Disseminated Strongyloides stercoralis infection in a dog following long-term treatment with budesonide.

CASE DESCRIPTION: A 1.5-year-old 1.5-kg (3.3-lb) castrated male Pomeranian was examined because of a 10-month history of diarrhea characterized by hematochezia and weight loss and an acute onset of respiratory distress (ie, tachypnea and dyspnea). A presumptive diagnosis of inflammatory bowel disease had been made previously, and the dog had been treated with budesonide and tylosin but continued to have diarrhea and weight loss.

CLINICAL FINDINGS: On initial examination, the dog was weak and slightly obtunded. Thoracic radiography revealed a moderate to severe, diffuse, unstructured interstitial pattern. Serum biochemical abnormalities consisted of mild hypoalbuminemia, hypoglycemia, hypocalcemia, hypomagnesemia, and hypocholesterolemia that were likely secondary to chronic gastrointestinal disease and malnutrition. Pyuria and moderate bacteriuria with a single live larva were found on microscopic evaluation of the urine sediment. Fecal examination revealed numerous nematode larvae; the morphology was consistent with first-stage, rhabditiform larvae of Strongyloides stercoralis.

TREATMENT AND OUTCOME: A diagnosis of disseminated S stercoralis infection was made. The dog was treated with fenbendazole and ivermectin but developed respiratory collapse approximately 12 hours later and was euthanized because of the poor prognosis. Postmortem examination revealed S stercoralis in the lungs, small intestine, and kidney.

CLINICAL RELEVANCE: Findings illustrated the importance of performing diagnostic testing, including routine fecal examination, to rule out infectious causes of diarrhea before beginning empirical treatment with glucocorticoids such as budesonide. Further, repeated fecal examinations, including Baermann tests, should be considered if a positive response to glucocorticoids is not observed.