lack of colonic motility) Leukocytosis (usually >15,000/mm³) Radiographic evidence of large-bowel dilation (eg, >6 cm in colon, >9 cm in cecum) Treatment of fulminant infection includes bowel rest, nasogastric tube placement, and aggressive antibiotic therapy against C difficile, which may include the addition of vancomycin enemas if ileus is present. In addition, surgical consultation should be initiated; surgical intervention (eg, colectomy) may be necessary if the patient develops peritonitis or colonic necrosis/perforation or if his condition clinically deteriorates despite medical therapy (Choice D). (Choice A) Colonoscopic decompression may be used in the management of sigmoid volvulus, which typically causes a single, closed loop of dilated bowel (vs colonic wall thickening and dilation) on CT scan. Colonoscopy is generally avoided in toxic megacolon because air insufflation and instrumentation within the inflamed, dilated colon carry a high risk of perforation. (Choice B) Intravenous corticosteroids are commonly used to treat flares of inflammatory bowel disease (IBD) and even IBD-induced toxic megacolon. However, they are not typically used in the management of toxic megacolon due to CDI; such use may be associated with increased mortality. (Choice C) Intravenous vancomycin therapy is not used in the management of CDI. In contrast, oral vancomycin is used; its poor absorption by the gastrointestinal tract allows it to be delivered to the colon, where it can treat C. difficile. If ileus is present, vancomycin enemas may be used. Educational objective: Clostridioides difficile infection can cause toxic megacolon, which is characterized by nonobstructive colonic dilation, severe systemic toxicity, abdominal pain and distension, and leukocytosis. Toxic megacolon requires aggressive antibiotic therapy, as well as surgical consultation. Surgical intervention may be necessary if the patient develops peritonitis or colonic necrosis/perforation or if the patient's condition clinically deteriorates despite medical therapy. References: ACG clinical guidelines: prevention, diagnosis, and treatment of Clostridioides difficile infections. (http://www.ncbi.nlm.nih.gov/pubmed/34003176) Toxic megacolon: background, pathophysiology, management challenges and solutions. (http://www.ncbi.nlm.nih.gov/pubmed/32547151) Clostridium difficile disease: diagnosis, pathogenesis, and treatment update. (http://www.ncbi.nlm.nih.gov/pubmed/28267992)

Question 19

A 77-year-old man calls the office on a Sunday evening due to fever and cough.  The patient has had a "cold" for several days but noticed worsened productive cough, fever, and chills over the last 24 hours.  He says "I know it's just a cold and will get better, but my wife worries too much and made me call."  The patient has a history of hypertension, chronic kidney disease, chronic obstructive pulmonary disease, and osteoarthritis.  He has had to use his albuterol inhaler more frequently during the last few days due to shortness of breath.  He has also been taking over-the-counter cough syrup without improvement.  The patient is up to date with influenza and pneumococcal vaccines.  He is a former smoker and does not use alcohol or illicit drugs.  He lives with his wife, who has early-stage dementia.  Which of the following is the best next step in management of this patient?

Accepted Answer

Explanation: 11ec2b69_bf92_c543_8f63_17f7988060f0_MD0005_00 This patient had viral upper respiratory symptoms for several days and now has worsening symptoms. His fever, chills, and productive cough raise concern concern for secondary pneumonia. Secondary pneumonia is a common complication of viral upper respiratory infections. Risk is greatest in patients of advanced age and those with underlying comorbidities (eg, chronic obstructive pulmonary disease [COPD]). Suspicion should be raised when patients with several days of upper respiratory infection symptoms develop worsening fever or pulmonary manifestations (eg, productive cough, dyspnea). Because pneumonia is a serious infection associated with significant morbidity and mortality, urgent evaluation is required. This patient should go to the nearest emergency department (ED) for examination, laboratory studies, and chest x-ray. If pneumonia is present, risk stratification with the pneumonia severity index or CURB-65 score can help determine the appropriate care setting; antibiotics will likely be required. CURB-65 score Even if the patient's symptoms are not due to pneumonia (eg, COPD exacerbation with no infiltrate on x-ray), ED evaluation is appropriate, particularly given the risk of respiratory deterioration with pneumonia. (Choices B and C) Community-acquired pneumonia (CAP) is a serious infection, particularly in patients of advanced age and with underlying pulmonary disease. Evaluation and treatment should not be delayed. (Choice D) Azithromycin monotherapy is sometimes used for CAP in previously healthy patients who are at low risk for complications in areas where macrolide-resistant Streptococcus pneumoniae is uncommon. This patient of advanced age has pulmonary disease (eg, COPD); azithromycin alone would be an insufficient treatment for CAP. Additional clinical data is required prior to hospitalization and treatment decisions. (Choice E) This patient is at high risk for upper viral respiratory infection complications due to his age and underlying lung disease. Because he has worsening symptoms after several days of illness, he requires evaluation for secondary pneumonia. Educational objective: Community-acquired pneumonia commonly occurs after viral upper respiratory infection. Risk is greatest in those of advanced age and with underlying comorbidities (eg, pulmonary disease). Prompt evaluation, imaging, and laboratory studies are required to risk stratify patients and determine the appropriate level of care.

