Strongyloides stercoralis hyperinfection syndrome in immunocompetent patients

A 73-year-old male farmer, with no prior chronic illnesses, was admitted to the Emergency Intensive Care Unit (EICU) with a two-day history of fever, productive cough, and dyspnea. Due to rapidly worsening respiratory distress and shock, he was intubated on the day of admission. A fiberoptic bronchoscopy was performed, and bronchoalveolar lavage fluid (BALF) was collected. Chest computed tomography (CT) revealed multiple segmental infections throughout the left lung, distributed along the bronchi (Fig. 1). Metagenomic next-generation sequencing (mNGS) of the BALF identified sequences of Strongyloides stercoralis, and live filariform larvae were observed in both BALF (Fig. 3) and stool specimens (Fig. 4) under microscopy. We initially used albendazole (0.4g bid nasal feeding), but the patient's respiratory function worsened. On the fourth day, we switched to ivermectin (12mg qd nasal feeding). By the 11th day, the patient's lung imaging and respiratory function improved (Fig.2), and the endotracheal tube was removed. However, he experienced gastrointestinal bleeding on days 15 and 35, which was confirmed via endoscopy to be due to gastric ulcers; no lesions were found in the colon or rectum. The patient was successfully discharged on day 53. Throughout his hospitalization, no underlying conditions causing immunosuppression were identified, and there was no history of immunosuppressive or corticosteroid medication use. While Strongyloides stercoralis hyperinfection syndrome is commonly seen in immunocompromised individuals, it can rarely occur in immunocompetent patients( 1 Czeresnia J.M. Weiss L.M. Strongyloides stercoralis. Lung. 2022; 200: 141-148https://doi.org/10.1007/s00408-022-00528-z Crossref PubMed Scopus (25) Google Scholar , 2 Gordon C.A. Utzinger J. Muhi S. Becker S.L. Keiser J. Khieu V. et al. Strongyloidiasis. Nat Rev Dis Primers. 2024; 10: 6https://doi.org/10.1038/s41572-023-00490-x Crossref Scopus (3) Google Scholar ). The identification of Strongyloides stercoralis sequences through mNGS in the patient's BALF was pivotal in guiding further microscopic examination of BALF and stool specimens, thus altering the early treatment strategy. Figure 3 View Large Image Figure Viewer Download Hi-res image Figure 4 View Large Image Figure Viewer Download Hi-res image Figure 2 View Large Image Figure Viewer Download Hi-res image