AMC MCQ AMC MCQ - Australian Medical Council Multiple Choice Questions Infectious Diseases and Immunology Questions and Answers 2 — Questions and Answers
Question 1: A 60-year-old renal transplant recipient presents with fever and a rising serum creatinine 3 months post-transplant. CMV antigenemia assay is positive. What is the treatment of choice?
- Acyclovir
- Ganciclovir (IV) or valganciclovir (oral) (Correct answer)
- Foscarnet
- Cidofovir
Correct answer: Ganciclovir (IV) or valganciclovir (oral)
Ganciclovir IV or oral valganciclovir is the first-line treatment for CMV disease in transplant recipients.
Question 2: A 25-year-old presents with fever, sore throat, lymphadenopathy, and a positive heterophile antibody (Monospot) test. Which virus is responsible?
- Cytomegalovirus
- Human herpesvirus 6
- Epstein-Barr virus (Correct answer)
- Adenovirus
Correct answer: Epstein-Barr virus
Epstein-Barr virus causes infectious mononucleosis, characterized by the triad of fever, pharyngitis, and lymphadenopathy with a positive Monospot test.
Question 3: Which immunoglobulin class is primarily responsible for the secondary (anamnestic) immune response?
- IgM
- IgG (Correct answer)
- IgA
- IgE
Correct answer: IgG
IgG is the predominant antibody of the secondary immune response, providing long-lasting humoral immunity.
Question 4: A healthcare worker is exposed to a needlestick from an HBeAg-positive patient. The worker is unvaccinated. What is the most appropriate immediate management?
- Hepatitis B vaccination alone
- Hepatitis B immune globulin (HBIG) plus hepatitis B vaccination (Correct answer)
- Tenofovir prophylaxis
- No intervention needed
Correct answer: Hepatitis B immune globulin (HBIG) plus hepatitis B vaccination
Post-exposure prophylaxis for hepatitis B in unvaccinated individuals requires both HBIG (immediate passive immunity) and hepatitis B vaccine.
Question 5: Deficiency of which complement protein predisposes to recurrent Neisseria infections?
- C1q
- C3
- C5–C9 (terminal complement) (Correct answer)
- C4b
Correct answer: C5–C9 (terminal complement)
Deficiency of terminal complement components (C5–C9, the membrane attack complex) impairs killing of Neisseria species, predisposing to recurrent meningococcal and gonococcal infections.
Question 6: A 40-year-old presents with chronic diarrhea, weight loss, and CD4 count of 50 cells/µL. Stool acid-fast staining shows 4–6 µm oocysts. What is the causative organism?
- Giardia lamblia
- Cryptosporidium parvum (Correct answer)
- Isospora belli
- Cyclospora cayetanensis
Correct answer: Cryptosporidium parvum
Cryptosporidium parvum causes severe, profuse watery diarrhea in HIV patients with CD4 <100; oocysts are 4–6 µm and acid-fast positive.
AMC MCQ AMC MCQ - Australian Medical Council Multiple Choice Questions Infectious Diseases and Immunology Questions and Answers 2
A 60-year-old renal transplant recipient presents with fever and a rising serum creatinine 3 months post-transplant.
CMV antigenemia assay is positive.
What is the treatment of choice?