ID board review: part 2

1. ID board review: part 2 CNS, fungal, viral, and tick-borne infections; HIV; immunology

2. Question 1 • A 35-year-old man is evaluated in the ED 72 hours after initiation of clindamycin and quinine therapy for peripheral blood smear–confirmed babesiosis. The patient showed improvement the first 48 hours after treatment, but his condition has now begun to deteriorate. Recent travel history includes a 1-month trip to Cape Cod, Massachusetts, from which he returned to his home in New York City 1 week ago. • On physical examination, temperature is 40.0 °C, blood pressure is 90/60 mm Hg, and pulse rate is 110/min. There is conjunctival icterus. Lymphadenopathy is absent, and the neck is supple. Cardiopulmonary examination is normal. Abdominal examination reveals a tender right upper quadrant with hepatomegaly.

3. Labs • Hemoglobin 9.2 g/dL • Platelet count 40,000/µL • Leukocyte count 2700/µL • Alanine aminotransferase 874 U/L • Blood cultures from 72 hours ago negative • Bilirubin 7.4 mg/dL • CXR normal

4. Which of the following is the most appropriate treatment at this time? • A: Begin cefepime and vancomycin • B: Begin corticosteroids • C: Begin doxycycline • D: Switch to atovaquone and azithromycin

5. C: Begin doxycycline • Babesia is transmitted by Ixodes scapularis ticks • Ixodes ticks can be doubly and triply infected with Babesia, Borrelia burgdorferi, and Anaplasma phagocytophilum. • HGA typically causes fever, headache and myalgias • HGA (and acute Lyme) treated with doxycycline

7. Anaplasmosis Babesiosis (maltese cross) P. falciparum (multiple parasites/RBC) P. ovale

8. Question 2 • A 62-year-old man is evaluated in July for a 24-hour history of fever, myalgia, and a frontal headache. He is otherwise healthy and takes no medications. • Recent travel includes a 2-week camping trip to the Blue Ridge Mountains of Virginia 11 days ago. The patient does not recall a specific insect or tick bite. • On physical examination, the patient appears mildly ill. Temperature is 38.7 °C (101.6 °F), blood pressure is 125/65 mm Hg, pulse rate is 90/min, and respiration rate is 18/min. There is no lymphadenopathy or rash. Cardiopulmonary and abdominal examinations are normal.

9. Labs

10. Which of the following is the most appropriate next step in management? • A: Doxycycline • B: Oseltamivir • C: Postpone treatment pending diagnostic test results • D: Vancomycin and ceftriaxone

11. A: Doxycycline • Rocky mountain spotted fever (RMSF) • R. rickettsiae • Only 15% of patients present with rash • Early treatment is indicated  infection can be fatal • Diagnosis typically by serology

13. Question 3 • A 24-year-old woman is evaluated for a 6-day history of progressively worsening generalized malaise, myalgia, frontal headache, and fever in addition to a small papule on the back of her left thigh. She returned 4 days ago from a 4-month trip to Botswana. Prior to the trip, she was immunized for hepatitis A. She has also been taking mefloquine as prophylaxis for malaria. • On physical examination, temperature is 38.7 °C, blood pressure is 110/70 mm Hg, and pulse rate is 66/min. She has a faint, maculopapular erythematous eruption on her trunk and a 1/2-cm × 1/2-cm, mildly tender, ulcerating papule on the left anterior thigh with an eschar that is surrounded by a halo of erythema. • Several ipsilateral femoral lymph nodes are enlarged.

14. Labs • Hemoglobin 12.1 g/dL • Leukocyte count 4300/µL • Creatinine 0.9 mg/dL • Alanine aminotransferase 92 U/L • Aspartate aminotransferase 94 U/L

15. Which of the following is the most likely cause of this patient’s illness? • A: Dengue virus • B: Leishmania major • C: Mycobacterium marinum • D: Rickettsia africae • E: Vibrio vulnificus

16. D. Rickettsia africae • African tick bite fever • Doxycycline for treatment • L. major Typically no systemic symptoms • Dengue fever  may have a rash but no eschar • M. marinum  waterborne, think aquariums or other water exposure • V. vulnificus  waterborne (salt water) and causes severe illness, think septic shock after eating oysters

17. Question 4 • A 30-year-old man with a 6-year history of AIDS is hospitalized for gradually increasing confusion, decreased vision, dysarthria, and right hemiparesis of 8 weeks’ duration. He has not visited his internist for more than 2 years. His CD4 cell count was 35/µL when last checked 2 years ago. There is no indication that he is currently taking any HIV-related medications. • On physical examination, he has evidence of wasting syndrome. Vital signs are normal. Funduscopic examination is normal. Neurologic examination discloses right hemiparesis and right hemianopia. He scores 18 of 30 on the Mini–Mental State Examination (normal >24/30). The remainder of the examination is normal.

