Question 1

A 23-year-old woman is brought to the emergency department with fever, rash, and decreased level of consciousness.  She is accompanied by her boyfriend.  The patient became increasingly confused throughout the morning and eventually unarousable, prompting him to call an ambulance.
After initial evaluation, lumbar puncture is performed and empiric antibiotic therapy is started.  Cerebral spinal fluid shows Gram-negative diplococci.  She is admitted to the intensive care unit.
Which of the following individuals needs antibiotics for post-exposure prophylaxis?

Accepted Answer

11ec193a_9645_1515_853d_5b3707b67a5f_MD0002_00 This patient's presentation of fever, rash, decreased level of consciousness and Gram-negative diplococci on lumbar puncture suggests likely meningococcal infection from Neisseria meningitidis. Meningococcus usually spreads through droplets of respiratory secretions and can transmit rapidly to contacts within close proximity (3-6 feet). Individuals require antibiotic prophylaxis if they have close contact and prolonged duration (> 8 hours) regardless of vaccination status. Healthcare workers (with close proximity and prolonged duration or exposure to respiratory secretions) and close contacts of infected patients with meningococcal disease ideally should receive antibiotic chemoprophylaxis within the first 24 hours of the patient's diagnosis. Exposure usually occurs during the week prior to onset of symptoms or 24 hours prior to antimicrobial therapy. Recommended regimens include rifampin, ciprofloxacin, or ceftriaxone. This patient's boyfriend would warrant antimicrobial therapy. (Choices A, B, and D) The nurse, medical resident, and transporter would need antibiotic prophylaxis only if they were exposed to respiratory secretions or were in very close proximity to the secretions for a prolonged period. These workers had a relatively short duration of exposure and would benefit less from antibiotic prophylaxis. If this patient required intubation, the physician who performed it would require antimicrobial prophylaxis. Educational objective: Regardless of vaccination status, healthcare workers (with close proximity and prolonged duration or exposure to respiratory secretions) and close contacts of infected patients with meningococcal disease should receive antibiotic chemoprophylaxis, ideally within the first 24 hours of patient diagnosis. Recommended regimens include rifampin, ciprofloxacin, or ceftriaxone. __________ References: Prevention and control of meningococcal disease. recommendations of the Advisory Committee on Immunization Practices (ACIP). (http://www.ncbi.nlm.nih.gov/pubmed/15917737)

Question 2

A 34-year-old man comes to the emergency department due to skin rash that he noticed this morning on his arms and legs.  He has also had fever and headache for 3 days.  The patient had a root canal 2 weeks ago with mild post-procedure pain and gum swelling.  Medical history is otherwise noncontributory.  He is an avid biker who enjoys spending time outdoors.  The patient does not use alcohol or tobacco.  He has a male partner with whom he has been in a stable relationship for the last 2 years.
Temperature is 39.7 C (103.5 F), blood pressure is 122/70 mm Hg, and pulse is 114/min and regular.  No lymph node enlargement is present.  There is no sinus tenderness to palpation.  The lungs are clear to auscultation.  There are no heart murmurs.  The abdomen is soft and nontender, and the tip of the spleen is not palpated.  Maculopapular rash with petechiae is present on the arms and legs.  There are no meningeal signs.
Laboratory results are as follows:
 Two blood smears are negative for potential blood-borne pathogens.
Which of the following is the most appropriate next step in management of this patient?

Accepted Answer

11ec193a_9640_5a1d_853d_cdcf56805cc7_MD0002_00 This patient's high fever, headache, and extremity rash raise suspicion for Rocky Mountain spotted fever (RMSF). RMSF is a potentially lethal tick-borne illness due to Rickettsia rickettsii. Although RMSF can occur throughout the United States, it is most common in the southeastern region. Peak incidence is in the spring and summer. Manifestations usually begin with nonspecific symptoms (eg, fever, severe headache, malaise, myalgias, arthralgias) followed 3-5 days later by a maculopapular rash that becomes petechial over time. The rash typically starts on the ankles and wrists and spreads centrally to the trunk and peripherally to the palms and soles. Hyponatremia, thrombocytopenia, and elevated serum transaminases are important diagnostic clues. Identifying potential cases of RMSF is often challenging due to the following: Approximately 35% of patients have no knowledge of tick bite (as in this case)Only 15% of patients have a rash at presentationA minority (~10%) never develop a rash ("spotless" RMSF) Approximately 35% of patients have no knowledge of tick bite (as in this case) Only 15% of patients have a rash at presentation A minority (~10%) never develop a rash ("spotless" RMSF) Because of these difficulties, empiric first-line treatment with doxycycline is typically administered to patients who develop a nonspecific febrile illness in the spring and summer if they are from an endemic area and have had known or possible tick exposure. Early treatment is crucial as antibiotic initiation ≥5 days after symptom onset is associated with much higher risk of morbidity (eg, encephalitis, gangrene of the digits) and death. The diagnosis is usually confirmed several days later with serology or skin biopsy (after the rash appears). (Choice B) Meningococcemia can also cause headache, fever, and a petechial rash, but most cases come to clinical attention <22 hours after symptom onset and are also associated with confusion and meningeal signs (eg, nuchal rigidity). If early meningococcemia cannot be differentiated from RMSF, patients sometimes require a combination of empiric ceftriaxone and doxycycline while awaiting cerebrospinal fluid results. (Choice C) Mononucleosis can cause high fever and a rash (usually after antibiotic administration), but patients also typically have sore throat, lymphadenopathy, malaise, and/or splenomegaly. (Choice D) Secondary syphilis can also cause a maculopapular rash that involves the palms and soles but is not usually associated with high fevers. Patients who may have secondary syphilis but are at risk for RMSF should be treated with doxycycline while syphilis serology is pending. (Choice E) Infective endocarditis can cause high fever and skin manifestations (eg, Janeway lesions, Osler nodes), but a maculopapular rash on the bilateral extremities would be atypical. Educational objective: Rocky Mountain spotted fever is a tick-borne rickettsial illness that causes nonspecific symptoms followed by a maculopapular rash 3-5 days later. The rash typically starts on the ankles and wrists and spreads centrally to the trunk and peripherally to the palms and soles. Empiric therapy with doxycycline should be started as soon as possible to decrease morbidity and mortality. __________ References: Rocky Mountain spotted fever. (http://www.ncbi.nlm.nih.gov/pubmed/11982306) Rocky Mountain spotted fever. (http://www.ncbi.nlm.nih.gov/pubmed/17961858)

Question 3

A 28-year-old man comes to the emergency department due to a cough, malaise, skin rash, and migratory joint pain that began 5 days ago. Two weeks ago, he returned from a hiking trip in the southwestern United States. The patient has a history of ulcerative colitis diagnosed 2 years ago, which has been in remission since infliximab was started 6 months ago. His tuberculin skin testing was negative 7 months ago. On examination, temperature is 38.3 C (101 F), blood pressure is 100/70 mm Hg, pulse is 92 /min, and respirations are 14/min. There are several tender, erythematous nodules 2-3 cm in size in both legs over the anterior shins. Oropharyngeal mucosa is dry without any erythema or exudate. On auscultation, fine basal crackles are heard on the left side. There is synovitis and tenderness of both knee joints. The rest of the examination is normal. Laboratory studies show white blood cells are 16,000/mm³ (72% neutrophils) and platelets are 650,000/mm³. Chest x-ray is unremarkable. Which of the following is the most likely diagnosis?

