Segmental colitis associated with diverticulosis | |
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Other names | SCAD |
Endoscopic image of segmental colitis associated with diverticulosis, Type A | |
Specialty | Gastroenterology |
Symptoms | Rectal bleeding, Abdominal cramping, Asymptomatic |
Usual onset | 64 years of age |
Types | A-D |
Diagnostic method | Colonoscopy |
Differential diagnosis | Bacterial colitis, Diverticulitis, NSAID-induced colitis, Crohn's disease, Ulcerative colitis |
Treatment | Antibiotics, Mesalamine, Prednisone, Surgery |
Prognosis | Benign |
Frequency | 0.3 - 1.3% |
Segmental colitis associated with diverticulosis (SCAD) is a condition characterized by localized inflammation in the colon, which spares the rectum and is associated with multiple sac-like protrusions or pouches in the wall of the colon (diverticulosis). Unlike diverticulitis, SCAD involves inflammation of the colon between diverticula (interdiverticular mucosa), while sparing the diverticular orifices. SCAD may lead to abdominal pain, especially in the left lower quadrant, intermittent rectal bleeding and chronic diarrhea. [1]
The cause of SCAD is unknown, but may be related to local colonic ischemia, fecal stasis, or mucosal prolapse. The factors that cause SCAD likely overlap with inflammatory bowel disease. There are four types of SCAD, which are categorized based on the appearance during colonoscopy. Pattern A is characterized by involvement of crescentic folds and is the most common type of SCAD (52%). [2] Pattern B has an appearance similar to mild-to moderate ulcerative colitis (30.40%), whereas pattern C appears similar to Crohn's disease (10.90%). [2] Pattern D is the least common, and appears similar to severe ulcerative colitis (6.50%). [2]
SCAD is diagnosed by colonoscopy. Additional testing may be necessary to rule out infectious causes of colitis. Evaluation should include assessment for additional causes of colitis, such as medication induced (checkpoint inhibitors, NSAIDs, etc.). Laboratory results are usually normal in SCAD, although the white blood cell count may be mildly elevated. Fecal calprotectin, a marker of colon inflammation, may be elevated. Computed tomography of the abdomen is not routinely necessary, but may show thickening or inflammation in the distal colon (sigmoid colon) with associated diverticulosis.
Treatment may consist of antibiotics, aminosalicylates (mesalamine), or prednisone. In rare cases, surgery with segmental resection may be considered. The long term prognosis is likely benign, although data is lacking. The prevalence of SCAD ranges from 0.3 - 1.3 percent.
There are four types of SCAD, based on endoscopic appearance. Pattern A is characterized by involvement of crescentic folds and is the most common type of SCAD (52%). [2] Pattern B has an appearance similar to mild-to moderate ulcerative colitis (30.40%), whereas pattern C appears similar to Crohn's disease (10.90%). [2] Pattern D is the least common, and appears similar to severe ulcerative colitis (6.50%). [2]
People with SCAD may develop left lower quadrant abdominal cramping, intermittent rectal bleeding, and chronic diarrhea. [1] Rectal bleeding (hematochezia) is the most common symptom, [3] and is the presenting complaint in more than 70% of individuals with SCAD. [4] Fever is rare. [5]
The cause of segmental colitis associated with diverticula is unknown. Several factors may influence the development of the disease, such as local colonic ischemia, fecal stasis, or mucosal prolapse. SCAD shares some features with inflammatory bowel disease, including the increase of tumor necrosis factor (TNF) alpha during active disease, and decrease in TNF during health improvement. The pathogenesis of SCAD likely overlaps with inflammatory bowel disease. [6]
SCAD is diagnosed via colonoscopy, often incidentally during examination for unrelated concerns. Colonoscopy shows erythema of the colonic mucosa, which may be characterized by friability and exudate. [1] The descending and sigmoid colon are typically involved. Biopsies of the affected area and the unaffected rectum confirm the diagnosis. [1] Biopsies of SCAD show evidence of chronic inflammation. Rectal biopsies show normal mucosa.
It is important and occasional difficult to distinguish SCAD from inflammatory bowel disease (IBD). [1] [7] Biopsies reveal histologic findings that are identical in both conditions. [1] However, ulcerative colitis usually affects the rectum and inflammation in IBD extends to areas of the colon without diverticulosis. [1]
Additional causes of colitis should be evaluated, including infectious and medication-induced, particularly NSAID-associated. [1]
Laboratory results are usually normal in individuals with SCAD. The white blood cell count may be mildly elevated. Fecal calprotectin, a marker of colon inflammation, may be elevated in individuals with SCAD. [8] Fecal calprotectin may assist in distinguishing SCAD from irritable bowel syndrome. [8]
Imaging tests, including CT abdomen, may show inflammation or thickening of the distal colon, with associated diverticulosis. There may be evidence of inflammation extending around the bowel (fat stranding).
