Info
🌱 來自: Huppert’s Notes
Other Diseases Affecting the Colon🚧 施工中
Other Diseases Affecting the Colon
Angiodysplasia of the colon (AV malformations, vascular ectasia)
• Clinical features: Tortuous dilated veins in the colon can rupture and cause a lower GI bleed. Classic association is Heyde’s syndrome (triad of aortic stenosis, acquired vWF deficiency due to shear stress from the aortic valve, and GI bleeding from angiodysplasia)
• Diagnosis: Colonoscopy
• Treatment: Bleeding is typically self-limited
Ischemic colitis
• Definitions: Ischemia in the mesenteric distribution specifically affecting the large intestine
• Pathophysiology: Colonic hypoperfusion in the setting of hypotension (e.g., MI, aortoiliac surgery)
• Clinical features: Sudden abdominal pain, diarrhea, hematochezia
• Diagnosis: CT abd/pelvis with contrast. Early colonoscopy shows patchy segmental ulcerations
• Treatment: Usually just supportive care; if severe and necrotic bowel, may need surgical resection
Colonic polyps
• Adenoma: Premalignant. Three subtypes: 1) Tubular adenoma, 2) Tubulovillous adenoma, 3) Villous adenoma (most worrisome)
• Serrated: 1) Hyperplastic polyp (benign), 2) Sessile serrated polyp (premalignant), 3) Traditional serrated adenoma (premalignant)
• Other: 1) Hamartomatous polyp (variable potential for transformation); 2) Inflammatory polyp (benign).
- After premalignant polyps are removed, typically recommend closer interval surveillance colonoscopy (interval depends on size and number).
Sigmoid volvulus
• Pathophysiology: Occurs when a loop of the sigmoid bowel twists around its own mesentery, resulting in obstruction and underperfusion.
• Clinical features: Insidious onset of abdominal pain, nausea, and distension, eventually with severe continuous abdominal pain and colicky episodes. More common age >70 yr, M>F, patients with comorbid neuropsychiatric diseases.
• Diagnosis: CT abd/pelvis with “whirl pattern” (dilated sigmoid around mesocolon/vessels) and “bird-beak” appearance of adjacent colonic segments; if not present, absence of rectal gas, separation of sigmoid walls, and two transition points are suggestive.
• Treatment: Emergent surgery if peritonitis/perforation. If stable, sigmoidoscopy to diagnose and detorse the twisted segment, followed by surgery.
Cecal volvulus
• Pathophysiology: Occurs when a segment of the cecum rotates/torses, resulting in obstruction and underperfusion. More common in younger women.
• Clinical features: Presentation varies widely from insidious abdominal pain/vomiting to abdominal catastrophe
• Diagnosis: CT abd/pelvis with “whirl pattern,” as with sigmoid volvulus, but with the anatomic location at the cecum.
• Treatment: Primarily surgical management
Radiation proctitis
• Pathophysiology: Inflammation of the rectum as a result of damage due to pelvic radiation (e.g., for prostate cancer, cervical cancer)
• Clinical features:
- Acute: Diarrhea, mucus discharge, urgency, and tenesmus within 6 weeks of radiation
- Chronic: Same symptoms >9 months after radiation exposure. Chronic radiation proctitis can cause bleeding. Treat with endoscopic argon plasma coagulation (APC).
• Diagnosis: Diagnosis of exclusion. Endoscopic findings are nonspecific (pallor with friability, telangiectasia); biopsy demonstrates submucosal fibrosis.
• Treatment: Supportive care, sucralfate enemas, hyperbaric oxygen
Hemorrhoids
• Pathophysiology: Varicose veins of the anus/rectum. Risk factors include constipation, pregnancy, portal hypertension, and obesity.
• Clinical features: Bright red blood on the toilet paper when wiping.
- External: Dilated veins from inferior hemorrhoidal plexus distal to dentate line (sensate area) – painful!
- Internal: Dilated submucosal veins of superior rectal plexus above dentate line (insensate area) – painless!
• Treatment: Sitz bath, ice packs, stool softeners, topical steroids. If internal hemorrhoids are severe, can pursue rubber band ligation or surgery.