Internal Medicine Exam Infectious Disease Management 3

Question 1

A 55-year-old patient on prolonged broad-spectrum antibiotics develops profuse watery diarrhea. Stool toxin assay is positive for Clostridioides difficile. He has WBC 18,000 and serum creatinine 1.8 mg/dL. What is the appropriate initial treatment?

Accepted Answer

Oral vancomycin 125 mg QID

Answer

Fidaxomicin or oral vancomycin is preferred over metronidazole for non-severe C. difficile infection; elevated WBC and creatinine indicate non-fulminant disease still treated with oral vancomycin per current IDSA guidelines.

Question 2

An HIV-positive patient with CD4 count of 150 cells/μL is started on antiretroviral therapy. Two weeks later he develops worsening cervical lymphadenopathy and fever. Lymph node biopsy shows non-caseating granulomas. What is the most likely diagnosis?

Accepted Answer

Immune reconstitution inflammatory syndrome (IRIS)

Answer

IRIS occurs when recovering immunity mounts an exaggerated response to a previously subclinical infection (here, likely mycobacterial), typically 2–8 weeks after ART initiation.

Question 3

A 70-year-old nursing home resident presents with altered mental status and dysuria. Urinalysis shows pyuria and bacteriuria. She is afebrile with stable vitals. What is the BEST management?

Accepted Answer

No antibiotic treatment; reassess in 48 hours

Answer

Asymptomatic bacteriuria in elderly women should not be treated with antibiotics, as treatment does not reduce morbidity and promotes resistance; altered mental status requires workup for other causes.

Question 4

A patient with infective endocarditis due to methicillin-susceptible Staphylococcus aureus (MSSA) on a native valve is being treated. Which antibiotic provides superior outcomes?

Accepted Answer

Nafcillin (or oxacillin)

Answer

Anti-staphylococcal penicillins (nafcillin/oxacillin) are superior to vancomycin for MSSA endocarditis due to better bactericidal activity and clinical outcomes.

Question 5

A 40-year-old cave explorer develops progressive pulmonary infiltrates and mediastinal lymphadenopathy 3 weeks after visiting bat-inhabited caves in Ohio. Serum urine antigen is positive. What is the treatment?

Accepted Answer

Itraconazole 200 mg BID

Answer

Mild-to-moderate pulmonary histoplasmosis is treated with itraconazole for 6–12 weeks; it is the drug of choice for non-severe Histoplasma capsulatum infection.

Internal Medicine Exam Practice Test

Internal Medicine Exam Practice Test

Internal Medicine Exam Infectious Disease Management 3