There are several options in treatment for SCAD. Data is lacking, and there are no prospective trials comparing different therapies for SCAD. As of 2017, there are no guidelines available to direct treatment. [6] Treatment may include antibiotics, aminosalicylates, and corticosteroids. Antibiotics include ciprofloxacin and metronidazole, given for 14 days. If symptoms recur after improvement with antibiotics, a second course of antibiotics may be given.
If an initial course of antibiotics is ineffective, then mesalamine may be tried. If mesalamine is ineffective, then a course of prednisone may be helpful. In severe cases of SCAD, where corticosteroids are unable to be discontinued, then surgery may be considered (segmental resection).
The natural history of SCAD lacks rigorous study, with little data regarding long term outcomes. However, the course appears to largely benign. In cases that require surgery, recurrence of disease is rare. [9] Long term medication therapy is rarely necessary. [6] Over a course of 7 years, about half of people with SCAD experience a recurrence of symptoms. [10] About a third of people have a mild recurrence. [10]
Among individuals with diverticulosis, the prevalence of SCAD ranges from 0.3 - 1.3%. [11] SCAD is more common in men. [5] [11] [12] SCAD often occurs in elderly individuals, with an average of 64 years upon diagnosis. [11] [12]
SCAD was first described in a case series in 1984. [13] SCAD was initially believed to represent a complication of diverticular disease. [14] As evidence suggested increasing overlap with inflammatory bowel disease, SCAD became recognized as a distinct condition. [14]
Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD). It is a long-term condition that results in inflammation and ulcers of the colon and rectum. The primary symptoms of active disease are abdominal pain and diarrhea mixed with blood (hematochezia). Weight loss, fever, and anemia may also occur. Often, symptoms come on slowly and can range from mild to severe. Symptoms typically occur intermittently with periods of no symptoms between flares. Complications may include abnormal dilation of the colon (megacolon), inflammation of the eye, joints, or liver, and colon cancer.
Haematochezia is the passage of fresh blood through the anus, usually in or with stools. The term is from Greek αἷμα ("blood") and χέζειν. Hematochezia is commonly associated with lower gastrointestinal bleeding, but may also occur from a brisk upper gastrointestinal bleed. The difference between hematochezia and rectorrhagia is that, in the latter, rectal bleeding is not associated with defecation; instead, it is associated with expulsion of fresh bright red blood without stools. The phrase bright red blood per rectum is associated with hematochezia and rectorrhagia.
Inflammatory bowel disease (IBD) is a group of inflammatory conditions of the colon and small intestine, with Crohn's disease and ulcerative colitis (UC) being the principal types. Crohn's disease affects the small intestine and large intestine, as well as the mouth, esophagus, stomach and the anus, whereas ulcerative colitis primarily affects the colon and the rectum.
Diverticulitis, also called colonic diverticulitis, is a gastrointestinal disease characterized by inflammation of abnormal pouches—diverticula—that can develop in the wall of the large intestine. Symptoms typically include lower abdominal pain of sudden onset, but the onset may also occur over a few days. There may also be nausea, diarrhea or constipation. Fever or blood in the stool suggests a complication. People may experience a single attack, repeated attacks, or ongoing "smouldering" diverticulitis.
Diverticulosis is the condition of having multiple pouches (diverticula) in the colon that are not inflamed. These are outpockets of the colonic mucosa and submucosa through weaknesses of muscle layers in the colon wall. Diverticula do not cause symptoms in most people. Diverticular disease occurs when diverticula become clinically inflamed, a condition known as diverticulitis.
Gastrointestinal diseases refer to diseases involving the gastrointestinal tract, namely the esophagus, stomach, small intestine, large intestine and rectum, and the accessory organs of digestion, the liver, gallbladder, and pancreas.
Colitis is swelling or inflammation of the large intestine (colon). Colitis may be acute and self-limited or long-term. It broadly fits into the category of digestive diseases.
Toxic megacolon is an acute form of colonic distension. It is characterized by a very dilated colon (megacolon), accompanied by abdominal distension (bloating), and sometimes fever, abdominal pain, or shock.
In medicine, the ileal pouch–anal anastomosis (IPAA), also known as restorative proctocolectomy (RPC), ileal-anal reservoir (IAR), an ileo-anal pouch, ileal-anal pullthrough, or sometimes referred to as a J-pouch, S-pouch, W-pouch, or a pelvic pouch, is an anastomosis of a reservoir pouch made from ileum to the anus, bypassing the former site of the colon in cases where the colon and rectum have been removed. The pouch retains and restores functionality of the anus, with stools passed under voluntary control of the person, preventing fecal incontinence and serving as an alternative to a total proctocolectomy with ileostomy.
Megacolon is an abnormal dilation of the colon. This leads to hypertrophy of the colon. The dilation is often accompanied by a paralysis of the peristaltic movements of the bowel. In more extreme cases, the feces consolidate into hard masses inside the colon, called fecalomas, which can require surgery to be removed.