Accepted Answer

This patient's presentation of cough, fever, arthralgia, and erythema nodosum after recent travel to the southwestern United States is consistent with coccidioidomycosis. In immunocompetent hosts, Coccidioides immitis may be asymptomatic or cause only a minor febrile respiratory syndrome ("valley fever"). However, in immunocompromised patients, C immitis can also cause acute pneumonia (most common), chronic progressive pneumonia, nodular or cavitary lung disease, extrapulmonary disease, or meningitis. Patients receiving tumor necrosis factor-alpha inhibitors, such as infliximab, are at increased risk for opportunistic fungal infections. erythema nodosum southwestern United States Diagnosis of coccidioidomycosis is primarily based on epidemiologic (ie, travel) history and clinical findings, and is confirmed with culture, microscopy (potassium hydroxide preparation), or serology. Most patients with valley fever improve without therapy; however, fluconazole or itraconazole should be considered for those with evidence of severe infection or immunosuppression. (Choice B) Hodgkin lymphoma most commonly presents with painless cervical adenopathy. Systemic symptoms may develop as the disorder progresses and adenopathy develops in contiguous areas (eg, mediastinum). This patient does not have lymphadenopathy. (Choice C) Sarcoidosis may present similarly to coccidioidomycosis with cough, fever, joint pain, and erythema nodosum. However, pulmonary involvement is present in >90% of patients with sarcoidosis, and most patients will have abnormal findings on chest x-ray (eg, hilar adenopathy). (Choices D and E) Although tuberculosis and tularemia may have varied presentations, this patient's negative tuberculin skin test, normal chest x-ray, and lack of relevant exposure history (eg, farm exposure or small animal handling for tularemia) make them less likely. Educational objective: Cough, fever, arthritis, and erythema nodosum after recent travel to the southwestern United States is consistent with coccidioidomycosis. Patients receiving tumor necrosis factor-alpha inhibitors are at increased risk for opportunistic infections, including fungal pathogens. __________ References: Update on the diagnosis of pulmonary coccidioidomycosis. (http://www.ncbi.nlm.nih.gov/pubmed/24575994) Increased risk of coccidioidomycosis in patients treated with tumor necrosis factor alpha antagonists. (http://www.ncbi.nlm.nih.gov/pubmed/15188373) Opportunistic infections with anti-tumor necrosis factor-a therapy in inflammatory bowel disease: meta-analysis of randomized controlled trials. (http://www.ncbi.nlm.nih.gov/pubmed/23649185)

Question 4

A 43-year-old man comes to the emergency department due to 5 days of slowly worsening fever, cough, and malaise. He has a history of HIV infection, and his last known CD4 count 3 months ago was 210/mm³. He also has a distant history of seizures. The patient drinks alcohol daily and was hospitalized for alcohol withdrawal a year ago. Temperature is 38.3 C (100.9 F), blood pressure is 98/62 mm Hg, pulse is 111/min and regular, and respirations are 20/min. The patient has poor dentition. Small, mobile lymph nodes are palpable in the submandibular area. Scattered rhonchi are heard bilaterally. Heart sounds are normal with no murmur. The tip of the spleen is not palpable, and the liver span is normal. Laboratory results are as follows: CT scan of the chest reveals several bilateral cavitating lesions. Blood cultures grow Staphylococcus aureus in 2 of 2 bottles. Which of the following is most often associated with this patient's condition?

Accepted Answer

This patient with Staphylococcus aureus bacteremia has several bilateral cavitating pulmonary lesions raising suspicion for septic emboli due to right-sided infective endocarditis (IE). Most cases of right-sided IE are due to injection drug use and are associated with the following clinical features: The tricuspid valve is most commonly affectedHeart murmurs are often absent on examinationS aureus is the most common pathogenUp to 75% of patients develop septic emboli and pneumoniaSeptic emboli can also affect other organs (eg, kidney, brain, spine)Heart failure is rarePatients commonly have coinfection with HIV, hepatitis B, and/or hepatitis C The tricuspid valve is most commonly affected Heart murmurs are often absent on examination S aureus is the most common pathogen Up to 75% of patients develop septic emboli and pneumonia Septic emboli can also affect other organs (eg, kidney, brain, spine) Heart failure is rare Patients commonly have coinfection with HIV, hepatitis B, and/or hepatitis C (Choice A) Aspiration pneumonia usually affects the dependent pulmonary zones (eg, lower lobes, posterior segments of the upper lobes), and anaerobic bacteria are most commonly involved. (Choice C) Latent tuberculosis (TB) is a dormant TB infection that can reactivate, causing symptomatic disease. Manifestations of active disease usually include indolent symptoms (eg, cough, weight loss, fevers) and focal infiltration/cavitation of the upper lobes of the lung. This patient with S aureus bacteremia is more likely to have IE. (Choice D) Poor dentition and periodontal infection/abscess increase the risk of developing IE with oral pathogens (eg, streptococcus). S aureus IE is not typically associated with poor dentition; injection drug use is more likely to be the underlying cause. (Choice E) S aureus pneumonia is a life-threatening complication of influenza infection. Most cases are marked by an initial improvement of influenza symptoms (eg, rhinorrhea, cough, fever) prior to developing worsened fever, respiratory symptoms, and a multilobar pneumonia. This patient with 5 days of progressive symptoms, no history of influenza-like upper respiratory symptoms, and cavitations with no lobar infiltrate is more likely to have septic emboli from right-sided IE. Educational objective: Injection drug users are at increased risk for infective endocarditis (IE) involving the right-sided heart valves. Staphylococcus aureus is the most common organism. Patients often present due to septic pulmonary emboli (eg, multiple bilateral cavitary lesions). Cardiac examination is usually normal (eg, no heart murmurs). __________ References: Tricuspid endocarditis and septic pulmonary embolism in an intravenous drug user with advanced HIV Infection. (http://www.ncbi.nlm.nih.gov/pubmed/22125735) Human immunodeficiency virus infection and infective endocarditis among injecting drug users. (http://www.ncbi.nlm.nih.gov/pubmed/8899380)

Question 5

A 33-year-old man comes to the emergency department with a 2-day history of generalized weakness, lightheadedness, palpitations, and poor energy.  Four weeks ago, he noticed an annular rash on his right thigh that lasted for a couple of days and then faded.  He has no fever, weight loss, chest pain, or headache.  He lives on Long Island, New York, and jogs 7 miles 3 times a week.
Which of the following is the most likely cardiac finding in this patient?

Accepted Answer

11ec193a_9645_6336_853d_ddca7e019f8d_MD0002_00 This patient is from a Lyme disease-endemic area and had a transient thigh rash 4 weeks earlier, suggesting Lyme disease caused by Borrelia burgdorferi. Patients typically present with initial erythema migrans and nonspecific flu-like symptoms (eg, fever, fatigue, headache, and body aches). As the disease disseminates in the following weeks to months, patients may present with acute neurologic and/or cardiac symptoms as the first clinical sign of the disease. Lyme carditis, as in this patient, may be asymptomatic or present with palpitations (most common), lightheadedness, syncope, dyspnea, or chest pain. Palpitations can be a nonspecific finding and may not represent true underlying heart disease. Lyme carditis most commonly presents (objectively) with atrioventricular (AV) conduction blocks that sometimes fluctuate between first- and second-degree block. Progression to complete heart block is possible, and the risk is increased with PR interval > 300 msec. Lyme myopericarditis is usually self-limited and sometimes causes mild pericardial effusion but rarely causes cardiomegaly (Choices C and D). Although cardiomyopathy has been reported in Europe, there have been no such cases reported in the United States. Atrial and ventricular tachyarrhythmias occur less commonly in Lyme carditis (Choices A and E). Diagnosis is confirmed by clinical features and positive ELISA and western blot Lyme serologies. Current guidelines recommend hospital admission with IV antibiotics (ceftriaxone preferred) to prevent long-term complications in symptomatic patients and those with second- or third-degree AV block or first-degree AV block with PR interval > 300 msec. Oral antibiotics (eg, doxycycline, amoxicillin, and cefuroxime) should be continued at discharge for a 21- to 28-day total course. Complete AV block requires temporary pacing as these blocks are self-limited and usually improve within 1 week. Lesser conduction disturbances may take up to 6 weeks for resolution. Educational objective: Lyme carditis can be asymptomatic or present with palpitations, lightheadedness, syncope, dyspnea, or chest pain. Atrioventricular conduction block is the most common cardiac presentation and can progress to complete heart block. Hospital admission with IV antibiotics (ceftriaxone preferred) is recommended for symptomatic patients and those with second- or third-degree AV block or first-degree AV block with PR interval > 300 msec. __________ References: Lyme disease and the heart. (http://www.ncbi.nlm.nih.gov/pubmed/12957829)

Question 6

A 40-year-old man with known HIV infection comes to the emergency department with lethargy and right-sided weakness.  He is accompanied by his girlfriend, who says that he has been behaving strangely for the past 3-4 weeks.  He has also been complaining of headaches.  The patient does not routinely follow up with his physician, and his last CD4 count 3 months ago was 50 cells/µL.
His temperature is 37.2° C (99° F), blood pressure is 140/80 mm Hg, pulse is 88/min, and respirations are 16/min.  Pulse oximetry shows 96% on room air.  The patient appears lethargic but follows commands.  He has poor dentition and oral thrush.  No neck stiffness is present.  He has a pronator drift in the right upper extremity with slightly increased tone and brisk reflexes.  The remainder of the examination is normal.
Diffusion-weighted magnetic resonance imaging of the brain with and without contrast reveals a large (4.2-cm) ring-enhancing deep subcortical white matter lesion with surrounding vasogenic edema and mass effect.
What is the most likely diagnosis in this patient?

