Pathophysiology of Colon Flashcards
(80 cards)
1
Q
Colon anatomy
A
5’
tubular structure with all 5 layres
- inner circular, outer longitudinal smooth muscle layers
- ileocecal valve, internal and external anal sphincters
- NO villi
2
Q
Multiple colonic functions
A
- water/ion absorption (ascending)
- bacterial fermentation of nonabsorbed nutrients (splenic flexure)
- storage of waste/indigestible materials (descending)
- elimination of waste/indigestible materials (rectum)
3
Q
IBD pathophys
A
genetic susceptibility, immune dysregulation, environmental triggers
4
Q
Diagnosis of IBD
A
When:
- suggestive symptoms > 2 weeks
- negative work-up for other causes of colitis (infection, ischemia, meds)
- extra-intestinal sxs
5
Q
type of IBD
A
Ulcerative colitis, Crohn’s dz (10-20% have features of both)
6
Q
signs/sxs of Ulcerative colitis
A
diarrhea, weight loss, fatigue, LOWER ad pain, Hematochezia, mcuus in stool, tenesmus (needing to defecate)
7
Q
Crohn’s sxs
A
diarrhea, weight loss, fatigue, mid or lower abd pain, nausea/vomiting, fistula sxs
8
Q
Crohns vs UC region affected
A
C: Entire GI tract
UC: Colon,
9
Q
C vs UC: Obstruction
A
C: yes
UC: no
10
Q
C vs UC: malabsorption?
A
C: Yes
UC: no
11
Q
C vs UC: Malignant potential
A
C: with colonic involvement
UC: yes
12
Q
C vs UC: recurrence after colectomy
A
C: common since can be affecting whole GI
UC: no
13
Q
C vs UC: Toxic megacolon?
A
C: no
UC: yes
14
Q
C vs UC: Inflammation- area affected
A
C: transmural
UC: mucosa and/or submucosa
15
Q
C vs UC: Ulcers?
A
C: deep, linear
UC: superficial, confluent
16
Q
C vs UC: Fibrosis?
A
C: Marked
UC: mild to none
17
Q
C vs UC: Granulomas?
A
C: Yes- 20%
UC: No
18
Q
Crohn’s fistula types
A
- entero-cutaneous
- entero-enteral,
- enterogastric,
- entero-vesical,
- entero-vaginal
19
Q
Treatment of fistulas
A
usually requires biologic therapy or surgery
20
Q
Extraintestinal manifestations
A
- mostly UC
- Eye– scleritis, episcleritis
- Skin – pyoderma gangenosum, erythema nodosum
21
Q
Extraintestinal liver manifestations
A
Primary sclerosing cholangitis (PSC)
22
Q
Joint involvement of IBD
A
sacroiliitis, ankylosing spondylitis
23
Q
IBD management
A
Start with medical treatment - corticosteroids - 5-aminosalicylates Immunomodulators TNF-alpha antagonists
Surgery–colectomy, partial SB resection or stricturoplasty
(refractory dz, obstruction, fistula, HG dysplasia, or cancer)
24
Q
Colon cancer surveillance
A
- risk increases with IBD duration
- yearly colonoscopy after 7-8 years
- biopsies from every segment
- LowGrade dysplasia common in IBD
- HighGrade dysplasia or cancer –> colectomy
25
Microscopic colitis prevalence
usually 50 -80, female: male 15:1
26
Microscopic colitis
autoimmune, trigger unknown
| - salt and water loss in colon
27
Microscopic colitis presentation
chronic secretory diarrhea
- watery, non-bloody
- 4-10 stools per day
- minimal nocturnal or fasting sxs
28
Subtypes of microscopic colitis
Lymphocytic, collagenous
29
microscopic colitis association
mild association with celiac dz
30
Prognosis of microscopic colitis
good prognosis
- no bleeding, dehydration, or other complications
- no increase in cancer risk/mortility
31
Diagnosis of microscopic colitis
- colonoscopy usually normal
| - Biopsy = definitive
lymphocytic infilatration ofmucosa and SM (LC); thickened collagenous band (CC
32
Histology
?
33
Ischemic colitis
90% of patients > 60 years old
- most have not vascular or GI disease
- Fundamental insult = acute compromise in blood flow
34
ischemic colitis triggers
vasospasm, dehydration, hypotension, or cardiopulmonary insult (e.g. MI, PE)
35
ischemic coliits areas affected
most common in watershed vascular areas (splenic flexure, rectosigmoid)
36
IC presentation
abrupt onset, crampy, lower abd pain;
- urgent need to defecate
- mild diarrhea and/or hematochezia (severe diarrhea/bleeding suggests other diagnosis)
37
ischemic colitis endoscopic findings
edema, ulceration/ +/- bleeding confined to avascular region
38
can ischemic colitis present with severe diarrhea or bleeding
NO--suggests other cause
39
Ischemic colitis less common cause
- Vasculitis (SLE, polyarteritis nodosa, Henoch-Schonlein)
- SUbstance abuse (cocaine, amphetamine)
- Meds (estrogens, migrain meds)
- mesenteric thrombosis (protein C/S deficiency, factor V Leiden def, etc)
- Rare: Marathon running, extreme dehydration
40
Infectious colitis
inflammatory diarrhea +/- hematochezia (mucosal infasion, toxin-related injury)
- Hx- short duraiton, travel, ill contacts, antibiotic use
41
Hx of acute diarrhea
Think infectious!!
