A 7-year-old child presents with dry cough, wheeze, fever, and marked blood eosinophilia. Chest radiograph shows bilateral patchy infiltrates. Sputum shows Charcot-Leyden crystals and larvae. The syndrome results from which process?

• A Immediate hypersensitivity reaction to inhaled adult worm antigens
• B Obstruction of bronchi by adult worms ascending from the intestine
• C Direct destruction of alveoli by hatching eggs in the pulmonary capillaries
• D Immunological reaction to migrating Ascaris lumbricoides larvae in the lungs ✓

Explanation

Loeffler syndrome is a transient eosinophilic pneumonitis caused by hypersensitivity to Ascaris lumbricoides larvae migrating through the lungs during their obligatory hepatopulmonary circuit after ingestion of eggs. Larvae break out of alveolar capillaries, provoking eosinophilic infiltration, and may be found in sputum along with Charcot-Leyden crystals. Adult worms live in the small intestine and never reach the lung, and eggs hatch in the intestine, not the pulmonary circulation.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.