Strictures in Crohn’s disease

Abbreviations

Introduction

Intestinal stricture, defined as abnormal narrowing of bowel lumen, has also been termed stenosis. A stricture can lead to a spectrum of narrowing from subtle to complete obstruction. In patients with inflammatory bowel disease (IBD), either Crohn’s disease (CD) or ulcerative colitis (UC), intrinsic stricture may result from disease process ranging from inflammation and fibrosis to malignancy in the mucosa, muscularis mucosae, submucosa, or muscularis propria, or combination. Extraintestinal or extraluminal disease process can also cause bowel stricture or obstruction (extrinsic stricture), such as abscess, adhesion, and compression from benign or malignant mass.

In the Montreal classification system, CD was divided into nonstricturing/nonpenetrating (B1), stricturing (B2), and penetrating (B3), based on clinical behavior, as shown in Chapter 4 , Crohn’s disease: inflammatory type ( Table 4.1 ) . Stricturing disease is believed to result from persistent inflammation (B1) and fibrosis. On the other hand, stricture is a major contributing factor for the formation of fistula (B3) and abscess. Strictures often lead to significant morbidities, particularly bowel obstruction. The main treatment strategies for stricture are the control of inflammation with medical therapy and relief of obstruction with mechanical force, such as endoscopic balloon dilation (EBD), endoscopic stricturotomy (ESt), bowel resection, and stricturoplasty .

Stricture in CD represents a spectrum of clinical phenotypes, underlying disease process, and prognosis. A classification of IBD-related stricture has been proposed ( Table 5.1 ) . In the classification system, IBD-related strictures are categorized based on the source, clinical presentation, underlying disease, the presence of prior surgery, malignant potentials, degree, location and length, and associated disease conditions. Proper diagnosis and classification of stricture will guide monitoring of disease progression and medical, endoscopic, and surgical therapy and improve quality of life and long-term outcome. For example, the treatment approach and outcome for the primary (or disease related) and secondary (surgery or medicine related) strictures are different.

Stricture is evaluated and diagnosed based on a combined assessment of clinical presentation, imaging, and endoscopy. The presence or absence, and degree and length of stricture on abdominal imaging and on endoscopy are not necessarily correlated. Endoscopy plays a key role in the assessment of degree, number, length, and associated mucosal inflammation as well as delivery of therapy (such as balloon dilation and ESt) in patients with strictures .

Esophageal and gastroduodenal stricturing Crohn’s disease

Isolated involvement of the esophagus CD is rare. Often esophageal strictures in patients with CD result from the use of medications (such as nonsteroidal antiinflammatory drugs and potassium tablets) or metabolic complications [such as iron deficiency ( Fig. 5.1 )]. Superimposed viral, bacterial, or fungal infection in the esophagus may manifest as esophageal ulcers but rarely as strictures.

The most common location of stricturing CD of the stomach is the pylorus or prepyloric area, which can occur in isolation or concurrently with gastroduodenal CD. Pyloric narrowing can manifest as nonulcerated tight stenosis or ulcerated stricture, ranging from 1 to 3 cm in length. Concurrent pre- or postpyloric nodularity or ulcers may be present ( Fig. 5.2 ). Severe pyloric or prepyloric stenosis is often associated with gastric outlet obstruction. Extreme precaution should be taken to avoid aspiration during endoscopy. Since medical and surgical treatment options of CD-associated pyloric strictures are limited, endoscopic therapy has been explored. EBD, ESt with needle knife or insulated-tip knife, and topical injection of botulin toxin have been used by this author’s team ( Figs. 5.2D and 5.3 ). For patients with symptomatic persistent gastric outlet obstruction, ventilation gastrostomy tube may be helpful.

Duodenum CD can present with inflammation, ulcers, or stricture on endoscopy. The most common location of stricturing CD in the duodenum is at the cap, that is, the junction between the first and second portions. Concurrent duodenum inflammation may be present or absent. Duodenum strictures may be subtle or severe, with normal, edematous, or ulcerated overlying mucosa ( Fig. 5.4 ). While concurrent mucosal or transmural inflammation may respond to aggressive medical therapy, duodenum strictures, particularly fibrotic stricture, poorly respond to medications. On the other hand, surgical strictureplasty or bypass with gastrojejunostomy has been performed for long, medically refractory duodenum strictures ( Fig. 8.21 ). EBD or ESt may be attempted in short duodenum strictures (<3 cm) ( Fig. 5.5 ).