Crohn’s disease

Crohn’s disease is a type of chronic inflammatory bowel disease that can affect any region of the digestive system.

A woman suffering from abdominal painDescription

Crohn’s disease is a chronic inflammatory bowel disease which is considered to be related to the impaired immune system. The disease onset takes place in young adults, typically in their 20-40ies. Any part of the digestive tract may be affected by Crohn’s disease from the mouth to the anus, although typically in one person only some parts of the gastrointestinal system are involved. Approximately in one-third of cases, the small bowel is affected and in about half of the cases, both the small bowel and colon are affected. Rarely the liver and pancreas may also be affected.

Common symptoms of Crohn’s disease include abdominal pain, diarrhea, weight loss, etc.

The disease has a chronic course with the periods of flare-ups and remissions. It is almost impossible to cure the disease, although the appropriate treatment can reduce the symptoms of the disorder and provide a better quality of life.

Causes

It is not known for sure what causes the development of the disorder.

Crohn’s disease is an immunity-mediated disorder which may be caused by the imbalance between the pro- and anti-inflammatory mediators (which are an essential part of the person’s immunity). This imbalance results in chronic bowel inflammation induced by the T-cell activation, which in turn damages the intestines.

The bowel becomes inflamed and infiltrated with the inflammatory cells, which invade the mucosa and results in the formation of granulomas. Leukocytes infiltrate the crypts in-between the folds of the intestines mucous membranes and cause the abscess development, ulceration, destruction of the crypts and colon atrophy. The affected mucous membrane appears as regions of relatively healthy and affected mucosa which remind cobblestones – these lesions are known as the skip lesions.

The whole bowel wall may be affected and when it is infiltrated it becomes thick, respectively, the bowel lumen narrows. This narrowing interferes with the normal passage of food causing bowel obstruction. Ulceration and abscess formation may result in the development of bowel perforation and fistulae between the intestines and other internal organs or the skin surface.  

Genetic susceptibility is also considered involved in the pathogenesis of Crohn’s disease.

 Risk factors

  • Inheritance pattern – those whose relatives have Crohn’s disease are more likely to become ill;
  • Smoking is associated with the increased risk of Crohn’s disease;
  • Consumption of high-fat foods was linked to the risk of Crohn’s disease;

 Symptoms

As mentioned before Crohn’s disease may affect any region of the digestive system, although typically the ileum and the colon are affected.

Symptoms of the disorder may vary depending on the affected site and include:

  • Diarrhea and bloody stool with mucus and pus, sometimes constipation, which is typically present in long-lasting disease;
  • Low-grade fever;
  • Abdominal pain (in different regions of the abdomen in accordance to the involved area, commonly in the right lower quadrant and around the navel) and cramping;
  • Abdominal bloating after the meal;
  • Mouth sores/ulcers;
  • Nausea and vomiting;
  • Pain around the anus; and pus-like discharge;
  • Fatigue;
  • Anorexia;
  • Weight loss;
  • General malaise;
  • Night sweats;

As long as the disease is caused by the immune imbalance other organs and body parts such as the eyes, skin, and joints may also be affected. Erythema nodosum is the most common extraintestinal manifestation of Crohn’s disease which appears as raised red nodules arising primarily on the shins. Sometimes a person may also suffer from alopecia (hair loss). Psoriasis may also develop in association with Crohn’s disease. In active disease, the white of the eye or the vascular layer may become inflamed.

Nonsteroidal anti-inflammatory drugs may worsen the course of the disease.

Diagnosis

The diagnosis of Crohn’s disease is made based on the typical presentation and the results of the further laboratory and instrumental studies.

A complete blood count may reveal the anemia which may develop due to chronic blood loss from the affected mucous membranes and malabsorption of the cyanocobalamin and folates – the vitamins essential for the hematopoiesis (production of the blood cells).

Increased levels of C-reactive protein and erythrocyte sedimentation rate are indicative of the inflammation. White blood cells, mucus, bacteria, and blood may be detected in the stool samples. Levels of fecal calprotectin and lactoferrin correlate with the intestinal inflammation.

Colonoscopy is helpful to diagnose Crohn’s disease and evaluate the extension of the disease and guts involvement.

CT and MRI scan s may be performed to determine the severity of the disease and other organs involvement.

 Treatment

Treatment of Crohn’s disease is mostly symptomatic and is administered in a “step-up” manner depending on the disorder severity. Typically, treatment starts with preparations of 5-aminosalicylic acid (5-ASA) and antibiotics. In more severe cases corticosteroids and cytostatics (medications that inhibit DNA synthesis) are used. If these medications are not effective biologic agents may be prescribed.

Surgical resection of the part of the bowel is considered when drugs fail. The complications of the disease such as the perforation of the bowel, gastrointestinal bleeding or abscesses may require urgent surgical treatment.

 Applicable medicines

  • 5-aminosalicylic acid (5-ASA);
  • Corticosteroids: prednisolone, dexamethasone;
  • Antibiotics: metronidazole, ciprofloxacin, tacrolimus;
  • Cytostatics: 6-mercaptopurine/azathioprine, methotrexate, cyclosporine;
  • Biologic agents: infliximab, adalimumab, certolizumab pegol, and natalizumab;
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