Accepted Answer

11ec193a_9645_ff77_853d_51d535322922_MD0002_00 This patient's presentation of severe immunosuppression, confusion, lethargy, hemiparesis, and MRI findings (large, ring-enhancing lesion with edema and mass effect) is most suggestive of primary central nervous system lymphoma (PCL). PCL occurs with advanced immunosuppression, such as CD4 counts < 50 cells/µL. Most patients present with confusion, motor deficits, aphasia, memory loss, and/or seizures. B symptoms such as fever, night sweats, and weight loss are present in about 80% of patients. In patients with AIDS, the differential diagnosis of CNS lesions that are ring-enhancing with edema and mass effect includes toxoplasma encephalitis and primary CNS lymphoma. Imaging features suggestive of PCL are solitary lesions, lesions > 4 cm, and those involving the corpus callosum, periventricular, or periependymal areas. Posterior fossa lesions are more suggestive of infection than PCL. Definitive diagnosis of PCL requires cerebrospinal fluid cytology, detection of Ebstein-Barr virus DNA in the cerebrospinal fluid, toxoplasma serologies, and/or brain biopsy. (Choice A) Cytomegalovirus encephalitis occurs in HIV patients with CD4 counts < 50 cells/µL who may present with confusion, dementia, delirium, and focal neurologic deficits. MRI usually reveals diffuse micronodular encephalitis or ventriculoencephalitis (periventricular inflammation). This patient's presentation and MRI findings are most suggestive of lymphoma. (Choice C) Patients with progressive multifocal leukoencephalopathy usually present with rapidly progressive neurologic deficits such as altered mental status, motor deficits, ataxia, aphasia, visual symptoms, and cognitive impairment. Suggestive MRI findings include asymmetric white matter lesions without enhancement, mass effect, or edema. (Choice D) Toxoplasma encephalitis occurs in HIV patients with CD4 counts < 100 cells/µL who are not on anti-toxoplasma prophylaxis. MRI findings may show multiple ring-enhancing lesions with mass effect and edema and a predilection for the basal ganglia. This patient's MRI findings of a solitary large lesion are more suggestive of lymphoma than toxoplasma encephalitis. Educational objective: In patients with AIDS, ring-enhancing central nervous system lesions with mass effect and edema are suggestive of primary central nervous system lymphoma (PCL) or toxoplasma encephalitis. Imaging features suggestive of PCL are solitary lesions, lesions > 4 cm, and those involving the corpus callosum, periventricular, or periependymal areas. Toxoplasma encephalitis should be suspected in patients with multiple ring-enhancing lesions and a predilection for the basal ganglia. __________ References: Use of CT and MR imaging to distinguish intracranial lesions and to define the need for biopsy in AIDS patients. (http://www.ncbi.nlm.nih.gov/pubmed/2213162) Primary CNS lymphoma in HIV positive and negative patients: comparison of clinical characteristics, outcome and prognostic factors. (http://www.ncbi.nlm.nih.gov/pubmed/20526793) Primary central nervous system lymphoma versus toxoplasmosis in AIDS. (http://www.ncbi.nlm.nih.gov/pubmed/2027999)

Question 7

A 62-year-old man with a history of coronary artery disease comes to the emergency department with 2 days of fever and fatigue.  Over the last 24 hours, he has developed progressive fatigue and confusion.  The patient's past medical history is notable for a coronary catheterization 2 weeks ago with placement of an intracoronary stent in the right posterior descending artery.  He was discharged home within 24 hours.  He has no other medical history or prior surgeries.  The patient lives in New York with his wife, who has been well.  He has no recent travel and currently works as an accountant.
On physical examination, the patient appears uncomfortable but is clinically stable.  His temperature is 38.6 C (101.5 F), blood pressure is 122/70 mm Hg, and pulse is 114/min and regular.  There is no lymph node enlargement.  There is no tenderness to palpation over the sinuses.  The lungs are clear on auscultation.  No heart murmurs are appreciated.  The abdomen is soft and nontender.  The tip of the spleen is not palpated.  There is no rash.  Laboratory results are as follows:

He is initially treated with vancomycin and piperacillin-tazobactam.  Forty-eight hours later, blood cultures from admission grow methicillin-resistant Staphylococcus aureus.
What is the best next step in management of this patient's infection?

Accepted Answer

This patient has methicillin-resistant Staphylococcus aureus (MRSA) bacteremia in the setting of a relatively recent hospitalization and cardiovascular procedure. Echocardiography is recommended for all patients with S aureus bacteremia due to the high risk of associated metastatic complications. A transthoracic echocardiogram (TTE) should be performed first, although a transesophageal echocardiogram is more sensitive in detecting valve vegetations and could be considered if there is no evidence of vegetations on TTE. (Choices A and B) The routine addition of gentamicin or rifampin is not recommended in cases of MRSA bacteremia. Gentamicin is sometimes added to shorter courses of penicillin therapy for selected patients with native-valve endocarditis due to penicillin-susceptible strains. Some guidelines recommend adding rifampin to vancomycin in patients with a penicillin allergy who are being treated for methicillin-susceptible native-valve endocarditis. (Choice C) Colonoscopy is recommended in cases of bacteremia caused by Streptococcus gallolyticus due to a strong association with colonic malignancy. There is no association between MRSA bacteremia and colonic lesions. (Choice E) Although metastatic complications to the eye can occur with MRSA bacteremia, they are uncommon, and ophthalmologic evaluation in a patient without visual symptoms is generally not recommended. In contrast, all patients with candidemia should undergo ophthalmologic evaluation. Educational objective: Echocardiography should be performed in all patients with Staphylococcus aureus bacteremia regardless of the presence of clinical signs suggestive of endocarditis. __________ References: Clinical practice guidelines by the Infectious Diseases Society of America for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children. (http://www.ncbi.nlm.nih.gov/pubmed/21208910) Clinical management of Staphylococcus aureus bacteremia: a review. (http://www.ncbi.nlm.nih.gov/pubmed/25268440)

Question 8

A 52-year-old man comes to the emergency department with fevers, cough, and headache.  The headache has worsened over the last week with localization to the right side and is associated with nausea.  Yesterday he noted left-hand weakness and difficulty grasping objects.  He has no history of travel outside of the northeastern United States or exposure to domestic animals or sick contacts.  The patient underwent liver transplantation for primary biliary cirrhosis 8 months ago and had an uneventful postoperative course.  His medications include prednisone and tacrolimus.  His preoperative tuberculin skin testing was negative and he has had no postoperative infections.  He is physically active and had walked 2-3 miles a day until 1 week ago.
His temperature is 38.2 C (100.8 F), blood pressure is 124/84 mm Hg, pulse is 96/min, and respirations are 18/min.  Crackles are present over the right upper lung field.  There are no heart murmurs.  The abdomen is soft without organomegaly.  There are no skin rashes.  Neurological examination is notable for left-hand weakness and decreased sensation of the left hand and forearm.
Chest x-ray reveals patchy alveolar opacities in the right upper lobe and a 3-cm abscess in the right middle lobe.  Head CT scan shows an abscess in the right cerebral hemisphere.  A transesophageal echocardiogram reveals no vegetations.
Which of the following conditions is most consistent with this patient's clinical presentation?

Accepted Answer

11ec193a_9642_cb20_853d_7fb45f97d017_MD0002_00 This patient with lung and CNS disease after organ transplantation has likely nocardiosis. Nocardia is found in the soil and can enter the body through inhalation or direct contact with soil. Because it is not part of normal human flora, isolation of the organism from any bodily fluids (eg, sputum) is considered an infection. Patients usually present with lung (primary site) infection. Nocardia has special tropism to neural tissue, and usually manifests as brain abscess. Immunocompromised patients presenting with pulmonary nocardiosis should therefore undergo brain imaging to rule out abscess. Diagnosis of nocardiosis is made clinically with symptoms and partially acid-fast, branching rods isolated in specimens. Aerobic cultures for Nocardia can take 5-20 days for growth. PCR testing for Nocardia is more rapid and accurate but is not widely available. Nonsevere cutaneous nocardiosis can be treated with oral antibiotics (eg, TMP-SMX); systemic disease requires IV antibiotics. Patients usually require antibiotics for prolonged periods due to the relapsing nature of the infection. Immunocompromised patients may require lifelong suppressive therapy with TMP-SMX or doxycycline. (Choice A) In contrast to Nocardia, Actinomyces is an anaerobic Gram-positive rod that is part of normal oral flora and contains sulfur granules. Actinomyces most commonly affects the face (usually after dental work/infections or oromaxillary trauma) and abdominal organs. CNS and pulmonary actinomycosis are less common. (Choice B) Atypical mycobacterial infections usually present with chronic pulmonary symptoms or soft-tissue infections but rarely become disseminated or involve the CNS. (Choice D) This patient's absence of known predisposing factors and vegetations on TEE makes endocarditis less likely. (Choice E) Toxoplasma gondii most commonly affects the CNS (95%) and rarely affects the lungs. Most infections occur due to reactivation of latent infection. CT usually shows multiple ring-enhancing brain lesions with surrounding edema, most commonly in the basal ganglia. Educational objective: Nocardia is commonly seen in immunocompromised patients and typically involves the lung, brain, and skin. Diagnosis is made clinically and confirmed with culture isolating acid-fast, filamentous Gram-positive rods. Treatment involves TMP-SMX, imipenem, amikacin, or third-generation cephalosporins. __________ References: Nocardiosis: updated clinical review and experience at a tertiary center. (http://www.ncbi.nlm.nih.gov/pubmed/20306281) Nocardiosis: updates and clinical overview. (http://www.ncbi.nlm.nih.gov/pubmed/22469352)

