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Colitis refers to inflammation of the inner lining of the colon. There are numerous causes of colitis including infection, inflammatory bowel disease (Crohn's disease and ulcerative colitis are two types of IBD), ischemic colitis, allergic reactions, and microscopic colitis.
Symptoms of colitis depend upon the cause and may include:
- • abdominal pain,
- • cramping,
- • diarrhea, with or without blood in the stool (one of the hallmark symptoms of colitis).
Associated symptoms depend upon the cause of colitis and may include:
- • fever,
- • chills,
- • fatigue,
- • dehydration,
- • eye inflammation,
- • joint swelling,
- • canker sores,
- • skin inflammation.
Blood in the stool is never normal and medical care should be sought for evaluation of the cause. Depending upon the history and physical examination, further testing may be necessary to find the cause of colitis and may include blood tests complete blood count, electrolytes, kidney function and inflammatory marker tests), urine and stool samples, colonoscopy, and barium enema.
Treatment of colitis depends upon the cause, and often is focused on symptom relief, supportive care, and maintaining adequate hydration and pain control. Antibiotics may be prescribed to treat infectious causes of colitis. Some bacterial infections that cause colitis resolve without any antibiotic treatment.
What are the symptoms of colitis?
Colitis can be caused by infections, loss of blood supply, or chronic diseases. Despite the cause, people suffering from colitis may have typical symptoms that include:
- • abdominal pain,
- • cramping,
- • bloating, and
- • diarrhea (bloody diarrhea with some types of colitis).
Colitis describes inflammation of the inner lining of the colon and can be associated with diarrhea, abdominal pain, bloating, and blood in the stool. This inflammation may be due to a variety of reasons, including the following:
- • Infection
- • Loss of blood supply to the colon (ischemia)
- • Inflammatory bowel disease (Crohn's disease, ulcerative colitis)
- • Allergic reactions
- • Invasion of the colon wall with lymphocytic white blood cells or collagen
Colitis and the anatomy of the colon
The colon, or large intestine, is a hollow, muscular tube that processes waste products of digestion from the small intestine, removes water, and ultimately eliminates the remnants as feces (stool) through the anus. The colon is located within the peritoneum, the sac that contains the intestine, located in the abdominal cavity.
The colon is surrounded by many layers of tissue. The innermost layer of the colon is the mucosa that comes into contact with the waste products of digestion. The mucosa absorbs water and electrolytes back into the blood vessels that are located just below the surface in the submucosa. This is surrounded by a circular layer of muscles and then another outer layer of longitudinal muscles that run along the length of the colon. The muscles work together to rhythmically squeeze liquid waste from the cecum through the entire length of the colon. Water is gradually removed, turning the waste into formed stool, so that it is excreted out of the anus in solid form.
The colon frames the organs within the peritoneum, and its segments are named based on their location.
The colon usually begins in the right lower quadrant of the abdomen, where the terminal ileum, the last part of the small intestine, attaches to the cecum, the first segment of the colon. The appendix is attached to the cecum.
The ascending colon begins at the cecum and arises from the right lower abdomen to the right upper abdomen near the liver. The colon then makes a sharp left turn called the hepatic flexure (hepatic=liver), and is referred to as the transverse colon, as it makes its way to the left upper quadrant of the abdomen near the spleen.
There is a sharp downward turn called the splenic flexure, and it is referred to as the descending colon as it runs from the left upper quadrant to the left lower quadrant of the abdomen. When it descends into the pelvis, it is referred to as the sigmoid colon.
The last several centimeters of the colon are referred to as the rectum. The anus is the final portion of the colon.
What are the causes (types) of colitis?
Colitis describes inflammation of the colon. Examples of causes of colitis include:
- • infection, for example, caused by bacteria 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);
- • allergic reactions.
Infectious causes of colitis
Many bacteria reside in the colon; they live in harmony with the body and cause no symptoms. However, some infections can result if a virus, bacteria, or parasite invade the small and/or large intestine.
Common bacteria that cause colitis include:
- • Campylobacter,
- • Shigella,
- • E. Coli,
- • Yersinia,
- • Salmonella.
