Crohn's disease

Crohn's disease (colitis regionalis, terminal ileitis) is a chronic inflammatory íntestinal disease
inflammation occurs in any part of the digestive tract and has a segmental character
- there are sections of healthy mucosa between the affected areas.
the most commonly affected area is the terminal ileum
inflammation affects the entire wall thickness of the organ and is characterized by the presence of non-caseifying epithelioid granulomas.

Crohn's disease is more common in younger people
the highest prevalence is in the group of 30-39 years. 10% of patients are diagnosed before the age of 17.
- the average prevalence in adults is about 130 / 100,000, the incidence is 5.6 / 100,000 inhabitants; •
- the incidence in children is on the rise, reaching up to 9-10 / 100,000, especially in northern Europe •
- the incidence in children in the Czech Republic is 6.2 / 100,000.

• Grade 1 relatives have a 10-35-fold higher risk of disease. •
Genetic mutations. •
High hygienic standards in childhood, smoking, early appendectomy, and non-steroidal anti-inflammatory drugs.

The cause of the disease is not yet known
This is probably a dysregulation of the immune response to common bacterial antigens
During the autoimmune reaction, transmural inflammation occurs, that affects the entire wall of the intestine, which often passes to the mesentery.
Epithelioid granulomas, ulcerations, and fissures form in the intestinal wall.
We often see intramural and intraperitoneal abscesses or fistulas (especially in the anal area).
Due to long-term inflammation, the bowel may narrow by scarring of the tissue (scar stricture).
Crohn's disease is characterized by segmental GIT involvement → alternating inflammatory and unaffected sections ("skip lesions").
Predilection areas include the terminal ileum and ascending colon, but any part of the GIT can be affected.

The entire intestinal wall is affected and the inflammation is segmental or plurisegmental.
Typically, the affected sections alternate with the unaffected sections (unlike ulcerative colitis).

Macroscopically, we see thickening of the intestinal wall and mesentery. Regional lymph nodes are often enlarged.
The mucosa is hypertrophic and edematous.
The image is often compared to cobblestones - elongated aphthous ulcers above the lymphatic follicles surrounding the unaffected mucosa, swollen fistula mouths, pseudopolyps.
Affected serosis leads to adhesions in which fistulas form. In the further course of the disease, fiber production follows, which leads to stenoses.

In the microscope we see mucosal edema with polymorphonuclear infiltration, followed by fiber production with the formation of tuberculoid granulomas (epithelioid cells and giant Langhans-type cells, unlike TB, do not caseify) in the submucosa, subserous, and regional nodes.

Like all autoimmune diseases, Crohn's disease manifests itself in multiple systems.

The typical manifestation is in the digestive tract, but the eyes, skin and mucous membranes, liver, pancreas, kidneys are also affected, and blood homeostasis is often disturbed.

Common symptoms include abdominal pain and chronic diarrhea (rarely with blood).
Fissures, perianal abscesses, fistulas, and mariske (anal lashes - skin growths in the area of the anus and skin transition) may occur around the rectum.

Extraintestinal symptoms occur in more than 40% of patients.
It often precedes intestinal manifestations by up to several years.
These are mostly non-specific symptoms such as recurrent fevers, anorexia, weight loss, and growth retardation, especially in children.
The main systems that tend to be affected include:

skeleton: growth failure and osteoporosis (proinflammatory cytokines suppress growth, suppress IGF-1 production, stimulate bone resorption; insufficient energy intake, malabsorption, loss of protein and trace elements in the stool, chronic treatment with corticosteroids)
skin and mucous membranes: aphthous stomatitis, gingivitis, granulomatosis cheilitis, erythema nodosum on the lower legs, and purulent pyoderma
eyes: iritis, uveitis, episcleritis; rare in children; corticoid therapy can cause cataracts and glaucoma
liver and pancreas: primary sclerosing cholangitis, cholecystolithiasis; pancreatitis after azathioprine or mesalazine therapy
vascular system: hypercoagulable state (thrombocytosis, increased fibrin, factor V and VII, decreased antithrombin), which may cause deep vein thrombosis, pulmonary embolism or CMP
kidneys and urinary tract: fistulas, urinary stones.

Inflammation often spreads to the surrounding area and forms fistulas (ie, canals connecting the sites of inflammation to any other site).
Fistulas can be: