colon, rectum, anus Flashcards
(201 cards)
1
Q
parts of the large intestine
A
- cecum is largest part and where small bowel joins colon (no distinct division between cecum and ascending colon which is retroperitoneal)
- hepatic flexure (inf to liver) bend in asc colon where it becomes transverse colon
- transverse colon suspends freely in peritoneal cavity by transverse mesocolon
- splenic flexure is where transverse colon bends at the spleen and is retroperitoneal
- descending colon is retorter down to sigmoid colon which is loop of redundant colon in llq
- distal colon is intraperi becomes the rectum at the sacrum then cont. to anal sphincters that form short (3cm) anal canal
2
Q
rectum anatomy
A
- 15cm long
- teniae coli disperse and disappear at level of sacral promontory resulting in longitudinal muscle layer that becomes continuous homogeneous layer
- prox rectum covered by peritoneum ant not post to 10cm above anal verge
3
Q
importance of knowing what part of the rectum is intraperitoneal
A
full thickness rectal bx taken from higher than 8-9cm above anal verge carries risk of free perf into peritoneal cavity
4
Q
where does the anal canal extend from
A
anorectal junction (dentate/pectinate line) to anal verge
5
Q
what does the dentate one mark
A
junction between columnar rectal epithelium (insensate) and the squamous anal epithelium (richly innervated by somatic sensory nerves)
6
Q
columns of Morgagni (rectal columns)
A
- immediately proximal to dentate line
- where perianal glands discharge secretions, level of anal crypts
7
Q
where do perirectal abscesses usually originate
A
columns of morgagni (anal crypts)
8
Q
what is the blood supply of ascending colon and prox half of transverse colon
A
branches of sma
9
Q
what is the blood supply of distal half of transverse colon, descending colon, and sigmoid colon
A
infer mesenteric artery
10
Q
importance of understanding arterial blood supply in certain areas of colon
A
-junction of two separate blood vessel systems, blood supply is poor so anastomoses in this region would carry higher risk of ischemic complications
11
Q
marginal artery of drummond
A
vessel runs parallel to about 2-3cm from descending colon wall and is a collateral that connects the middle colic and left colic systems
-provides adequate blood supply to descending colon even if left colic artery has to be sacrificed during sigmoid or distal descending colon surgery
12
Q
venous drainage of large bowel
A
- most branches accompany the arteries and eventually drain into portal system
- inf mesenteric vein drains into splenic vein which joins w super mesenteric vein to form portal vein
13
Q
arterial supply of rectum
A
branch of inf mesenteric artery (sup hemorrhoidal artery) for upper rectum and from branches of internal iliac arteries (middle hemorrhoidal arteries) and internal pudendal arteries (inf hem arteries) for the middle and lower rectum
14
Q
venous supply of rectum
A
veins from upper rectum drain into portal system through inf mes vein; middle and inf rectal veins drain into systemic circulation through the internal iliac and pudendal veings
15
Q
what are hemorrhoids
A
physiologic venous cushions that connect the two systems
16
Q
lymphatic drainage of large intestine
A
parallels arterial blood supply w several levels of lymph nodes between periaortic plexus and parabolic lymph nodes
17
Q
order of tumor metastases of lymph nodes
A
paracolic lymph nodes then middle tier of lymph nodes then periaortic lymph nodes
18
Q
layers of bowel wall of colon
A
mucosa, submucosa, muscularis and serosa
19
Q
what is the major histologic difference between colon and small intestine
A
- colon has no villi
- outer longitudinal smooth muscle layer is separated into 3 bands (teniae coli) that cause out pouching of bowel between teniae (haustra)
20
Q
internal sphincter
A
continuation of the circular muscular layer of the rectum; invol sphincter made of smooth muscle
21
Q
external sphincter
A
- striated voluntary muscle
- 3 parts: subq, superficial and deep portions
- deep portion is continuity w legator ani muscles (base of pelvic floor)
22
Q
most important control of colon activity
