ITE Infectious Disease Management 5 — Questions and Answers
Question 1: A 28-year-old man presents with genital ulcers and painful inguinal lymphadenopathy (buboes). He recently returned from a trip to Africa. The ulcers are soft and painful. What is the most likely diagnosis and treatment?
- Syphilis; benzathine penicillin G IM
- Chancroid; azithromycin 1g single dose (Correct answer)
- Genital herpes; acyclovir 400mg TID
- LGV; doxycycline 100mg BID x 21 days
Correct answer: Chancroid; azithromycin 1g single dose
Chancroid (Haemophilus ducreyi) presents with painful soft ulcers and suppurative buboes; azithromycin 1g PO single dose is one of the recommended treatments.
Question 2: A 50-year-old woman on long-term prednisone for rheumatoid arthritis develops disseminated Strongyloides infection. What is the treatment?
- Mebendazole 500mg single dose
- Ivermectin 200mcg/kg daily x 2 days (Correct answer)
- Albendazole 400mg BID x 7 days
- Praziquantel 20mg/kg TID x 1 day
Correct answer: Ivermectin 200mcg/kg daily x 2 days
Ivermectin is the drug of choice for Strongyloides stercoralis; in disseminated disease, it is given daily until stool exams are negative for 2 consecutive weeks.
Question 3: A 40-year-old HIV-positive man (CD4 40) on antiretrovirals develops vision loss. Fundoscopic exam shows yellow-white perivascular exudates with hemorrhage ('pizza pie' appearance). What is the diagnosis and treatment?
- Toxoplasma retinitis; pyrimethamine plus sulfadiazine
- CMV retinitis; IV ganciclovir or oral valganciclovir (Correct answer)
- Ocular histoplasmosis; itraconazole
- Cryptococcal chorioretinitis; fluconazole
Correct answer: CMV retinitis; IV ganciclovir or oral valganciclovir
CMV retinitis in advanced AIDS presents with the classic 'pizza pie' fundoscopic appearance and is treated with valganciclovir 900mg BID for induction followed by maintenance therapy.
Question 4: A 65-year-old immunocompetent man presents with fever, altered mental status, and CSF pleocytosis with lymphocyte predominance, elevated protein, and normal glucose. HSV-1 encephalitis is suspected. What test confirms the diagnosis?
- CSF culture for HSV
- Brain biopsy for Cowdry type A inclusions
- CSF HSV PCR (Correct answer)
- Serum HSV IgM antibodies
Correct answer: CSF HSV PCR
CSF HSV PCR is the diagnostic test of choice for HSV encephalitis, with sensitivity >95% and specificity >99%, replacing brain biopsy as the gold standard.
Question 5: A 45-year-old patient from the Ohio River Valley presents with fever, weight loss, and mediastinal lymphadenopathy. BAL reveals intracellular yeast within macrophages. What is the treatment for severe disseminated histoplasmosis?
- Fluconazole 400mg daily x 12 months
- Liposomal amphotericin B followed by itraconazole (Correct answer)
- Voriconazole 200mg BID
- Echinocandin plus itraconazole
Correct answer: Liposomal amphotericin B followed by itraconazole
Severe or disseminated histoplasmosis is treated with liposomal amphotericin B for induction (1-2 weeks) followed by step-down to itraconazole for 12 months.
Question 6: A 70-year-old nursing home resident develops fever, productive cough, and hypoxia. Urinary antigen is positive. She has sulfa allergy. CXR shows lobar consolidation. What is the most likely pathogen and first-line treatment?
- Legionella pneumophila; azithromycin or fluoroquinolone (Correct answer)
- Streptococcus pneumoniae; ceftriaxone
- Klebsiella pneumoniae; piperacillin-tazobactam
- Staphylococcus aureus; vancomycin
Correct answer: Legionella pneumophila; azithromycin or fluoroquinolone
Positive urinary antigen in pneumonia diagnoses Legionella; first-line treatment is a macrolide (azithromycin) or respiratory fluoroquinolone (levofloxacin).
Question 7: A 32-year-old woman with no prior medical history presents with fever, myalgias, and rash one week after tick removal in New England. CBC shows leukopenia and thrombocytopenia. What is the most likely diagnosis?
- Rocky Mountain Spotted Fever
- Anaplasmosis (Anaplasma phagocytophilum) (Correct answer)
- Lyme disease
- Babesiosis
Correct answer: Anaplasmosis (Anaplasma phagocytophilum)
Anaplasmosis (formerly HME/HGA) presents with fever, leukopenia, thrombocytopenia, and elevated transaminases after Ixodes tick bite in the Northeast; treated with doxycycline.
ITE Infectious Disease Management 5
A 28-year-old man presents with genital ulcers and painful inguinal lymphadenopathy (buboes).
He recently returned from a trip to Africa.
The ulcers are soft and painful.
What is the most likely diagnosis and treatment?