Diseases of the Colon Flashcards
Right colon func, transverse/desc/sig func
r: absorb ions, water
transverse/descending/sigmoid: store waste and indigestible materials
other: bacterial fermentation of nonabsorbed nutrients; elimination of waste and indig materials
Gold standard of IBD dx
Direct visualization and biopsy
when:
sx >2 wks (diarrhea, crampy abd pain, bleeding)
Neg work up for other causes
Extra-intest sx
IBD types
UC
Crohn’s
UC signs/sx
diarrhea
weight loss
fatigue
LOWER abd pain
hematochezia (bright red blood in stool)
mucus in stool
tenesmuc
Crohn’s signs/sx
diarrhea
weight loss
fatigue
Mid or lower abd pain
N/v
fistula sx
Macroscopic features of Crohn's vs UC bowel region fistulae or abscess strictures distribution
*pics 10/19
Bowel region:
Crohn’s: entire GI tract
UC: colon
Fistulae or abscess:
Crohn’s yes
UC no
strictures:
Crohn’s: common
UC: no
Distribution:
Crohn’s: skip lesions
UC: diffuse
UC= “hamburger meat appearance”; pseudopolyps
Pathologic features of Crohns vs UC inflammation ulcers fibrosis granulomas
Inflammation:
Crohn’s: transmural
UC: mucosa +/- SM
Ulcers:
Crohn’s: deep, linear
UC: superficial, confluent
Fibrosis:
Crohn’s: marked
UC: mild to none
Granulomas:
Crohn’s: yes ~20%
UC: no
Crohn's vs UC obstructive malabsorption malignant potential recurrence after colectomy toxic megacolon
Obstructive:
Crohn’s: yes
UC: no
Malabsorption:
Crohn’s: yes
UC: no
Malignant potential:
Crohn’s: with colonic involvement
UC: yes
recurrence after colectomy:
Crohn’s: common
UC: no
toxic megacolon
Crohn’s: no
UC: yes
Types of Crohn’s fistulas
Entero-cutaneous Entero-enteral Entero-gastric Entero-vesical Entero-vaginal
Extraintestinal manifestations
mostly UC
Eye: scleritis, episcleritis
Skin: pyoderma gangrenosum, erythema nodosum
Liver: primary sclerosing cholangitis (PSC)
Joints: sacroiliitis, ankylosing spondylitis
IBD management
Corticosteroids (topical or absorbed) - flares
5-aminosalicylates, PO or PR (Sulfasalazine, olsalazine, mesalamine, balsalazide)
Immunomodulators
(6-mercaptopurine, Azathioprine, Methotrexate)
TNF-alpha antagonists (IV or SC)
(Infliximab, Adalimumab, Natalizumab)
Surgery – colectomy, partial SB resection, or stricturoplasty (Refractory disease, obstruction, fistula, HG dysplasia, or cancer)
Colon cancer surveillance and IBD
- risk increases w/ duration
- yearly colonoscopy after 7-8 yrs
- bx from every segment
- LG dysplasia is common in IBD
- HG dysplasia or cancer–> colectomy
Microscopic colitis
2-5 per 100,000 indiv
- 50-80y, F:M 15:1
- autoimmune, trigger unknown
- salt and water loss in colon
Presentation= chronic secretory diarrhea
- watery, nonbloody
- 4-10 per day
- minimal nocturnal or fasting sx
2 subtypes (hist)
lymphocytic colitis
collagenous colitis
Mild assoc w/ celiac
good prognosis (no increased cancer risk, etc)
Dx of microscopic colitis
biopsy (bc colonoscopy is usually normal)
LC: lymphocytic infiltration of mucosa and SM
CC: thickened subepi collagenous band
Ischemic colitis
90% >60 y -most w/o vascular or GI disease -acute compromise in colonic blood flow -triggers: vasospasm dehydration, hypotension, cardiopulm insult (MI, PE)
Most common areas of ischemic colitis
Watershed vascular areas:
splenic flexure
rectosigmoid
Presentation of ischemic colitis
Abrupt-onset, crampy, lower abdominal pain
Urgent need to defecate
Mild diarrhea and/or hematochezia
(Severe diarrhea or bleeding– diff dx)
Endoscopic findings - edema, ulceration, +/- bleeding confined to a vascular region
Complete recovery usually in 1-2 weeks
Less common causes:
Vasculitis – Lupus (SLE), Polyarteritis Nodosa (PAN), Henoch-Schonlein
Substance abuse - cocaine, amphetamines
Medications - estrogens, migraine medications
Mesenteric thrombosis - Protein C/S deficiency, Factor V Leiden def., etc.
