Chronic colitis

Etiology and risk factors

The development of chronic colitis is most often caused by the prolonged impact of damaging factors on the mucous membrane of the large intestine. Pathophysiology identifies several key groups of etiological factors:

1. Intestinal infections. These act as one of the main triggers. Bacterial pathogens include microorganisms causing dysentery, salmonellosis, and yersiniosis. Protozoan and parasitic infestations also play a major role: amoebiasis, giardiasis, trichomoniasis, and balantidiasis.
2. Alimentary factor. Irregularities in diet and eating habits inevitably affect the condition of the intestine. The risk increases with a monotonous diet (excess of carbohydrates or proteins), vitamin deficiencies, regular consumption of spicy and hard-to-digest foods, and alcohol abuse.
3. Congenital enzymopathies. With a deficiency of certain enzymes (e.g., disaccharidase deficiency), food is not fully digested. Incompletely digested products directly irritate the intestinal mucosa, triggering inflammation.
4. Intoxications. Toxic effects can be both external and internal:
5. Exogenous intoxications occur in case of poisoning with heavy metal salts (lead, mercury), as well as arsenic and phosphorus.
6. Endogenous intoxications develop against the background of systemic pathologies: uremia, liver failure, or hyperthyroidism.
7. Iatrogenic (drug-induced) factors. Uncontrolled and prolonged use of certain medications (laxatives, antibiotics, salicylates, digitalis preparations) can cause severe damage to the intestinal wall.
8. Radiation exposure. Massive X-ray irradiation or radiation therapy leads to the death of actively dividing intestinal epithelial cells.
9. Ischemic disorders. Blood circulation disorders in the mesenteric vessels cause tissue hypoxia. This factor is especially relevant for elderly patients suffering from atherosclerosis.

Pathogenesis of chronic colitis

Prolonged exposure to toxic, infectious, radiation, allergic, and other damaging factors triggers a complex cascade of pathological changes in the large intestine. The pathogenetic chain includes several sequential stages:

• Primary mucosal injury. Pronounced inflammatory and immunopathological damage to the tissues of the intestinal wall forms.
• Impairment of core functions. Against the background of inflammation and dystrophy, organ function suffers: secretory, motor, and absorptive functions are inhibited or distorted.
• Damage to the nervous apparatus. The pathological process affects the innervation of the intestine. On the one hand, this leads to severe motility disorders, and on the other hand, it worsens trophic disorders in the intestinal tissues themselves, creating a vicious circle.
• Microbiological and enzymatic shifts. Due to environmental changes in the intestine, dysbiosis develops and secondary enzymopathy forms. Intestinal dyspepsia appears, which further disrupts digestion and the assimilation of essential nutrients.
• Systemic body reactions. The local process transitions to a systemic level: intestinal autoinfection and autointoxication develop. In response to the damage of own tissues and the absorption of toxins, secondary immunopathological reactions are initiated.

Clinical consequences

Although chronic colitis is a disease of the large intestine, its consequences affect the entire body. The main clinical manifestation that completes the pathogenetic chain is malabsorption syndrome.

Due to the loss of absorptive function, dysbiosis, and accelerated (or spastic) motility, the body does not receive enough nutrients, vitamins, and trace elements. Combined with constant autointoxication and endogenous poisoning by decay products, this leads to exhaustion, metabolic disorders, and a decrease in the patient's general compensatory capabilities.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Mechanisms of development of malabsorption syndrome in GI pathologies
• The role of dysbiosis and secondary enzymopathies in the pathogenesis of colitis
• Intestinal autointoxication: pathways of toxin entry into the bloodstream
• Features of ischemic intestinal damage in mesenteric vascular atherosclerosis

Other topics in "Chapter 24. Typical Forms of Digestive System Pathology"

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