Question 1

A 67-year-old man is brought to the emergency department by his wife due to progressive lethargy over the last 24 hours.  Before going to bed, he had a fever, chills, headache, and neck pain and was "feeling tired."  His wife had difficulty waking him up this morning.  The patient has had no sick contacts, recent travel, flu-like symptoms, or skin rashes.  He has a history of type 2 diabetes mellitus, hypertension, hyperlipidemia, and ischemic stroke with a complete recovery of neurologic deficits.  The patient takes aspirin, metformin, chlorthalidone, lisinopril, and atorvastatin.  He is a retired school teacher and has no history of tobacco, alcohol, or illicit drug use.
Temperature is 39.1 C (102.3 F), blood pressure is 140/90 mm Hg, pulse is 110/min, and respirations are 16/min.  Pulse oximetry shows an oxygen saturation of 97% on room air.  The patient is obtunded and does not follow commands but is able to localize to pain in the upper extremities and withdraw the lower extremities to noxious stimuli.  Physical examination is otherwise unremarkable.  Fingerstick glucose level is 190 mg/dL.  Blood cultures are drawn.
Which of the following is the best next step in immediate management of this patient?

Accepted Answer

This patient has high fever, neck pain, and altered mental status, the 3 classic manifestations of acute bacterial meningitis. Most cases are caused by Streptococcus pneumoniae, but Neisseria meningitis, group B streptococci, Haemophilus influenzae, and Listeria monocytogenes (in patients age >50) are also frequently isolated. Blood cultures and lumbar puncture (LP) are required for definitive diagnosis. Blood cultures successfully identify the underlying pathogen in 50%-90% of cases and should always be drawn prior to antimicrobials to maximize their yield. The timing of LP is more nuanced as patients with any of the following require a preceding noncontrast head CT scan: Altered mental status (as in this patient)Immunocompromised stateHistory of central nervous system diseaseNew-onset seizurePapilledemaFocal neurologic deficit Altered mental status (as in this patient) Immunocompromised state History of central nervous system disease New-onset seizure Papilledema Focal neurologic deficit Head CT scan often results in treatment delays of up to 6 hours, which can increase the risk of death and neurologic sequelae. As such, patients with suspected bacterial meningitis who require a head CT scan prior to LP should first receive empiric treatment with antibiotics and adjuvant dexamethasone (Choices D and E). Antimicrobial treatment prior to LP can reduce the yield of cerebrospinal fluid gram stain and culture, but most pathogens can still be successfully cultivated for 4-10 hours after antibiotic initiation. Patients who do not require a head CT scan prior to LP should undergo LP before the administration of antimicrobials. Most patients with suspected bacterial meningitis are also treated with empiric acyclovir to cover for possible herpes simplex encephalitis. (Choice A) Bedside electroencephalogram monitoring is often used to evaluate for nonconvulsive status epilepticus, which can occur in the setting of an infectious encephalopathy and lead to mental status changes. However, this patient should first receive empiric antibiotics; electroencephalogram can be considered if there is no mental status improvement. (Choice B) Brain MRI takes longer to perform than a head CT scan. Therefore, urgent noncontrast head CT scan is preferred in patients with acute mental status changes to rule out space-occupying lesions. Educational objective: Patients with suspected acute bacterial meningitis require early treatment with empiric antibiotics and dexamethasone to limit neurologic sequelae and death. Those who need a head CT scan (eg, altered mental state, focal neurologic deficit, immunocompromised state, new-onset seizure, papilledema, history of central nervous system disease) prior to lumbar puncture should first receive blood cultures, antibiotics, and dexamethasone. Patients who do not require a head CT scan should receive blood cultures and lumbar puncture prior to treatment. __________ References: Dexamethasone in adults with bacterial meningitis. (http://www.ncbi.nlm.nih.gov/pubmed/12432041) Bacterial meningitis: current therapy and possible future treatment options. (http://www.ncbi.nlm.nih.gov/pubmed/22029523) Practice guidelines for the management of bacterial meningitis. (http://www.ncbi.nlm.nih.gov/pubmed/15494903)

Question 2

A 42-year-old woman comes to the emergency department due to shortness of breath. Approximately 2 weeks ago, the patient developed shortness of breath on exertion that has become progressively worse. She also reports mild chest pain with deep inspiration. She has had no weight loss, fever, cough, or sputum production. Medical history includes diet-controlled type 2 diabetes mellitus and locally advanced infiltrating ductal carcinoma of the left breast, for which she underwent neoadjuvant chemotherapy followed by surgical resection and radiation approximately 2 years ago. The patient is a lifetime nonsmoker and has no significant second-hand tobacco exposure. She lives with her family and works as a teacher. Family history is notable for colon cancer in her father. Temperature is 37.6 C (99.7 F), blood pressure is 122/78 mm Hg, pulse is 92/min, and respirations are 20/min. Oxygen saturation is 92% on ambient air. Physical examination shows moist mucous membranes with no jugular venous distension or lymphadenopathy. Heart rate is regular with no murmurs or gallops. Auscultation reveals decreased breath sounds over the right lower lung with dullness to percussion. Extremities have no edema. The remainder of the examination is normal. Upright chest x-ray reveals the following: The patient undergoes thoracentesis. Pleural fluid analysis shows 3,500/mm³ nucleated cells, predominantly lymphocytes. Additional pleural fluid analysis results are as follows: Gram stain and culture of the pleural fluid are negative. What is the most appropriate next step in management of this patient?

Accepted Answer

This patient's exudative pleural effusion by Light criteria and history of recent breast cancer raise suspicion for malignant pleural effusion due to breast cancer recurrence. Most malignant pleural effusions are lymphocyte-predominant. The sensitivity of pleural fluid cytology for detecting malignancy varies with pH. Low pH suggests high malignant cell burden and is associated with high sensitivity of fluid cytology, whereas relatively high pH (≥7.3) is associated with low fluid cytology sensitivity. Light criteria When fluid analysis fails to confirm the etiology of pleural effusion, CT scan of the chest with pleural phase contrast enhancement is typically the most appropriate next step. In this case, it will allow evaluation for metastatic lesions or areas of pleural thickening that may be amenable to diagnostic tissue biopsy. (Choice A) Bronchoscopy with bronchoalveolar lavage (BAL) allows investigation for opportunistic pulmonary infection (eg, aspergillosis) or eosinophilic pneumonia, but moderate to large pleural effusion would be rare in these conditions. Bronchoscopy with BAL is sometimes used in the evaluation of nonresolving pneumonia (eg, endobronchial obstruction due to carcinoma), which would likely cause fever and cough. The sensitivity of BAL for detecting metastatic breast cancer is likely low. (Choice C) Nonsteroidal anti-inflammatory drugs are appropriate treatment for viral pleuritis. Associated pleural effusions are also typically exudative and lymphocyte-predominant, but the high suspicion for recurrent malignancy in this patient necessitates further diagnostic workup. (Choice D) Antibiotics and clinical follow-up are appropriate for community-acquired pneumonia with an uncomplicated parapneumonic effusion. However, the absence of fever and cough in this patient makes community-acquired pneumonia unlikely. parapneumonic effusion (Choice E) Thorascopic pleural biopsy can be useful in diagnosing suspected malignant pleural effusion or pleural effusion of unknown etiology; however, CT scan should be performed first to guide the location of biopsy. Educational objective: Malignant pleural effusions are exudative by Light criteria and usually lymphocyte-predominant. Pleural fluid cytology has low sensitivity for malignancy in the setting of high pH (≥7.3). When fluid analysis fails to confirm the etiology of pleural effusion, CT scan of the chest with pleural phase contrast enhancement provides guidance for diagnostic tissue biopsy. __________ References: Standard pleural biopsy versus CT-guided cutting-needle biopsy for diagnosis of malignant disease in pleural effusions: a randomised controlled trial. (http://www.ncbi.nlm.nih.gov/pubmed/12711467)

Question 3

An 82-year-old nursing home resident with a history of hypertension and chronic obstructive pulmonary disease (COPD) is brought to the emergency department after 2 days of fever, cough, and lethargy.  He was treated with acetaminophen at the nursing home, but was found to be very confused this morning.  His oral intake has also been poor.  His daily medications include lisinopril, hydrochlorothiazide, and tiotropium.  He has never been hospitalized for a COPD exacerbation or pneumonia.  At the nursing home, there have been two cases of mild febrile illness over the past two weeks.
In the emergency department, he is ill-appearing and obtunded.  His temperature is 39.4 C (103 F), blood pressure is 107/60 mm Hg, pulse is 68/min, and respirations are 26/min.  Pulmonary examination reveals crackles at the left lung base.  Bowel sounds are hyperactive and his abdomen is soft.  There are no meningeal signs present.
Laboratory studies reveal:

A chest x ray reveals an ill-defined infiltrate at the left lung base.     
Piperacillin-tazobactam and vancomycin are started empirically.  Over the next 48 hours, his clinical status continues to deteriorate.  A repeat chest x ray reveals progressive infiltrates with worsening left lower lobe consolidation.
This patient's condition is most likely to respond to which of the following?

Accepted Answer

11ec193a_9631_b414_853d_875480b6758e_MD0002_00 This patient's underlying risk factors (elderly age, COPD, nursing home resident), clinical presentation (confusion, high fever with bradycardia), laboratory abnormalities (hyponatremia, thrombocytopenia, elevated LFTs), and failure to respond to vancomycin and piperacillin-tazobactam are strongly suggestive of Legionella pneumonia. Legionella species are facultative intracellular gram-negative bacilli whose natural habitats are aquatic bodies (e.g., lakes, streams, man-made reservoirs, standing water). There are no pathognomonic or highly specific clinical, laboratory, or radiological features for Legionella infection. The most common x-ray finding is a unilobar infiltrate that progresses to consolidation. Patients with suspected Legionella pneumonia should have both a urinary Legionella antigen test (detects only L. pneumophila, serogroup 1) and a respiratory sample (e.g., sputum, BAL) for Legionella culture. Suspected or proven Legionella pneumonia requires treatment with a respiratory fluoroquinolone (e.g., levofloxacin) or "newer" macrolide (e.g., azithromycin), as both have good lung penetration with potent intracellular activity. (Choice A) Ampicillin and piperacillin-tazobactam are both beta-lactam antibiotics and are ineffective against Legionella. Ampicillin is commonly used to treat Listeria, which causes meningitis/sepsis but not pneumonia. (Choice C) Linezolid is approved for treating MRSA pneumonia and is as effective as vancomycin. However, vancomycin and linezolid are not effective against Legionella. (Choice D) Metronidazole is effective for anaerobic aspiration pneumonia but not for Legionella. (Choice E) Oseltamivir treats primary influenza pneumonia, which more commonly shows bilateral reticular or reticulonodular opacities. Educational objective: Legionella pneumonia usually presents with fever, relative bradycardia, possible neurologic and GI symptoms, and potential unilobar chest x-ray infiltrate progressing to consolidation. Suspected patients with Legionella pneumonia should have both a urinary antigen test and a Legionella culture from a respiratory sample to confirm diagnosis. Treatment consists of respiratory fluoroquinolones (e.g., levofloxacin) or "newer" macrolides (e.g., azithromycin) while awaiting results. __________ References: An update on Legionella (http://www.ncbi.nlm.nih.gov/pubmed/20051846)

Question 4

A 23-year-old woman with known sickle cell disease comes to the emergency department with a 3-day history of malaise, lethargy, and severe exertional dyspnea.  She has no cough, chest pain, vomiting, or blood in the stool.  Two years ago, she was hospitalized with acute chest syndrome and required mechanical ventilation.  Her last hospitalization was 7 months ago for a painful crisis, and she underwent an exchange transfusion at that time.  Her current medications are hydroxyurea, folic acid, extended-release morphine, and oxycodone for breakthrough pain.
Her temperature is 100° F (37.8° C), blood pressure is 122/76 mm Hg, and pulse is 112/min and regular.  Oxygen saturation is 96% on room air.  Examination shows pale palms.  Lungs are clear to auscultation.  The abdomen is nontender.
Laboratory results are as follows:
 Chest x-ray shows no infiltrates.  Blood cultures show no growth.
Which of the following is the most likely cause of her symptoms?

Accepted Answer

11ec193a_9619_22e7_853d_c5c3a6d837a4_MD0002_00 This patient's presentation of worsening anemia in sickle cell disease (SCD) is likely due to aplastic crisis. SCD can present with acute worsening anemia possibly due to splenic sequestration crisis, aplastic crisis, or hyperhemolytic crisis. Aplastic crisis is a transient bone marrow arrest leading to decreased erythropoiesis, markedly decreased hemoglobin, and little or no reticulocytosis. Patients typically present with profound anemia and pallor, weakness, lethargy, and dyspnea. Parvovirus B-19 is the most likely cause, but other pathogens include Streptococcus pneumoniae, Salmonella, and Epstein-Barr virus. Treatment is mainly supportive (eg, transfusions, rest, analgesics, hydration, and oxygenation). Recurrent aplastic crisis from parvovirus is rare due to immunity. Splenic sequestration is vasoocclusive crisis within the spleen and is seen particularly in young patients who do not yet have a fibrosed spleen. It is characterized by a fall in hemoglobin, persistent elevated reticulocytosis, and rapidly enlarging spleen. Hyperhemolytic crisis is a sudden worsening of anemia with reticulocytosis that can present after acute sickling events (eg, painful crisis, acute chest syndrome), drug exposure, or infections. Both hyperhemolytic crisis and splenic sequestration crisis present with reticulocytosis; aplastic crisis presents with little or no reticulocytosis, as seen in this patient (Choices B and D). (Choice A) Hydroxyurea is an antimetabolite that increases fetal hemoglobin production to decrease the frequency of SCD episodes. Hydroxyurea can cause myelosuppression, commonly resulting in leukopenia/neutropenia first. Severe anemia is rare. (Choice C) Iron deficiency occurs in up to 20% of SCD patients and is due to increased urinary iron loss. However, ferritin is typically <25 ng/mL. This patient's elevated ferritin makes this unlikely and is probably due to previous transfusions and chronic hemolysis. Educational objective: Aplastic crisis may cause acute worsening anemia in sickle cell disease patients and is usually due to a bone marrow infection causing decreased erythropoiesis. Parvovirus B-19 is the most common cause and treatment is supportive (eg, transfusions, rest, analgesics, hydration, and oxygenation). __________ References: Aplastic crisis caused by parvovirus B19 in an adult patient with sickle-cell disease. (http://www.ncbi.nlm.nih.gov/pubmed/11064584) Clinical presentations of parvovirus B19 infection. (http://www.ncbi.nlm.nih.gov/pubmed/17304869)

Question 5

A 22-year-old woman comes to the emergency department due to heavy vaginal bleeding.  The patient has always had heavy menses, but this time the bleeding has not stopped since it started 5 days ago.  She has had to change her pad every 1-2 hours.  The patient is recovering from an upper respiratory tract infection.  Her medications include ibuprofen for headaches and iron supplementation for iron deficiency anemia.  She has no other significant medical history.  Her mother had heavy menstrual periods and frequent nosebleeds.
Vital signs are within normal limits.  Bimanual examination reveals no palpable abnormalities.
Laboratory results are as follows:
 Which of the following is the best next step in management of this patient?

Accepted Answer

11ec193a_9619_bf29_853d_01bc030988ea_MD0002_00 This patient has heavy menstrual bleeding (eg, mucocutaneous bleeding), normal coagulation studies and platelet counts, and a family history suggestive of bleeding diathesis (mother with heavy menses and nosebleeds), consistent with von Willebrand disease (an autosomal dominant disorder). In such patients, use of nonsteroidal anti-inflammatory drugs (eg, ibuprofen) may precipitate bleeding. Von Willebrand factor (vWF) binds to platelets and subendothelial collagen receptors at exposed injury sites. It also binds to adjacent platelets and is a carrier protein for factor VIII (FVIII), which has reduced concentration and half-life in the unbound state. Therefore, a deficiency of vWF typically prolongs activated PTT (aPTT). However, in some patients, mild to moderate vWF deficiency may not cause elevated aPTT levels. aPTT can also be falsely normal due to increased vWF (acute phase reactant) and FVIII levels during stress, pregnancy, oral contraceptive use, or liver disease. These tests should be repeated after resolution of these conditions. aPTT Patients with suspected von Willebrand disease require additional testing (Choice D). Screening tests include plasma vWF antigen, plasma vWF activity (ristocetin cofactor activity), and FVIII activity. Treatment includes desmopressin (DDAVP), which causes release of vWF and FVIII from endothelial cells. (Choice A) Mild factor IX deficiency (hemophilia B) can also present with bleeding and normal coagulation studies (rather than prolonged PTT). However, hemophilia (A and B) typically presents with recurrent hemarthroses (ie, joint bleeding) and soft-tissue hematoma in addition to mucocutaneous bleeding. Hemophilia has an X-linked inheritance pattern; therefore, most patients are men. (Choice B) Fibrinogen is required to produce fibrin clotting at the end of the coagulation pathway. Therefore, fibrinogen disorders will result in prolonged PT, aPTT, and thrombin time. (Choice C) Mixing studies are performed in patients with coagulation defects (prolonged prothrombin time and/or PTT) and bleeding diathesis. The coagulation studies correct with plasma mixing in factor deficiencies; an inhibitor (or presence of lupus anticoagulant) will cause persistently prolonged PTT or prothrombin time with plasma mixing. Educational objective: Von Willebrand disease is a common bleeding disorder that can present with mucocutaneous bleeding (eg, epistaxis, heavy menses) and normal platelet counts and coagulation studies. Diagnosis requires plasma von Willebrand factor antigen and activity assays. Treatment is with desmopressin (DDAVP), which causes release of von Willebrand factor and factor VIII from endothelial cells. __________ References: Von Willebrand disease: pathogenesis and management. (http://www.ncbi.nlm.nih.gov/pubmed/23452742) High resolution multimer analysis and the PFA-100 platelet function analyser can detect von Willebrand disease type 2A without a pathological ratio of ristocetin cofactor activity and von Willebrand antigen level. (http://www.ncbi.nlm.nih.gov/pubmed/23289190)

