Common Infectious Diseases Flashcards
7 cards from real Internal Medicine Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Common Infectious Diseases flashcards as text
A 40-year-old patient develops fever, headache, and a petechial rash spreading from wrists and ankles centrally after a camping trip in North Carolina. What is the most likely diagnosis?
Answer: Rocky Mountain spotted fever
Rocky Mountain spotted fever (Rickettsia rickettsii) classically begins with fever and headache before a centripetal petechial rash appears on wrists and ankles; immediate doxycycline is life-saving.
Which antibiotic is first-line for treatment of Lyme disease presenting with erythema migrans in an adult?
Answer: Doxycycline 100mg orally twice daily for 10–21 days
Doxycycline orally for 10–21 days is first-line for early Lyme disease (erythema migrans) in adults; IV ceftriaxone is reserved for neurologic or cardiac involvement.
A patient with recurrent furunculosis caused by MRSA is cleared but continues to have household transmission. Which decolonization strategy is most appropriate?
Answer: Intranasal mupirocin ointment plus chlorhexidine body wash
Intranasal mupirocin and chlorhexidine bathing decolonize MRSA carriage in both the index patient and household contacts, reducing recurrence.
A 65-year-old immunocompromised patient develops fever and a new pulmonary infiltrate with a halo sign on CT chest. What is the most likely diagnosis?
Answer: Invasive pulmonary aspergillosis
The halo sign (ground-glass opacity surrounding a nodule) on CT chest in an immunocompromised host is classic for invasive pulmonary aspergillosis.
A 50-year-old patient with cirrhosis presents with fever, abdominal pain, and ascites with PMN count > 250 cells/μL on paracentesis. What is the empiric treatment of choice?
Answer: IV cefotaxime (or ceftriaxone)
IV third-generation cephalosporins (cefotaxime or ceftriaxone) are the standard empiric therapy for spontaneous bacterial peritonitis.
Which HIV-associated opportunistic infection is prevented by trimethoprim-sulfamethoxazole prophylaxis when the CD4 count falls below 200 cells/μL?
Answer: Pneumocystis jirovecii pneumonia (PCP) and Toxoplasma
TMP-SMX prophylaxis at CD4 < 200 cells/μL prevents both PCP and Toxoplasma encephalitis (the latter when CD4 < 100 and Toxoplasma IgG positive).
A traveler returns from Southeast Asia with watery diarrhea, nausea, and abdominal cramps starting 6 hours after eating rice. No fever is present. Which pathogen is most consistent with this presentation?
Answer: Bacillus cereus (emetic toxin)
Bacillus cereus emetic syndrome presents within 1–6 hours of ingesting preformed toxin in starchy foods like rice, causing vomiting and cramps without fever.