Incidental Discovery of Early Strongyloides stercoralis Colitis in an Active Duty Service Member

Abstract

Strongyloides stercoralis is a potentially lethal parasitic infection with a broad range of clinical and endoscopic manifestations. While hyperinfection can result in dramatic colonoscopic findings that mimic ulcerative colitis, asymptomatic patients may exhibit more subtle findings such as erythema or nonspecific white lesions. A 43-year-old Nigerian born woman was referred to the gastroenterology clinic for workup of longstanding constipation. She reported onset related to her uncomplicated spontaneous vaginal deliveries. Varied laxative use yielded no improvement. The patient denied weight loss, fatigue, tenesmus, urgency, or incomplete evacuation. Travel history was remarkable for recent travel to Nigeria and annual vacations in Belize. Abdominal exam was unremarkable. A rectal exam revealed a palpable mass in the left lateral rectal wall. Laboratory evaluation was notable for a mild normocytic anemia and peripheral eosinophilia. Computed tomography of the pelvis with contrast revealed retroversion of the uterus with suggestion of mass effect on the rectum and sigmoid colon. Defacography confirmed mild uterine prolapse and a small rectocele. A subsequent optical colonoscopy revealed grossly normal colonic mucosa, with exception of external hemorrhoids and punctate white papules in the proximal right colon. Biopsy and histologic examination of the lesions revealed colonic mucosa with eosinophilic infiltrate and filariform S. stercoralis larva. The patient was subsequently treated with ivermectin, and referred to urogynecology for pelvic floor physical therapy. This case illustrates subtle colonoscopic findings of S. stercoralis colitis. Endoscopy in foreign born patients with a history of exotic travel requires a high index of suspicion for diagnosis of parasitic infections. In this case, the burden of parasitic disease was unlikely a prime contributor to her presenting symptom profile; however, the biopsy of suspicious lesions led to an early diagnosis of a potentially life threatening infection. Recognition of the more subtle colonoscopic findings is key to early diagnosis and treatment to prevent significant morbidity and mortality.Figure