18. Imaging • MRI of the brain with contrast shows five bilateral, hypodense, nonenhancing lesions in the white matter of the periventricular parieto-occipital region with no mass effect.

19. Which of the following is the most likely diagnosis? • A: Cytomegalovirus encephalitis • B: Primary central nervous system lymphoma • C: Progressive multifocal leukoencephalopathy (PML) • D: Toxoplasmosis

20. C: PML • Demyelinating disease caused by JC virus • Typically occurs at CD4 count <50 • No mass effect on imaging • Treatment is HAART • CNS lymphoma  often mass effect • CMV encephalitis  usually periventricular • Toxoplasmosis  ring enhancing, mass effect

22. Question 5 • A 25-year-old pregnant woman at 25 weeks’ gestation undergoes a new-patient evaluation. She has recently diagnosed HIV infection and has never taken antiretroviral therapy. Her current CD4 cell count is 550/µL, and her HIV viral load is 20,000 copies/mL. She takes no medications except for a daily PNV. • Physical examination, including vital signs, is normal.

23. Which of the following is the most appropriate management of this patient? • A: Initiate antiretroviral therapy when CD4 cell count is <500/µL • B: Initiate zidovudine-lamivudine and efavirenz now • C: Initiate zidovudine, lamivudine, and lopinavir-ritonavir now • D: Initiate zidovudine therapy at delivery

24. C: AZT, 3TC, Kaletra • Pregnancy is an indication for HAART at all CD4 counts • With virologic suppression there is very low risk of MTCT • Zidovudine should always be included in regimen • Efavirenz is teratogenic

25. Question 6 • A 36-year-old woman is evaluated for repeated episodes of sinusitis. Five years ago, she had a prolonged episode of maxillary sinusitis requiring treatment with amoxicillin. Since then, she has had three episodes of sinusitis and two episodes of bacterial pneumonia that have responded well to antibiotic therapy. The patient is otherwise well. • On physical examination, vital signs are normal. BMI is 26. Pulmonary examination reveals a few crackles at the right posterolateral lung base. Complete blood count, serum electrolytes, renal function tests, and HIV serologies are normal. • Radiographs of the chest reveal diffuse, right lower lobe densities. A CT scan of the head shows mucosal thickening in the maxillary, sphenoid, and ethmoid sinuses, and a CT scan of the chest reveals bronchiectasis and bullous changes in the right lower lobe.

26. Which of the following is the most appropriate next diagnostic step? • A: Bone marrow aspirate • B: Bronchoscopy with bronchoalveolar lavage • C: HIV RNA viral load testing • D: Quantitative immunoglobulin assay • E: T-cell subset panel

27. D: Quantitative immunoglobulin assay • Typical presentation for common variable immunodeficiency (CVID) • Bronchoscopy  unlikely to yield cause of recurrent sinus infections • HIV VL  Not a good history for acute HIV • Bone marrow  No hematologic abnormalities

28. Question 7 • A 26-year-old man with a history of AIDS is evaluated for a sudden widespread eruption of skin lesions. His last office visit was 1 year ago when his CD4 cell count was 50/µL. At that time, Bactrim, azithromycin, and HAART were initiated, but the patient discontinued them owing to persistent nausea and vomiting and did not return for follow-up care until today. • On physical examination, he appears cachectic. Temperature is 38.3 °C. Skin findings, which are widely disseminated but concentrated on the face, scalp, and neck, consist of 2- to 5-mm umbilicated papules with surrounding erythema. • The remainder of the physical examination is normal.

29. Which of the following is the most likely diagnosis? • A: Cytomegalovirus infection • B: Disseminated cryptococcal infection • C: Herpes simplex virus infection • D: Mycobacterium avium complex

30. B: Disseminated cryptococcal infection • Must have high index of suspicion in HIV patients • Lesions appear similar to molluscum contagiosum • CMV and MAI don’t usually cause rash • HSV rash causes vesicles

31. Treatment of cryptococcal infection in HIV infected patients • CNS disease: • Amphotericin B +/- flucytosine • Pulmonary/disseminated disease: • Mild/moderate: fluconazole, itraconazole, voriconazole, posaconazole • Severe: Amphotericin B

