163. Clinical Features Colonic Disorders

Question 1

Define Diverticulosis

Pathophys of Diverticuli formation

difference b/w true and false/pseudo diverticuli

Answer 1

Diverticulosis: presence of diverticula - sac-like protrusion of the colonic wall, may be sx or asx

PPhys: abnormal contraction = higher pressure on wall = more wall tension = outpouching
Laplace law: site of colon with highest likelihood of diverticuli is SIGMOID COLON (smallest radius = highest wall pressure)

True diverticuli: herniation of entire bowel wall (all layers)

False/Pseudo-diverticuli: only mucosa protrudes through muscularis propria

Points of weakness: where vasa recta penetrates smooth inner circular muscle, areas without teniae coli (3 bands of longitudinal muscle

Question 2

Diverticular Bleeding: CP, location, tx

Diverticulitis: define, CP, dx, tx
Hinchey Classification of Diverticulitis

Answer 2

DBleeding: painless hematochezia, in R COLON, tx is supportive, colonoscopy, angiography with embolization

diverticulitis: fecolith obstructs diverticula opening
CP: abd pain, fever, leukocytosis, anorexia
Dx: distension, tenderness, peritonitis, leukocytosis, CT IS DIAGNOSTIC (see diverticula, inflammation/fluid collection, thickened colonic wall)
I: inflammation + pericolonic abscess (confined)
II: inflammation + distant abscess
III: inflammation + purulent peritonitis
IV: inflammation + fecal peritonitis
TX: colonoscopy AFTER 1st attack, supportive care, bowel rest (if complicated - IV abx, abscess drainage, surgery)

Question 3

SCAD vs SUDD

Answer 3

SCAD: segmental colitis assoc w/ diverticula

• inflammation in interdiverticular musoca w/o involvement of diverticula (in b/w diverticula)
• due to prolapse, fecal stasis, localized ischemia, dysbiosis

SUDD: sudden uncomplicated diverticular disease

• persistent abd pain attributed to diverticula in absence of overt colitis/diverticulitis
• CT: wall thickening but without inflammatory changes

Question 4

Ischemic Colitis

• common locations
• 2 main mechanisms of injury, 2 main cellular mechanisms of injury
• dx, colonoscopy sign

difference b/w colonic ischemia and small bowel ischemia

Answer 4

Areas of watershed
Griffith’s point: SMA/IMA - dual supply at splenic flexure
Sudeck’s point: IMA/Internal iliac - at recto-sigmoid junction
1. Non-occlusive ischemia = chronic hypoperfusion = collateral blood flow = mucosal infarction of watershed areas
2. Embolic/Thrombotic = acute compromise of major vessel = infarction = MURAL infarction - often transmural
Cellular: 1. Hypoxic injury (at onset, minimal), 2. REPERFUSION (leakage of free radicals, inflammatory mediators, more harmful)

Dx: high inflammation markers (Lactate, LDH, Creatinine-phos, WBC), COLONOSCOPY IS DX (single stripe sign of ulceration)
Tx: supportive (spontaneously resolve)

Colonic: usually over 60yo, do not appear severely ill (mild pain), bloody diarrhea, dx with colonoscopy

Small bowel: any age, acute cause, SEVERELY ill, bleeding uncommon, need angiography/CT for dx

Question 5

Microscopic Colitis

• epi (type of pt)
• RF
• CP
• Dx
• Tx

Answer 5

Epi: older women, assoc w/ other autoimmune disease
RF: smoking, medications (CAUSATIVE - PPIs, NSAIDs, sertraline, ranitidine)
CP: chronic watery diarrhea
Dx: histo (lymphocytic - high lymphs in LP, collagenous - collagen band subepithelial)
tx: sx, antidiarrheal agent (loperamide, bismuth subsalicylate)