Question 9

A 28-year-old woman with fever and lethargy is brought to the emergency department accompanied by her roommate.  The roommate reports that the patient appeared well last night but awoke this morning confused.  Throughout the morning she became increasingly confused and eventually unarousable, prompting her roommate to call an ambulance.  Her past medical history is significant for idiopathic thrombocytopenia purpura.  There is no history of recent travel.
Her temperature is 39.4 C (103 F), blood pressure is 84/42 mm Hg, pulse is 122/min, and respirations are 28/min.  Oxygen saturation is 90% on room air.  Physical examination shows an ill-appearing woman.  Pupils are equal and round but sluggish.  Lungs have patchy rales.  Abdominal examination reveals a surgical scar in the left upper quadrant.  There are diffuse ecchymotic areas throughout the torso and lower extremities, with areas of bullae and vesicle formation.  There is no rash on the palms or soles.  There are no meningeal signs.
Laboratory results as follows:

Chest x-ray reveals bilateral pulmonary infiltrates.
Which of the following antibiotics would be most effective at targeting the suspected pathogen?

Accepted Answer

11ec193a_9641_b9af_853d_45d4083b9b2c_MD0002_00 This patient has fever, hypotension, altered mental status, and rash (very likely purpura fulminans). She likely has a history of splenectomy (left upper quadrant surgical scar), which increases her risk for an encapsulated organism (eg, Neisseria meningitidis, Streptococcus pneumoniae, or Haemophilus influenzae). Her presentation and rapid deterioration with severe sepsis and DIC make meningococcemia from N meningitidis the most likely diagnosis. N meningitidis is the second most common cause of adult bacterial meningitis in the world and is transmitted via the respiratory route through pharyngeal secretions. Patients may present with fever, severe myalgias (often misdiagnosed early as viral influenza), or severe sepsis without focal signs of meningitis (summarized in the table). Nearly 25% of patients may present with purpura fulminans due to circulating bacterial endotoxin causing cutaneous hemorrhage, progressive skin and soft-tissue necrosis, and subsequent DIC. Early empiric broad-spectrum antibiotics, aggressive fluids, oxygen, and vasopressor support should be initiated immediately. Third-generation cephalosporins (eg, ceftriaxone or cefotaxime) are the most appropriate therapy for N meningitidis, but vancomycin is also added to cover for possible pneumococcal infection until final culture results are available. (Choice A) Ampicillin is effective for suspected Listeria meningitis, which is seen more commonly in neonates, adults > age 50, and immunocompromised patients. (Choice C) Clindamycin is used to treat streptococcal toxic shock syndrome (TSS), which usually presents with extremity or soft-tissue pain followed by ecchymoses, skin sloughing, and necrotizing myositis/fascitis. Although TSS can present with fever and altered mental status, it does not usually have the petechial rash seen in this patient. Clindamycin also does not have activity against Neisseria species. (Choice D) Doxycycline is used to treat Rocky Mountain spotted fever, in which rash usually does not appear until the third to fifth day after onset of fever. The rash starts around the ankles and wrists, involves the palms and soles, and is usually petechial. This patient's rash started abruptly along with the fever, has evolved into bullae, and is not present on the palms and soles. (Choice E) Vancomycin is added to a third-generation cephalosporin for the treatment of bacterial meningitis to include coverage for possible penicillin-resistant pneumococcus. However, it is not effective against N meningitidis and should not be used as monotherapy. Educational objective: Patients with history of splenectomy are susceptible to severe infections from encapsulated bacteria (eg, N meningitidis). Meningococcemia may present with fever, myalgias, purpura fulminans, meningitis, DIC, and shock (with or without adrenal insufficiency). Treatment includes third-generation cephalosporins (eg, ceftriaxone or cefotaxime) and vancomycin. Close respiratory contacts of affected individuals require prophylaxis with rifampin, ciprofloxacin, or ceftriaxone. __________ References: Purpura fulminans in sepsis. (http://www.ncbi.nlm.nih.gov/pubmed/17170624) Meningococcemia. (http://www.ncbi.nlm.nih.gov/pubmed/8958165)

Question 10

A 24-year-old man comes to the emergency department after 1 week of fever, chills, and headache.  He also complains of nausea and an episode of vomiting.  He has no abdominal pain or diarrhea.  Three weeks ago, he returned from travelling in southern Africa, where he volunteered at a medical clinic in rural Malawi for 3 months.  He took doxycycline for the entire trip until returning to the United States.  He drank mostly bottled water but did eat local cooked food.  He had no sexual activity, injected drug use, or freshwater exposure during his travels.
His temperature is 39.4 C (103 F), blood pressure is 120/76 mm Hg, pulse is 106/min, and respirations are 18/min.  He is uncomfortable but nontoxic-appearing.  There is no skin rash.  Pupils are equal, round, and reactive and there is mild scleral icterus but no conjunctival lesions or suffusion.  There is no neck stiffness or meningeal signs.  Abdominal examination reveals tenderness in the left upper quadrant and mild splenomegaly.
Laboratory results are as follows:

Which test is most likely to establish the diagnosis in this patient?

Accepted Answer

11ec193a_9644_2ab3_853d_1388a9a667f6_MD0002_00 This patient with recent travel to Sub-Saharan Africa has an acute-onset febrile illness, scleral icterus, mild splenomegaly, anemia, and thrombocytopenia. This presentation is most consistent with malaria. Plasmodium falciparum accounts for the majority of deaths from malaria, followed by Plasmodium vivax. Many of the clinical symptoms seen in malaria are due to the infected parasite-containing red blood cells adhering to nearby vessels, causing small infarcts, leakage of capillaries, and, ultimately, organ dysfunction. Diagnosis is confirmed with examination of a peripheral blood smear looking for trophozoites. peripheral blood smear Commonly used malaria prophylaxis drugs (eg, chloroquine, mefloquine, and doxycycline) target the blood stage of the parasite (blood schizonticides) when released from the liver. Tissue schizonticides (eg, atovaquone/proguanil) are designed to target the liver stage, where the parasites grow and can stay dormant in the liver (or other tissues). The blood schizonticides must be continued for at least 4 weeks after leaving an endemic area to ensure eradication of parasites released from the liver. This patient did take doxycycline for malaria prophylaxis but discontinued his medication on return to the United States, causing it to be ineffective. (Choice A) Blood culture is of limited utility in the diagnosis of malaria as the organism cannot be cultured in traditional media. For bacterial infections such as salmonellosis (typhoid fever), fungal infection, and meningococcemia, blood cultures would be an appropriate diagnostic test. (Choice B) In the absence of meningeal signs (eg, neck stiffness and rash) lumbar puncture is less helpful. (Choice D) Acute viral hepatitis can cause jaundice and right upper-quadrant pain but would not result in anemia and splenomegaly. (Choice E) Stool sample for ova and parasites would be helpful for infections such as schistosomiasis, but this patient did not drink fresh water or swim during his travels. The lack of eosinophilia argues against this testing. Educational objective: Malaria should be considered in a traveler returning from an endemic area who has acute febrile illness, anemia, splenomegaly, and jaundice. Persons who have received inadequate prophylaxis are at risk. Identification of the parasite on peripheral blood smear can establish the diagnosis. __________ References: Spectrum of disease and relation to place of exposure among ill returned travelers. (http://www.ncbi.nlm.nih.gov/pubmed/16407507) Imported malaria. clinical presentation and examination of symptomatic travelers. (http://www.ncbi.nlm.nih.gov/pubmed/7717795) Fever after a stay in the tropics. diagnostic predictors of the leading tropical conditions. (http://www.ncbi.nlm.nih.gov/pubmed/17220752)

Question 11

A 72-year-old woman comes to the emergency department for a rash on her forehead.  The rash has been present for 3 days and is getting worse.  She also complains of moderate frontal headache, malaise, and fever.  The patient has no neck pain, nausea, or vomiting.  She has not had similar symptoms before.  She is otherwise healthy and takes no medications.
Her temperature is 38.5 C (101.3 F).  Her forehead is shown in the photograph below.

