Question

A patient who was on steroids presented with nocturnal cough and chronic urticaria. BAL stain was done. Identify the organism.

• A. Strongyloides stercoralis
• B. Enterobius
• C. Ancylostoma
• D. Capillaria philippinensis

Hint:

In an immunocompromised patient on steroids with pulmonary symptoms, think of the nematode known for autoinfection and hyperinfection syndrome.

Answer 1

The Correct Option is A

Step 1: Analyze the clinical context. The patient is on steroids (immunocompromised). Symptoms are nocturnal cough and chronic urticaria, and a BAL (bronchoalveolar lavage) stain was performed.

Step 2: Identify which parasite causes severe infection in immunocompromised patients. Strongyloides stercoralis is unique among intestinal nematodes in its ability to cause hyperinfection syndrome and Disseminated Strongyloidiasis in immunocompromised patients (e.g., those on steroids, HIV patients, HTLV-1).

Step 3: Explain the pathophysiology. S. stercoralis undergoes autoinfection -- larvae penetrate the intestinal wall or perianal skin, re-enter the bloodstream, and migrate to the lungs. This causes pulmonary symptoms (cough, wheezing) and skin symptoms (larva currens -- urticaria). BAL may reveal filariform (L3) larvae.

Step 4: Eliminate other options.

• Enterobius: causes perianal itching, not pulmonary symptoms, not associated with immunosuppression hyperinfection
• Ancylostoma: causes hookworm disease (anaemia), but hyperinfection in immunocompromised is not characteristic
• Capillaria philippinensis: causes severe malabsorption, not primarily pulmonary

Answer: Strongyloides stercoralis