These infections usually occur because the patient has eaten contaminated food. Symptoms can include diarrhea with or without blood, abdominal cramps, and dehydration from water loss because of numerous watery, bowel movements. Other organs can also be affected by the infection or the toxins that the bacteria can produce.
Clostridium difficile, commonly referred to as C. diff, is a bacterial cause of colitis that often occurs after a person has been prescribed an antibiotic or has been hospitalized. C. diff is found in the colon of healthy people and coexists with other "normal" bacteria. But when antibiotics are prescribed, susceptible bacteria in the colon can be destroyed, allowing the clostridia to grow unchecked, causing colitis. Patchy membranes form over the colon mucosa and some health care professionals refer to C. diff colitis as pseudomembranous colitis. The bacteria also may be found on many surfaces in the hospital (for example, bedrails, toilets, and stethoscopes), and the infection may spread from person to person (it is highly contagious). Unfortunately, this infection is becoming more common outside the hospital environment, and people can develop community acquired C. diff colitis without exposure to antibiotics or a medical facility.
Worldwide, the most common parasite infection to cause colitis is Entamoeba histolytica. It is acquired by drinking infected water and can also be passed from person to person because of poor sanitation and hygiene.
Ischemic causes of colitis
The colon can be thought of as a hollow muscle. It requires a normal blood supply to deliver oxygen and nutrients for the muscle to function normally. When the colon loses its supply of blood and becomes ischemic, it may become inflamed. Ischemia or lack of blood supply causes inflammation of the colon leading to fever, and diarrhea (bowel movements may contain blood).
As a person ages, the arteries that supply blood to the colon gradually narrow and can cause ischemic colitis. Risk factors for narrowed arteries are the same as atherosclerotic heart disease, stroke, and peripheral artery disease (PAD). These include diabetes, high blood pressure, high cholesterol and smoking.
Ischemia caused by low blood pressure or anemia (low red blood cell count) can decrease oxygen delivery to the colon.
Patients who have atrial fibrillation (AFib) and are not anticoagulated are at risk for developing ischemic bowel. Small blood clots can form in the heart and embolize (travel) to block arteries that supply the colon with blood. This is the same mechanism that can cause a stroke in patients with AFib.
The blood supply to the colon may be compromised when blood vessels are mechanically obstructed, for example by a twisting of the bowel (volvulus) or a herniation of the colon through openings in the abdomen wall (an incarcerated hernia).
Inflammatory bowel disease (IBD) and colitis
Ulcerative colitis and Crohn's disease are the two types of inflammatory bowel disease (IBD) that cause colitis. Crohn's disease and ulcerative colitis are considered autoimmune diseases (the body's immune system "attacks" itself).
Ulcerative colitis always begins in the rectum and may spread to the rest of the rest of the colon, spreading from the rectum to the sigmoid, descending, transverse, and finally the ascending colon and cecum in that order. Ulcerative colitis is considered an autoimmune disease, and symptoms include abdominal pain, and bloody, diarrheal bowel movements.
Crohn's disease may occur anywhere in the gastrointestinal tract (GI), including the esophagus, stomach, small intestine, and colon. In Crohn's disease, there may be "skip lesions," that is, abnormal segments of the GI tract interspersed with normal segments.
Both Crohn's disease and ulcerative colitis may have other organ systems involved in addition to the gastrointestinal tract.
Microscopic colitis
There are two types of microscopic colitis: 1) collagenous colitis and 2) lymphocytic colitis. Either collagen or lymphocytes (a type of white blood cell) infiltrate into the layers of the wall of the colon, presumably as a result of inflammation. This is an uncommon illness and may be an autoimmune disease. The diarrhea often is watery, and no blood is present in the stool.
Allergic colitis in infants
In infants younger than 1 year of age, colitis is often due to allergies to cow or soy milk. Allergic colitis may be seen in breastfed babies, where mothers drink cow's milk and pass that protein into their breast milk.
What are colitis symptoms and signs?
