FREE Internal Medicine Common Infectious Diseases Questions and Answers

Question 1

A 72-year-old male recently treated with clindamycin presents with 5-6 watery, non-bloody stools per day for three days.
He has lower abdominal cramping but no fever.
His WBC count is 10,500/μL and serum creatinine is 1.0 mg/dL.
A stool test is positive for Clostridioides difficile toxin.
According to the most recent IDSA guidelines, which of the following is the most appropriate initial treatment for this patient's non-severe C. difficile infection?

Accepted Answer

Oral Fidaxomicin 200 mg twice daily for 10 days

Answer

Oral Metronidazole 500 mg three times daily for 10 days

Answer

Oral Vancomycin 125 mg four times daily for 10 days

Answer

Oral Rifaximin 400 mg three times daily for 10 days

Question 2

A 28-year-old healthy, non-pregnant female presents with a 3-day history of dysuria, urinary frequency, and urgency. She has no fever or flank pain. A urine dipstick is positive for nitrites and leukocyte esterase. Assuming no drug allergies and local E. coli resistance rates to trimethoprim-sulfamethoxazole are known to be >20%, which of the following is the most appropriate first-line oral antibiotic?

Accepted Answer

Nitrofurantoin

Answer

Ciprofloxacin

Answer

Amoxicillin-clavulanate

Answer

Cephalexin

Question 3

A 55-year-old male with type 2 diabetes presents with a 2-day history of a warm, tender, erythematous rash on his left lower leg. The area is non-fluctuant and there is no purulent drainage or abscess. He is afebrile and hemodynamically stable. What is the most appropriate initial oral antibiotic therapy for this patient's non-purulent cellulitis?

Accepted Answer

Cephalexin

Answer

Trimethoprim-sulfamethoxazole

Answer

Doxycycline

Answer

Clindamycin

Question 4

A 45-year-old man presents with a 36-hour history of fever, myalgias, headache, and a non-productive cough during peak influenza season. A rapid influenza antigen test is positive. For an otherwise healthy outpatient, antiviral treatment with a neuraminidase inhibitor is most effective when initiated within what timeframe from symptom onset?

Accepted Answer

Within 48 hours

Answer

Within 24 hours

Answer

Within 72 hours

Answer

At any time as long as the patient is symptomatic

Question 5

A 35-year-old healthcare worker has a newly positive tuberculin skin test (12 mm induration) as part of an annual screening. A chest X-ray is normal, and she denies any symptoms such as cough, fever, or weight loss. Which of the following is a preferred short-course regimen for the treatment of latent tuberculosis infection (LTBI) in this patient?

Accepted Answer

Isoniazid and rifapentine weekly for 3 months

Answer

Isoniazid daily for 9 months

Answer

Rifampin daily for 6 months

Answer

Ethambutol and pyrazinamide daily for 2 months

Question 6

A 40-year-old man with a history of intravenous drug use presents with fever and malaise. Blood cultures are drawn, and an echocardiogram is ordered. According to the modified Duke criteria for infective endocarditis, which of the following is considered a major criterion for diagnosis?

Accepted Answer

Positive blood culture with a typical microorganism

Answer

Fever > 38.0°C (100.4°F)

Answer

Vascular phenomena, such as Janeway lesions

Answer

Immunologic phenomena, such as Osler nodes