SM_163b: Clinical Features of Colonic Disorders Flashcards
Colon functions are ____, ____ and ____
Colon functions are absorption, recycling and secretion, and stool formation and defecation
- Colon has segmental and propagated activity
Diveticulosis is the presence of ____, which are ____
Diveticulosis is the presence of diverticula, which are sac-like protrusions of the colonic wall
- May be symptomatic or asymptomatic
Diverticular diseases are ____
Diverticular diseases are clinically significant and symptomatic diverticulosis
- Diverticular bleeding
- Diverticulitis
- Segmental colitis associated with diverticula (SCAD)
- Symptomatic uncomplicated diverticular disease
Describe anatomy and pathophysiology of diverticular diseases
Anatomy and pathophysiology of diverticular diseases
- LaPlace’s Law: P = kT/R
- True diverticulum: involves herniation of the entire bowel wall (i.e. all layers)
- False / pseudo-diverticulum: mucosa protrudes through muscularis propria
Diverticular bleeding presents as ____
Diverticular bleeding presents as painless hematochezia due to segmental weakness of the vasa recta associated with a diverticulum
- 10% of patients with diverticulosis
- Most common cause of hematochezia in > 60 years
- Risk factors for bleeding: HTN, atherosclerosis, NSAID use
Diverticular bleeding most often occurs in the ____ and the majority of bleeds are ____
Diverticular bleeding most often occurs in the right colon and the majority of bleeds are self-limited
- Localization: colonoscopy (diagnostic and therapeutic), angiography (diagnostic and therapeutic), tagged RBC scan (diagnostic ), and segmental colonic resection
- Treatment: supportive care, colonscopy, angiography with embolization, surgical resection
____ is inflammation of the diverticula
Diverticulitis is inflammation of the diverticula
- Obstructed diverticula opening
Diverticulitis presentation may be ____ or ____
Diverticulitis presentation may be uncomplicated or complicated
- Uncomplicated: abdomianl pain, fever, leukocytosis, anorexia
- Complicated: abscess, macro-perforation, stricture, fistula
Diverticulitis diagnosis often involves ____, ____, and ____
Diverticulitis diagnosis often involves distention / tenderness with palpation / signs of peritonitis, leukocytosis, and CT scan with presence of diverticula / thickened colonic wall > 4 mm, inflammation within pericolic fat ± fluid collection
- CT scan is diagnostic
Describe the Hinchey classification for diverticulitis
Hinchey classification for diverticulitis
- I: inflammation + pericolic abscess or phlegmon (confined)
- II: inflammation + retroperitoneal or pelvic abscess (distant)
- III: inflammation + purulent peritonitis
- IV: inflammation + focal peritonitis
Prior uncomplicated attacks ___ predict high incidence or higher severity of recurrence of diverticulitis
Prior uncomplicated attacks do NOT predict high incidence or higher severity of recurrence of diverticulitis
- Need colonscopy following first attack
- Uncomplicated diverticular disease: bowel rest, supportive care, ± antibiotics
- Complicated diverticular disease: bowel rest, IV antibiotics ± abscess drainage ± surgery
Diverticulitis diet therapy involves ____, ____, ____, and ____
Diverticulitis diet therapy involves high fiber diet, physical activity, reducing obesity, and reducing fat and red meat
Segmental colitis associated with diverticula (SCAD) is ____
Segmental colitis associated with diverticula (SCAD) is inflammation in the interdiverticular mucosa without involvement of the diverticular orifices
- Possibly related to mucosal prolapse, fecal stasis, and localized ischemica or alterations in the microbiome
Symptomatic uncomplicated diverticular disease (SUDD) is ____
Symptomatic uncomplicated diverticular disease (SUDD) is persistent abdominal pain attributed to diverticula in the abscence of overt colitis or diverticulitis
- Symptoms + wall thickening on CT without inflammatory changes or mucosal abnormalities on colonoscopy