Question 6

A 54-year-old woman who recently received a renal transplant comes to the emergency department due to fevers and malaise for the past 24 hours.  She also has had a cough productive of yellow sputum over the past 2 days.  No one around her has similar symptoms.
Three weeks ago, the patient underwent cadaveric renal transplant for long-standing renal disease.  Her immediate postsurgical course was uneventful, and she was extubated 3 days after surgery.  Her other medical problems include gastroesophageal reflux, hyperlipidemia, and eczema.
After the transplantation, she moved in with her sister, who had just donated her 2 cats to a local pet store.  The patient does not use tobacco or alcohol.  Her current medications include prednisone, tacrolimus, mycophenolate, valganciclovir, sulfamethoxazole/trimethoprim, pravastatin, and omeprazole.  She has no known drug allergies.
Her temperature is 38.5 C (101.3 F), blood pressure is 130/80 mm Hg, pulse is 98/min, and respirations are 18/min.  Pulse oximetry shows oxygen saturation of 95% on room air.  Breath sounds are decreased in the left lung base with mild wheezing over the upper lung fields bilaterally.  Her abdomen is soft and nontender without a palpable spleen tip.  Neurologic examination is within normal limits.
Laboratory results are as follows:

Chest-x ray reveals a left lower lobe infiltrate.
Which of the following is the most likely cause of her condition?

Accepted Answer

11ec193a_9622_4aba_853d_e5931b45114f_MD0002_00 This patient's presentation is concerning for nosocomial pneumonia following recent hospitalization for cadaveric renal transplant. The table summarizes common infections seen in solid organ transplant patients based on the amount of time elapsed following surgery. Within the early posttransplant period (<1 month), patients are at risk for nosocomial infections due to prolonged hospitalization and multiple catheter and device placements/instrumentations. Transplant patients requiring mechanical ventilation are particularly susceptible to nosocomial infections due to gram-positive organisms (eg, vancomycin-resistant Enterococcus, methicillin-resistant Staphylococcus aureus), gram-negative organisms (eg, Legionella, Pseudomonas), fungi (eg, Candida species), and Clostridium difficile colitis. Pseudomonas commonly colonizes hospital equipment (eg, mechanical ventilation) and is the most likely cause of this patient's pneumonia. (Choice A) Cytomegalovirus (CMV) infections usually occur between 1-6 months after transplantation and would be unlikely in this patient taking valganciclovir, which is effective for CMV prophylaxis. (Choice B) Opportunistic infection (OI) with Nocardia is rare in the early posttransplant period; it tends to occur >6 months following transplantation, likely reflecting the impact of immunosuppression duration on OI development. (Choice C) Pasteurella multocida is usually found in the normal respiratory flora of domestic pets (eg, dogs, cats). Human infection (eg, cellulitis, respiratory infections, or bone/joint disease) is typically due to animal bites or scratches. This patient's sister donated her cats, and there is no history of animal bites to suggest Pasteurella infection. (Choice D) Pneumocystis jirovecii usually causes pulmonary complications in transplant patients 3-4 months after surgery. In addition, this patient is on sulfamethoxazole/trimethoprim for P jirovecii pneumonia prophylaxis. Educational objective: Solid organ transplant patients are more susceptible to nosocomial infections within a month of surgery due to prolonged hospitalization, mechanical ventilation, immunosuppression, and exposure to multiple catheters or devices. Common organisms causing nosocomial pneumonia in transplant patients include vancomycin-resistant Enterococcus, methicillin-resistant Staphylococcus aureus, Candida, and Pseudomonas. __________ References: The rapid diagnosis of pulmonary infections in solid organ transplant recipients. (http://www.ncbi.nlm.nih.gov/pubmed/2160717) A model for diagnosis of pulmonary infections in solid-organ transplant recipients (http://www.ncbi.nlm.nih.gov/pubmed/20674061) Bacterial pneumonia in solid organ transplantation. (http://www.ncbi.nlm.nih.gov/pubmed/2188317)

Question 7

A 28-year-old man comes to the emergency department due to cramping abdominal pain, nausea, anorexia, and multiple episodes of loose stools for the last 2 days.  The patient is a medical student who returned from rural Indonesia a week ago after volunteering at a hospital for a month.  Several days into his travel, he experienced watery diarrhea that spontaneously resolved within a few days.  After his return, he had fever and sore throat for which his primary care physician prescribed amoxicillin, which he finished taking 2 days ago.  The patient has no chronic medical conditions, takes no other medications, and has no known allergies.  His older brother has ulcerative colitis and his mother has hypertension.
Temperature is 39 C (102.2 F), blood pressure is 94/45 mm Hg, and pulse is 112/min and regular.  The abdomen is soft and diffusely tender with maximum tenderness in the right lower quadrant.  There is no rebound tenderness or rigidity.
Laboratory results are as follows:
 Which of the following is the most likely cause of this patient's condition?

Accepted Answer

11ec193a_961f_b2a5_853d_1951fd3e7002_MD0002_00 This patient's presentation (loose stools, abdominal pain, and significant leukocytosis developing days after antibiotic therapy) is most consistent with a diagnosis of Clostridium difficile infection (CDI). C difficile can present in a variety of ways (Table), but it usually colonizes normal gut flora altered by antibiotic use. Symptoms typically start during antibiotic therapy or 5-10 days afterward. Penicillins, fluoroquinolones, and clindamycin are most commonly associated with CDI; however, virtually any antibiotic may be involved. Lower abdominal tenderness, nausea, anorexia, and diarrhea with mucus or occult blood are common presentations. Diagnosis is suggested by clinical findings and recent antibiotic use; C difficile stool studies can be confirmatory. If there is high clinical suspicion, empiric treatment with oral vancomycin or fidaxomicin can be considered when awaiting test results. Fulminant disease (eg, hypotension, ileus, megacolon) requires the addition of intravenous metronidazole to high dose-vancomycin. Patients who are refractory to treatment may need further evaluation with colonoscopy or sigmoidoscopy; however, extreme caution should be used in patients with fulminant colitis due to perforation risk. (Choice A) Appendicitis most commonly presents with right lower quadrant abdominal pain, anorexia, and nausea/vomiting. However, this patient has had multiple episodes of loose stools over the past 2 days, and his abdomen is soft and diffusely tender (without rebound tenderness, making peritonitis less likely). This presentation makes infectious diarrhea with colitis more likely than appendicitis. (Choice C) Endotoxin-producing Shigella usually presents with bloody, mucoid diarrhea; fever; and abdominal pain. It resolves spontaneously in most patients. This patient's current episode of diarrhea is more likely due to C difficile given the high degree of leukocytosis; lack of bloody, mucoid diarrhea; and timing of symptoms shortly after antibiotic use. (Choice D) The majority (~90%) of Entamoeba histolytica infections are asymptomatic, whereas symptomatic patients have bloody diarrhea with abdominal pain. Symptoms usually have a subacute onset over 1-3 weeks. (Choice E) Inflammatory bowel disease usually presents with the gradual onset of diarrhea after previous self-limited episodes of rectal bleeding/diarrhea. This patient's timing of symptoms following antibiotic use makes this less likely. Educational objective: Clostridium difficile infection usually presents with multiple episodes of watery diarrhea after recent antibiotic use. Diagnosis is confirmed by stool studies, and treatment involves oral vancomycin or fidaxomicin. Patients refractory to treatment may need further investigation with sigmoidoscopy or colonoscopy. __________

Question 8

A 71-year-old man is brought to the emergency department because of a 2-day history of excruciating left thigh pain, weakness, and nausea.  His medical problems include type 2 diabetes mellitus, hypertension, and benign prostatic hyperplasia.  He is a lifetime non-smoker.
His blood pressure is 85/40 mm Hg and pulse is 114/min and regular.  Mucous membranes are dry.  Examination reveals magenta-bronze discoloration, crepitus, tenderness, and significant swelling over the left thigh.
Laboratory results are as follows:

A Foley catheter was placed and 200 mL of concentrated urine was drained.  Intravenous antibiotics, analgesics, and bolus fluids were administered.  CT scan of the thigh showed gas gangrene.  He was emergently taken to the operating room for debridement.  Four days later, the patient feels better.  The Foley catheter is removed and he urinates without difficulty.  Two sets of blood cultures sent on admission grow Clostridium septicum.
Which of the following additional studies would be indicated in this patient?

