Retention of a Patency Capsule Shell in a Nonsteroidal Anti‐Inflammatory Drug‐Induced Small‐Bowel Stricture, Detected and Retrieved by Balloon‐Assisted Enteroscopy: Emphasizing the Importance of Confirming Capsule Excretion

A 49-year-old woman had developed marked eosinophilia (15.9 × 109/L), erythematous rash, peripheral neuropathy, and pulmonary ground-glass opacities 6 months before her admission, leading to a diagnosis of eosinophilic granulomatosis with polyangiitis (EGPA). She was treated with corticosteroids, cyclophosphamide, intravenous immunoglobulin, and mepolizumab, after which most EGPA activity-related manifestations resolved. However, she later experienced recurrent abdominal pain, vomiting, and diarrhea, prompting hospitalization. Abdominal computed tomography (CT) revealed diffuse edematous thickening of the small bowel wall with ascites, suggesting enteritis (Figure 1a). Because her condition improved only partially despite 10 days of inpatient conservative treatment, she was transferred to our institution for further evaluation. Antegrade balloon-assisted enteroscopy (BAE; EN-580 T, Fujifilm, Tokyo, Japan) showed retention of the shell of a patency capsule (PC) that was ingested 8 days earlier without confirmed excretion, along with an oblique shallow ulcer—presumably caused by mechanical irritation from the shell—in the ileum (Figure 1b). After removal of the shell, a pinhole-like stricture was observed beneath it (Figure 1c). A fluoroscopic Gastrografin study demonstrated a diaphragm-like configuration of the stricture (Figure 1d; black arrow). Histopathological examination of biopsy specimens showed no eosinophilic infiltration, necrotizing vasculitis, or increased epithelial apoptosis (Figure 1e). Further questioning revealed daily use of nonsteroidal anti-inflammatory drugs (NSAIDs) for approximately 30 years, suggesting an NSAIDs-induced small bowel stricture. The retained PC shell was retrieved endoscopically (Figure 1f). As a fluoroscopic Gastrografin study had also confirmed that the stricture was located in the distal ileum (Figure 1d), retrograde BAE was subsequently performed in several sessions to dilate the lesion. Thereafter, her gastrointestinal symptoms resolved and did not recur for 19 months. Although PC-related complications are uncommon, symptomatic retention—including abdominal pain, vomiting, and ileus—has been reported [1]. Even the PC shell, typically considered safe [2], can lodge within severe strictures [3] and cause mucosal injury, as seen in our case; the PC shell retention may be easily overlooked yet clinically relevant. Lack of confirmation of intact PC excretion, especially in patients with symptoms suggesting impaired passage, should be regarded as an important warning sign and prompt early endoscopic evaluation. Careful pre-assessment of the intestinal condition prior to PC use is also essential, particularly in high-risk patients [2]. The authors declare no conflicts of interest. The data that support the findings of this study are available from the corresponding author upon reasonable request.