The first report on small-bowel diaphragm disease was published in 1988 by Lang et al.¹ Non-steroidal anti-inflammatory drugs (NSAIDs) are regarded to be the most common cause.² Other causes include celiac disease, eosinophilic gastroenteritis, and radiation exposure are other factors.³ The disease typically presents as a small bowel obstruction, but it can also manifest as protein-losing enteropathy or iron-deficiency anemia. Diagnosing diaphragm disease without a histopathological examination can be challenging.

We report a case involving a 16-year-old boy who presented with a 2-month history of generalized weakness and easy fatigability. He had no history of overt gastrointestinal bleeding, altered bowel habits, worms in stool, weight loss, or oral ulcerations. Upon investigation (Table 1), he was found to have iron-deficiency anemia. He was initially transfused with packed red cells and started on iron supplements. However, three months later, he returned with the same complaints. Repeat investigations (Tables 1, 2) revealed persistent iron-deficiency anemia. Stool examination ruled out any occult blood loss, and hemoglobin electrophoresis was normal. Fecal calprotectin levels were elevated. Esophagogastroduodenoscopy (EGD) and colonoscopy results were normal.

Table 1 . Blood Test Findings.

Parameter	October 2019	January 2020	May 2022
Hemoglobin (g/dL)	4.5	7.8	4.8
Total leucocyte count (/mm3)	4,400	8,700	5,500
Platelet count (/mL)	380,000	270,000	416,000
Mean corpuscular volume (fL)	64.7	62.2	66.5
Mean corpuscular hemoglobin (pg)	15.8	17.3	18.0
Mean corpuscular hemoglobin concentration (g/dL)	24.4	26.7	29.4
Red cell distribution width (fL)	20.1	14.4	21.2
Retic count (RBCs/mL)	0.92	1.3	1.5

Table 2 . Iron Profile.

Serum iron profile	May 2022
Serum iron (μg/dL)	18
Total iron-binding capacity (μg/dL)	332
Percentage saturation (%)	12
Serum ferritin (ng/mL)	4.18

Computed tomography (CT) enterography was performed, which revealed multiple sub-centimetric discrete lymph nodes in the preaortic and paraaortic regions along the mesenteric vessels. These nodes showed inhomogeneous post-contrast enhancement. Mild splenomegaly was also noted, but his bowel appeared normal with no evidence of strictures. A video capsule endoscopy was attempted, but the capsule became lodged at the antrum, EGD was done which revealed a narrowing at the junction of the first and second parts of the duodenum. This was dilated with a controlled radial expansion balloon dilator, and the capsule was placed beyond endoscopically. Unfortunately, the capsule was damaged during the procedure, and images could not be obtained.

The patient was lost to follow-up due to the COVID-19 pandemic for 2 years. When he returned with similar complaints, investigations again revealed iron-deficiency anemia. EGD, colonoscopy, and push enteroscopy results were normal. An erect abdominal X-ray revealed a retained object, which was confirmed by CT enterography to be a foreign body in the distal ileum. This was the capsule he had ingested two years prior (Fig. 1).

Figure 1. Abdominal X-ray showing a capsule.

The decision was made to proceed with diagnostic laparoscopy with intraoperative endoscopy through a planned enterotomy. The capsule was felt 80 cm proximal to the ileocecal junction (Fig. 2), and an enterotomy was performed to retrieve it. An EGD was passed via the enterotomy site to the duodenum-jejunal flexure proximally and to the caecum distally. Multiple (> 10) short segment strictures were noted both proximal and distal to the enterotomy site, with luminal narrowing and circumferential ulcerations. The distal extent of the strictures was 60 cm (Fig. 3, 4). A 60-cm segment of the ileum with multiple strictures was resected, and a side-to-side ileo-ileal anastomosis was performed.

Figure 2. Intraoperative finding of the lost capsule.

Figure 3. Endoscopic appearance of the mucosal diaphragm in colon.

Figure 4. Endoscopic appearance of the mucosal diaphragm in jejunum (arrow).

Pathological analysis of the specimen revealed thin stricture-like areas throughout the resected segments, along with focal superficial ulcers and congestion in the intervening mucosa (Fig. 5). Microscopic examination showed stricture-like areas with ulcerated ileal mucosa covered with granulation tissue, fibrinous exudates, and acute inflammatory cell infiltrate. The mucosa and submucosa exhibited fibrosis and numerous blood vessels, along with scattered lymphoid aggregates. The muscularis mucosa showed a haphazard arrangement of muscle fiberes. Lymph nodes showed reactive changes, and there was no evidence of granuloma, inflammatory bowel disease, or malignancy (Fig. 6). The final diagnosis was diaphragm disease, based on these findings. Since it was a retrospective analysis, we got a waiver from institutional ethical committee of Lokmanya Tilak Municipal Medical College and Hospital (approval No. IEC-65/23). The consents were obtained from the legal guardians.

Figure 5. Gross specimen showing the mucosal diaphragm (arrows).

Figure 6. Microscopic appearance (arrows) of haphazard arrangement of muscle fibers in muscularis mucosa (H&E stain [high power field, ×40]).

Diaphragm disease is defined by the development of thin-walled strictures, similar to a diaphragm, in the small bowel. These strictures narrow the lumen to a pinpoint and are often linked to long-term NSAID use. Diagnosing diaphragm disease can be challenging because symptoms are typically ambiguous and radiological tests often yield inconclusive results.⁴ Due to a low degree of suspicion, diaphragm disease may persist for years without detection or may be incorrectly diagnosed as other conditions such as ileocecal tuberculosis, structuring Crohn's disease, or a tumor.

Ingestion of NSAIDs is implicated in 58% of cases, leading to many being classified as idiopathic.⁵ The ileum is the most frequently affected area (67%).⁶ The signs of diaphragm disease are frequently vague. Anemia (42%) and chronic abdominal pain (58%) are two common symptoms.^4,5 CT and magnetic resonance enterography first-line imaging modalities for patients with small-bowel disease.⁵ CT can show abnormal findings in the small bowel: strictures, focal thickening of the bowel wall and, less commonly, bowel dilatation.⁵ Capsule endoscopy is seldom used to diagnose diaphragm disease, as there is risk of capsule retention necessitating a surgical intervention. Surgical intervention remains the preferred treatment and typically involves resection of the affected segment. In cases of extensive or recurrent disease, stricturoplasty may be the preferred option.⁷ In some instances, the disease can affect the entire length of the small bowel. In such cases, it may be necessary to leave some residual disease after the initial resection of the lesions.

The histological characteristics of the lesions include a thickening and disordered arrangement of muscular bundles in the muscularis mucosae, fibrosis in the lamina propria, consistent mucosal ulceration at the apex of the diaphragm, and a high number of vessels, ganglion cells, nerve fiberes, and eosinophils in the mucosa.⁸

In this report, we present a unique and rare condition that poses a diagnostic challenge for physicians. Physicians must maintain a high level of suspicion when encountering a patient with chronic, colicky abdominal pain or anemia, especially if multiple strictures and saccular dilatations are observed on a CT scan, even if there is no history of long-term NSAID use. Surgical intervention, accompanied by intraoperative enteroscopy, should be considered for both diagnosis and management.

None.

The data that support the findings of this study are available from the corresponding author upon reasonable request.

No potential conflict of interest relevant to this article was reported.