Gastrointestinal Anisakidosis: Watch What You Eat!

Abstract

Gastrointestinal anisakidosis is an under-reported and often a misdiagnosed parasitic infection caused by the larvae of a nematode anisakis. Majority of the cases are seen in Japan due to the consumption of raw and undercooked fish dishes or cephalopods (marine mollusks such as squids, octopus); however the incidence is likely to rise in the United States given the rising popularity of Japanese cuisine like sashimi or sushi. We report a case of a 37-year-old female, who presented a day after consuming sushi at a restaurant, with severe colicky abdominal pain in the epigastrium and progressed gradually towards the periumbilical region, associated with nausea and vomiting clear fluid. On examination she was febrile with a temperature of 100.4degreeF and diffuse abdominal tenderness on palpation. The only significant lab abnormality included a WBC count of 16,000 /uL with 94% granulocytes. There were no eosinophils on differentiation. The liver profile and lipase levels were unremarkable. Qualitative beta HCG was negative. Abdominal ultrasound and computed tomography revealed free pelvic fluid collection (fig1) without any other abnormality. The patient was started on meropenem empirically. She then underwent a diagnostic laparotomy which revealed yellowish fluid in all quadrants and some induration in the lesser and greater curvature of the stomach and the ligament of treitz. Scattered exudates were seen along the small bowel and mesentery without any perforation. No obvious source of bilious peritonitis prompted an open laparotomy, which revealed a 2cm long, and 4mm wide white wriggling worm (fig2) in the peritoneal exudate. This was later confirmed on microscopic examination to be an anisakid nematode. The ascitic fluid had numerous wbc's but did not grow any organism on culture. The patient gradually improved with oral albendazole, and was discharged without any complications. This unique report highlights the importance of considering aniskiasis in the differential diagnoses for patients with non-specific abdominal symptoms with a recent history of raw or undercooked fish consumption. Thus, avoiding invasive procedures by conservatively treating with oral albendazole, if infection strongly suspected. The diagnosis can be made with the help of immunologic studies like antianisakidae antibodies i.e IgA, IgG and IgE, which have sensitivity as high as 70-80% but takes a longer time to get the results which is not helpful in critical situations. (Figure Presented).