CM- Approach to Colon and IBD Flashcards
How does the colonic mucosa differ from intestinal mucosa?
Colonic - intestinal epithelium. with specialized cells to absorb and secrete, lamina propria and muscularis mucosa
Colon does NOT have villi and consists mainly of crypts.
What is the definition of constipation?
- decrease in # of BMs
2. difficulty defacating regardless of # of stools
What are the 2 causes of constipation and how do you differentiate them?
- Colonic inertia (pumps too slow)
- outlet obstruction
To differentiate, a radioopaque markers (Sitz) is ingested.
If the markers are scattered throughout the colon is is colonic inertia.
If the markers are concentrated at the distal colon it is an outlet obstruction.
What is treatment for constipation?
- increase stool water content (bulking agent or non-reabsorbable liquid like miralax)
- Biofeedback if patient has pelvic floor dysenergia
What is pseudo-obstruction and what are the causes?
It is when there is colonic dilation and signs/symptoms of obstruction with no obstructing lesion present.
- smooth muscle disorder
- myenteric plexus
- neuro dysfunction
- endocrine/metabolic disorders
5 drugs - idiopathic ** most common
What is treatment for pseudo-obstruction?
- rule out colonic obstruction by hypaque enema
2. position changes to move air toward the rectum
What is fecal incontinence?
What are 3 decently common causes?
What is treatment/management?
It is when stool cannot be retained until voluntary evacuation.
It is common with previous trauma to the anal canal so:
1. pregnancy
2. prior hemorrhoid surgery
3. diabetes
Treatment:
- exercise pelvic floor muscles
- biofeedback
- US to see if the sphincter is amenable to surgery
What are the 4 most important structural diseases of the colon?
- obstruction
- CRC
- diverticular disease
- IBD
A patient presents with abdominal distension and obstipation [they have not been able to pass any luminal contents including gas]. They now feel nauseas and have vomited multiple times.
What is the likely problem?
What 4 things are the most common causes?
Obstruction-
- intraperitoneal adhesions
- torsion of the colon upon itself (volvulus)
- intraluminal mass (cancer)
- diverticular stricture
What is microscopic colitis?
What is seen grossly?
What do labs show?
What is noted histologically?
Chronic watery diarrhea with no blood, abdominal pain, or signs of malabsorption.
Lab tests and gross examination are normal, however, histology shows chronic inflammatory cells.
- lymphocytic colitis
- collagenous colitis
What are the 2 types of idiopathic IBD?
- UC
2. Crohn disease
What part of the GI tract is affected by UC?
What are typical GI symptoms?
What are systemic symptoms?
UC affects the entire colon but not other parts of the gut.
Typical symptoms are small volume bloody diarrhea.
Systemically they can experience fever and malaise.
What are the most dreaded complications of UC?
- Toxic megacolon - risk for perforation)
- Primary sclerosing cholangitis (PSC)
- Cholangiocarcinoma
- colon cancer
What part of the GI tract is affected by Crohn disease?
What are systemic symptoms?
CD is a disease of the entire intestinal wall and has skip areas of the colon starting on the right side. It can affect any area of the GI tract from nasopharynx to rectum.
Systemic manifestations of Crohn are:
- symmetric arthralgias in appendicular joints
- gallstone disease
- renal stones
How are treatments different for Crohn and UC?
They are essentially the same, except for surgical considerations.
- surgery is curative in UC, not Crohn
- UC can’t get segmental resections. Take the whole colon
- Crohn must get segmental resections and thus multiple surgeries over lifetime
- Ileal pouch reconstructions with anal anastamoses lead to long term continence in total proctocolectomies in UC patients
What are the 5 treatments for UC and Crohn from most preferred to least preferred?
What are the pros and cons of each?
- Mesalamine- safests, reduced cancer risk. Poor compliance, expensive
- Systemic steroids- dramatic results, once daily, cheap. Serious side effects in 100% of ppl on long term therapy
- Azathioprine/6MCP- used if tapering of steroids leads to relapse. Hepatotoxic, suppress marrow, pancreatitis
- Biologics (TNF-binding Ab)- miraculous but super expensive and must be on treatment forever bc going off it leads to serious allergic problems
- Surgery- last ditch effort
What is the screening process for IBD colitis and the development of cancer?
Colonoscopies are done 7 years after disease initiation for pancolitis and 10 years for segmental.
Colonoscopies are repeated every 1 to 2 years and biopsies must be done at 4 quadrants 10cm apart.
When screening for CRC in patients with IBD, why must biopsies be taken for every colonoscopy?
What is treatment?
Increased cancer risk comes from NON-poylpoid dysplasia in Crohn/UC where the gross appearance is NOT abnormal.
[they get cancer w/o going through the polyp phase]
Treatment is segmental resection of the dysplastic area
What are the 5 most commonly involved areas for extra-colonic manifestations of UC?
- Skin (erythema nodosum, pyoderma gangrenosum)
- eyes (episcleritis, uveitis)
- Joints (pauci articular = less than 4, big joints. Poly articular = more than 5 smaller joints)
- Mouth -aphthous ulcers
- Hepatobiliary - PSC, cholangiocarcinoma
What are the 2 skin manifestations associated with UC?
When UC is in remission, do they persist or clear?
- erythema nodosum - resolves
2. pyoderma gangrenosum - persists
What is the main oral manifestation of UC? Does it clear or persist when you clear the underlying UC?
Aphthous ulcers- clear with improvement of bowel disease
What are the joint manifestations associated with UC? What are the durations of each? What joints are involved?
- Pauciarticular - 4 or less joints, tend to be large appendicular [knees>ankle>wrist]. Lasts 5 wks
- Polyarticular - 5 or more joints, tend to be smaller joints [MCP>knee>PIP]. Pattern is independent of bowel disease and up to 3years
What are the hepatobiliary effects of UC?
What changes are seen in lab values?
Does it persist or remiss when bowel problems are controlled?
PSC- structuring of biliary tract intra and extrahepatically.
Alk phos rises due to small and large obstructions. Bilirubin doesn’t rise until total bile flow is sharply curtailed.
It does NOT improve with UC activity.
What are the extraintestinal manifestations of Crohn disease?
- Skin - same as UC but also with distal ulcers
- Joints-both type I and type II more common than UC. Osteopenia
- Eyes- episcleritis is more common than in UC
- Renal - oxalate stones form after surgery due to loss of Ca and fat and hyperabsorption of oxalate
- Coagulation - prothrombic tendency
Describe the pathology of ischemic colitis.
What areas of the colon are most affected?
What is treatment?
What if symptoms continue?
It is when vascular insufficiency (usually due to low flow) leads to mucosal ischemia of the bowel with pain and hemorrhage.
It occurs at watershed areas (splenic flexure and the recto-sigmoid) and is treated with support to the vascular system.
If it continues it might mean transmural ischemia which would require surgical resection.
Who is most frequently affected by ischemic colitis?
It often occurs in young healthy people with normal arteries anatomically
What are factors that predispose people to infectious colitis?
How long does infectious colitis last?
Travel, immunodeficiency, diet etc EHEC, EIEC Shigella Salmonella Campylobacter Yersinia E. histolytica C. diff MAC CMV
It lasts no more than 10-21 days so if colitis is present for months/years it is NOT infectious
What are the symptoms of IBS?
What is thought to be the cause of IBS?
What tests are done for it?
Pain, bloating, diarrhea OR constipation.
It is thought to be caused by abnormalities in serotonergic function.
Little is known about the disease pathologically or pathophysiologically. NO tests are positive and there is no structural cause identified.