Pain from inflammation
Inflammation of the colon causes the muscle layers to go into intermittent spasm, causing colicky or cramp-like pain that comes and goes. The pain usually is in the lower abdomen but can be felt anywhere along the course of the colon. Since the muscles fail to contract in a normal pattern and the colonic contents move through the colon rapidly, there is little opportunity for water to be reabsorbed. This leads to watery diarrhea. If the lining of the colon becomes inflamed and breaks down, bleeding may occur. In ulcerative colitis, small ulcers form and are the cause of bleeding.
Pain before, during, and/or after an episode of diarrhea
With colitis, particularly colitis involving the distal colon (rectum and sigmoid colon), the pain often crescendos and precedes a diarrheal bowel movement. After the bowel movement, the pain may subside but then returns with the next episode of diarrhea. The person also may have a feeling of urgency to have a bowel movement.
Other symptoms of colitis
Depending upon the cause of the colitis, other organ systems in the body may be involved and produce symptoms such as
- fever,
- chills,
- malaise,
- fatigue,
- dehydration. (Symptoms of dehydration include weakness, lightheadedness, and decreased urine output.)
Both ulcerative colitis and Crohn's diseases may have associated symptoms outside of the colon due to the body itself attacking other organs. These may include
- joint swelling,
- eye inflammation (iritis),
- canker sores in the mouth (aphthous ulcer),
- skin inflammation (pyoderma gangrenosum).
When should someone contact a doctor about colitis?
Diarrhea is a common sign of colitis. It is usually self-limited and resolves on its own with supportive care, including rest and a short course of a clear-fluid diet. However, seek medical care if the diarrhea persists for more than two to three weeks, if there is blood in the stool, fever, or the person has signs of dehydration.
Blood in the stool is never normal and should always be evaluated. Common causes of blood in the stool include hemorrhoids; however, other serious causes of bleeding need to be investigated. Colitis is not the only cause of rectal bleeding. Others causes include diverticular disease of the colon (diverticulitis), colon polyps, anal fissures, and cancer.
Chronic diarrhea may lead to dehydration and changes in the electrolyte balance in the body. If it is severe enough, the dehydration may require treatment with IV fluids or oral rehydration therapy. The symptoms of dehydration may include:
- • lightheadedness (dizziness), especially when changing from a sitting or lying position to standing position (orthostatic hypotension)
- • weakness
- • dry mouth
- • dry eyes
- • decreased output of urine
- • High fever associated with diarrhea may be a warning sign that a significant infection may be present
- • Abdominal pain is not normal, and while diarrhea may be associated with mild cramps, the presence of increasing abdominal pain requires the need to seek prompt medical attention
What kind of doctor diagnoses and treats colitis?
Most often colitis is treated by a primary health care provider or internal-medicine specialist, especially when the colitis is first diagnosed and the cause is uncertain. Once the cause is found, that health care provider may be the only person needed to continue care. Should there be a need for further investigation and diagnostic testing, specialists may be consulted, such as a gastroenterologist. If an infection is the cause of colitis, an infectious-disease specialist may be consulted. In some cases, other specialists may be involved in treatment, such as surgeons and interventional radiologists.
Patient history
In patients with abdominal pain and diarrhea, it is important to find out when the symptoms began, how long they have lasted, whether they come and go, and what makes them better or worse.
Travel history is important, especially if the patient has recently visited an area with potentially contaminated water supply or poor food hygiene. Patients often ask if the symptoms are caused by food poisoning, but that is a difficult question to answer immediately. Usually this occurs with the consumption of poorly handled or stored food in a home or a family gathering event and symptoms occur within a few hours after the food was eaten. Moreover, others at the gathering may experience similar symptoms.
Blood in the stool, whether it is mixed in with the bowel movement or just drops in the toilet bowl, is not normal. While it may be due to hemorrhoids, other potential causes that are more worrisome may need to be explored. Questions might be asked about bowel habits, weight loss, weakness, or family history of bowel disorders, including cancer or colon polyps. Depending on the health care professional's concerns, information may need to be obtained about other body systems, past medical history, social habits (including smoking, drinking, and occupational hazards or risks).