Question 20

A 67-year-old man comes to the emergency department due to abdominal cramps, diarrhea, and fever that started 3 days ago. The patient initially had 3 or 4 stools per day for 2 days but, today, had 7 watery stools; the stools have not had gross blood or mucus or black discoloration. The patient has also had generalized weakness and malaise. Two weeks ago, he was treated with oral antibiotics for acute cellulitis. Since then, the patient's appetite has decreased, and he has had mild bloating. He has no history of recent travel, unusual foods, or sick contacts with similar symptoms. Other medical conditions include type 2 diabetes mellitus, hypertension, and hyperlipidemia. Temperature is 38.7 C (101.7 F), blood pressure is 110/70 mm Hg, and pulse is 95/min. Physical examination shows moderate abdominal tenderness. The cellulitis has resolved. Leukocytes are 26,000/mm³, serum creatinine is 1.9 mg/dL (increased from 1.2 mg/dL 2 months ago), and serum albumin is 2.9 g/dL. The patient does not want to be admitted to the hospital and would like to be treated as an outpatient. The patient is at most risk for developing which of the following complications?

Accepted Answer

Explanation: 11ec2b69_bf8f_42cd_8f63_9b8cf6974d62_MD0005_00 This patient who recently completed a course of antibiotics for cellulitis now has profuse watery diarrhea accompanied by abdominal bloating, fever, and leukocytosis. This presentation is most concerning for Clostridioides difficileinfection (CDI). Profuse watery diarrhea (≥3 loose stools/24 hr) is the hallmark symptom of CDI, which is suspected when major risk factors (eg, recent antibiotic use, advanced age [>65]) for CDI are present. Other common features include abdominal pain and leukocytosis; fever is present in approximately 15% of patients. CDI is typically classified as nonsevere, severe (leukocytes >15,000/mm³ and/or serum creatinine >1.5 mg/dL), or fulminant (eg, severe CDI with hypotension, ileus, or megacolon). This patient has markers of severe disease (eg, leukocytes 26,000/mm³, creatinine 1.9 mg/dL) with hypoalbuminemia, which can occur in CDI due to inflammatory protein-losing enteropathy. He is at risk, especially without appropriate treatment, for developing fulminant disease, in which severe colonic dilation (ie, megacolon) and/or necrosis can occur, leading to perforation. (Choices A and C) Infection with Shiga toxin-producing Escherichia coli (STEC) can cause fever, abdominal pain, and, initially, watery diarrhea that may convert to bloody diarrhea. In addition, STEC may be complicated by hemolytic uremic syndrome (characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury). However, STEC rarely causes fever >38.5 C (101.3 F), and stools typically become bloody within 1-3 days of diarrhea onset. (Choice B) Demyelination of axons, as seen in Guillain-Barré syndrome, can occur as a complication of Campylobacter gastroenteritis. Campylobacter infection can cause fever, abdominal pain, and profuse watery diarrhea; however, the diarrhea also typically contains mucus and/or blood. Leukocytosis may be present but is typically mild (not 26,000/mm³). (Choice E) Infection with Shigella can present with high fever, abdominal pain, and diarrhea. Although mild disease may cause only watery diarrhea, most cases (and especially those with numerous diarrheal episodes per day) have mucoid and/or bloody diarrhea. In addition, tenesmus (not present in this patient) is common due to preferential involvement of the rectosigmoid region. When present, Shigella may be complicated by seizures; however, this occurs almost exclusively in children age <15. Educational objective: Clostridioides difficile infection (CDI) is characterized by profuse watery diarrhea and should be suspected when major risk factors (eg, recent antibiotic use, age >65) are present. Severe CDI is characterized by leukocytosis (>15,000/mm³) and elevated serum creatinine (≥1.5 mg/dL) and can progress to fulminant disease, which may be complicated by colonic dilation, necrosis, and perforation. References: ACG clinical guidelines: prevention, diagnosis, and treatment of Clostridioides difficile infections. (http://www.ncbi.nlm.nih.gov/pubmed/34003176) Clinical practice guideline by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA): 2021 focused update guidelines on management of Clostridioides difficile infection in adults. (http://www.ncbi.nlm.nih.gov/pubmed/34164674)

Exam 1: Advanced Clinical Medicine