Accepted Answer

11ec193a_962d_bc71_853d_b5572896bb97_MD0002_00 Clostridium septicum is commonly associated with spontaneous gas gangrene. Unlike other Clostridium species (e.g., Clostridium perfringens), a history of trauma is not required for infection. Infection usually spreads hematogenously from GI tract pathology. Most patients have underlying colonic malignancy, but other conditions such as inflammatory bowel disease and diverticulitis have also been associated with C. septicum infection. Thus, all patients with C. septicum bacteremia should be evaluated with colonoscopy. (Choice B to E) Clostridium septicum is not usually associated with lung, bladder, prostate, or cardiac pathology. Educational objective: Clostridium septicum usually presents with bacteremia followed by spontaneous gas gangrene in an extremity without a history of trauma. Since the bacteria originates in the GI tract and is associated with GI pathology (e.g., colon cancer), all patients with C. septicum bacteremia should undergo a colonoscopy. __________ References: Clostridium septicum aortitis with associated sigmoid colon adenocarcinoma (http://www.ncbi.nlm.nih.gov/pubmed/22304871) Clostridium septicum Sepsis and Colon Carcinoma: Report of 4 Cases. (http://www.ncbi.nlm.nih.gov/pubmed/21747861)

Question 9

A 40-year-old man is brought to the emergency department by his wife for progressive lethargy, fever, and headache over the last 24-hours.  He underwent craniotomy for meningioma resection 1 week ago.  Since yesterday evening, the patient has had confusion, headaches, and a few episodes of vomiting.  His wife denies any sick contacts, recent travel, flu-like symptoms, or skin rashes.
His temperature is 39.6 C (103.3 F), blood pressure is 140/90 mm Hg, pulse is 110/min and regular, and respirations are 16/min.  There is no skin rash.  The craniotomy incision is healing normally.  On neurological examination, he is obtunded and does not follow commands.  There is prominent neck stiffness.  He is able to localize to noxious stimuli in the upper extremities and withdraw in the lower extremities.
Stat CT scan of the head shows no bleeding or masses.  Lumbar puncture (LP) shows elevated opening pressure, white blood cell count of 1,200 cells/µL with 90% neutrophils, protein of 200 mg/dL, and glucose of 20 mg/dL.
Which of the following is the best next step in this patient's management?

Accepted Answer

11ec193a_962c_0ebf_853d_ab4e943265da_MD0002_00 This patient presents with acute hospital-acquired (healthcare-associated) bacterial meningitis after recent brain surgery. The lumbar puncture findings of neutrophilic pleocytosis, elevated protein, and low CSF glucose strongly suggest a bacterial etiology. Following brain surgery, the most likely organisms to cause meningitis include gram-negative bacilli (e.g., Pseudomonas aeruginosa) and gram-positive cocci (e.g., methicillin resistant Staphylococcus aureus). Both cefepime and ceftazidime have good CNS penetration as well as broad coverage against gram-negative organisms, especially Pseudomonas aeruginosa, and some coverage against gram-positive organisms (e.g., Streptococcus pneumoniae). Vancomycin is effective against MRSA. (Choices B and C) Ceftriaxone and vancomycin are appropriate for empiric treatment of community-acquired meningitis in patients aged 2-50 years, as this combination retains good coverage against S. pneumoniae. However, ceftriaxone does not adequately cover Pseudomonas. Acyclovir is not needed as HSV meningitis is unlikely. (Choice D) Ampicillin is usually added in suspected bacterial meningitis to cover for Listeria monocytogenes in patients > age 50 or the immunocompromised. (Choice E) Piperacillin/tazobactam has good coverage against Pseudomonas and other gram-negative organisms, but does not have good CNS penetration. Educational objective: Patients with hospital-acquired meningitis should be empirically treated with an antipseudomonal cephalosporin and vancomycin. Cefepime, ceftazidime, and meropenem are all highly effective against gram-negative organisms (e.g., Pseudomonas) and have good CNS penetration. __________ References: Cephalosporins in the treatment of meningitis. (http://www.ncbi.nlm.nih.gov/pubmed/3319497) Healthcare-associated bacterial meningitis. (http://www.ncbi.nlm.nih.gov/pubmed/21526350)

Question 10

A 36-year-old woman comes to the emergency department due to right lower leg pain and ankle edema. Her symptoms began 2 days ago after a 14-hour flight from India. The patient has had no leg trauma, fever, chest pain, or shortness of breath. She has a history of asthma and takes inhaled albuterol as needed. The patient has no family history of blood clots. Temperature is 36.8 C (98.2 F), blood pressure is 142/72 mm Hg, pulse is 98/min, and respirations are 16/min. BMI is 26 kg/m². Cardiopulmonary examination shows no abnormalities. There is 2+ right lower extremity pitting edema extending to the mid-calf, and right foot dorsiflexion results in right calf pain. Left lower extremity examination is normal. Stool guaiac is negative. Laboratory results are as follows: Compression ultrasonography of the right lower extremity shows no evidence of deep venous thrombosis. D-dimer is 65 µg/mL (normal: <0.5). Which of the following is the most appropriate next step in management of this patient?

Accepted Answer

11ec193a_961a_827b_853d_ad5f2d37c69d_MD0002_00 Although not enough clinical information is provided to assess this patient's modified Wells score, her recent long air flight, new-onset unilateral leg edema/pain, and positive Homan sign (pain in the calf on dorsiflexion of the foot) suggest a high pretest probability for deep venous thrombosis (DVT). Patients with suspected DVT are evaluated based on pretest probability as follows: Low probability - Obtain moderate- or high-sensitivity d-dimer level. A normal d-dimer rules out DVT (d-dimer has a sensitivity of up to 96% but specificity is low); an elevated d-dimer necessitates further evaluation with compression ultrasonography (CUS).High probability - Proceed directly to CUS, which has a diagnostic sensitivity of >97% for DVT. As false negatives can occasionally (<3%) occur, patients with a high pretest probability of DVT who have negative CUS testing, continue to be symptomatic, have no clear alternate diagnosis, and have an elevated d-dimer should have repeat CUS within days. Low probability - Obtain moderate- or high-sensitivity d-dimer level. A normal d-dimer rules out DVT (d-dimer has a sensitivity of up to 96% but specificity is low); an elevated d-dimer necessitates further evaluation with compression ultrasonography (CUS). Low probability - Obtain moderate- or high-sensitivity d-dimer level. A normal d-dimer rules out DVT (d-dimer has a sensitivity of up to 96% but specificity is low); an elevated d-dimer necessitates further evaluation with compression ultrasonography (CUS). High probability - Proceed directly to CUS, which has a diagnostic sensitivity of >97% for DVT. As false negatives can occasionally (<3%) occur, patients with a high pretest probability of DVT who have negative CUS testing, continue to be symptomatic, have no clear alternate diagnosis, and have an elevated d-dimer should have repeat CUS within days. High probability - Proceed directly to CUS, which has a diagnostic sensitivity of >97% for DVT. As false negatives can occasionally (<3%) occur, patients with a high pretest probability of DVT who have negative CUS testing, continue to be symptomatic, have no clear alternate diagnosis, and have an elevated d-dimer should have repeat CUS within days. Patients with moderate pretest probability can be initially evaluated with either high sensitivity d-dimer (normal rules out; elevated requires CUS) or CUS. (Choice A) Patients with low or moderate probability DVT who have negative CUS can be treated with symptomatic care. This patient has a clinical presentation highly concerning for DVT and an elevated d-dimer; repeat CUS should be performed to ensure that the original test was not falsely negative. (Choice B) Although CT angiography has a marginally better sensitivity than ultrasound, it is invasive, expensive, difficult to perform and interpret, and associated with a risk of complications (eg, renal failure, allergic reaction). As such, this test is rarely performed; CUS should be repeated instead. (Choice C) Screening for hypercoagulable disorders is not generally undertaken in the setting of acute thrombus as the level/activity of many of the anticoagulant factors is altered, which confounds the interpretation of results. Testing is generally undertaken approximately 2 weeks after the cessation of anticoagulation. (Choice D) Although rivaroxaban can be used for anticoagulation in acute DVT, anticoagulation should not be initiated prior to radiographic diagnosis due to risk of bleeding. This is in contrast to suspected pulmonary embolism, in which anticoagulation is initiated while awaiting diagnostic confirmation due to the immediately life-threatening nature of the condition. Educational objective: Patients with a high pretest probability of deep venous thrombosis (DVT) should undergo compressive ultrasonography for diagnosis. False negatives occur in 3% of high probability cases; patients who have negative initial testing, continue to be symptomatic, have no clear alternate diagnosis, and have an elevated d-dimer should be retested with whole leg compressive ultrasound within 24 hours. __________ References: Diagnosis of DVT: antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. (http://www.ncbi.nlm.nih.gov/pubmed/22315267)

Question 11

A 19-year-old man from Arizona is brought to the emergency department by his parents due to a high-grade fever, chills, and headache.  He also complains of severe pain in the groin and axillary areas, which was preceded by swelling.  Two days prior to this event, the patient's father was changing carpet in the patient's room and noticed a dead rat.
His temperature is 39.6 C (103.3 F), blood pressure is 100/70 mm Hg, and pulse is 98/min.  Examination shows multiple severely tender, non-fluctuant, enlarged nodules in the axillary and groin regions.  The skin over these areas is edematous and erythematous.  Blood cultures are obtained.
Which of the following organisms is most likely responsible for this patient's infection?

