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
