BACKGROUND
Extreme hypereosinophilia is an uncommon but clinically important laboratory finding that may indicate serious underlying disease. In tropical regions, parasitic infections, particularly Strongyloides stercoralis, should be considered. However, the diagnosis may be overlooked in critically ill patients with multiple concurrent infections. Because disseminated strongyloidiasis carries high mortality when diagnosis is delayed, early recognition and empirical anti-helminthic therapy are essential in endemic settings.
CASE REPORT
A 63-year-old Vietnamese farmer was transferred after 18 days of treatment for bacterial meningitis, intraventricular hemorrhage, Corynebacterium striatum pneumonia, and Candida auris infection. She remained critically ill and required respiratory support through a tracheostomy. Laboratory testing showed marked leukocytosis with extreme hypereosinophilia, severe anemia, profound hypoalbuminemia, acute kidney injury, electrolyte disturbances, and severe systemic inflammation. Arterial blood gas analysis confirmed hypoxemic respiratory failure. Given the extreme eosinophilia and endemic setting, disseminated strongyloidiasis was suspected, and empirical oral ivermectin was started before diagnosis. Strongyloides-specific IgG serology was positive, and Strongyloides stercoralis larvae were identified in sputum, confirming the diagnosis. The absolute eosinophil count declined from >10 000 cells/µL to 450 cells/µL by the next day, 180 cells/µL by treatment day 3, and 140 cells/µL by day 5. Her systemic condition remained stable for approximately 2 weeks; however, she subsequently developed recurrent intracranial hemorrhage and died in hospital.
CONCLUSIONS
This case highlights that strongyloidiasis should be considered in patients with unexplained marked eosinophilia, even when severe bacterial or fungal infections dominate the clinical presentation. In endemic regions, early clinical suspicion and timely empirical anti-helminthic therapy may be crucial to prevent potentially fatal disseminated strongyloidiasis, particularly in malnourished and medically complex patients.

Keywords: Eosinophilia; Helminths; Hypereosinophilic Syndrome; Strongyloidiasis