Accepted Answer

11ec193a_962e_7fc2_853d_111604183271_MD0002_00 This patient's presentation is consistent with infection by Yersinia pestis (bubonic plague), a gram-negative coccobacillus transmitted by infected fleas. The main Yersinia pathogens include Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis. Yersinia pestis causes plague, while the other two cause diarrheal illnesses. It is transmitted by infected fleas from rodents, scratches/bites from infected cats, eating contaminated food, direct handling of infected animals, and respiratory transmission from infected humans. Urban plague involves rats, which have been the major reservoir for human epidemics. Diagnosis requires high clinical suspicion in patients with travel to endemic areas (e.g., Southwestern US) or animal exposure, and unexplained fever with regional lymphadenitis. Diagnosis can be confirmed with blood cultures, fluid culture (e.g., bubo aspirate or CSF), peripheral blood smear (Wright-Giemsa stain) showing rod-shaped organisms, or serologic titers. Untreated disease can lead to bacteremia, multiorgan failure, and death in nearly 75% of patients. Suspected patients should be promptly treated with tetracyclines or streptomycin. Post-exposure prophylaxis with doxycycline is recommended for contact with known cases. (Choice A) Coccidioides immitis is endemic in the Southwestern United States. Patients usually have nonspecific systemic symptoms, dry cough, pneumonia, or skin lesions in the immunocompromised. This patient's regional lymphadenitis is not usually seen in coccidiomycosis. (Choice B) Francisella tularensis (tularemia) is transmitted via contact with infected animals (e.g., rabbits). Patients most commonly present with ulceroglandular disease with a single erythematous papular skin ulcer with central eschar, tender local lymphadenopathy, and sudden onset of systemic symptoms (e.g., fever, chills, etc.). (Choice C) Pasteurella multocida infection results from bites or scratches from domestic pets. Patients usually present with localized cellulitis within 24 hours, regional lymphadenopathy, and sometimes bacteremia with osteomyelitis, meningitis, or endocarditis. (Choice D) Streptobacillus moniliformis commonly causes rat bite fever. Patients usually present with fever, severe myalgias, asymmetrical arthralgias, and a fine macular rash. However, it usually does not cause regional lymphadenitis. Educational objective: Yersinia pestis infection causes the highly lethal bubonic plague and presents with swollen and painful lymph nodules and sudden onset of high-grade fever. Suspected patients should be treated rapidly with tetracyclines or streptomycin. Post-exposure prophylaxis with doxycycline is recommended for contact with known cases. __________ References: Humoral and cellular immune responses to Yersinia pestis infection in long-term recovered plague patients (http://www.ncbi.nlm.nih.gov/pubmed/22190397) Expression during host infection and localization of Yersinia pestis autotransporter proteins (http://www.ncbi.nlm.nih.gov/pubmed/21873491) Yersinia pestis--etiologic agent of plague. (http://www.ncbi.nlm.nih.gov/pubmed/8993858)

Question 12

A 31-year-old man comes to the emergency department because of a high-grade fever and multiple painful skin nodules that began 2 days ago.  The skin lesions are red and painful, and gradually developed on both arms before spreading to the chest and legs.  He also notes fatigue, poor appetite, dry cough, and mild shortness of breath.  One week ago, the patient was helping his father in the garden.
The patient had an allogeneic bone marrow transplantation for acute leukemia 3 months ago complicated by pneumonia, catheter-associated bacteremia, and chronic gastrointestinal graft-versus-host-disease.  His medications include prednisone, valganciclovir, and trimethoprim/sulfamethoxazole.  
His temperature is 39.4 C (103.0 F), blood pressure is 90/60 mm Hg, pulse is 106/min, and respirations are 28/min.  Examination shows dry mucus membranes, diffuse crackles in the lung fields, and mild splenomegaly.  Skin examination reveals dry skin with multiple raised, erythematous, and tender nodules on his upper extremities, lower extremities, and upper chest.
Laboratory results are as follows:

The patient is admitted to the hospital and started on empiric antibiotic therapy.  Blood cultures are obtained and grow mold-like organisms.
Which of the following is the most likely cause of his condition?

Accepted Answer

11ec193a_9620_75f7_853d_773cd685d2f6_MD0002_00 This patient's presentation is most concerning for Fusarium species, which is the second most common pathogenic mold. Fusarium is found in soil and plant debris and directly invades tissue to cause destruction. Invasive disease most commonly occurs in severely immunosuppressed patients (i.e., neutropenia, lymphopenia, graft-vs-host disease, and corticosteroids), particularly those with hematologic malignancies receiving induction chemotherapy or bone marrow transplantation. Patients typically present with refractory fever (> 90%) to antibacterial and/or antifungal therapy, skin lesions (precede fungemia by approximately 5 days), and sinopulmonary infections (~75%). Fusarium Diagnosis is suggested by skin biopsy (> 50% of patients) and/or positive blood cultures (~40% of patients) that usually grow a mold. Patients without a definitive skin biopsy diagnosis require tissue biopsy. Fusarium is resistant to many antifungal agents and carries a high mortality (60-80%) in immunocompromised patients, particularly those who are neutropenic or taking steroids. High-dose amphotericin B and/or voriconazole are most often used with varying degrees of success. Prevention is key with patients avoiding tap water or soil contact to areas of broken skin. (Choice A) Aspergillus fumigatus may cause pneumonia and skin lesions, but usually does not have positive blood cultures. Immunocompromised patients also tend to present more often with pulmonary complaints progressing to multi-organ failure rather than primary skin lesions. Aspergillus fumigatus (Choice B) Candida albicans is a diploid fungus rather than a mold. Also, C. albicans typically presents in the first 60 days after organ transplantation with clusters of painless pustules on an erythematous base. (Choice D) Histoplasma capsulatum is a fungus that is rare in bone marrow transplant patients, but more common in patients with HIV, solid organ transplants, and in those taking anti-TNF therapy. (Choice E) Nocardia is a weakly staining gram-positive, rod-shaped bacteria that forms partially acid-fast beaded branching filaments. Nocardiosis with skin disease usually presents as ulcerations, pyoderma, cellulitis, nodules, and subcutaneous abscesses. Nocardia Educational objective: Fusariosis can occur in severely immunocompromised patients. Inoculation commonly occurs when breaks in the skin are exposed to tap water or soil. Patients can present with refractory fever, skin lesions, and pulmonary disease. Diagnosis is suggested by skin biopsy (> 50% of patients) and/or positive blood cultures (~40% of patients) that usually grow a mold. Treatment is with amphotericin B +/- voriconazole with varying efficacy. __________ References: Disseminated fusariosis in immunocompromised patients. (http://www.ncbi.nlm.nih.gov/pubmed/21708518) The challenge of managing fusariosis. (http://www.ncbi.nlm.nih.gov/pubmed/21304267)

Question 13

A 37-year-old woman comes to the emergency department due to joint pain for the past 3 weeks. The pain is primarily in the lower extremities and is not associated with joint swelling or redness. She has had no skin rashes, chest pain, or urinary symptoms but has had malaise, profound fatigue, and decreased appetite. The patient's symptoms began after she visited her family in Connecticut. She has a history of mitral valve prolapse, and her current medications include oral contraceptives and a multivitamin. The patient works as a paralegal. She does not use tobacco or illicit drugs and drinks alcohol occasionally. Her mother has rheumatoid arthritis. Temperature is 38 C (100.4 F), blood pressure is 105/70 mm Hg, pulse is 89/min, and respirations are 18/min. BMI is 23 kg/m². The patient is mildly ill-appearing but in no acute distress. Dental hygiene is poor. Cardiopulmonary auscultation reveals clear lung fields and a 3/6 holosystolic murmur at the cardiac apex that radiates to the axillae. There is tenderness to palpation in the left upper quadrant with an enlarged spleen. No joint swelling or erythema is present, and there is no skin rash or lymphadenopathy. Laboratory results are as follows: Which of the following is most likely to establish the diagnosis in this patient?

