Term
| What is the basic theory of why diarrhea occurs? |
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Definition
Increase in secretion (Cl-) or Decrease in absorption (Na+ and Cl-)
Crypt cells deal with secretion
Villi cells deal with absorption |
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Term
| What are the 4 pathophysiolgoical mechanisms that generate diarrhea? |
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Definition
1) Osmotic diarrhea
- unusual amount of poorly absorbable, osmotically active solutes in gut lumen
- alcohols or ions (laxatives) prevent maintenance of osmotic gradient between lumen and bodily fluids.
- Stool osmolol gap > 100 mOsm/kg
2) Secretory diarrhea
- Intestinal ion secretion or inhibition of normal active ion absorption often due to infection
- Stool osmolol gap < 50 mosm/kg
3) Deranged intestinal motility
- Neurohormonal due to anxiety, stress, nicotine, methylxanthine.
4) Exudation/Inflammation
- mucus, blood and protein from sites of inflammation. |
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Term
| What kind of diarrhea disappears with fasting and presents with a stool osmolal gap > 100 mOsm/kg? |
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Definition
Osmotic diarrhea from consumption of poorly absorbed alcohols or ions (laxative-magnesium, sulfate, lactose)
Secretory diarrhea would have a gap < 50 mOsm/kg and is usually due to infection. Also, 24h fasting stool would be > 200! |
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Term
| How can infection cause diarrhea? |
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Definition
| Secretory diarrhea where enterotoxins increase anion (Cl- or HCO3-) secretion or decrease anion/cation absorption (Na/H ATPase) |
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Term
| Why is cholestyramine often given to patients with Crohn's disease? |
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Definition
Bile salt binder to prevent bile salt diarrhea.
CD patients will have illeum issues, so bile salts that are usually absorbed in the terminal illeum and recycled via enterohepatic circulation and instead fed to the colon, where they stimulate water secretion and intestinal motility. |
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Term
| What is neurohormonal diarrhea? |
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Definition
| Diarrhea caused by either increased intestinal motility (Decreased absorption time), or by decreased motility (increased chance of bacterial infection and resulting diarrhea) |
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Term
A patient presents complaining of straining while trying to pass bowel movements, bloating, incomplete evacuation and hard/small stools.
How do you objectively determine whether a patient is constipated or not? What are the 2 mechanisms generating constipation? |
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Definition
By ROME criterion, you already have 2 characteristics, but usually need BM < 3 times per week
1) Obstruction of movement of luminal contents
2) Decreased colonic propulsive activity. |
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Term
| What are the 8 primary causes of constipation? |
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Definition
1) Functional (dietary, motility disorders)
2) Structural (strictures or masses)
3) Endocrine/metabolic (hypothyroid, hypokalemic, DM)
4) Neurogenic (CV events, MS, PD, spinal chord tumor)
5) Connective tissue/smooth muscle (Amyloidosis, Scleroderma)
6) Psychogenic (Anxiety, depression)
7) Neuromuscular (Hirschprung's, Chagas)
8) Medications (Antacids, anti-depressents, ect). |
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Term
True or False:
Acute constipation is more associated with organic disease than long-standing constipation. |
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Definition
True! Also more associated than acute diarrhea!
You must discern whether patient has signs or symptoms of neurological, endocrine, neoplastic or metabolic disorder |
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Term
| Which adults with constipation should receive a colonoscopy? |
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Definition
1) Positive guaiac test (blood)
2) Iron-deficiency anemia
3) First degree relative with colon cancer. |
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Term
| What are the primary available treatments for chronic constipation? |
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Definition
Laxatives
1) Bulk-forming (fiber)- safest
2) Stimulants- Bisacodyl and senna are OTC options
3) Osmotics (polyethylene glycol:Mirilax)
- cause fluid to flow into colon and cause bowel distention (useful for idiopathic cases)
4) Stool softener
- Docusate- use in people who should avoid straining
5) Lubricant- Fleet and Zymenol to greese stool
6) Saline- acts like sponge to draw water into colon (Milk of Magnesia)
- use in acute constipation if no indication of obstruction
7) Chloride channel activator (Lubiprostone) for those with fiber/laxative-refractory cases. |
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Term
| What kind of diarrhea is caused by lactose intolerance? |
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Definition
| Osmotic (Osm gap > 100 mOsm/kg |
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Term
Which of the following is NOT correct.
1) Acute diarrheal illness tends to be a benign and self-limiting event
2) Acute onset of constipation more commonly indicates an organic cause
3) Chronic diarrhea is more likely to involve significant pathology
4) Chronic constipation is less likely to be functional and lifestyle-related |
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Definition
4) Chronic constipation (unlike acute), is usually a functional/life-style issue and not organic disease.
Chronic diarrhea on the other hand IS organic-disease related, unlike acute diarrhea, which is usually self-limited and not serious. |
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Term
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Definition
Live microorganisms (mostly bacteria) that are similar to beneficial organisms found in the human gut.
Must..
- Adhere to intestinal mucosa and colonize the GI tract.
- Documented health benefits
- Easily grown in vitro
- Nonpathogenic
- Resistant to gastric acid, pancreatic enzymes and bile |
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Term
| How can pro-biotics be used to treat diarrhea? |
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Definition
1) Prophylaxis for drug-induced diarrhea
2) Decrease length of infectious diarrhea (traveler's, rotavirus, C. dif) |
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Term
| What is S. boulardii, and how is it used clinically? |
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Definition
Secondary prevention of CDAD (C dif. diarrhea) when used in combination with vancomycin to treat recurrent episode.
- a yeast found on the lychee fruit, works by producing a protease that destroys the toxin A receptor site. |
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Term
| How can probiotics be used in IBD patients? |
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Definition
| ONLY in MAINTENANCE OF REMISSION for pouchitis in post-surgical CD patients and UC |
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Term
| What group of irritable bowel patients benefit from pro-biotics? |
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Definition
- Only short-term outcomes demonstrated with modest benefit.
- Appear to be most beneficial in diarrhea-predominant subset of patients. |
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Term
| What are the major indicated uses of probiotics currently? |
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Definition
1) Antibiotic associated diarrhea
2) Infectious diarrhea (including rotavirus and CDAD –treatment, primary and secondary prevention)
3) Maintenance of remission in ulcerative colitis
4) Maintenance of remission for pouchitis
5) Treatment of minimal hepatic encephalopathy
6) Prevention of NEC in premature infants |
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