- Undercooked beef- e coli
- Contaminated poultry, eggs, milk, lettuce (salmonella/shigella, campylobacter, yersinia)
- antibiotic use, hospitalization (C diff)
42
other Colitis
Hx important
- Endoscopy (location/appearance)
- Biopsy if needed, definitive
43
management of Non-IBD coliitis?
- microscopic: antidarrheals, BIsmuth, topical steroids
- infectious- support +/- antibiotics
- ischemic: support: antibiotics, volume support
- Drug-induced: support, d/c offending
drug
- Radiation colitis - topical agents, endoscopic ablation
- Surgery- rare; severe/ refractory cases
44
Diverticulosis prevalence
- >50% in elderly
- Western > developing countries (increased intra-colonic pressure, low-fiber diet)
- 80% asymptomatic
- 20% diverticulitis, hemorrhage
45
Diverticulitis
outpouching of bowe wall
46
Prevalence/cause of diverticular hemorrhage
- 5% pts with diverticulosis
- usually from right colon
- vasa recta within dome of diverticula
47
Presenation of diverticular hemorrhage
painless hematochezia, often heavy, typically stops w/in 2-3 days
48
Acute diverticulitis
- 10-15% pts with diverticula
- fecolith obstructs diverticulum --> distention from bacterial gas/neutrophils, nicroperforation, abscess, macroperforation with peritonitis
49
Acute diverticulitis sxs
LLQ pain, nausea, fever
50
Diverticulitis diagnosis/management
- Diagnosis: CT or MRI
- Treat: oral or IV antibiotics, abscess drainage, surgery
strictures may require dilation/resection
51
Lower GI bleeding
- bleeding distal to ligament of Treitz
- colonic bleeding >>> SB bleeding
- usually hematochezia (less commonly melena)
52
Lower GI bleeding mortality
1-2%; ceases in 90% without intervention
53
Recurrence of GI bleeding
frequent if cause not identified
54
Etiologies of lower GI bleeding
Diverticulosis, arteriovenous malformations, colitis, neoplaslm, radiation colitis, post-polypectomy/biopsy, miscellaneous (internal hemorrhoids, solitary rectal ulcer, anal fissure, Dieulafoy's lesion)
55
Chronic abdominal pain and diarrhea history cue?
IBD
56
Cue for weight loss, new constipation, anemia
neoplasia
57
Sudden onset and vessation of bleeding,elderly pt cues to...
Diverticulosis
58
Hematochezia after surgery or MI cues ...
ischemic colitis
59
Acute dysentery, travel, ill contacts, or antibiotics, --cues...
infectious diarrhea
60
Chronic microcytic anemia cues...
neoplasia or arteriovenous malformation
61
NSAIDs cues---
drug-induced colitis
62
History of pelvic radiation cues---
radiation proctitis
63
Lower GI bleeding daignosis
colonoscopy, tagged rbc scan, angiography
64
Lower GI bleed treatment
support, endoscopic therapy, angiographic therapy, surgical resection (refractory or recurrent bleeding)
65
arteriovenous malformation
junction between artery/vein in colon wall--can burst and bleed
66
Treat AVM
go in and ablate
67
Colon obstruction sxs
N/V, abd distension, constipation or obstipation (severe/complete constipation)
68
Colon obstruction causes
cancer, adhesions, strictures, volvulus (twisting), foreign body (inserted/ingestion)
69
Colon obstruction diagnosis
tentative- plain x-ray, confirmed and defined with CT or MRI for surgery
- don't need endoscopy
70
colonic obstruction- treatment
admission to hospital, NPO, NGT tube decompression, colonoscopy if suspected cancer or volvulus, surgical resection standard, metal stent for select patients
71
Lower abd pain + hematochezia associated with?
colitis (can be cancer)
| - DIagnose via endoscopy/bx
72
Microscopic colitis
mild secretory diarrhea in elderly women, manage medically
73
colonic obstruction sxs and diagnosis
- N/V and abd
| - diagnose by Xray/CT
74
suggestive IBD sxs
diarrhea, crampy abd pain, bleeding > 2 weeks
75
Diagnosis IBD
- imaging can be suggestive
| - direct visualization/biopsy= gold standard
76
C/UC fistula or abscess?
C: yes
UC: no
77
C vs UC: strictures
C: common
UC: no
78
C vs UC distribution
C: "Skip lesions"
UC: diffuse
79
Celiac Disease extraintestinal manifestations
fatigue, Fe deficiency anemia, pubertal delay, short stature, aphthous stomatitis, dermatitis herpetiformis (blistering skin dz)
- increased incidence of lymphocytic gastritis/colitis
80
Celiac-associated malignancies
Enteropathy-associated T cell lymphoma (EAT lymphoma) and small intestinal adenocarcinoma
