Intestinal anisakiasis as a rare cause of small bowel obstruction

Anisakiasis, a parasitic infection by larvae of the nematode Anisakis found in raw or undercooked saltwater fish, mostly involves stomach but rarely small intestine. We report a rare case of a 61-year-old man who presented with abdominal pain and developed small bowel obstruction caused by intestinal anisakiasis. Abdominal computed tomography revealed segmental edema of the intestinal wall with proximal dilatation. The patient underwent urgent laparotomy because strangulated small bowel obstruction was suspected. A localized portion of the intestine around jejunoileal junction was found to be erythematous, edematous, and hardened, which was resected. The resected specimen showed a linear whitish worm, Anisakis simplex, penetrating into the intestinal mucosa. It is often clinically challenging to consider intestinal anisakiasis in the differential diagnosis because of its nonspecific abdominal symptoms and findings. Although gastrointestinal anisakiasis is still rare in the United States, the incidence is expected to rise given the growing popularity of Japanese cuisine such as sushi or sashimi. Anisakiasis should be considered as one of the differential diagnoses in patients with nonspecific abdominal symptoms after consumption of raw or undercooked fish.