In addition to admission to the hospital and intravenous acyclovir, which of the following is the best next step in management of this patient?

Accepted Answer

This patient presents with headache, malaise, fever, and a skin rash, all highly suggestive of herpes zoster. The vesicular, crusty skin eruption on her forehead also involves the eyelids, with evidence of edema and drooping. She is at risk of developing herpes zoster ophthalmicus (HZO). HZO is a serious, vision-threatening complication of reactivation of varicella zoster virus in the trigeminal nerve root ganglion. Some patients present with headache, malaise, eye pain, and fever before developing a rash on the face. Once the rash develops, patients can also have conjunctivitis, keratitis, or episcleritis. Vesicles near the nose are also associated with a high risk of HZO. Patients at risk for herpes zoster ophthalmicus require an urgent ophthalmology consultation. Immunocompromised patients with sight-threatening ophthalmicus should receive intravenous acyclovir. When urgent evaluation by an ophthalmologist is not available, topical steroid eye drops can be used to decrease the inflammatory response. (Choices A & E) Gabapentin and topical capsaicin can provide relief from pain of post-herpetic neuralgia, defined as persistent pain after resolution of the initial rash. However, these agents are not helpful for pain from acute neuritis. (Choice B) The risk of aseptic meningitis is higher in immunocompromised than immunocompetent (0.5%) individuals. This patient has no meningeal signs or risk factors for immunosuppression; hence, a lumbar puncture is not needed at this time. (Choice D) Systemic glucocorticoids, when used in combination with antiviral therapy for treatment of herpes zoster, can increase the risk of secondary bacterial skin infections. They are not recommended in this patient. Educational objective: Herpes zoster ophthalmicus is a serious, vision-threatening complication of latent varicella zoster virus infection. Treatment consists of intravenous acyclovir and urgent ophthalmologic evaluation. __________ References: Herpes zoster ophthalmicus complicated by ipsilateral isolated Bell's palsy: a case report and review of the literature. (http://www.ncbi.nlm.nih.gov/pubmed/22883841)

Question 12

A 24-year-old man comes to the emergency department in January due to fever and shortness of breath. A week ago, he developed fever, malaise, muscle aches, and rhinorrhea. The symptoms largely resolved 2 days ago, but this morning the patient began having productive cough of green-yellow sputum, shortness of breath, and pleuritic chest pain. He has had no recent travel or other significant illness. The patient has not received the influenza vaccine. He has a history of type 1 diabetes mellitus and takes insulin. Temperature is 39.1 C (102.4 F), blood pressure is 135/67 mm Hg, pulse is 104/min, and respirations are 22/min. Pulse oximetry shows 90% on room air. The patient is ill-appearing and in mild respiratory distress. He coughs frequently during the examination. Lung examination shows bronchial breath sounds and crackles in the right lower lung field. Leukocyte count is 14,000/mm³ with 82% neutrophils. Chest x-ray shows a dense right lower-lobe consolidation with a small area of lucency and small right-sided pleural effusion. Rapid influenza test is positive. Which of the following empiric treatments is most appropriate for this patient?

Accepted Answer

This young patient had influenza symptoms, transiently improved, and then developed worsened fever and lower respiratory manifestations (productive cough, pleurisy, dyspnea), raising strong suspicion for influenza complicated by secondary bacterial pneumonia. Streptococcus pneumoniae and Staphylococcus aureus are the leading pathogens; Haemophilus influenzae is sometimes isolated. Most cases occur in patients age >65 or those with certain underlying conditions. Young, previously healthy patients can also be affected; these cases are often linked to community-acquired methicillin-resistant Staphylococcus aureus (MRSA). underlying conditions The empiric treatment of post-influenza pneumonia should include: Typical community-acquired pneumonia coverage (eg, ceftriaxone and azithromycin)MRSA coverage (eg, vancomycin)Antiviral treatment (eg, oseltamivir) - patients who develop influenza complications such as secondary pneumonia are typically treated with antivirals even if they present >48 hours after influenza symptom onset Typical community-acquired pneumonia coverage (eg, ceftriaxone and azithromycin) MRSA coverage (eg, vancomycin) Antiviral treatment (eg, oseltamivir) - patients who develop influenza complications such as secondary pneumonia are typically treated with antivirals even if they present >48 hours after influenza symptom onset (Choice A) Primary tuberculosis typically presents with the gradual onset of fever and pleuritic chest pain, sometimes with fatigue, cough, or arthralgias. Chest x-ray usually shows hilar adenopathy without the dense consolidation seen in this patient. (Choice B) Community-acquired MRSA is a common cause of secondary bacterial pneumonia following influenza infection and must be covered empirically with vancomycin. If cultures or Gram stain reveal that MRSA is unlikely, vancomycin can be discontinued. (Choice C) Piperacillin/tazobactam is typically added for anti-pseudomonal coverage in hospital-acquired pneumonia. This patient has no risk factors for pseudomonal pneumonia (eg, prior hospitalization, immunocompromised status, cirrhosis, recent antibiotic or glucocorticoid use) and should receive vancomycin plus community-acquired pneumonia treatment. (Choice E) Patients with uncomplicated influenza who have had >48 hours of symptoms are generally managed with supportive care. Supportive care would be insufficient for this patient with pneumonia (fever, productive cough, leukocytosis, pulmonary infiltrate). Educational objective: Secondary bacterial pneumonia is typically characterized by a transient improvement of influenza symptoms followed by worsened fever and lower respiratory tract illness. Most cases are caused by Streptococcus pneumoniae, but methicillin-resistant Staphylococcus aureus (MRSA) is also a frequent culprit, particularly in young, previously healthy patients. Empiric treatment should include coverage for community-acquired pneumonia (eg, ceftriaxone and azithromycin) and for MRSA (eg, vancomycin). __________ References: Bacterial coinfection in influenza: a grand rounds review. (http://www.ncbi.nlm.nih.gov/pubmed/23321766) Staphylococcus aureus community-acquired pneumonia during the 2006 to 2007 influenza season. (http://www.ncbi.nlm.nih.gov/pubmed/18534715)

Question 13

A 51-year-old woman comes to the emergency department due to fever and generalized weakness.  She was diagnosed with metastatic ovarian cancer 3 months ago and is on systemic chemotherapy after undergoing cytoreduction surgery.  Cycle 2 of chemotherapy was completed 10 days ago.  The patient initially had nausea and vomiting but was feeling better the last few days.  However, yesterday afternoon she became quite fatigued, and this morning she had a temperature of 39.1 C (102.4 F).  Her oncologist recommended a visit to the emergency department for evaluation.  The patient has had no sore throat, sinus pain, cough, shortness of breath, chest pain, diarrhea, or urinary symptoms.  She has no other chronic medical problems but had prolonged neutropenia after her first cycle of chemotherapy.  She does not use tobacco or alcohol and has no known drug allergies.
Temperature is 38.6 C (101.5 F), blood pressure is 110/70 mm Hg, pulse is 112/min and regular, and respirations are 20/min.  Pulse oximetry shows 96% on room air.  The patient is alert and cooperative.  No lymphadenopathy is present.  There is no skin rash or erythema or tenderness around the subcutaneous venous access device.  Lungs are clear to auscultation, and no heart murmurs are present.  The abdomen is soft and nontender.  Neurologic examination shows no abnormalities.
Laboratory results are as follows:
 Chest-x ray reveals no new parenchymal opacities or pleural effusion.  Urinalysis reveals no pyuria.  Two sets of blood cultures are drawn and intravenous fluids are administered.
Which of the following is the best initial treatment for this patient?