Accepted Answer

This patient with poor dentition and a history of mitral valve prolapse has low-grade fever, arthralgias, and likely mitral regurgitation (apex murmur radiating to axilla), raising concern for infective endocarditis (IE). Further evaluation with 3 sets of blood cultures and echocardiography is now required to estimate the likelihood of IE using the modified Duke criteria. modified Duke criteria Patients with suspected IE also usually receive a chest x-ray, ECG, and additional laboratory studies. Common laboratory abnormalities include normochromic/normocytic anemia, leukocytosis with left shift, elevated erythrocyte sedimentation rate (90% of cases), decreased complement levels (C3, C4, and CH50), and positive rheumatoid factor due to circulating immune complexes. Imaging of the spine for vertebral myelitis or abdomen for splenic infarcts (as is likely in this case) is also warranted in the appropriate clinical setting. (Choice A) Antineutrophil cytoplasmic antibodies are commonly seen in granulomatosis with polyangiitis and microscopic polyangiitis. Although both syndromes can be associated with arthralgias and systemic symptoms, most patients also have ear (eg, otitis), nose (eg, rhinorrhea, sinusitis), throat (eg, hoarseness), and/or renal manifestations (eg, glomerulonephritis). Cardiac involvement would be atypical. (Choice C) Bone marrow biopsy is most commonly performed to evaluate for hematologic malignancy. Although this patient does have splenomegaly and complete blood count abnormalities, given her dental disease, mitral valve prolapse, and constellation of manifestations, she should first undergo an evaluation for IE with blood cultures and echocardiogram. Splenomegaly can sometimes be seen with IE. If the modified Duke criteria reveals a low probability of IE, she may require bone marrow biopsy for further evaluation. (Choice D) Cervical smear and culture could diagnosis Neisseria gonorrhea infection. Disseminated gonococcus can cause a triad of symptoms (ie, tenosynovitis, pustular skin lesions, polyarthralgias) or purulent arthritis without skin lesions. This patient with polyarthritis has a cardiac murmur, splenomegaly, and no skin lesions, making IE more likely. (Choice E) Lyme disease is a tick-borne illness caused by Borrelia burgdorferi. Although this patient visited an endemic region (the northeastern United States), Lyme carditis typically presents with atrioventricular conduction block or decreased contractility due to myopericarditis. A new cardiac murmur and splenomegaly are more suggestive of IE. Educational objective: Patients with suspected infective endocarditis require blood cultures (3 sets) and echocardiography to estimate its likelihood using the modified Duke criteria. __________ References: Acute infective endocarditis. (http://www.ncbi.nlm.nih.gov/pubmed/19665088) Infectious endocarditis: diagnosis and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/22612050)

Question 14

A 27-year-old woman comes to the emergency department after waking with new left-sided facial weakness. She has also had headaches over the last 10 days that are throbbing, 4 of 10 in intensity, located "all over" her head, and associated with photophobia but no nausea. She has had no double vision, limb weakness, numbness, difficulty swallowing, or recent head trauma, but she does note some malaise and mild neck stiffness. The patient has a history of migraines but says her current headaches are different in quality and more persistent. She has seasonal allergies and takes over-the-counter antihistamines as needed. She traveled to India 4 months ago and is currently living with her grandparents in Connecticut for the summer. She is single and does not use tobacco, alcohol, or illicit drugs. Temperature is 37 C (98.6 F), blood pressure is 130/80 mm Hg, pulse is 80/min and regular, and respirations are 15/min. BMI is 30 kg/m². Mucous membranes are dry. Neurologic examination shows slight nuchal rigidity and photophobia. Cranial nerve testing reveals a decreased corneal reflex on the left as well as upper and lower left-sided facial weakness. The remainder of the physical examination is unremarkable. Which of the following is the most likely complication if this patient's condition is left untreated?

Accepted Answer

11ec193a_9621_1238_853d_97c73ff50c1a_MD0002_00 This patient who currently resides in Connecticut has evidence of facial nerve palsy (unilateral facial weakness, impaired corneal reflex) and likely meningitis (headache, photophobia, nuchal rigidity), raising suspicion for early disseminated Lyme disease. Lyme disease is a tick-borne illness endemic to the northeastern United States. Manifestations typically arise in 3 progressive clinical stages: northeastern United States Early localized disease - A few weeks of viral-like symptoms and a spreading, annular rash (erythema migrans).Early disseminated disease - Several weeks or months later, patients can develop acute arthralgias, carditis (eg, atrioventricular block), and neurologic disease (eg, facial nerve palsy, meningitis).Late Lyme disease - Late symptoms usually occur months or years after the initial inoculation. The most common manifestation is intermittent or persistent arthritis in >1 large joints (particularly the knee). More serious neurologic disease such as Lyme encephalopathy can also occur. Early localized disease - A few weeks of viral-like symptoms and a spreading, annular rash (erythema migrans). Early localized disease - A few weeks of viral-like symptoms and a spreading, annular rash (erythema migrans). erythema migrans Early disseminated disease - Several weeks or months later, patients can develop acute arthralgias, carditis (eg, atrioventricular block), and neurologic disease (eg, facial nerve palsy, meningitis). Early disseminated disease - Several weeks or months later, patients can develop acute arthralgias, carditis (eg, atrioventricular block), and neurologic disease (eg, facial nerve palsy, meningitis). Late Lyme disease - Late symptoms usually occur months or years after the initial inoculation. The most common manifestation is intermittent or persistent arthritis in >1 large joints (particularly the knee). More serious neurologic disease such as Lyme encephalopathy can also occur. Late Lyme disease - Late symptoms usually occur months or years after the initial inoculation. The most common manifestation is intermittent or persistent arthritis in >1 large joints (particularly the knee). More serious neurologic disease such as Lyme encephalopathy can also occur. Although Lyme disease usually progresses in a stepwise fashion, there can occasionally be manifestations of multiple stages at the same time. Patients can also have symptoms of early disseminated or late Lyme disease without having manifestations of previous stages. (Choice B) Lyme carditis generally occurs within a few months of infection and is considered a manifestation of early disseminated Lyme disease. The most common finding is atrioventricular conduction block, but patients can also occasionally develop myopericarditis. Chronic dilated cardiomyopathy is rare. (Choice C) Lower extremity paraplegia and meningitis can be seen with tuberculosis infections of the central nervous system. Although this patient did travel to a TB-endemic country (India), central nervous system tuberculosis is much less common than Lyme disease and rarely causes facial nerve palsy. (Choice D) Seizures are more common with encephalitis (eg, herpes encephalitis) than with meningitis. Lyme disease is not typically associated with an increased risk of seizures. (Choice E) Conjunctivitis is seen in approximately 10% of cases of early disseminated Lyme disease. Other ocular manifestations are rare. Late Lyme disease is most likely to cause arthritis, not vision loss. Educational objective: The manifestations of Lyme disease are typically categorized into 3 progressive stages. Early localized infection is marked by a viral-like syndrome and erythema migrans. Weeks or months later, patients can develop signs of early disseminated disease such as arthralgias, carditis (eg, atrioventricular block), and nervous system abnormalities (eg, facial nerve palsy, meningitis). Late Lyme disease is typically associated with intermittent or persistent arthritis in >1 large joints (particularly the knee). __________ References: Lyme disease: Part I. Advances and perspectives. (http://www.ncbi.nlm.nih.gov/pubmed/21414493) Lyme disease: Part II. Management and prevention. (http://www.ncbi.nlm.nih.gov/pubmed/21414494)

Question 15

A 24-year-old man with sickle cell disease (hemoglobin SS) comes to the emergency department with chest pain and shortness of breath.  He has felt unwell for the last several days with increasing extremity, abdominal, and chest pain.  The patient took extra doses of oral morphine with little relief.  He stopped taking hydroxyurea 4 months ago due to stomach upset.
His blood pressure is 122/72 mm Hg, pulse is 108/min, respirations are 22/min, and oxygen saturation is 84% on room air.  Bilateral crackles are heard on chest auscultation.  A 2/6 midsystolic murmur is heard at the left upper sternal border.  The abdomen is diffusely tender without rebound.  There is no swelling of the extremities.
Laboratory results are as follows:

Chest x-ray reveals bilateral dense infiltrates involving both upper and lower right lung fields and the lower left lung field.  Intravenous fluids, supplemental oxygen, and antibiotics are initiated.
Which of the following is the best next step in management of this patient?

