A farm worker who ate raw vegetables grown in soil fertilised with human faeces develops dry cough, wheezing, and blood-tinged sputum two weeks later. Chest radiograph shows fleeting infiltrates and his eosinophil count is markedly raised. The pulmonary findings are caused by:

• A Adult worms lodged in the bronchial lumen
• B Embryonated eggs embolising to the lung parenchyma
• C Third-stage larvae breaking out of pulmonary capillaries into alveoli ✓
• D Direct invasion of lung tissue by ingested ova

Explanation

This is Loeffler syndrome due to Ascaris lumbricoides. Ingested eggs hatch in the jejunum, and third-stage larvae enter the circulation, pass through the liver and heart, and break out of pulmonary capillaries into the alveolar spaces before being swallowed again. Adults remain confined to the small intestine and never lodge in bronchi, and eggs are passed in stool rather than reaching lung tissue, so options A, B and D are incorrect.

Reference: Paniker's Textbook of Medical Parasitology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.