Accepted Answer

11ec193a_9636_bd28_853d_6dcf91260b98_MD0002_00 This patient with ovarian cancer who recently received chemotherapy has febrile neutropenia, which is generally defined as a temperature >38.3 C (>101 F) and an absolute neutrophil count <500/mm³. Most cases are due to gram-positive pathogens such as Staphylococcus epidermidis (most common), Staphylococcus aureus, and streptococci, but gram-negative bacteria (eg, Pseudomonas) are isolated in approximately 25% of cases and are often associated with more severe illness. ³ Monotherapy with an anti-pseudomonal beta-lactam (eg, piperacillin-tazobactam, cefepime) or a carbapenem is considered first-line treatment in the inpatient setting. Studies have shown no improvement in mortality with the routine addition of a second agent (eg, vancomycin) targeting gram-positive pathogens (Choice A). Indications for vancomycin include: Hemodynamic instabilitySevere sepsisPneumoniaPositive blood cultures for a gram-positive organism (prior to speciation results)Suspected catheter-related infection (eg, chills during infusion, cellulitis around entry site)Skin or soft-tissue infection Hemodynamic instability Severe sepsis Pneumonia Positive blood cultures for a gram-positive organism (prior to speciation results) Suspected catheter-related infection (eg, chills during infusion, cellulitis around entry site) Skin or soft-tissue infection (Choice B) Ceftazidime plus ciprofloxacin are sometimes used in combination to double cover potential Pseudomonas infections. However, Pseudomonas double coverage is controversial and typically reserved for those who are severely ill (eg, patients with sepsis/septic shock, burn patients with severe infection) and at high risk for multidrug-resistant infections. Ceftazidime monotherapy should be avoided in neutropenic fever due to rising resistance in gram-negative bacteria and limited activity against gram-positive organisms (eg, viridans streptococci). Adding ciprofloxacin may improve gram-negative coverage but would not provide better gram-positive coverage. (Choice D) Empiric antifungal treatment for febrile neutropenia is generally reserved for patients who have been febrile >4-7 days, those who are undergoing intensive induction chemotherapy for acute leukemia, or those who have recently undergone hematopoietic stem cell transplantation. (Choice E) Trimethoprim-sulfamethoxazole can be used to treat urinary tract and skin/soft-tissue infections but is not a mainstay antibiotic for febrile neutropenia. Low-risk febrile neutropenia can be treated with oral ciprofloxacin and amoxicillin-clavulanate. Educational objective: Hospitalized patients with neutropenic fever should generally receive monotherapy with an anti-pseudomonal beta-lactam (eg, piperacillin-tazobactam) or a carbapenem. The routine addition of a second agent (eg, vancomycin) targeting gram-positive pathogens is not recommended. __________ References: Use of empiric antimicrobial therapy in neutropenic fever. Australian Consensus Guidelines 2011 Steering Committee. (http://www.ncbi.nlm.nih.gov/pubmed/21272173) Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 update by the Infectious Diseases Society of America. (http://www.ncbi.nlm.nih.gov/pubmed/21258094)

Question 14

A 48-year-old man comes to the emergency department with a 4-day history of shortness of breath and fever.  He is a chronic injection drug user.  He has a history of a rash secondary to penicillin but has been treated previously for skin abscesses with cephalexin.
His temperature is 38.5 C (101.4 F).  Cardiac examination reveals a faint diastolic murmur at the left sternal border.  Skin examination shows needle track marks on both arms.
All 4 bottles of blood cultures obtained on admission grow Staphylococcus aureus (methicillin-susceptible).  Intravenous cefazolin is initiated.  A transthoracic echocardiogram reveals a 0.9 cm aortic valve vegetation with mild aortic regurgitation and normal left ventricular ejection fraction.  On the third day of hospitalization, he is intermittently febrile and develops respiratory failure.  Endotracheal intubation and mechanical ventilation is initiated.  Chest x-ray reveals bilateral alveolar opacities consistent with pulmonary edema.
Which of the following is the best next step in the management of this patient?

Accepted Answer

11ec193a_9649_5adc_853d_a33656014c6b_MD0002_00 This patient with aortic valve endocarditis was initially appropriately treated with intravenous antibiotics. However, his sudden clinical deterioration with respiratory failure and pulmonary edema suggests a mechanical complication of endocarditis. The most common cause of acute congestive heart failure (CHF) in patients with infective endocarditis is valvular insufficiency, either due to valve leaflet perforation or worsening regurgitation. The best next step for evaluation is a transesophageal echocardiogram (TEE). TEE is superior to TTE (transthoracic echocardiogram) for detecting complications such as leaflet perforation, aneurysm formation, and secondary infection of other valve structures. Refractory CHF due to mitral or aortic valvular insufficiency from an infected valve is an indication for surgery. (Choice A) Early CHF in a patient with endocarditis is not an indication of microbiologic treatment failure. Moreover, addition of gentamicin is not recommended for the treatment of native valve endocarditis as the risk of nephrotoxicity outweighs the potential benefit. (Choice B) Rifampin is used as an essential component of the antibiotic regimen for treatment of staphylococcal prosthetic valve endocarditis. However, it is not recommended for native valve endocarditis. (Choice C) Vancomycin is recommended for the treatment of methicillin-resistant Staphylococcus endocarditis. However, this patient has a methicillin-susceptible Staphylococcus aureus strain and switching antibiotics is not indicated. (Choice D) A CT scan of the chest will likely reveal bilateral pulmonary edema as seen on the chest x-ray, but would not show valvular pathology and is unlikely to add additional diagnostic information. TEE is more appropriate for definitive diagnosis in this setting. Educational objective: Transesophageal echocardiogram is highly sensitive for the diagnosis of infective endocarditis and its complications; it should be obtained early in patients with suspected complications or sudden clinical deterioration. __________ References: The importance of secondary mitral valve involvement in primary aortic valve endocarditis; the mitral kissing vegetation. (http://www.ncbi.nlm.nih.gov/pubmed/11741365) The diagnostic utility of transthoracic echocardiography for the diagnosis of infective endocarditis in the real world of the Italian Registry on Infective Endocarditis. (http://www.ncbi.nlm.nih.gov/pubmed/23489364)

Question 15

A 24-year-old woman comes to the emergency department with a cat bite.  There was blood at the puncture site, which she rapidly cleaned with water.  The cat demonstrated no abnormal behavior.  The patient has no significant past medical history and received a tetanus booster 4 years ago.  She developed hives after receiving penicillin 5 years ago but has since tolerated cephalosporins without allergic reaction.  She takes no medications.
She is afebrile, her vital signs are normal, and she has no rash.  There is a clean-appearing puncture wound on the medial left hand with mild swelling and surrounding erythema.  There is no tenderness over the surrounding bone.  The wound is cleaned.
Which of the following is the best next step in managing this patient?

Accepted Answer

11ec193a_963a_b4c9_853d_b79efe4954e8_MD0002_00 This patient presents with a cat bite resulting in a deep puncture wound to the hand. Cat bites can be quite deep. Although cat saliva contains multiple different bacteria (eg, Streptococcus and anaerobic bacteria), Pasturella multocida is found in nearly 50% of cat bites. These infections, particularly when located on extremities, can progress to bone and/or joint infections. Antibiotic prophylaxis can reduce infection rates and is recommended for animal bite wounds near lymphatics and blood vessels, on the hand, close to joints and/or bones, requiring surgical intervention, and in immunocompromised hosts. Amoxicillin/clavulanate is preferred for prophylaxis and doxycycline/metronidazole is recommended in patients with penicillin allergy. Doxycycline or TMP-SMX-based regimens also are used to treat MRSA infections in high-risk patients. Antibiotics ineffective against P multocida include first-generation cephalosporins (cephalexin), penicillinase-resistant penicillins (dicloxacillin), and macrolides (erythromycin) (Choice A). Wounds should be irrigated with debris removal and should be left open to heal by secondary intention rather than primary closure (Choice C). Careful follow-up is warranted to assess for deeper infection that may require extended antibiotic therapy. Primary closure may be done at that time if there are no signs of infection. Nonhealing wounds will likely require surgical debridement. Patients should also receive tetanus booster if indicated and be considered for rabies vaccine. (Choice D) Tetanus immunoglobulin is recommended for patients with high-risk bites who have not been recently immunized against tetanus (< 5 years). < (Choice E) Wound culture following animal bites has not been demonstrated to be clinically useful. Some organisms, including P multocida, are fastidious and difficult to grow in culture. Educational objective: Prophylactic antibiotics are warranted following a cat bite with deep injury. Antibiotic coverage should include an agent that treats Pasturella multocida. Amoxicillin/clavulanate is preferred as first-line therapy, and doxycycline/metronidazole is used in patients with penicillin allergy. Many physicians give the first dose intravenously followed by oral medications for 3-5 days. __________ References: Bite wounds and infection. (http://www.ncbi.nlm.nih.gov/pubmed/1562653) Dog, cat and human bites: a review. (http://www.ncbi.nlm.nih.gov/pubmed/7490347) Management of cat and dog bites. (http://www.ncbi.nlm.nih.gov/pubmed/7625323)

Question 16

A 20-year-old college student is brought to the emergency department due to progressive lethargy and confusion.  He is obtunded and unable to answer questions, but his friend says the patient has had shaking chills and diarrhea since last night.  He has no prior medical problems other than a nasal fracture following a bar fight 3 days ago, which was reduced and stabilized with nasal packing at another hospital.  The patient takes no medications and has no known drug allergies.  He lives in a dormitory and recently returned from a hiking trip in North Carolina.
Temperature is 39.4 C (103 F), blood pressure is 84/42 mm Hg, pulse is 126/min, and respirations are 18/min.  Examination shows an ill-appearing man.  Pupils are equal, round, and reactive.  Anterior packing is present in the left nostril.  There is diffuse erythema of the mucous membranes and skin, including the palms and soles.  Mild pitting edema is present in both legs.
Laboratory results are as follows:
 CT scan of the head reveals no abnormalities.  Venous access is established, and intravenous fluids are administered.
Which of the following is the most appropriate antimicrobial therapy for this patient?