Rare: Marathon running, extreme dehydration
Infectious colitis
-inflammatory diarrhea +/- hematochezia (mucosal invasion; toxin related injury)
Hx: short duration, travel, ill contacts, abx use
Ex: pseudomembranes seen w/ C. diff
Undercooked beef: E. coli
Poultry, eggs, milk, lettuce: salmonella/shigella, campylobacter, yersinia
Abx use/hosp: C. diff
Anal intercourse: venereal proctitis
Non IBD colitis management
Microscopic colitis – antidiarrheals (loperamide, diphenoxylate), Bismuth, topical steroids
Infectious colitis – support, +/- antibiotics
Ischemic colitis – support, antibiotics, volume support
Drug-induced – support, d/c offending drug
Radiation colitis – topical agents, endoscopic ablation
Surgery – rare; severe/refractory cases
Diverticulosis
> 50% in the elderly
Western >developing (increased intracolonic, pressure, low fiber)
80% asymptomatic
20% diverticulitis, hemorrhage
(endoscopy shows large “holes”)
Diverticular hemorrhage
5% of patients with diverticulosis
Usually from RIGHT colon
Vasa recta within the dome of diverticulum
Painless hematochezia, often heavy, typically stops w/in 2-3 days
Does NOT occur with diverticulitis
Acute diverticulitis
10-15% of patients w/ diverticula
Fecolith obstructs diverticulum:
Distension from bacterial gas and neutrophils
Microperforation, abscess
Macroperforation with peritonitis
Sx: LLQ pain, nausea, fever
Management of diverticulitis
Diagnosis: CT or MRI
Tx: oral or IV abx; abscess drainage; surgery
Strictures may require dilation or resection
Lower GI bleeding
Bleeding distal to ligament of Treitz
colonic bleeding»_space;> SB bleeding
Usually hematochezia, less commonly melena
Mort: 1-2%
(UGI bleed higher)
Ceases w/o intervention in most
Recurs freq w/o cause ID
Lower GI Bleeding etiologies
Diverticulosis AVM Colitis Neoplasm Radiation colitis Post-polypectomy or biopsy Miscellaneous: Internal hemorrhoids Solitary rectal ulcer Anal fissure Dieulafoy’s lesions
Chronic abdominal pain and diarrhea
IBD
weight loss, new constipation, anemia
neoplasia
Sudden onset & cessation of bleeding, elderly patient
diverticulosis
Hematochezia after surgery or MI
ischemic colitis
Acute dysentery, travel, ill contacts, or antibiotic use
infectious diarrhea
Chronic, microcytic anemia
neoplasia or AVMs
NSAIDs
drug induced colitis
History of pelvic radiation
Radiation proctitis
Dx/tx lower GI bleeding
Diagnosis
Colonoscopy
Tagged rbc scan
Angiography
Treatment Support Endoscopic therapy Angiographic therapy Surgical resection: -Refractory bleeding -Recurrent bleeding
Colon obstruction
N/V, abd. distension, constipation or obstipation Diagnosis Tentative - plain x-ray Confirmed and defined with CT Causes Malignancy Benign – adhesions, strictures, volvulus Foreign body – inserted or ingested
Tx: Admission to hospital, NPO NGT tube decompression Colonoscopy if suspected cancer or volvulus Surgical resection is standard Metal stent for select patients
