Clinical and radiological features of gastric and small intestinal anisakiasis: comparison with gastric ulcers and crohn's disease

Abstract

Purpose: To compare the clinical and radiological features of gastric and small intestinal anisakiasis with those of gastric ulcers and Crohn's disease.

Materials and methods: In this retrospective cohort study, 205 cases of anisakiasis (148 gastric; 53 small intestinal) were identified between July 2003 and February 2022. The control groups included 130 and 31 patients with gastric ulcers and Crohn's disease, respectively. Clinical and imaging findings were compared between the groups using the chi-square test, Fisher's exact test, Mann-Whitney U test, and t-test.

Results: Patients with gastric anisakiasis were younger (median age, 40 [21-85] years; 87 men) than those with gastric ulcers (median age, 64.5 [29-90] years; 101 men). Abdominal pain was common in the gastric anisakiasis group, whereas bleeding symptoms were frequent in the gastric ulcer group. Patients with small intestinal anisakiasis were older (mean age, 51.2 [38.6-63.7] years; 44 men) than those with Crohn's disease (mean age, 35.9 [21.6-50.3] years; 22 men). Patients with gastric anisakiasis exhibited more edematous wall thickening, increased surrounding fat density, ascites, and thickening of other intestinal walls than those with gastric ulcers. Patients with small intestinal anisakiasis showed greater wall edema, perienteric fat stranding, proximal dilatation, clamp sign, and ascites than those with Crohn's disease. Interobserver agreement was moderate to excellent, except for esophageal findings.

Conclusion: Anisakiasis demonstrates clinical and radiological features distinct from those of gastric ulcers and Crohn's disease. Recognizing these differences may aid in the differential diagnosis of gastrointestinal disorders, particularly in regions with high levels of raw fish consumption. This retrospective study compared CT findings of gastric and small intestinal anisakiasis with gastric ulcers and Crohn's disease. Anisakiasis exhibited distinct features, including edematous wall thickening, increased surrounding fat density, and ascites. These findings can aid in differential diagnosis, particularly in regions where raw fish consumption is common.

Keywords: Abdominal pain; Anisakiasis; Crohn’s disease; Gastric ulcer; Seafood.

Fig. 1

Flowchart of patient selection of anisakiasis cases

Fig. 2

Flowchart of patient selection of comparison cases

Fig. 3

A 55-year-old man presented to the emergency department with a complaint of abdominal pain since the day before. Contrast-enhanced CT images in the coronal plane demonstrate edematous wall thickening of the stomach and increased density of the surrounding fat tissue (Fig. 3a, arrow). Similar edematous wall thickening and increased fat density are seen in the small intestine and colon at the ileocecal region on coronal and axial contrast-enhanced CT images (Fig. 3b, C, arrows). An Anisakis larva was identified and removed during upper gastrointestinal endoscopy (Fig. 3d, arrow)

Fig. 4

A 56-year-old man presented to the emergency department with a complaint of abdominal pain since the previous day. Axial post-contrast CT images show edematous wall thickening of the small intestine (Fig. 4a, arrow), along with proximal small bowel dilatation (Fig. 4a, arrowhead) and increased fat density. Coronal and sagittal post-contrast CT images demonstrate progressive intestinal wall thickening at the site of caliber change (clamp sign, Fig. 4b, c, arrows). Ascites is noted in the pelvic cavity (Fig. 4d, arrow)