Accepted Answer

11ec193a_963d_25cb_853d_970d494067cc_MD0002_00 This patient who had nasal packing 3 days ago now has manifestations of toxic shock syndrome (TSS). TSS is usually caused by a powerful Staphylococcus aureus exotoxin, which acts as a superantigen and results in the widespread activation of T cells, leading to a massive inflammatory response. Most cases are associated with menstrual tampons, nasal packing, or surgical/postpartum wound infections. Staphylococcal TSS is marked by rapid-onset fever (>38.9 C [102 F]), hypotension, diffuse erythroderma, desquamating rash, and multiorgan failure. Encephalopathy can occur secondary to cerebral edema. S aureus can usually be isolated from the infection source, but blood cultures are rarely (<5%) positive. Management is focused on supportive therapy, removal of the foreign material (eg, nasal packing, tampon) or surgery (eg, wound infections), and the initiation of antistaphylococcal antibiotics. Clindamycin and vancomycin are used most commonly; clindamycin is highly effective at inhibiting toxin production. Eradication of S aureus from the nares with mupirocin may be considered after recovery. TSS can also be caused by group A streptococcus, but patients typically have a painful skin infection and are less likely to develop erythroderma. (Choice A) Meningococcemia can cause rapid-onset fever, altered mental status, hypotension, and rash. However, petechial rash (not erythroderma) is the norm, and patients also frequently have myalgias, meningeal signs, and headache. Suspected cases are usually treated empirically with ceftriaxone and vancomycin. (Choice B) Rocky Mountain spotted fever is a tick-borne illness that usually begins with nonspecific systemic symptoms followed 3-5 days later by a maculopapular/petechial rash (starts on ankles/wrists and spreads centrally and to the palms/soles). Early treatment with doxycycline is required to prevent morbidity and death. (Choice C) Secondary syphilis is treated with penicillin G. Although secondary syphilis can cause a diffuse maculopapular rash, it is unlikely to cause rapid decompensation with hypotension. (Choice D) Vancomycin and cefepime would be indicated if this patient suffered a basal skull fracture during his fight and developed meningitis. Although he does have high fever and altered mental status, the presence of nasal packing, erythroderma, and multiorgan failure makes TSS more likely. Educational objective: Staphylococcal toxic shock syndrome (TSS) must be considered in patients with abrupt onset of fever, hypotension, and diffuse erythroderma. Most cases occur in the setting of menstrual tampons, nasal packing, or surgical/postpartum wound infections. Treatment involves supportive care, removing the foreign material (or surgery), and broad-spectrum antistaphylococcal antibiotics (eg, clindamycin and vancomycin). __________ References: Gram-positive toxic shock syndromes. (http://www.ncbi.nlm.nih.gov/pubmed/19393958) Staphylococcal toxic shock syndrome 2000-2006: epidemiology, clinical features, and molecular characteristics. (http://www.ncbi.nlm.nih.gov/pubmed/21860665)

Question 17

A 23-year-old woman is brought to the emergency department with fever, rash, and decreased level of consciousness.  She is accompanied by her boyfriend.  Throughout the morning, she became increasingly confused and eventually unarousable, prompting him to call an ambulance.  He does not know of any specific medical problems but reports that the patient had abdominal surgery after a bad automobile accident.  After initial evaluation, lumbar puncture is performed and empiric antibiotic therapy is started.  Cerebral spinal fluid shows Gram-negative diplococci.  The patient is transferred to the intensive care unit.
Which of the following is the best initial choice for infectious precaution measures?

Accepted Answer

11ec193a_9644_c6f4_853d_73da2c28c147_MD0002_00 Meningococcal infection should be suspected in a young patient who presents with fever, rash, decreased level of consciousness, and Gram-negative diplococci in the spinal fluid. A history of abdominal surgery and possible splenectomy also increases the risk of meningococcal disease. Droplet precautions and antibiotic chemoprophylaxis should be instituted for those in close contact with the patient (eg, family members, healthcare workers). Droplet precautions should be in effect for the first 24 hours of antimicrobial therapy and involve wearing a facemask if within 6-10 feet of the patient. Use of a higher-level respirator mask or closing the door of the patient's room is not necessary. Rifampin, ciprofloxacin, and ceftriaxone are the recommended antibiotic chemoprophylaxis drugs for persons at risk. persons at risk (Choices A, B, and D) Neisseria meningitidis is transmitted via droplets. Unlike infectious agents transmitted in an airborne mode, it usually does not spread more than 3 feet. Educational objective: For patients with meningococcal infection, droplet precautions should be in effect for the first 24 hours of antimicrobial therapy and involve wearing a facemask if within 6-10 feet of the patient. Rifampin, ciprofloxacin, and ceftriaxone are recommended antibiotic chemoprophylaxis drugs for persons at risk. __________ References: Prevention and control of meningococcal disease. recommendations of the Advisory Committee on Immunization Practices (ACIP). (http://www.ncbi.nlm.nih.gov/pubmed/15917737)

Question 18

A previously healthy 24-year-old woman comes to the emergency department because of fever, chills, and severe throat pain for the last 2 days.  She reports having a sore throat 1 week prior, which did not resolve with amoxicillin therapy.  She takes no other medications and denies any recent travel or illicit drug use.
Her temperature is 39.4 C (103 F), blood pressure is 90/62 mm Hg, pulse is 114/min, and respirations are 18/min.  There is no skin rash.  Oral examination reveals moist mucus membranes, erythema involving the oropharynx, and tonsillar enlargement without exudates.  The right side of her neck is swollen and tender.  There are no heart murmurs.  There is no hepatomegaly or splenomegaly.
Laboratory results are as follows:

Chest x-ray reveals two round opacities in the right upper lung.
Which of the following is the most likely cause of this patient's current condition?

Accepted Answer

11ec193a_9634_4c26_853d_d72fe2fe38a8_MD0002_00 This patient's clinical presentation is suggestive of septic thrombophlebitis involving the internal jugular vein (Lemierre's syndrome). Infection is usually caused by the anaerobic bacterium Fusobacterium necrophorum. Previously healthy young adults are most commonly affected, and present with pharyngitis or dental infection. The infection may improve spontaneously, extend to the lateral pharyngeal space, or involve the carotid sheath (e.g., internal jugular vein, internal carotid artery, vagus nerve) to produce a sepsis syndrome with a high mortality rate. The condition should be suspected in patients with a recent history of pharyngitis who develop neck pain, neck swelling, and persistent fever despite appropriate oral antibiotic therapy. Septic pulmonary emboli and other embolic phenomenon (e.g., arthritis, osteomyelitis) are common. Diagnosis is suggested by radiographic imaging showing internal jugular vein thrombophlebitis and is confirmed with blood or tissue cultures growing the causative oropharyngeal pathogen. Treatment usually involves 4 weeks of antibiotics that have anaerobic coverage, such as beta-lactams with beta-lactamase inhibitors (e.g., ampicillin-sulbactam), clindamycin, or carbapenems. (Choice B) Corynebacterium diphtheria infection usually presents with a sore throat with gray and white tonsillar exudates (pseudomembrane), cervical lymphadenopathy, fever, and sometimes cutaneous ulcers. The infection can extend into the neck and respiratory tract to cause respiratory distress. However, septic emboli are not seen. (Choice C) Infectious mononucleosis usually presents as a systemic illness with fever, fatigue, sore throat with tonsillar exudates, splenomegaly, and posterior cervical lymphadenopathy. This patient's lack of splenomegaly and presence of septic emboli make this diagnosis less likely. (Choice D) MRSA can cause skin infections and pneumonia, but it is a less common cause of pharyngitis. (Choice E) Mycobacterial infection can cause cervical lymphadenitis with neck swelling, but it is usually more gradual in onset without the sudden appearance of systemic symptoms as seen in this patient. Educational objective: Septic thrombophlebitis of the internal jugular vein should be suspected in patients with a recent history of pharyngitis who develop neck pain, neck swelling, persistent fever despite antibiotic therapy, and cavitary lung lesions. Infection is usually due to the anaerobic organism Fusobacterium necrophorum. Treatment involves 4 weeks of antibiotics with anaerobic coverage. __________ References: Lemierre's Syndrome (http://www.ncbi.nlm.nih.gov/pubmed/15192164)

