7. DIARRHEA

Question 1

Definition

Cut off ng acute & chronic

Answer 1

Acute – lasting for a few hours or days

Chronic (persistent) – lasting for >2 weeks

Question 2

PATHOGENESIS or MECHANISMS OF DIARRHEA
S.O.M.I.

Secretory

Answer 2

Secretagogue (e.g. Cholera toxin) binds to receptor on the surface of the epithelium of the bowel to stimulate

—> intracellular accumulation of cAMP or cGMP

—> leading to excessive secretion of Chloride or Bicarbonate with decreased absorption of Sodium and Water

(+) watery, large volume fecal outputs, painless

PERSISTS WITH FASTING

Question 3

PATHOGENESIS or MECHANISMS OF DIARRHEA
S.O.M.I.

Osmotic

Answer 3

Ingestion of osmotically active or poorly absorbed solute which draw enough fluid into the lumen to exceed the reabsorptive capacity of the colon

(+) watery acidic stools

LAXATIVES, LACTULOSE

Resolves with fasting

Question 4

PATHOGENESIS or MECHANISMS OF DIARRHEA
S.O.M.I.

Motility

Answer 4

Inc. Intestinal Motility meaning decreased ang intestinal transit time which is normally 72 hours (up to 72 hours)

IBS, Thyrotoxicosis, Postvagotomy Dumping Syndrome

Question 5

PATHOGENESIS or MECHANISMS OF DIARRHEA
S.O.M.I.

Inflammatory

Answer 5

Inflammatory mediators can DESTROY MUCOSAL LINING DECREASING ABSORPTIVE SURFACE leading to osmotic diarrhea & allow passage of RBCs and WBCs.

Mediators can also trigger a secretory type of diarrhea by increasing net secretion

infections: Infectious: Salmonella, shigella, amebiasis, Yersinia etc

Non-infectious: IBD, autoimmune, Crohn’s disease, Ulcerative colitis

Question 6

Dysentert

Answer 6

Shigella

TMP + SMX

Question 7

Zinc

Answer 7

<6 mos 10 mg more than six months give 10 mg