A
mediated by regional reflex activity that occurs in submucosal plexuses
23
Q
3 ways colon and rectum play role in maintaining hemeostasis
A
- absorb water and electrolytes from liquid stool
- through fermentation, help digest some starches and protein that are resistant to digestion and absorption by small bowel
- serve as storage for feces
24
Q
mc anaerobic colonic organism
A
bacteroides fragilis
25
mc aerobic colonic organisms
e coli and enterococci
26
function of colonic bacteria
- degradation of bile pigments
- production of vitamin k
- fermentation of undigested starches and proteins
- produce short chain fatty acids that are absorbed by the colon
27
does a resection of entire colon and rectum impact a person's capacity to maintain normal nutrition
no
28
what many L of chyme does the small bowel deliver to the cecum each day
1-2L
most is absorbed in ascending and transverse colon leaving
29
what does the colon absorb and secret
absorbs sodium and chloride
| secretes bicarb and potassium
30
what regulates the final evacuation of solid stool
anorectum
31
how many ml/day of colonic gas does bacterial fermentation produce
800-900mL/day
32
what gives colonic gas its odor
indole and skatole
33
dx evaluation of colon and rectum
- DRE
- rigid sigmoidoscopy which been replaced by fiberoptic flexible sigmoidoscopy
- fiberoptic colonoscopy (most accurate)
- abd series (flat plate and upright radiograph)
- barium enema
- virtual colonoscopy or ct colography
- technetium labeled rbi scanning
- angiography
34
what should a sigmoidoscopy be performed
pts >50yr and performed every 3-5yrs
35
double contrast barium enema
using air insufflation while some intraluminal barium remains in the colon is particularly sensitive in detecting polyps and small lesions
36
what is a barium enema helpful in dx
tumors
diverticulosis
volvulus
obstruction
37
what is technetium labeled rbc scanning used
eval of lower gi bleeding (less rapid and pt stable)
38
what is angiography useful for
moderate or rapid colonic bleeding
39
what is a colostomy
surgical procedure in which the colon is divided and the proximal end is brought through a surgically created defect in abd wall and distal end is either overseen and placed in peritoneal vanity as a blind limb (Hartmann's procedure) or brought out inferiorly to colostomy through abd wall as mucous fistula
40
what is the purpose of a colostomy
divert stool from a diseased segment distally in the colon or rectum or to protect a distal anastomosis
41
how is a loop colostomy created
bringing a loop of colon through a defect in abd wall, placing a rod underneath, and making a small hole in the loop to allow stool to exit into colostomy bag
42
what is an ileostomy
similar to colostomy in which the ileum is brought through the abd wall to divert its contents from distal ds or in proctocolectomy, to serve as permanent stoma
43
why are stomas created
(1) to allow healing from a distal anastomosis before bowel continuity is restored; (2) the ends of the bowel are not suitable for an immediate anastomosis after resection (e.g., severely inflamed bowel, questionable vascular supply); (3) when the conditions are not right for proceeding (e.g., severe fecal peritonitis, patient too unstable or too sick to tolerate the procedure); and (4) when there is not enough bowel left for reanastomosis (abdominoperineal resection [APR]).
44
proctocolectomy
operative removal of entire colon and rectum (ulcerative colitis or polyposis syndromes)
45
abdominoperineal resection
surgical tx of very low rectal cancers; removal of lower sigmoid colon and entire rectum and anus leaving a permanent proximal sigmoid colostomy
46
low anterior resection
tx cancers of middle and upper sections of rectum; removal of distal sigmoid colon and apporx one half of rectum w primary anastomosis of prox sigmoid to distal rectum
47
what are the white lines of toldt
lateral peritoneal reflections of the ascending and descending colon
48
what parts of gi tract do not have serosa
esophagus, middle and distal rectum
49
major differences between colon and small bowel