Question 19

A 43-year-old man with a history of active intravenous drug use comes to the emergency department with 2 weeks of malaise, dry cough, and increasing dyspnea on exertion. He admits to anorexia and a 5-kg (11-lb) weight loss over the past 3 weeks. About 2 hours ago, he felt sudden, sharp, right-sided chest pain and became acutely dyspneic. Pulse oximetry on ambulance arrival showed 80% on room air. The patient was started on 5 L O₂/min with notable improvement of saturation. He has known HIV and chronic hepatitis C infections but is not receiving any therapy. He smokes a pack of cigarettes daily and last sniffed heroin this morning. His temperature is 37.2 C (99 F), blood pressure is 136/88 mm Hg, pulse is 102/min, and respirations are 18/min. Pulse oximetry shows 94% on 4 L O₂/min. Examination shows a cachectic man in mild respiratory distress. The lymph nodes are not enlarged. There is a faint systolic murmur at the left sternal border and tachycardia. Decreased breath sounds are heard on the right with clear lungs on the left. There is hyperresonance to percussion on the right side of the chest. There is no peripheral edema or skin rashes. Laboratory results are as follows: Arterial blood gas analysis shows pH of 7.48, PCO₂ of 31 mm Hg, and PO₂ of 71 mm Hg. Chest x-ray shows a 30% right-sided pneumothorax with bibasilar reticular opacities and a thin-walled cavitary lesion in the left upper lung field. Which of the following is the most likely diagnosis?

Accepted Answer

This patient with HIV likely has Pneumocystis jirovecii pneumonia (PCP) complicated by pneumothorax. A subacute course with dyspnea, dry cough, and fever is classic for PCP. Other symptoms include chest pain, malaise, weight loss, headache, night sweats, chills, and fatigue. Of AIDS patients with PCP, 6%-7% may be asymptomatic. Lack of fever (as in this patient) does not exclude PCP, although it does make a bacterial or mycobacterial source less likely. Nearly 90% of patients have lactate dehydrogenase (LDH) levels >50 U/L above baseline; an LDH >450 U/L is predictive of PCP rather than another pulmonary process. Arterial blood gas analysis usually shows hypoxemia, an increased alveolar-arterial oxygen gradient, and respiratory alkalosis. The most commonly described radiographic appearance in PCP is interstitial infiltrates (unilateral, bilateral, or diffuse), although a normal chest x-ray can be seen. Thin-walled cavitary lesions may be present. Spontaneous pneumothorax develops in approximately 5% of PCP patients. Pneumothorax is thought to develop primarily in the setting of rupture of cystic lesions that may be present in active disease or remaining from an earlier infection. (Choices A and E) Many of this patient's symptoms are also features of mycobacterial infection. However, the constellation of pneumothorax, LDH >450 U/L, relatively short duration of symptoms, lack of documented fevers, and thin-walled cavity on radiograph makes PCP more likely. (Choice C) Chronic necrotizing pulmonary aspergillosis is a subacute infection most commonly seen in patients with altered local defenses from pre-existing pulmonary disease or those with risk factors that alter systemic immune status. This infection is less likely given the lack of "fungus ball" appearance on chest x-ray and the likely only mild pre-existing pulmonary disease. (Choice D) Staphylococcal lung abscess can be seen in patients with septic emboli from endocarditis. This patient has a pneumothorax and not the multiple thick-walled cavities typical of septic emboli; he also has no fever or elevated white blood cell count. Educational objective: Nearly 90% of patients with Pneumocystis jirovecii pneumonia (PCP) will have lactic acid dehydrogenase levels >50 U/L above baseline; a level >450 U/L is predictive of PCP rather than another pulmonary process. The most commonly described radiographic appearance in PCP is diffuse interstitial infiltrates. Spontaneous pneumothorax develops in approximately 5% of patients. __________ References: HIV-associated opportunistic pneumonias. (http://www.ncbi.nlm.nih.gov/pubmed/19645867) HIV-associated Pneumocystis pneumonia. (http://www.ncbi.nlm.nih.gov/pubmed/21653531)

Question 20

A 68-year-old man is brought to the emergency department due to lethargy and fever.  He called his daughter this morning and told her that he had been having fever, chills, and headache.  When she visited him a few hours later, he was warm to the touch and lethargic and soon had a tonic-clonic seizure.  The patient is a widower who lives independently and is in excellent health.  He has no history of previous seizure and has not recently traveled.  He does not use alcohol or tobacco and has no allergies.
Temperature is 39.4 C (103 F), blood pressure is 80/50 mm Hg, pulse is 98/min, and respirations are 20/min.  Pulse oximetry shows 96% on room air.  The patient is lethargic and oriented only to person.  He responds intermittently to questions but moves all 4 extremities on command.  Moderate neck pain and stiffness are present.  Deep-tendon reflexes are symmetric.  No genital lesions are noted.
Laboratory workup is obtained and head CT scan and lumbar puncture are planned.
Which of the following is the best next step in management of this patient?

Accepted Answer

11ec193a_9646_c2c8_853d_d392990e9779_MD0002_00 This older patient has all 3 classic manifestations (high fever, neck stiffness, altered mental state) of acute bacterial meningitis. Most cases are due to Streptococcus pneumoniae (~70%), but Neisseria meningitidis, group B streptococci, Haemophilus influenzae, and Listeria monocytogenes (in those age >50) are also common culprits. The underlying organism is typically identified by blood and/or cerebrospinal fluid (CSF) cultures. Patients with suspected acute bacterial meningitis require urgent empiric treatment to limit neurologic sequelae and reduce the risk of death. First-line antibiotic therapy includes ceftriaxone, vancomycin, and ampicillin (added for those age >50 to empirically cover L monocytogenes). In addition, dexamethasone is given just prior to or with the first dose of empiric antibiotics to reduce neurologic sequelae (eg, hearing loss) and mortality in those with pneumococcal meningitis; it should be discontinued if CSF gram stain or culture (or blood culture) indicates infection with a nonpneumococcal organism. Most patients are initiated on treatment after blood cultures and lumbar puncture. However, those who require a head CT scan prior to lumbar puncture (eg, altered mental state, new seizure, focal deficit, immunocompromise, central nervous system disease, papilledema) should first receive empiric therapy to limit treatment delays. (Choice A) Acyclovir is used to treat herpes encephalitis, which commonly presents with high fever, altered mental status, seizure, and/or focal neurologic deficits but is rarely associated with neck stiffness or nuchal rigidity. Most (85%) cases of herpes meningitis are accompanied by genital lesions. Compared to bacterial meningitis, herpes central nervous system (CNS) infections are less likely to cause marked hypotension (as seen in this patient) in the absence of immunosuppression. Although patients undergoing empiric treatment for bacterial meningitis sometimes receive concurrent empiric acyclovir therapy until herpes CNS infection is ruled out, acyclovir would not be used alone. (Choices B and D) Cefepime or meropenem are used in place of ceftriaxone for the empiric treatment of bacterial meningitis when patients have underlying immunocompromise or health care-associated meningitis (eg, head trauma, recent neurosurgery) to cover for opportunistic bacterial pathogens such as Pseudomonas aeruginosa. This patient has no evidence of immunocompromise or risk for health care-associated meningitis. (Choice E) Because this patient is age >50, he requires ampicillin to cover for L monocytogenes. In addition, dexamethasone is required to reduce adverse outcomes in the setting of possible pneumococcal meningitis. Educational objective: Patients with suspected acute bacterial meningitis require urgent empiric treatment with ceftriaxone and vancomycin. Ampicillin should be added for those age >50 to empirically cover for Listeria monocytogenes. All patients should also receive adjunctive dexamethasone to reduce risk of neurologic sequelae and death from potential pneumococcal meningitis. __________ References: Delays in the administration of antibiotics are associated with mortality from adult bacterial meningitis. (http://www.ncbi.nlm.nih.gov/pubmed/15760921) Corticosteroids for acute adult bacterial meningitis. (http://www.ncbi.nlm.nih.gov/pubmed/19386456)

Exam 1: Emergency Department