Ulcerative colitis and Crohn’s disease are the most common types of inflammatory bowel disease. Ulcerative colitis affects only the colon and rectum. Crohn’s can affect any part of the digestive tract.
- Infection, for example, those caused by bacterial like C. Difficile, viruses, and parasites),
- Inflammatory bowel disease like Crohn’s disease and ulcerative colitis,
- Ischemic colitis caused by decreased blood supply,
- Microscopic colitis (lymphocytic/collagenous colitis), and
- Allergic reactions.
NEC is a common cause of colitis in newborns. Very small and ill preterm infants are particularly susceptible to NEC. NEC is multifactorial, but prematurity and the presence of bacteria in the GI tract are significant risk factors associated with NEC.
NEC appears to involve an inappropriate inflammatory response in an immature intestine. The final common pathway seems to include the endogenous production of inflammatory mediators, such as endotoxin lipopolysaccharide, platelet-activating factor, tumor necrosis factor, and other cytokines, decreased epidermal growth factor, and progressive mucosal damage by free radical production.
Hypoxic ischemia and aggressive enteral feedings are also associated with the pathogenesis of NEC. Varying degrees of mucosal or transmural necrosis of the intestine and colon are recognized. The distal ileum and proximal colon are most frequently involved; in severe cases, gangrene may involve the whole bowel from the rectum to the stomach.
NEC presents with the gas accumulation in the submucosa of the bowel wall and progresses to necrosis leading to perforation of the bowel, peritonitis, and sepsis. Histological changes in NEC include mucosal edema, hemorrhage, coagulation necrosis, and mucosal ulceration.
In children aged 2 weeks to 1 year, the most common form of colitis is allergic colitis, which results from hypersensitivity, commonly to cow’s milk and soy milk. So-called breast milk allergy is a status of food allergy induced in breastfed babies by heterologous proteins (typically cow’s milk proteins) ingested by their mothers and appearing in their breast milk. Immunologic responses may range from classic allergic mast cell activation to immune complex formation.
Pseudomembranous colitis is a form of inflammatory colitis characterized by the pathologic presence of pseudomembranes consisting of mucin, fibrin, necrotic cells, and polymorphonuclear leukocytes (PMNs).
This form of colitis is pathognomonic of infection by toxin-producing Clostridium difficile and develops as a result of altered normal microflora (usually by antibiotic therapy) that favors overgrowth and colonization of the intestine by Clostridium difficile and production of its toxins. Although every antibiotic has been reported to be associated with pseudomembranous colitis, cephalosporin and beta-lactam antibiotics are most frequently implicated in children. Cases in children with underlying comorbid conditions, IBD in particular, are also common.
Symptoms of colitis will depend upon the type of colitis that is present, but in general, colitis most often is associated with abdominal pain and diarrhea.
Other symptoms of colitis that may or may not be present include
- Blood in the bowel movement may or may not be present. Diarrhea can sometimes cause hemorrhoids, which can bleed. However, blood with a bowel movement is not normal and the affected person should contact their health care practitioner or seek other medical care.
- Tenesmus may exist; this is the constant urge to have a bowel movement.
- The abdominal pain may come in waves, building to diarrhea, and then waning.
- There may be constant pain.
- Fever, chills, and other signs of infection and inflammation may be present depending upon the cause of colitis.
Early Tests and Exams
Your doctor will conduct a physical exam of your body and interview you to learn more about your general health, diet, family history, and environment.
Early steps in the diagnostic process can include laboratory tests of blood and fecal matter. Stool specimens are analyzed to eliminate the possibility of bacterial, viral, or parasitic causes of diarrhea. Blood tests can check for signs of infection as well as for anemia, which may indicate bleeding in the colon or rectum.
Endoscopy and Biopsy
Your doctor may recommend endoscopy, which is the use of medical instruments to visually examine the interior of your colon with a lighted tube that is inserted through the anus. Your doctor may recommend two types of endoscopic examinations: a sigmoidoscopy and a total colonoscopy.
- Sigmoidoscopy involves the insertion of a flexible instrument into the rectum and lower colon that allows the doctor to visualize the extent and degree of inflammation in these areas.
- Total colonoscopy is a similar exam, but it visualizes the entire colon.
During these procedures, your doctor may wish to obtain a sample of affected tissue, called a biopsy. Biopsied tissues are then analyzed in pathology to determine the presence of disease.
While endoscopy and biopsy may sound invasive, modern medical technology and techniques have made these procedures virtually painless and easily accomplished during an outpatient visit.
Your doctor may recommend a colonoscopy to look for any polyps or pre-cancerous changes in the setting of colitis. Chromoendoscopy is a technique of spraying a blue liquid dye during the colonoscopy in order to increase the ability of the endoscopist specialist to detect slight changes in the lining of your intestine. The technique may identify early or flat polyps which can be biopsied or removed. It is common to have blue bowel movements for a short time following this procedure.
The definitive treatment of colitis is dependent upon the cause. Many cases require little more than symptomatic care, including clear fluids to rest the bowel and medications to control pain. Some patients become acutely ill and will need intravenous (IV) fluids and other interventions to treat their illness.
- Infections: Infections that cause diarrhea and colitis may or may not require antibiotics, depending upon the cause. Viral infections resolve with the supportive care of fluids and time. Some bacterial infections likeSalmonella also do not need antibiotic therapy; the body is able to get rid of the infection on its own. Other bacterial infections like Clostridium difficile always require treatment with antibiotics.
- IBD: Inflammatory bowel diseases (IBDs) like ulcerative colitis and Crohn’s disease, are often controlled by a combination of medications that are used in a step-wise approach. Initially, anti-inflammatory medications are used, and if these are less than successful, medications that suppress the immune system can be added. In the most severe cases, surgery may be required to remove all or parts of the colon and small intestine.
- Ischemic colitis: Treatment of ischemic colitis is initially supportive, using intravenous fluids to rest the bowel and prevent dehydration. If adequate blood supply to the bowel isn’t restored, surgery may be required to remove parts of the bowel that have lost blood supply.
- Diarrhea and abdominal pain: Most causes of colitis present with diarrhea and crampy abdominal pain. These symptoms are also found with mild illnesses like viral enteritis (inflammation of the colon). Initial treatment at home may include a clear fluid diet for 24 hours, rest, and acetaminophen (Tylenol) as needed for pain. Often symptoms resolve quickly and no further care is needed.