- Abnormal motility ± visceral hypertensitivity play a role in symptom perception
Ischemic colitis is ___
Ischemic colitis is insufficient perfusion to the colon that produces ischemic tissue injury
- Ischemia: reduction in blood flow to a level that is insufficient for delivery of oxygen and nutrients required for cellular metabolism
- Older adults, female > male
Ischemic colitis may occur due to ____ or ____
Ischemic colitis may occur due to non-occlusive ischemia or embolic / thrombotic occlusion (arterial or venous)
Describe non-occlusive ischemia as a cause of ischemic colitis
Non-occlusive ischemia as a cause of ischemic colitis
- Chronic progressive hypoperfusion
- Collateral blood flow allows perfusion
- Mucosal infarction limited to muscularis mucosae, watershed areas affected
Causes: cardiac failure, shock, dehydration, extreme exercise, use of vasoconstrictive drugs
Describe embolic / thrombotic occlusion (arterial or venous) as a cause of ischemic colitis
Embolic / thrombotic occlusion (arterial or venous) as a cause of ischemic colitis
- Acute compromise of a major vessel
- Infarction
- Mural infarction of mucosa / submucosa or transmural infarction
Causes: severe atherosclerosis, aortic aneurysm, hypercoagulable states, oral contraceptive use, embolization of vegetations or atheromas, aortic instrumentation, vasculitis
Ischemic colitis may involve ____ and ____ injury
Ischemic colitis may involve hypoxic and reperfusion injury
- Hypoxic: at onset of vascular injury, minimal injury at surface but can progress to transmural necrosis
- Reperfusion injury: restoration of blood supply, leakage of bacterial products / free radical production / neutrophil infiltration / release of inflammatory mediators
Ischemic colitis presents as ____ and ____
Ischemic colitis presents as sudden onset abdominal cramping / tenderness / urgency and mild/moderate amounts of rectal bleeding / blood diarrhea
- Hyperactive phase
- Paralytic phase
- Shock phase
X-ray / CT of ischemic colitis may show ____
X-ray / CT of ischemic colitis may show thumbprinting (submucosal edema) pneumoatosis (air within the bowel)
- Labs
Rule out infectious or inflammatory causes and mesenteric ischemia (affecting small bowel) - High index of suspicion
- Treatment: supportive care, antibiotics, antithrombotic therapy, surgery, endovascular intervention
Intestinal ischemia may result from ____ or ____
Intestinal ischemia may result from colonic ischemia or small bowel / mesenteric ischemia
- Both can involve superior mesenteric artery
Describe colonic ischemia
Colonic ischemia
- > 60 years
- Acute precipitating cause rare
- Do not appear severely ill
- Mild abdominal pain / mild tenderness
- Rectal bleeding / bloody diarrhea
- Colonscopy for diagnosis
Describe small bowel / mesenteric ischemia
Small bowel / mesenteric ischemia
- Age varies
- Acute precipitating cause typical
- Patients severely ill
- Pain severe / initially mild tenderness
- Bleeding uncommon until late
- Angiography or CT for diagnosis
Microscopic colitis is ____
Microscopic colitis is chronic inflammatory disease of the colon characterized by chronic water diarrhea with normal appearing mucosa on colonoscopy
- Older women, associated with other autoimmune diseases
Microscopic colitis diagnosis is ____
Microscopic colitis diagnosis is histologic
- Lymphocytic colitis: intraepithelial lymphocytic infiltrate (> 20/HPF)
- Collagenous colitis: colonic subepithelial collagen band (> 10 um)
____ and ____ are risk factors for microscopic colitis
Medications and smoking are risk factors for microscopic colitis
- NSAIDs, PPIs, ranitidine, sertraline
Microscopic colitis presents as ____, biopsies should specifically focus on the ____, and treatment goal is to ____
Microscopic colitis presents as chronic watery diarrhea, biopsies should specifically focus on the right colon and rectosigmoid, and treatment goal is to achieve symptomatic improvement
