Digestive anisakiasis: clinical manifestations and diagnosis according to localization

Digestive anisakiasis is a parasitic disease whose clinical manifestations depend on the effect of Anisakis simplex on the digestive tract wall. Larvae are acquired by eating raw or poorly cooked fish. It is estimated that this entity is currently under-diagnosed, although publications are becoming increasingly common. We analyse our series of digestive anisakiasis checking localization and studying its relationship with symptoms and method of diagnosis.

We review 23 cases of digestive anisakiasis registered between 1989 and 2001, and confirmed by the measurement of specific serum Ig E antibodies. We analyse clinical symptoms and method of diagnosis according to whether localization was gastro-duodenal or intestinal, evaluating whether surgical intervention was needed for a correct diagnosis. The statistical analysis is made using Fisher's test.

23 patients were included between 1989 and 2001, 8 with gastro-duodenal localization and 15 with intestinal localization. All patients with intestinal localization had abdominal pain. Symptoms were less severe for gastro-duodenal cases, and diagnosis was made by clinical suspicion and subsequent gastroscopy, whereas more than a half of intestinal cases required histological examination of a surgical specimen for correct diagnosis. In the remaining half, diagnosis was made by abdominal ultrasonography. We also observed that the need for surgery has decreased with time from 6/6 cases in the 1989-1996 period of time to 2/9 in the 1997-2001 period of time.

Clinical manifestations of anisakiasis vary depending on localization, symptoms being more severe in intestinal forms. The diagnosis of gastro-duodenal anisakiasis did not need surgery and was based mainly on gastroscopy findings, whereas intestinal forms frequently required histological examination of the surgical specimen. In our hospital, a higher index of clinical suspicion allowed us to diagnose intestinal anisakiasis without examination of surgical specimens in the last years.