Crohn's disease

Pathomorphological features

A key characteristic of Morbus Crohn is the specific pattern of spread of the inflammatory process. The disease develops in a segmental (discontinuous) manner. This means that in the gastrointestinal tract, inflamed areas alternate with absolutely healthy, intact tissues (so-called skip-lesions).

The pathological process can be localized in absolutely any part of the digestive tract. However, in pediatric practice, there is a dominant pattern: approximately 50% of children present with ileocolitis, a combined involvement of the small and large intestine.

The most important feature of the disease lies in the depth of the lesion. The inflammation is transmural, meaning that all layers of the intestinal wall, from the mucosa to the serosa, are inevitably involved in the pathological process.

Endoscopic and macroscopic picture

The visual picture during endoscopic examination directly reflects the pathogenetic mechanisms of the disease. It is important to understand that visible changes in the mucosa are merely the "tip of the iceberg." The primary focus of inflammation, where specific epithelioid granulomas begin to form, is located significantly deeper — in the submucosal layer.

Specific visual signs that an endoscopist discovers during examination include:

• The presence of multiple aphthae on the mucosal surface.
• The formation of deep fissure ulcers that penetrate deep into the submucosa.
• Cobblestone appearance is a classic sign of the active phase of the disease. This unique mucosal relief is formed due to the intersection of deep longitudinal and transverse fissure ulcers that stand out against the background of pronounced edema of the preserved, intact tissue.

It is the deep, transmural spread of inflammation that causes the development of typical and most severe complications of Crohn's disease: the formation of intestinal strictures (narrowings) and fistulas.

Instrumental and histological diagnostics

Diagnostic workup is based on a combination of visual and morphological data. Endoscopy allows the detection of a patterned mucosal lesion (cobblestone appearance), which is highly specific for the active phase. Final confirmation of the diagnosis requires morphological examination of a biopsy sample, the main histological sign of which is the detection of epithelioid granulomas.

Diagnosis of the small bowel form of the disease presents a particular challenge, as standard visualization of small intestine lesions is extremely difficult. In such clinical situations, the only informative methods that allow confirming this localization of the process are:

1. Video capsule endoscopy.
2. Magnetic resonance imaging (MRI) of the abdominal cavity.

Dietary therapy approaches

To date, gastroenterology has not developed a single, universal specialized diet for patients with inflammatory bowel disease (IBD). Nevertheless, nutritional support plays a crucial role in the management of such patients.

Basic recommendations include prescribing a high-protein diet (standard bowel diet). A special place in the treatment of Crohn's disease is occupied by enteral nutrition. Clinical practice demonstrates high efficacy of using specialized nutrient formulas that help provide the body with essential nutrients against the background of severe intestinal inflammation.

Class and exam questions

What else to study on this topic

• The mechanism of formation of epithelioid granulomas in the submucosal layer
• Pathogenesis of intestinal strictures and fistulas formation
• Principles of video capsule endoscopy in children
• Composition and types of specialized formulas for enteral nutrition in IBD

Other topics in "Chapter 7. Digestive System Diseases"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.