Blood in stool or rectal bleeding looks different depending on how early it enters the digestive tract—and thus how much digestive action it has been exposed to—and how much there is. The term can refer either to melena, with a black appearance, typically originating from upper gastrointestinal bleeding; or to hematochezia, with a red color, typically originating from lower gastrointestinal bleeding. Evaluation of the blood found in stool depends on its characteristics, in terms of color, quantity and other features, which can point to its source, however, more serious conditions can present with a mixed picture, or with the form of bleeding that is found in another section of the tract. The term "blood in stool" is usually only used to describe visible blood, and not fecal occult blood, which is found only after physical examination and chemical laboratory testing.
Pouchitis is an umbrella term for inflammation of the ileal pouch, an artificial rectum surgically created out of ileum in patients who have undergone a proctocolectomy or total colectomy. The ileal pouch-anal anastomosis is created in the management of patients with ulcerative colitis, indeterminate colitis, familial adenomatous polyposis, cancer, or rarely, other colitides.
Lower gastrointestinal bleeding, commonly abbreviated LGIB, is any form of gastrointestinal bleeding in the lower gastrointestinal tract. LGIB is a common reason for seeking medical attention at a hospital's emergency department. LGIB accounts for 30–40% of all gastrointestinal bleeding and is less common than upper gastrointestinal bleeding (UGIB). It is estimated that UGIB accounts for 100–200 per 100,000 cases versus 20–27 per 100,000 cases for LGIB. Approximately 85% of lower gastrointestinal bleeding involves the colon, 10% are from bleeds that are actually upper gastrointestinal bleeds, and 3–5% involve the small intestine.
In the anatomy of humans and homologous primates, the descending colon is the part of the colon extending from the left colic flexure to the level of the iliac crest. The function of the descending colon in the digestive system is to store the remains of digested food that will be emptied into the rectum.
Stercoral ulcer is an ulcer of the colon due to pressure and irritation resulting from severe, prolonged constipation due to a large bowel obstruction, damage to the autonomic nervous system, or stercoral colitis. It is most commonly located in the sigmoid colon and rectum. Prolonged constipation leads to production of fecaliths, leading to possible progression into a fecaloma. These hard lumps irritate the rectum and lead to the formation of these ulcers. It results in fresh bleeding per rectum. These ulcers may be seen on imaging, such as a CT scan but are more commonly identified using endoscopy, usually a colonoscopy. Treatment modalities can include both surgical and non-surgical techniques.
Pancolitis, in its most general sense, refers to inflammation of the entire colon. This can be caused by a variety of things. Pancolitis or universal colitis is frequently used in a more specific fashion to denote a very severe form of ulcerative colitis. This form of ulcerative colitis is spread throughout the entire large intestine including the right colon, the left colon, the transverse colon, descending colon, and the rectum. A diagnosis can be made using a number of techniques but the most accurate method is direct visualization via a colonoscopy. Symptoms are similar to those of ulcerative colitis but more severe and affect the entire large intestine. Patients with ulcerative colitis generally exhibit symptoms including rectal bleeding as a result of ulcers, pain in the abdominal region, inflammation in varying degrees, and diarrhea. Pancolitis patients exhibit these symptoms and may also experience fatigue, fever, and night sweats. Due to the loss of function in the large intestine patients may lose large amounts of weight from being unable to procure nutrients from food. In other cases the blood loss from ulcers can result in anemia which can be treated with iron supplements. Additionally, due to the chronic nature of most cases of pancolitis, patients have a higher chance of developing colon cancer.
Faecal calprotectin is a biochemical measurement of the protein calprotectin in the stool. Elevated faecal calprotectin indicates the migration of neutrophils to the intestinal mucosa, which occurs during intestinal inflammation, including inflammation caused by inflammatory bowel disease. Under a specific clinical scenario, the test may eliminate the need for invasive colonoscopy or radio-labelled white cell scanning.
Rectal discharge is intermittent or continuous expression of liquid from the anus. Normal rectal mucus is needed for proper excretion of waste. Otherwise, this is closely related to types of fecal incontinence but the term rectal discharge does not necessarily imply degrees of incontinence. Types of fecal incontinence that produce a liquid leakage could be thought of as a type of rectal discharge.
Colonic ulcer can occur at any age, in children however they are rare. Most common symptoms are abdominal pain and hematochezia.
Checkpoint inhibitor induced colitis is an inflammatory condition affecting the colon (colitis), which is caused by cancer immunotherapy. Symptoms typically consist of diarrhea, abdominal pain and rectal bleeding. Less commonly, nausea and vomiting may occur, which may suggest the present of gastroenteritis. The severity of diarrhea and colitis are graded based on the frequency of bowel movements and symptoms of colitis, respectively.
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