Ostomy-related complications
Common complications of an ostomy (a common surgery in Crohns disease) are: Mucosal edema, Peristomal dermatitis, Retraction, Ostomy prolapse, Mucosal/skin detachment, Hematoma, Necrosis, Parastomal hernia, and Stenosis. Etiology
The etiology of Crohns disease is unknown. Many theories have been disputed, with four main theories hypothesized to be the primary mechanism of Crohns disease. In autoimmune diseases, antibodies and T lymphocytes are the primary mode of inflammation. These cells and bodies are part of the adaptive immune system, or the part of the immune system that learns to fight foreign bodies when first identified. Autoinflammatory diseases are diseases where the innate immune system, or the immune system we are genetically coded with, is designed to attack our own cells. Crohns disease likely has involvement of both the adaptive and innate immune systems. Autoinflammatory theory
Crohns disease can be described as a multifactorial autoinflammatory disease. The etiopathogenesis of Crohns disease is still unknown. In any event, a loss of the regulatory capacity of the immune apparatus would be implicated in the onset of the disease. In this respect interestingly enough, as for Blaus disease (a monogenic autoinflammatory disease), the NOD2 gene mutations have been linked to Crohns disease. However, in Crohns disease, NOD2 mutations act as a risk factor, being more common among Crohns disease patients than the background population, while in Blaus disease NOD2 mutations are linked directly to this syndrome, as it is an autosomal-dominant disease.
Under a microscope, biopsies of the affected colon may show mucosal inflammation, characterized by focal infiltration of neutrophils, a type of inflammatory cell, into the epithelium. This typically occurs in the area overlying lymphoid aggregates. These neutrophils, along with mononuclear cells, may infiltrate the crypts, leading to inflammation (crypititis) or abscess (crypt abscess).Granulomas, aggregates of macrophage derivatives known as giant cells, are found in 50% of cases and are most specific for Crohns disease. The granulomas of Crohns disease do not show "caseation", a cheese-like appearance on microscopic examination characteristic of granulomas associated with infections, such as tuberculosis. Biopsies may also show chronic mucosal damage, as evidenced by blunting of the intestinal villi, atypical branching of the crypts, and a change in the tissue type (metaplasia). One example of such metaplasia, Paneth cell metaplasia, involves the development of Paneth cells (typically found in the small intestine and a key regulator of intestinal microbiota) in other parts of the gastrointestinal system. Diagnosis
The diagnosis of Crohns disease can sometimes be challenging, and many tests are often required to assist the physician in making the diagnosis. Even with a full battery of tests, it may not be possible to diagnose Crohns with complete certainty; a colonoscopy is approximately 70% effective in diagnosing the disease, with further tests being less effective. Disease in the small bowel is particularly difficult to diagnose, as a traditional colonoscopy allows access to only the colon and lower portions of the small intestines; introduction of the capsule endoscopy aids in endoscopic diagnosis.