Accepted Answer

11ec193a_961b_e20d_853d_2951329a7536_MD0002_00 This patient with sickle cell disease has features characteristic of severe acute chest syndrome (ACS): multiple lobar infiltrates on chest imaging associated with chest pain, and dyspnea with hypoxemia. Initial supportive measures in ACS include intravenous hydration, analgesics, broad-spectrum antibiotics, incentive spirometry, and supplemental oxygen. chest imaging In addition, definitive management of moderate or severe ACS includes blood transfusions, which acutely increase oxygenation. Moderate cases (<2 pulmonary lobes involved on imaging and SaO₂ >85% on room air) may be managed with conventional red cell transfusions. However, most experts advise exchange transfusion for severe ACS (>2 lobes involved or SaO₂ <85%) to enable rapid replacement of red cell mass without causing hemoconcentration and hyperviscosity. < (Choice B) Glucocorticoids as a treatment for ACS have been shown to reduce length of hospitalization. However, concern for significant complications, including rebound vaso-occlusive events, increased risk of avascular necrosis, and an association with hemorrhagic stroke, has limited the clinical utility of glucocorticoids. (Choice C) Hydroxyurea is recommended to decrease the frequency of pain crises and acute chest syndrome in sickle cell disease, but it would not be helpful in the acute setting. (Choice D) Low-dose naloxone, an opioid antagonist, can be used occasionally to relieve opioid-induced nausea and pruritus without affecting the analgesic benefit of opioids. However, this approach is not recommended routinely. (Choice E) Noninvasive ventilation has been suggested as an additional supportive measure in ACS. However, in trials, noninvasive ventilation failed to show improvement in hypoxemia, transfusion rates, pain, or length of stay. Educational objective: Acute chest syndrome in sickle cell disease is characterized by pulmonary infiltrates associated with fever, pain, hypoxemia, and pulmonary crackles. Management includes supplemental oxygen, intravenous hydration, broad-spectrum antibiotics, and pain medication. Mild cases may be managed without transfusion. Moderate cases require conventional red cell transfusion, and exchange transfusion is recommended in severe cases. __________ References: Pulmonary complications of sickle cell disease. (http://www.ncbi.nlm.nih.gov/pubmed/22447965)

Question 16

A 60-year-old woman comes to the emergency department due to 2 weeks of worsening bilateral headaches, blurry vision, dizziness, and tingling sensation in her feet.  She has had no fevers, night sweats, unintentional weight loss, or jaw pain but has had several episodes of epistaxis.  The patient has a history of hypertension and takes chlorthalidone.  She does not use tobacco, alcohol, or illicit drugs.
Temperature is 37.2 C (99.0 F), blood pressure is 166/98 mm Hg, pulse is 85/min, and respirations are 14/min.  Physical examination shows moist mucous membranes, normal tympanic membranes, and no sinus tenderness.  Bilateral pupils are equal and reactive.  Visual acuity is decreased in both eyes, and funduscopic examination reveals dilated, segmented, and tortuous retinal veins.  Facial sensation and strength are normal.  Bilateral upper- and lower-extremity muscle strength is normal.  There is decreased pinprick sensation and loss of ankle reflex bilaterally.
Laboratory results are as follows:
 Which of the following is the most appropriate next step in management of this patient?

Accepted Answer

This patient with an elevated gamma gap (total protein − albumin > 4 g/dL) has several clinical features concerning for Waldenström macroglobulinemia (WM), a rare lymphoplasmacytic lymphoma marked by excessive circulating monoclonal IgM. Patients often present with constitutional symptoms, oozing from mucosal sites, and manifestations related to: The infiltration of hematopoietic tissue with neoplastic cells, leading to hepatosplenomegaly, lymphadenopathy, and cytopenias (particularly anemia)Excessive IgM in the blood, leading to cryoglobulinemia, sensorimotor peripheral neuropathy, and hyperviscosity syndrome (blurred vision, headache, vertigo) The infiltration of hematopoietic tissue with neoplastic cells, leading to hepatosplenomegaly, lymphadenopathy, and cytopenias (particularly anemia) The infiltration of hematopoietic tissue with neoplastic cells, leading to hepatosplenomegaly, lymphadenopathy, and cytopenias (particularly anemia) Excessive IgM in the blood, leading to cryoglobulinemia, sensorimotor peripheral neuropathy, and hyperviscosity syndrome (blurred vision, headache, vertigo) Excessive IgM in the blood, leading to cryoglobulinemia, sensorimotor peripheral neuropathy, and hyperviscosity syndrome (blurred vision, headache, vertigo) Other common findings include "sausage link" retinal veins, markedly elevated erythrocyte sedimentation rate, and rouleaux formation on peripheral blood smear. Patients with suspected WM should undergo screening with serum protein electrophoresis. The presence of monoclonal IgM gammopathy supports the diagnosis; confirmation requires bone marrow aspiration and biopsy (≥10% plasmacytoid or plasma cell infiltration with characteristic immunophenotype patterns). plasma cell infiltration WM is not curable with current therapies, so treatment is geared toward controlling symptoms and limiting end-organ involvement. Those with hyperviscosity syndrome are treated with emergent plasmapheresis to reduce circulating IgM. Median survival is approximately 10 years. (Choice A) Carbonic anhydrase inhibitors and loop diuretics are used in the treatment of idiopathic intracranial hypertension, which often presents with headache and transient visual symptoms. However, funduscopic examination almost always reveals papilledema. In addition, a gamma gap and signs of peripheral neuropathy are not features of this disease. (Choices B and E) High-dose glucocorticoids are used to treat giant cell arteritis, which can present with constitutional symptoms, headache, transient vision loss, and elevated erythrocyte sedimentation rate. However, vision loss is usually monocular, and funduscopic examination is typically normal (or shows signs of ischemia). Temporal artery biopsy aids in diagnosis. (Choice C) Patients with hypertensive crisis can develop headache and encephalopathy, but most cases occur when blood pressure is severely elevated (>180/120 mm Hg), not moderately elevated. In addition, this patient's gamma gap and "sausage link" retinal veins make WM far more likely than hypertensive crisis. Educational objective: Waldenström macroglobulinemia often presents with constitutional symptoms, oozing from mucosal sites, and manifestations related to neoplastic infiltration of hematopoietic tissue (eg, hepatosplenomegaly, lymphadenopathy, cytopenias) or high levels of IgM (eg, cryoglobulinemia, peripheral neuropathy, hyperviscosity syndrome). Diagnosis is made with serum protein electrophoresis and bone marrow biopsy. __________

Question 17

A 61-year-old woman comes to the emergency department due to fever, chills, and left flank pain that began abruptly last evening. A month ago, the patient was treated for a urinary tract infection with a short course of ciprofloxacin. She otherwise has no medical problems and currently takes no medications. She has no history of hospitalizations or surgeries. Temperature is 39.4 C (103 F), blood pressure is 80/40 mm Hg, pulse is 120/min, and respirations are 24/min. Pulse oximetry shows 94% on room air. Mucous membranes are dry and jugular veins are flat. Cardiopulmonary auscultation reveals clear lung fields and normal heart sounds without murmurs. The abdomen is soft and nontender. Left costovertebral angle tenderness is present. Skin examination is normal. The extremities are warm with no edema. Neurologic examination is within normal limits. Laboratory results are as follows: Broad-spectrum antibiotics and intravenous fluids are initiated, and the patient is admitted to the intensive care unit. Enoxaparin is given for prophylaxis against deep vein thrombosis. On hospital day 2, urine and blood cultures are positive for Escherichia coli and antibiotics are narrowed based on culture sensitivities. Repeat laboratory testing is similar to admission, except platelet count has dropped to 105,000/mm³. Which of the following is the most appropriate next step in management of this patient?

Accepted Answer

11ec193a_961c_7e4f_853d_87425d59859c_MD0002_00 This patient with likely Escherichia coli pyelonephritis had a decline in platelets on hospital day 2 after starting enoxaparin for prophylaxis against deep vein thrombosis. Platelet declines in patients on heparin should prompt a consideration of heparin-induced thrombocytopenia (HIT) type 2, a life-threatening condition. To evaluate for HIT type 2, the 4 Ts score (see the image above) is typically used. This patient has a score of 1 due to a platelet decline <30% (0 points), onset <5 days with no known heparin exposure (0 points), no evidence of thrombosis (0 points), and likely other causes of thrombocytopenia (1 point). As such, HIT type 2 is unlikely, and no change in therapy is required (enoxaparin may be continued). There are many potential causes for this patient's thrombocytopenia, including >1 of the following: Disseminated intravascular coagulation - presence of prolonged INR/PTT and low to normal fibrinogenAntibiotics - many antibiotics (eg, ceftriaxone) can result in thrombocytopeniaHIT type 1 - typically causes platelet nadir ~100,000/mm³ <2 days after heparin initiation Disseminated intravascular coagulation - presence of prolonged INR/PTT and low to normal fibrinogen Antibiotics - many antibiotics (eg, ceftriaxone) can result in thrombocytopenia HIT type 1 - typically causes platelet nadir ~100,000/mm³ <2 days after heparin initiation ³ (Choices B, C, and D) Patients with HIT type 2 require the immediate discontinuation of all heparin products (eg, enoxaparin), PF4 (HIT) antibody testing, and alternate anticoagulation (eg, argatroban). (Choice E) Tinzaparin is also a low-molecular-weight heparin; if HIT type 2 were suspected, this would not be a suitable alternate anticoagulant as all heparin products must be avoided. Educational objective: Patients who develop thrombocytopenia after initiation of heparin products should be evaluated for heparin-induced thrombocytopenia (HIT) type 2 with a 4 Ts score. Patients with low (<3) scores are unlikely to have HIT type 2 and can continue heparin therapy without additional testing or change in treatment. __________

