Diarrhea Flashcards
- Stool mass best gauge of diarrhea
- Normal: in U.S. 250 gm; contains 70-95% water; frequency >2 times daily
Stool perceived as Diarrhea
Osmotic
Secretory
Abnormal motility
Exudative
Mechanisms of Diarrhea
Occurs when the intraluminal water load exceeds the absorptive capacity of the gastrointestinal tract
- occurs when there is ingestion of nonabsorbable or poorly absorbed solutes
- reduces with fasting
- Osmotic gap > 50 mOsm
- Exogenous type: Laxatives (Golytely, MOM); Antacids (containing Mg); Artificial sugars (sorbitol, mannitol, xylitol); Medications (cholestyramine)
- Endogenous type: Congenital (e.g., lactase insufficiency); Generalized; Acquired (post-enteritis disaccharide deficiency; pancreatic insufficiency)
Osmotic Diarrhea
- calculation performed to distinguish among different causes of diarrhea:
(Na + K) x 2 - if greater than 50 mOsm, you have a gap
- When there is an osmotic gap, the difference is approximately equivalent to the concentration of the osmotically active substances causing the diarrhea
Osmotic gap equation
- type of osmotic diarrhea
- SYMPTOMS: Abdominal distension, bloating, cramps, borborygmi (intestinal rumbling/gurgling), flatulence, diarrhea
Lactase deficiency
- Active intestinal secretion or inhibition of ion absorption with concomitant flow of water
- Categories: INFECTIOUS; NEOPLASTIC; MISCELLANEOUS
- Small bowel morphology is usually normal
- Colon usually has normal absorptive and secretory capacities
Characteristics:
- Large volume diarrhea (>1 liter daily)
- Persists during fasting
- small osmotic gap (ions similar to plasma)
- mucosa may be normal
Secretory Diarrhea
Enterotoxin mediated
- Vibrio cholera, E.coli, Bacillus cereus, Clostridium perfringens
Infectious Secretory diarrhea
Hormone producing: (more common)
- pancreatic cholera, carcinoid, medullary carcinoma of the thyroid
Non-hormone producing: villous adenoma
Neoplastic diarrhea
- Classic example of secretory diarrhea
- Caused by enterotoxin Vibrio cholera
- Severe diarrhea can result in volume depletion, dehydration, acidosis, death (50%j)
Cholera
WDHA Syndrome: watery diarrhea, hypokalemia, achlorhydria
- Non-beta, islet cells of pancreas produce VIP
- Profuse, watery diarrhea
– diarrhea (100%), achlorhydria (60%), hypercalcemia (75%), glucose intolerance (50%), flushing (20%)
Pancreatic Cholera
- Malabsorption syndrome due to autoantibodies to gluten
- primarily affects distal duodenum or proximal jéjunum
- Histology shows loss of villi
Celiac Sprue
RAPID TRANSIT
Pyloroplasty, hemigastrectomy, hyperthyroidism, irritable bowel syndrome
DELAYED TRANSIT
Collagen-vascular disease, intestinal strictures, pseudo-obstruction
Motility Disorders
- Results from disruption of integrity of intestinal mucosa due to inflammation
- Loss of proteins, blood, mucus and pus
- Fecal water and electrolytes are high
INFECTIOUS DISEASES
- Salmonella, Shigella, Campylobacter, Entamoeba
INFLAMMATORY BOWEL DISEASE
- Ulcerative colitis, Crohn’s disease
Exudative Diarrhea
- Salmonella, Shigella, Campylobacter, Entamoeba
- In infectious diarrhea, the number of bowel movements is often >6 daily, but the volume is usually <1 liter daily
Infectious Exudative Diarrhea
usually small bowel or proximal colon
Large volume diarrhea
often associated with diseases of the left colon or rectum
SMALL VOLUME DIARRHEA
indicates inflammatory, infectious or neoplastic condition
BLOODY STOOL
indicates inflammatory or infectious condition
ASSOCIATED WITH MUCUS OR PUS
hyperthyroid –> diarrhea
hypo –> constipation
Thyroid involvement
