Small bowel obstruction caused by Anisakis and Meckel's diverticulum: a rare case

Anisakiasis is a parasitic infection caused by the ingestion of raw fish contaminated by larval nematodes of Anisakis species. Intestinal or extraintestinal manifestations are rated to > 4% and >1% respectively.

A 61-year old patient was admitted to our General Surgical and Emergency Unit because of sudden abdominal pain, vomit and constipation. He had eaten raw fish 3 days before admission. Laboratory data showed high levels of WBC and PCR. CT scanning showed "dilation of jejunum and ileum loops, thickening of the terminal ileum and cecum and signs of inflammation of the intestinal wall and mesentery". The following emergency surgical procedure was performed: laparotomy with evidence of obstruction of the small bowels, a giant Meckel's diverticulum, resection of terminal ileum and cecum and ileocolonic anastomosis. At the microscopic examination, the intestinal wall appeared occupied by a transmural inflammatory infiltrate, mainly eosinophilic, edema and nematode larvae, referable to Anisakis, surrounded by necrotic-inflammatory material. Moreover, there was evidence of giant a Meckel's diverticulum.

Normally, enteric anisakiasis exhibits leukocytosis with eosinophilia and high CRP levels. There are cases of successful medical treatment and other cases of endoscopic treatment avoiding surgical procedure. In our case, enteric Anisakias had not been taken into consideration at the moment of the operation and only histopathology could reveal Anisakis larvae inside the intestinal wall.

Our surgical approach is considered in literature as the best one for this clinical presentation. Those patients need to be better studied and more attention should be paid to their history.