Gi - Diarrhea And Colonic Diseases

Front 1

Celiac sprue

Back 1

Allergy to wheat, rye, and barley

Celiac sprue can present as chronic diarrhea without blood or as iron deficiency anemia. It is more common in individuals of Irish decent. Treatment is dietary avoidance of wheat, rye, and barley. Present in 1 out of 122 persons.

Front 2

Clostridium difficile

Back 2

A species of Gram-positive, anaerobic, spore-forming rods that cause acute diarrhea without blood with antibiotics wipe out the normal bacterial flora of the bowel.

Most of the time C difficile infection is associated with previous hospitalization or exposure. There is an onset of voluminous, foul smelling, and watery diarrhea. C difficile infection is diagnosed with stool analysis for C difficile toxin A and B. Treatment is metronidazole 500 mg TID for 10 days.

Front 3

Bile salt deficiency

Back 3

One of the causes of steatorrhea and osmotic diarrhea. Bile salt deficiency results in decreased micelle formation. This can be due to terminal ileal disease or resection, bacterial overgrowth, or hepatic disease.

Front 4

cAMP

Back 4

In secretory diarrhea, cAMP is increased in small bowel epithelial cells resulting in increased secretion.

Front 5

Carcinoid syndrome

Back 5

Carcinoid syndrome refers to the array of symptoms that occur secondary to carcinoid tumors. The carcinoid syndrome occurs in approximately 10% of carcinoid tumors and becomes manifest when vasoactive substances from the tumors enter the systemic circulation escaping hepatic degradation. This is the case when carcinoid tumors metastasize to the liver or they arise for example in the bronchus.

Carcinoid syndrome can cause secretory diarrhea by the excess production of serotonin (5-HIAA).

Front 6

Exudative diarrhea

Back 6

Mucus, pus, and blood contributes to diarrhea but usually not of enough volume to significantly increase stool volume. If there is significant diarrhea it is often caused by another mechanism as well. These mechanisms can include inflammatory bowel disease, carcinoma, and invasive organisms.

Front 7

Motility diarrhea

Back 7

Motility-related diarrhea is caused by the rapid movement of food through the intestines (hypermotility). If the food moves too quickly through the GI tract, there is not enough time for sufficient nutrients and water to be absorbed.

Causes include irritable bowel syndrome, diabetes, hyperthyroidism, vagotomy, etc.

Front 8

Secretory diarrhea

Back 8

Classic mechanism is toxin or peptide that increases cAMP in small bowel epithelial cells resulting in increased secretion.

Daily volume is usually > 1 liter. Diarrhea persists with fasting. There is a low fecal osmolality gap.

Front 9

Osmotic diarrhea

Back 9

Caused by ingesting solutes that cannot be normally digested or absorbed. This osmotically active solute then draws water into the lumen of the gut.

Daily stool volume is usually < 1 liter. Diarrhea decreases or resolves with fasting. Fecal Na+ is low and there is a high fecal osmotic gap.

Front 10

Zollinger Ellison (ZE) syndrome

Back 10

Causes excess gastrin to be produced, resulting in excessive gastric secretion overwhelming GI absorption ability. The diarrhea in ZE is often multifactorial - resulting in a mixed secretory and osmotic pattern.

Front 11

Ileal resection

Back 11

Can cause loss of bile salts, steatorrhea, and osmotic diarrhea.

Front 12

Irritable bowel syndrome

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Irritable bowel syndrome (IBS or spastic colon) is a functional bowel disorder characterized by chronic abdominal pain, discomfort, bloating, and alteration of bowel habits in the absence of any detectable organic cause.

Can cause motility related diarrhea and chronic diarrhea without blood.

Front 13

Fecal osmotic gap

Back 13

Fecal osmolality (~290) - [2 x (Na + K)] > 50

Fecal osmotic gap is high in osmotic diarrhea (since the abnormal osmotically active solute has replaced sodium) but low in secretory diarrhea.

Front 14

Lactase deficiency

Back 14

An example of carbohydrate malabsorption due to disaccharidase deficiency. It is a cause of osmotic diarrhea.

< 15% - White Americans, Northwest Europeans, and Scandinavians
60-80% - US blacks, Jews, Indians, and Mexicans
80% - Japanese, Eskimos, and Nigerians

Front 15

Steatorrhea

Back 15

The presence of excess fat in feces. It results from the maldigestion or malabsorption of fats.

This can be due to pancreatic insufficiency resulting in lipase deficiency, bile salt deficiency resulting in decreased micelle formation (terminal ileal disease or resection, bacterial overgrowth, or hepatic disease), or small bowel mucosal disease.

Front 16

Vibrio cholera

Back 16

A cause of secretory diarrhea. Produces a toxin that results in increased secretion by increasing intracellular cAMP. Importantly, absorption mechanisms remain intact, so that despite the massive secretion and diarrhea, oral solutions with glucose and sodium can be successful treatments.

Front 17

Fecal incontinence

Back 17

Not necessarily diarrhea. Refers to the involuntary release of rectal contents.

Front 18

D-xylose test

Back 18

Test used when malabsorption/maldigestion is suspected presenting as steatorrhea with chronic non-blood diarrhea.

If abnormal, this suggests small bowel malabsorption. If normal, this suggests other than small bowel etiology, most likely pancreatic.

Front 19

Diverticulosis

Back 19

The condition of having diverticula in the colon, which are outpocketings of the colonic mucosa and submucosa through weaknesses of muscle layers in the colon wall. These are more common in the sigmoid colon, which is a common place for increased pressure.

Treatment includes high fiber diet with or without trial of oral antibiotics.

Front 20

Diverticulitis

Back 20

Develops from diverticulosis, which involves the formation of pouches (diverticula) on the outside of the colon. Diverticulitis results if one of these diverticula becomes inflamed.

Symptoms include abdominal pain, impaired bowel function, and fever. Treatment includes IV antibiotics, oral antibiotics, low fiber diet then high fiber diet after 6-8 weeks, and surgery. 50-70% of patients with one episode of diverticulitis will not have another episode.

Front 21

Thyrotoxicosis

Back 21

Hyperthyroidism is one of the possible causes of osmotic diarrhea.

Front 22

Fecal leukocytes

Back 22

Diagnostic test for diarrhea disorders. Best seen with methylene blue stain and positive if more than 50% of the total cells are leukocytes.

Positive in bacterial infections, IBD, ischemic colitis, and others. Negative in viral infections, IBS, and many osmotic and secretory etiologies.

Front 23

Fecal electrolytes

Back 23

Diagnostic test for diarrhea disorders. Osmotic diarrheas will show unexplained osmotic gap.

Front 24

Medullary thyroid cancer

Back 24

Causes excess calcitonin and prostaglandin production. A hormonal cause of secretory diarrhea.

Front 25

Factitious diarrhea

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Diarrhea caused by something the patient is doing to his or her own body, usually surreptitious laxative abuse.

Front 26

Choleretic enteropathy

Back 26

Bile salt induced increased secretion by the colon. Results from ileal resection or disease. It causes a type of secretory diarrhea.

Front 27

Bacillary dysentery

Back 27

Bacillary dysentery is a type of dysentery, and is a severe form of shigellosis. Shigella infection causes an exudative diarrhea.

Front 28

Ova and parasites

Back 28

Diagnostic test for diarrhea disorders. Test is for amoeba, giardia, hookworm ova, and strongyloides. Can be false negative for giardia, so repeating can improve yield. Duodenal aspirate is best for giardia.