32. Question 8 • A 31-year-old man is evaluated for a 12-day history of low-grade fever, pleuritic chest pain, and a nonproductive cough. Two weeks ago, the patient traveled to Phoenix, Arizona, for 3 days to play in a golf tournament. He lives in central Pennsylvania. Medical history is noncontributory, and he takes no medications. • On physical examination, temperature is 37.7 °C (100.0 °F). The remaining vital signs are normal. Chest examination reveals occasional bibasilar crackles. • The leukocyte count is 7400/µL (7.4 × 109/L) with 52% neutrophils, 32% lymphocytes, 10% monocytes, and 6% eosinophils. Chest radiographs show bilateral small, scattered infiltrates and bilateral pleural effusions. • Thoracentesis is performed and yields 300 mL of amber-colored turbid fluid with a leukocyte count of 1200/µL (1.2 × 109/L) with 88% lymphocytes and 12% neutrophils. Gram stain and acid-fast bacilli stain show no organisms.

33. Which of the following is the most likely cause of this patient’s illness? • A: Blastomyces dermatitidis • B: Coccidioides immitis • C: Cryptococcus neoformans • D: Fusarium oxysporum • E: Histoplasma capsulatum

35. Histoplasmosis (Ohio River Valley Fever) Coccidiodomycosis (San Jauquin River Valley Fever) Blastomycosis

36. Question 9 • A 52-year-old woman is evaluated for a 6-week history of generalized malaise and fatigue. She received a kidney transplant 15 years ago for hypertension-related renal failure. Her current medications include CSA and AZA. • The vital signs and general physical examination are normal. • CBC is normal. The BUN is 56 mg/dL and the serum creatinine level is 3.0 mg/dL compared with a value 2 months ago of 1.7 mg/dL. UA is significant for 19 leukocytes/hpf, no erythrocytes, 2+ protein, and many squamous and renal tubular epithelial cells, some of which have intranuclear inclusions.

37. Infection with which of following is the most likely cause of this patient’s worsening kidney function? • A: Cytomegalovirus • B: Epstein-Barr virus • C: Human herpesvirus-8 • D: Polyomavirus BK virus • E: Polyomavirus JC virus

38. D: Polyomavirus BK virus • BKV induced cystitis and nephropathy occur post-kidney transplant • Often hemorrhagic • CMV doesn’t typically cause nephropathy • EBV doesn’t cause nephropathy • HHV-8 causes Kaposi’s sarcoma • JCV causes PML

39. Question 10 • A 35-year-old woman is evaluated for chronic, nonhealing, painful erosive genital lesions. The lesions have been treated with IV acyclovir, 15 µg/kg three times daily, for 14 days. The patient has AIDS with a CD4 cell count of 55/µL. She recently began taking HAART and Bactrim daily. • Physical examination discloses multiple 2- × 3-cm erosive lesions surrounding the vaginal introitus and on the right labia. • Viral culture is positive for HSV- 2 that is resistant to acyclovir.

40. Which of the following is the most appropriate treatment? • A: Famciclovir • B: Foscarnet • C: Penciclovir • D: Valacyclovir

41. B: Foscarnet • Foscarnet is the drug of choice for acyclovir resistant HSV • Doesn’t require TK mediated phosphorylation • Primary foscarnet toxicity is nephrotoxicity • Famciclovir, penciclovir work by same mechanism as acyclovir • Valacyclovir is oral prodrug of acyclovir

42. Question 11 • A 57-year-old man is evaluated for a 2-day history of fever, severe myalgia, and a frontal headache. He denies cough, diarrhea, abdominal pain, or urinary tract symptoms. He returned 1 week ago from a vacation in Puerto Rico. He slept in a well-screened room under mosquito netting. • On physical examination, the patient is moderately ill appearing. Temperature is 39.2 °C, blood pressure is 108/75 mm Hg, pulse rate is 96/min, and respiration rate is 18/min. There is a maculopapular rash on his trunk. The remainder of the examination is normal.

43. Labs • Hemoglobin 14.8 g/dL • Leukocyte count 3700/µL • Platelet count 99,000/µL • Creatinine 1.1 mg/dL • Alanine aminotransferase 84 U/L • Aspartate aminotransferase 92 U/L • INR 1.1 • Activated partial thromboplastin time 27s • Urinalysis normal

44. Which of the following is the most likely diagnosis? • A: Chikungunya • B: Dengue • C: Influenza • D: Malaria • E: Typhoid fever

45. B: Dengue • Typical presentation for dengue • Chikungunya occurs in Asia, Africa • Influenza not associated with rash, thrombocytopenia, LFT abnormalities • Malaria doesn’t occur in Puerto Rico • Typhoid may present similarly but rash is not as prominent or absent