large intestine Flashcards

1
Q
failure of neural crest cell migration
dysfunctional Auerbach (muscularis externa layer) + Meissner plexus (submucosal layer) → abnormal peristaltic waves
A

Hirschsprung disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

congenital megacolon with meconium ileus or if less severe, chronic constipation as infant (chronic distention)

A

Hirschsprung disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

twisting of colon around mesentary → ischemia

A

volvulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

most common location of volvulus in elderly (most commonly affected by volvulus)

A

cecum or sigmoid colon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

most abundant bacterial flora in large intestine

A
#1 bacteroides fragilis
#2 E. coli (enterobacteraciae)
other enterobacteraciae:
proteus mirabilis
proteus vulgaris
salmonella
shigella
klebsiella pneumoniae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

complication of obstruction of appendicitis with:

adults: fecalith (fecal stone)
kids: viral infection (hyperplasia of lymphoid tissue= MALT tissue)

A

appendicitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

N/V
diffuse periumbilical pain → later, pain localizes to RLQ (McBurney’s point)
rebound tenderness in RLQ
leukocytosis on CBC

A

appendicitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

McBurney’s point

A

2/3 the way from umbilicus to ASIS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

confirm diagnosis of appendicitis

A

r/o ectopic pregnancy with female (serum bHCG)
adults: CT scan
kids or pregnant: US

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

line anus that marks end of endoderm and beginning of ectoderm (squamous cell)

A

pectinate line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

pathology proximal to pectinate line

A

internal hemorrhoids: not painful, may bleed

tx: can band → necrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

sensory + arterial blood supply + venous drainage above and below pectinate line

A

above: no sensation, superior rectal artery (from IMA), superior rectal vein (to IMV)
below: sensation, inferior rectal artery (from pudendal artery - not IMA), inferior rectal vein (to internal pudendal vein → to internal illiac vein→to IVC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

cancer above pectinate line is most likely

A

adenocarcinoma (rectal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

pathology distal to pectinate line

A

external hemorrhoids: very painful

tx: numbing agent -symptomatic relief

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

cancer below pectinate line is most likely

A

squamous cell carcinoma (anus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

biggest risk factor for squamous cell carcinoma of anus

A

HPV 16, 18, 31

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

inflammation of perianal region + rectum due to fecal matter in area for an extended period of time
associated with ulcerative colitis
tx: topical steroids

A

proctitis

18
Q

most common type of polyp in colon - found in rectum or rectosigmoid

A

hyperplastic polyp

19
Q

polyp with no precancerous risk (benign)

removed during colonoscopy since need bx to prove not cancerous

A

hyperplastic polyp

20
Q

types of adenomatous polyp (neoplastic - precancerous polyp for adenocarcinoma)

A
tubular adenomas (lots of glands)
tubulovillous adenomas
villous adenomas (most VILLainOUS - most precancerous, lots of finger-like projections)
21
Q

child

A

juvenile polyps
if one: no malignant potential
if many: juvenile polyposis syndrome →↑ risk adenocarcinoma

22
Q

AD
multiple benign hamartomas in GI tract (excess accumulation of normal tissue that is located at the site of growth)
hyperpigmentation: lips, mouth, hands, genitalia
↑ risk cancer (50% by 60 yo): colorectal cancer, small intestinal, stomach, pancreatic, breast, ovarian, uterine

A

Peutz-Jeghers Syndrome

23
Q

risk factors for colon cancer

A

IBD: UC > chron’s
smoking
high fat/low fiber diet
alocohol use
obesity
adenomatous polyps (villous adenomatous polyps greatest risk)
strep bovis bacteremia: 50% of colon cancer patients colonized it in their stool
polyposis syndrome: FAP, HNPCC, Peutz-Jeghers syndrome, juvenile polyposis

24
Q

fatigue, weight loss, LAD, night sweats
abdominal pain, bowel obstruction → N/V
change in bowel habits if L-sided colon affected: “pencil-thin stools”
hematochezia: if rectosigmoid region affected
IDA - chronic GI bleed: if R-sided colon

A

colon cancer

25
Q

incidental finding of anemia in >50 yo

A

screen for colon cancer (GI bleed - most commonly R. sided cancer)

26
Q

diagnosis of colon cancer

A
colonoscopy: >50 yo
fecal occult blood testing
barium enema
flexible sigmoidoscopy
confirmation: tissue bx
27
Q

“apple-core” lesion with barium enema

A

narrowing of lumen of colon

suggest colon cancer

28
Q

CEA is a tumor marker for

A

colon cancer

nonspecific: but useful for monitoring for recurrence after treatment for colon cancer

29
Q

AD (germline) mutation in APC gene
1000s of polyps begin at young age
100% progress to colorectal cancer unless colon is resected

A

familial adenomatous polyposis (FAP)

30
Q

FAP (mutation of APC gene, 1000s of polyps) + malignant CNS tumors (medulloblastoma)

A

turcot syndrome

TURcot = TURban (brain tumors)

31
Q

FAP (mutation of APC gene, 1000s of polyps) + bone and soft tissue tumors (lipomas, retinal hyperplasia)

A

Gardner syndrome

lumpy vegetables in garden = lumps, bumps all over body

32
Q

AD mutation in DNA mismatch repair gene → microsatelite instability pathway
colorectal cancer DOESN’T arise from polyp (nonpolyposis colorectal cancer)
PROXIMAL colon cancer (vs 50% of colon cancer in distal 1/3 -distal to splenic flexure)

A

Heriditary nonpolyposis colorectal cancer (HNPCC/Lynch syndrome)

33
Q

> 60 yo with many blind pouches in sigmoid colon
usually asymptomatic or
vague pain in LLQ RELIEVED with defecation or
painless rectal bleeding

A

diverticulosis

34
Q

true diverticula

A

outpouching of all three layers of gut wall

example: meckel diverticulum

35
Q

false diverticula

A

outpouching of only mucosa + submucosa due to weak spots in muscularis externa (where vasa recta perforate muscularis externa)
example: colonic diverticulum

36
Q

diagnosis

A

barium enema

37
Q
LLQ pain (sigmoid colon)
fever
elevated WBC count
rectal bleeding
constipation due to inflammation in colon
peritonitis (if perforation)
A

diverticulitis

38
Q

free air in abdomen (below diaphragm) on CT scan

A

perforated bowel from:
appendix
PUD
diverticulitis

39
Q

treatment of acute flare of diverticulitis

A

antibiotics: metronidazole (anaerobic bacteria) + TMP-SMX or FQ (ciprofloxacin)

40
Q

screening colonoscopy guidelines

A

begin at 50 yo
if + family history: begin at 40 yo or 10 yr before youngest 1st degree relative diagnosis
if FAP: every year from 10-12 yr to 35-40 yr
if Lynch syndrome: begin at 20-25 yo or 10 yr before youngest relative diagnosis