colon has taeniae coli, haustra, and appendices epiploicae (fat appendages) whereas the small intestine is smooth
50
blood supply of proximal rectum and venous drainage
superior hemorrhoidal (superior rectal) from IMA
imv to splenic vein then to portal vein
51
blood supply of middle rectum
middle hemorrhoidal (midde rectal) from hypogastric (internal iliac)
iliac vein to ivc
52
blood supply of distal rectum
inf hemorrhoidal (inf rectal) from pudendal artery (branch of hypogastric artery)
iliac vein to ivc
53
what is the mc gi cancer
colorectal carcinoma
54
risk factors for colorectal carcinoma
diet- low fiber, high fat
genetic- famhx, FAP, lynch syndrome
IBD- UC > crohns, age, prev colon cancer
55
what is lynch's syndrome
HNPCC= Hereditary NonPolyposis Colon Cancer
autosomal dominant inheritance of high risk for dev of colon cancer
56
ACS recommendations for polyp/colorectal screening in asymp pts without 1st degree fam hx of colorectal cancer
starting age 50:
- colonoscopy q 10yrs
- double contrast barium enema (DCBE) q 5yrs
- flex sigmoidoscopy q 5yrs
- Ct colonography q5yrs
57
ACS recommendations for polyp/colorectal screening in asymp pts with 1st degree fam hx of colorectal cancer
colonoscopy at age 40 or 10 years before age at dx of youngest 1st deg relative and every 5 yrs thereafter
58
s/sx assoc w right sided lesions
r side of bowel has lg luminal diameter so tumor may attain a lg size before causing problems
microcytic anemia, occult/melena more than hematochezia PR, postprandial discomfort, fatigue
59
s/sx assoc w left sided lesions
left side fo bowel small lumen and semisolid contents
change in bowel habits (small caliber stools), colicky pain, signs of obstruction, abd mass, +heme, or gross red blood
n,v,constipation
60
from which site is melena more common
right sided colon cancer
61
which site is hematochezia more common
left sided colon cancer
62
s/sx of rectal cancer
mc is hematochezia or mucus
tenesmus, feeling of incomplete evacuation of stool, rectal mass
63
dx tests for colorectal cancer
```
hx/pe
heme occult
cbc
barium enema
colonoscopy
```
64
what ds does microcytic anemia signify until proven otherwise in man or postmenopausal woman
colon cancer
65
preop w/u for colorectal cancer
```
hx
pe
lfts
cea
cbc
chem 10
pt/ptt
type/cross 2u
prbcs
cxr
ua
abdominopelvic ct
```
66
means by which cancer spreads
direct extension-circumferentially and through bowel wall to later invade other abdominoperineal organs
hematogenous- portal circulation to liver; lumbar/vertebral veins to lungs
lymphogenous-regional lymph nodes
transperitoneal
intraluminal
67
what unique dx test is helpful in pts w rectal cancer
endorectal US
68
tnm stages
stage1- invades submucosa or muscularis propria (T1-2 N0 M0)
stage2- invades through muscularis propria or surrounding structures but w negative nodes (t3-4, N0, M0)
stage3- positive nodes, no distant metastasis (any T, N1-3, M0)
stage4- positive distant metastasis (any T, any N, M1)
69
preop bowel prep
1. golytely colonic lavage or fleets phospho-soda until clear effluent per rectum
2. PO abx (1g neomycin and 1g erythromycin x3doses)
pt should also receive preop and 24hr IV abx
70
common preop IV abx
cefoxitin (mefoxin), carbapenem
if alx- IV cipro and flagyl (metronidazole)
71
what determines low ant resection (LAR) vs abd perineal resection (APR)
distance from anal verge, pelvis size
72
what do all rectal cancer operations include
total mesorectal excision- remove rectal mesentery, including lymph nodes
73
what surgical margins are needed for colon cancer
traditionally >5cm; margins must be at least 2cm
74
how many lymph nodes should be resected w colon cancer mass
12min= for stage and may improve prognosis
75
adjuvant tx stage 3 colon cancer
5fu and leucovorin chemo
76
adjuvant tx for t3-4 rectal cancer
preop radiation therapy and 5fu chemo
77
mc site distant metastasis from colorectal cancer
liver
78
surveillance regimen of colorectal cancer
```
pe
stool guaiac
cbc
cea
lfts- every 3m for 3y then every 6m for 2y
cxr every 6m for 2yr then yearly
colonoscopy at yrs 1 and 3 postop
ct scans directed by exam
```
79
mc causes of colonic obstruction in adult population
