Ascites Caused by Intestinal Anisakiasis: A Case Report and Literature Review

Anisakiasis is a parasitic infection affecting the human gastrointestinal tract. It is caused by the consumption of contaminated, raw or inadequately cooked fish or squid, which is typically used for making sushi and sashimi. Most cases involve gastric anisakiasis, whereas intestinal anisakiasis is rare. This report describes the case of a 63-year-old Japanese woman with a history of raw fish consumption who presented with acute-onset abdominal pain and vomiting. Abdominal computed tomography (CT) demonstrated thickened small bowel loops and ascites on the liver surface. The patient was admitted for supportive care. On the second day of hospitalization, contrast-enhanced abdominal CT revealed that the ascites had moved from the liver surface to the pouch of Douglas. On the fifth day of hospitalization, the patient was discharged with a substantial improvement in abdominal pain. Five days after the discharge, her eosinophil count was elevated, and parasitic disease was therefore suspected. Anti-Anisakis IgG/A and IgE (RAST) antibody levels were elevated, confirming the diagnosis of intestinal anisakiasis. A review of 51 reported cases of intestinal anisakiasis suggests that the presence of ascites and measurement of anti-Anisakis antibody titers are helpful for diagnosis in cases presenting with nonspecific abdominal symptoms after consumption of raw or undercooked fish.