BMS Pathology and Microbiology 5 — Questions and Answers
Question 1: Which protozoan parasite, identified in brain tissue at autopsy, causes ring-enhancing lesions and is common in AIDS patients?
- Toxoplasma gondii (Correct answer)
- Plasmodium falciparum
- Trypanosoma brucei
- Naegleria fowleri
Correct answer: Toxoplasma gondii
T. gondii reactivates in immunocompromised patients (especially CD4 <100), forming multiple ring-enhancing abscesses in the basal ganglia.
Question 2: Spongiosis of the gray matter with astrocytic proliferation (gliosis) found at autopsy is characteristic of:
- Creutzfeldt-Jakob disease (Correct answer)
- Multiple sclerosis
- Alzheimer disease
- Parkinson disease
Correct answer: Creutzfeldt-Jakob disease
Prion diseases cause spongiform encephalopathy — vacuolization of neuropil creating a sponge-like appearance with reactive gliosis but no inflammation.
Question 3: Which bacterium produces a potent exotoxin causing the 'washerwoman hands' skin appearance seen in cholera victims?
- Vibrio cholerae (Correct answer)
- Clostridium botulinum
- Bacillus anthracis
- Corynebacterium diphtheriae
Correct answer: Vibrio cholerae
Cholera toxin activates adenylate cyclase, causing massive secretory diarrhea leading to severe dehydration and the characteristic wrinkled skin of hands and feet.
Question 4: At autopsy, brown induration of the lung suggests chronic pathology associated with which condition?
- Left-sided heart failure (Correct answer)
- Pulmonary tuberculosis
- Lung carcinoma
- Sarcoidosis
Correct answer: Left-sided heart failure
Chronic left heart failure causes repeated pulmonary congestion; hemosiderin-laden macrophages ('heart failure cells') accumulate, producing brown induration.
Question 5: Which universal precaution is most critical when performing autopsies on decedents with known bloodborne pathogen infections?
- Double gloving with cut-resistant gloves (Correct answer)
- Using alcohol-based hand rub only
- Avoiding use of sharps entirely
- Working without ventilation
Correct answer: Double gloving with cut-resistant gloves
Double gloving with cut-resistant inner gloves significantly reduces percutaneous injuries and the risk of HBV, HCV, and HIV transmission during autopsy.
Question 6: Which type of cell death is characterized by cell shrinkage, chromatin condensation, and membrane blebbing without inflammation?
- Apoptosis (Correct answer)
- Necrosis
- Pyroptosis
- Necroptosis
Correct answer: Apoptosis
Apoptosis is programmed cell death that is non-inflammatory because the cell is packaged into apoptotic bodies rapidly cleared by phagocytes.
Question 7: A postmortem liver biopsy stained with Oil Red O shows lipid droplets within hepatocytes. This finding is most consistent with:
- Hepatic steatosis (fatty change) (Correct answer)
- Glycogen storage disease
- Wilson disease
- Hemochromatosis
Correct answer: Hepatic steatosis (fatty change)
Oil Red O is a lysochrome dye that stains neutral triglycerides and lipids orange-red, confirming fatty change within hepatocytes.
BMS Pathology and Microbiology 5
Which protozoan parasite, identified in brain tissue at autopsy, causes ring-enhancing lesions and is common in AIDS patients?