A Rare Case of Strongyloides stercoralis Hyperinfection Syndrome in an Immunocompetent Host

Abstract

Strongyloides stercoralis is an intestinal nematode endemic in humid and tropical regions. In the US, most cases occur in immigrants and military veterans who have lived in endemic regions. Immunocompetent patients usually develop an asymptomatic, chronic or mildly symptomatic infection. In immunocompromised, Strongyloides stercoralis may lead to an overwhelming infestation known as a Strongyloides hyperinfection syndrome (SHS). An 88-year-old Hispanic man presented with a three-day history of non-productive cough, nausea, vomiting, abdominal pain, and melena. Medical history was significant for atrial fibrillation (on warfarin); and transitional cell carcinoma of the kidney, status-post right nephrectomy, in remission. On initial evaluation, vital signs and abdominal examination were normal. His Initial laboratory workup was significant for an INR of 4.7 and a hemoglobin (Hb) of 12 gm/dL. Soon after admission, he had an isolated episode of hematemesis with a decline of Hb (6.5gm/dL). Prompt endoscopy revealed antral ulceration with no visible vessel. Biopsy sample obtained from third part of duodenum revealed Strongyloides stercoralis infection in the glandular epithelium. Labs were also significant for eosinophilia and elevated IgE levels. However, stool analysis (ova and parasite) were negative. Hospital course was further complicated by respiratory failure and cardiac arrest. Subsequent bronchoscopy with a bronchoscopic alveolar lavage revealed fragments suggestive of a parasite, though a definitive pathogen could not be identified. Ivermectin was initiated, which resulted in a significant improvement of clinical symptoms. Strongyloidiasis is often underdiagnosed due to nonspecific symptoms. An alteration of the immune status can increase the number of parasites and lead to SHS, dissemination, and death, if unrecognized. As illustrated in our case, SHS patients with dissemination may present with severe gastrointestinal complaints such as bleeding or ulcers, and/or significant respiratory complaints, that lead to the diagnosis of strongyloidiasis via endoscopy or bronchoscopy. SHS is usually associated with immunosuppression. However, SHS should be suspected in immunocompetent patients who hail from endemic areas, and who have persistent gastrointestinal and/or pulmonary manifestations. Rapid diagnosis and treatment can prevent high case-fatality rates.Figure