Albendazole for the Treatment of Anisakiasis Ileus

Sir—Anisakis simplex is a nematode parasite that belongs to the family Anisakidae. Humans can become accidental hosts by eating raw or undercooked fish that contain the third-stage larvae of A. simplex parasites [1]. Clinical presentations of anisakiasis range from allergic manifestations to different digestive symptoms, depending on the effect the parasite has on the digestive tract wall [1]. Common sites for this disease are the stomach and the small bowel [1]. Clinical diagnosis of intestinal anisakiasis is difficult because the symptoms are not specific. Intestinal anisakiasis may resolve spontaneously with conservative treatment, but some paitents develop serious complications, such as intestinal perforation, or end up requiring surgery because of intestinal obstruction [2, 3]. Here we describe 3 patients with small bowel obstruction who underwent empirical treatment with albendazole on the basis of clinical suspicion of anisakiasis. Informed consent was obtained from all patients, and the ethics committee of our institution approved our study. All 3 patients had a previous history of ingestion of anchovies in vinegar and were admitted to the emergency department with abdominal pain. All had a normal temperature, and x-ray films of the abdomen showed small bowel obstruction, with a dilated small bowel loop and/or air-fluid levels (table 1). Albendazole tablets were administered at a dosage of 400 mg orally twice per day, followed by gastric decompression with a nasogastric tube for 1 h. After this, each patient had A. simplex infection confirmed with a skin-prick test (International Pharmaceutical Immunology) and/or by the presence of specific IgE against A. simplex (CAP system, Pharmacia). The detection limit for specific IgE against A. simplex is <0.35 kU/L. Sensitization to seafood was not detected. In patient 1, gastroscopy showed gastric erosion without visible larvae. A pathologic examination revealed focal lymphocyte infiltrates and isolated plasma cells in the lamina propria. There were rare Helicobacter pylori, but neither eosinophils nor parasites were found. Patient 2 required surgery 24 h after the start of albendazole therapy. The decision to perform surgery was based on the worsening of abdominal symptoms and an increase in the leukocyte count to 20,000 cells/µL. Laparoscopy was performed and showed free peritoneal fluid and segmental dilatation of the small bowel. There was no obvious mechanical obstruction, and intestinal resection was not performed. The postoperative evolution was uneventful. A great proportion of the patients with small bowel obstruction end up requiring surgery, although the percentage varies widely depending on the etiology and on the protocol of the particular hospital. In those cases caused by Anisakis species the percentage of patients who require surgery is not known, but it could reach 50% [4]. Anisakis parasites may cause intestinal obstruction by inflammatory reaction and thickening of the intestinal wall [1], in the intestinal segment where they penetrate the intestinal wall [2]. Although treatment of intestinal obstruction with intravenous fluid and gastric decompression reduced the abdominal cramps and the radiological signs of intestinal obstruction [4], surgery is usually indicated when the disease is refractory to a conservative approach [2]. The activity of albendazole against larval A. simplex has been shown both in vitro and in experimentally infected guinea pigs [5]. There are some reports of albendazole or thiabendazole treatment in isolated cases of human anisakiasis; however, to our knowledge, no case of intestinal obstruction has been treated with albendazole. We describe 3 patients with small bowel obstruction who received empirical treatment with albendazole in which intestinal resection was not necessary. This report is the first to show a possible therapeutic benefit for albendazole treatment for patients with intestinal obstruction caused by Anisakis parasites. Potential conflicts of interest. All authors: no conflicts. Clinical and serological findings for the 3 patients treated with albendazole for anisakiasis ileus.