colon cancer
diverticular ds
colonic volvulus
80
what are colonic and rectal polps
tissue growth into bowel lumen usually consisting of mucosa, submucosa or both
81
how are colonic and rectal polyps anatomically classified
sessile=flat
| pedunculated= on a stalk
82
histologic classifications of inflammatory (pseudopolyp) colonic/rectal polyps
crohns or ulcerative colitis
83
histologic classifications of hamartomatous colonic/rectal polyps
normal tissue in abn configuration
84
histologic classifications of hyperplastic colonic/rectal polyps
benign-normal cells, no malignant potential
85
histologic classifications of neoplastic colonic/rectal polyps
proliferation of undifferentiated cells; premalignant or malignant cells
86
subtypes of neoplastic polyps
```
tubular adenomas (pedunculated)
tubulovillous adenomas
villous adenomas (sessile and look like broccoli heads)
```
87
what determines malignant potential of an adenomatous polyp
size
histologic type
atypia of cells
88
mc type of adenomatous polyp
tubular
89
correlation between size and malignancy of polyps
polyps larger than 2cm higher risk
90
what about histology and cancer potential of an adenomatous polyp
villous > tubovillous > tubular
villous=villain
91
where are most polyps found
rectosigmoid
92
s/sx of polyp
```
bleeding
change in bowel habits
mucus per rectum
electrolyte loss
totally asyptomatic
```
93
dx tests for polyps
colonoscopy*
barium enema and sigmoidoscopy
94
tx polyp
endoscopic resection (snared)
| if lg sessile villous adenomas - removed w bowel resection and lymph node resection
95
familial polyposis (familial adenomatous polyposis=FAP)
hundreds of adenomatous polyps within the rectum and colon that begin developing at puberty
untx develop cancer by ages 40-50
96
inheritance pattern of FAP and genetic defect
autosomal dominant
adenomatous polyposis coli= APC gene
97
tx FAP
total proctocolectomy and ileostomy
total colectomy and rectal mucosal removal (musosal proctectomy) and ileoanal anastomosis
98
what other tumor must be looked for with FAP
duodenal tumors
99
Gardner's syndrome
neoplastic polyps of small bowel and colon
cancer by age 40 if undx
100
assoc findings of gardners syndrome
```
desmoid tumors (abd wall or cavity)
osteomas of skull
sebaceous cysts
adrenal and thyroid tumors
retroperitoneal fibrosis
duodenal and periampullary tumors
```
101
what is a desmoid tumor
tumor of musculoaponeurotic sheath, usually of abd wall
benign but grows locally
tx w wide resection
102
what meds can slow growth of desmoid tumor
tamoxifen, sulindac, steroids
103
what is peutz jeghers syndrome
hamartomas throughout the GI tract (jejunum/ileum >colon > stomach)
assoc w ovarian cancer
auto dom
104
s/sx and tx peutz jeghers syndrome
melanotic pigmentation (black/brown) of buccal mucosa, lips, digits, palms, feet
Peutz=pigmented
removal of polyps if symp or large (>1.5cm)
105
what are juvenile polyps
benign hamartomas in small bowel and colon, not premalig
"retention polyps"
106
Cronkhite Canada syndrome
diffuse GI hamartoma polyps assoc w malabsorption/wl, diarrhea, and loss of electrolytes/protein
signs- alopecia, nail atrophy, skin pigmentation
107
turcot's syndrome
colon polyps w malignant CNS tumors
108
tx diverticulitis
acute- admit to hospital, IV hydration, NPO, IV abx for 5-7d
recurrent- sigmoid colectomy
109
operation w diverticular ds w acute perf or obstruction
segment resected, diverting colostomy brought to abd wall and distal rectal stump oversewn (Hartmann)
then colostomy takedown and anastomosis to rectal stump (3months)
110
tx for colovesical fistula
surgery- primary closure of bladder and resection of sigmoid colon w primary anastomosis
111
what is considered massive bleeding related to diverticular bleeding
bleeding that is sufficient to warrant transfusion of more than 4units of blood in 24hr to maintain normal hemodynamics
rapid colonic bleeding= rate of 0.5mL/min
112
dx procedure of choice to rule out lower GI sources of bleeding
colonoscopy
113
tx diverticular bleeding
most stop on own
id of site allows surgical resection of colon
vasopressin through angiography (temporary)
coil emobolization (temp)