Question 18

A 67-year-old man comes to the emergency department due to 2 days of fever, malaise, headache, and myalgia.  He has also noticed a nonpruritic skin rash on his right leg.  The patient has had no abdominal pain, vomiting, or diarrhea.  Prior medical problems include hypertension, type 2 diabetes mellitus, and chronic obstructive pulmonary disease.  He is an ex-smoker and does not use alcohol or illicit drugs.  The patient lives in Texas and a week ago returned from visiting family in Connecticut, where he spent most of his time outdoors.
Temperature is 39.4 C (103 F), blood pressure is 124/84 mm Hg, pulse is 102/min, and respirations are 20/min.  Examination shows no scleral icterus or lymphadenopathy.  Breath sounds are mildly decreased throughout.  The abdomen is soft with no hepatosplenomegaly.  There is no neck stiffness.  A 4-cm, erythematous skin rash with central clearing is present on the right popliteal area.
Laboratory results are as follows:
 Chest x-ray reveals no parenchymal opacity or pleural effusion.
Which of the following diagnostic studies is most appropriate for this patient?
A)Anti-parvovirus antibodies
B)Antirickettsial antibodies
C)Bone marrow biopsy
D)Borrelia burgdorferi serology
E)Peripheral blood microscopy

Accepted Answer

The answer of A 67-year-old man comes to the emergency...

Question 19

A 62-year-old man is brought to the emergency department because of watery diarrhea, skin rash, and confusion.  He has had diarrhea for the past 1-2 days and took some over-the-counter medicines.  He returned from a cruise to Mexico 4 days ago.  He ate shellfish and raw oysters with fried rice at a local restaurant 2 days ago.
His other medical problems include alcoholic liver cirrhosis, type 2 diabetes mellitus, hypertension, and mild chronic kidney disease.  His medications include spironolactone, long-acting insulin, and propranolol.  He is an ex-smoker and drinks 1-2 cans of beer on weekends.  He occasionally smokes crack cocaine and marijuana.
His temperature is 38.9 C (102 F), blood pressure is 70/30 mm Hg, pulse is 124/min, and respirations are 22/min.  Examination shows bilateral basal crackles.  The abdomen is distended and non-tender.  His skin shows multiple bullous lesions.
Laboratory results are as follows:
 Despite aggressive fluid resuscitation and antibiotics, the patient dies in the emergency department.
Which of the following is most likely responsible for this patient's initial presentation?

Accepted Answer

This patient's presentation is consistent with Vibrio vulnificus infection, a gram-negative bacterium that causes serious wound infections and sepsis. The organism is most virulent in patients with cirrhosis, hemochromatosis, and chronic diseases (e.g., diabetes mellitus, chronic kidney disease, hepatitis). Vibrio vulnificus is associated with undercooked or raw shellfish, especially raw oysters. Since the infection can be fatal, high-risk patients should avoid eating, or even handling, raw shellfish. Patients typically present with wound infections, sepsis without a clearly defined infectious source, and/or gastroenteritis with characteristic bullous skin lesions. Diagnosis is confirmed with culture (wound, stool, blood), and suspected patients should receive immediate antibiotics (e.g., tetracycline) with close ICU monitoring. Patients can rapidly decompensate (within 12 hours) and develop bullous lesions, DIC, and even death. (Choice A) Crack cocaine use is usually associated with decreased gastric motility, euphoria, chest pain, shortness of breath, and occasional vasculitis in the skin. This patient's diarrhea, sepsis, and bullous lesions make this less likely. (Choice B) Norwalk virus is associated with cruise ships and can survive chlorination and other forms of disinfection. The virus usually presents with self-limited diarrhea (2-3 days) without the skin lesions seen in this patient. (Choice C) Toxins in fried rice are typically associated with Bacillus cereus food poisoning. Patients usually present with a self-limited and rapid onset of nausea and vomiting, usually within 1-6 hours of ingestion. Diarrhea may occur later in the disease, but it rarely causes sepsis as seen in this patient. (Choice D) Although a visit to Mexico can expose the patient to multiple organisms that cause diarrhea or acute gastroenteritis, it is not a significant risk factor for V. vulnificus infection. Educational objective: Vibrio vulnificus is found in shellfish and can cause potentially fatal infections in patients with chronic liver disease and cirrhosis. Suspected patients should be treated promptly with antibiotics and ICU monitoring. High risk groups (i.e., hepatitis, hemochromatosis, cirrhosis) should avoid consumption or contact with raw shellfish. __________ References: Vibrio vulnificus oysters: pearls and perils (http://www.ncbi.nlm.nih.gov/pubmed/21367733) Vibrio vulnificus infection: an important cause of septicemia in patients with cirrhosis. (http://www.ncbi.nlm.nih.gov/pubmed/9347818) Spontaneous Vibrio vulnificus peritonitis and primary sepsis in two patients with alcoholic cirrhosis. (http://www.ncbi.nlm.nih.gov/pubmed/3898820)

Question 20

A 50-year-old man is brought to the emergency department due to fever, malaise, confusion, and worsening headache for the last 8 days. He has a history of advanced AIDS and is noncompliant with antiretroviral therapy. His most recent CD4 lymphocyte count a month ago was 29/mm³. His other medical problems include hypertension and chronic hepatitis C infection. The patient's temperature is 38.8 C (101.8 F), blood pressure is 110/70 mm Hg, pulse is 94/min, and respirations are 16/min. He is disoriented to place and time and has a left-sided visual field deficit. The remainder of the examination is unremarkable. CT scan of the head without contrast is normal. A lumbar puncture yields the following results: India ink preparation of the cerebrospinal fluid shows encapsulated yeast. The patient is started on amphotericin B. In addition to antifungal therapy, which of the following is the most effective strategy to improve this patient's outcome?

Accepted Answer

11ec193a_9627_f00d_853d_2f6d8d12e61a_MD0002_00 This patient's presentation is consistent with cryptococcal meningoencephalitis, an invasive fungal infection caused by Cryptococcus neoformans. Although the organism originates from a pulmonary infection, patients with HIV most commonly have meningoencephalitis symptoms (eg, headache, fever, stiff neck, malaise). Antifungal therapy is the preferred initial treatment for yeast eradication and is frequently given in several phases. Induction therapy consists of 2 weeks of amphotericin B +/- flucytosine. Patients who achieve cerebrospinal fluid (CSF) yeast eradication may be switched to 8 weeks of consolidation therapy with fluconazole. Most are then given daily maintenance fluconazole for 1 year, but it is discontinued in select asymptomatic patients whose CD4 counts increase to >100/mm³ with antiretroviral therapy. ³ Increased intracranial pressure (ICP), indicated by CSF opening pressure >200 mm H₂O (20 cm H₂O), occurs in >50% of cryptococcal meningoencephalitis patients and can cause headache, altered mentation, visual/hearing loss, and cranial nerve deficits. Increased ICP is associated with increased mortality. If there are symptoms of increased ICP, lumbar puncture (LP) is recommended to reduce ICP to <200 mm H₂O (20 cm H₂O) or by 50%. It often needs to be repeated daily if ICP elevation and symptoms persist. Patients who do not respond to serial LPs and antifungal therapy may require ventriculostomy drain. (Choice A) Acetazolamide is often used to reduce ICP and pulmonary edema in altitude sickness, but it is not effective in cryptococcal meningoencephalitis. In addition, acetazolamide may lead to renal injury when given with amphotericin B. (Choice B) Corticosteroids may reduce intracerebral edema (eg, vasogenic edema around brain tumors), but they are not effective in reducing ICP due to cryptococcal meningoencephalitis. (Choice C) It is unclear when to start antiretroviral therapy in the setting of cryptococcal meningoencephalitis, but giving it prematurely may lead to immune reconstitution inflammation syndrome. Most clinicians prefer to start antiretroviral therapy 2-10 weeks after starting antifungal therapy. (Choice D) Mannitol can reduce ICP from cerebral edema (eg, traumatic brain injury), but it is not effective in cryptococcal meningoencephalitis. Educational objective: Cryptococcal meningoencephalitis usually presents in HIV patients with headache, fever, stiff neck, and possible altered mental status with neurological deficits. Treatment involves prompt antifungal therapy in 3 phases (induction, consolidation, and maintenance). Patients often require serial lumbar punctures to reduce the increased intracranial pressure frequently seen with the infection. __________ References: Clinical practice guidelines for the management of cryptococcal disease: 2010 update by the Infectious Diseases Society of America. (http://www.ncbi.nlm.nih.gov/pubmed/20047480) Treatment of acute cryptococcal meningoencephalitis in HIV infected adults, with an emphasis on resource-limited settings. (http://www.ncbi.nlm.nih.gov/pubmed/18843697)

Exam 1: Emergency Department