A 63‐year‐old male Vietnam War veteran noted a 6‐month history of watery diarrhea; he was admitted for volume depletion. The patient had been in Vietnam for 1 year in 1970; there were no recent travels. Vital signs demonstrated a BP of 85/41 mm Hg and a pulse of 101 beats/minute; the physical examination was otherwise unremarkable. His hypotension and tachycardia resolved with volume repletion. Lab work revealed peripheral eosinophilia of 20.9%. Three stool samples were negative for ova and parasites. Serum enzyme‐linked immunosorbant assay (ELISA) demonstrated a positive strongyloides IgG Ab. His serum was sent to the National Institutes of Health (NIH) for a luciferase immunoprecipitation systems (LIPS) assay; it was also positive for strongyloides. The patient was treated with ivermectin 200 μg/kg/day for 2 consecutive days. Two weeks postdischarge, his eosinophilia had decreased to 11.6%; 2 months postdischarge, it had decreased to 5.3%, and his diarrhea had resolved.
Invasive strongyloidiasis is endemic in the tropical and subtropical areas of Southeast Asia and Africa. It is uncommon in the United States, with a prevalence of approximately 4% concentrated in the eastern areas of the country; for those patients diagnosed in this country, the infection is most commonly found in immigrants and refugees from endemic areas. Although 3 stool samples were negative for parasites, the sensitivity of detecting strongyloides in the stool is low, estimated at only 50% with 3 samples. In addition, although the strongyloides IgG ELISA was positive, the positive test can be secondary to cross‐reactivity from helminth infections. The newer LIPS assay for strongyloides has been shown to be not only more sensitive, but also more specific, as studies demonstrate no cross‐reactivity from helminth infections. Further, for patients who either are immunocompromised at baseline or will be administered corticosteroids, an accurate diagnosis becomes particularly important, because hyperinfection syndrome and disseminated disease can develop; without treatment the mortality rate approaches 100% in these super‐infected patients.
Although not common in the United States, invasive strongyloidiasis should be considered in patients with chronic diarrhea and peripheral eosinophilia, especially in people who inhabit endemic areas. Negative stool studies for parasites should not exclude the diagnosis of invasive strongyloides. The newer LIPS assay can diagnose strongyloides infection with greater sensitivity and specificity than the more commonly used ELISA. The point of this abstract is to reinforce how to accurately diagnose invasive strongyloides, which becomes critical for immunocompromised patients and also to educate physicians on the availability of the newer LIPS assay.
To cite this abstract:Thamwiwat A, Bates J. Chronic Diarrhea in a Vietnam War Veteran. Abstract published at Hospital Medicine 2013, May 16-19, National Harbor, Md. Abstract 411. https://www.shmabstracts.com/abstract/chronic-diarrhea-in-a-vietnam-war-veteran/. Accessed February 18, 2019.