114
what is ulcerative colitis
IBD that involves mucosa and submucosa of large bowel and rectum
ages 15-30 then >55
115
what is crohns ds
transmural ds that can involve any portion of the alimentary canal
116
UC vs crohns
crohns- rectal sparing, skip lesions, aphthous sores, linear ulcers, thickening, strictures, string sign,fibrosis
UC-diarrhea severe, bloody, rectum/terminal ileum, continuous, friable, exudates, lead pipe, foreshortening, crypt abscesses
117
what leads to pseudo polyp formation assoc w UC
coalescing of crypt abscess (Lieberkuhn) and erosion of mucosa
118
s/sx UC
watery diarrhea that contains blood, pus and mucus
cramping
abd pain
tenesmus
urgency
varying- wl, dehydration, pain, fever
119
dx UC
endoscopy w bx- friable, reddish mucosa w no normal intervening areas, mucosal exudates, and pseudopolyposis
barium enema
shortening of colon, loss of normal austral markings and lead pipe appearance
120
tx UC and crohns
initial is medical therapy- antidiarrheal agents (loperamide) and bulking agents (psyllium)
moderate- sulfasalazine or mesalamine
severe- steroid
crohns- infliximab (remicade)
uc- surgery, total colectomy w proctectomy and ileoanal pull through
121
mc site of colonic obstruction
sigmoid colon
122
mc causes of colonic obstruction
adenocarcinoma
scarring assoc w diverticulitis
volvulus
123
s/sx colonic obstruction
abd distension, cramping abd pain, n, v, obstipation
pe- abd distention, tympany, high pitched metallic rushes, gurgles, localized tender palpable mass ( indicates strangulated closed loop or diverticular ds)
124
radiologic and ct findings colonic obstruction
proximal colon, air fluid levels, no distal rectal air
125
dx colonic obstruction
axr
water soluble contrast enema
barium enema
colonoscopic esp w Ogilvie's syndrome (localized paralytic ileus of colon without mechanical obstruction)
126
why should barium never be given orally w colonic obstruction
accumulates proximal to the obstruction and cause a barium impaction
127
tx large bowel obstruction
IV fluids,NG suction, continuous observation
emergency lap for acute w cecal distention >12cm, severe tenderness, evidence of peritonitis, generalized sepsis
perf from volvulus/cancers/diver-lap w resection and diverting colostomy
cancer wout peritonitis-colonic stent placement allows decompression
Ogilvie's- IV neostigmine
128
complications of lg bowel obstruction
perforation, peritonitis, sepsis
129
what is a volvulus
rotation of a segment of the intestine on axis formed by mesentery
stretching and elongation w age
hypermobile cecum
130
mc site of volvulus lg bowel
sigmoid and cecum
131
s/sx volvulus
abd distention, v, abd pain, obstipation, tachypnea
pe-distention, tympany, high pitched tinkling sounds, rushes
132
dx volvulus
axr
water soluble contrast enema- funnel narrowing resembles birds beak or ace of spades
ct scan
133
tx volvulus
sigmoidoscopy w rectal tube insertion to decompress sigmoid volvulus
cecal volvulus- cecopexy (suturing the cecum to parietal peritoneum) or w right hemicolectomy w ileotransverse colostomy
134
tx tubular polyp
endoscopic excision
135
tx villous polyp
surgical removal
136
tx of hamartoma polyp
excise for bleeding or obstruction
137
tx inflammatory polyp
observation
138
tx hyperplastic polyp
observation
139
where do most large bowel cancers occur
lower left side of colon near rectum
140
mild risk factors for colorectal cancer
```
age
diet
physical inactivity
obesity
smoking
race
alcohol
```
141
screening guidelines for polyps and cancer
1. flex sigmoid every 5yr
2. colonoscopy ever 10yr
3. double contrast barium enema every 5yr
4. ct colonography every 5 yr
all start at age 50 unless fhx or higher risk then age 40 or 10yr before person with cancer age
higher risk also do every 3-5yr instead of 10yr
142
symptoms assoc w cancer of right colon
- exophytic lesions
- occult blood loss=fe def anemia
- weight loss
- mass
- virchows node
- blunder's shelf
143
symptoms assoc w cancer of left colon
- +/- weight loss
- rectal bleeding
- blunder's shelf
- obstruction
144
symptoms assoc w cancer of rectum
-rectal bleeding
-tympany
-obstruction
+/- alt diarrhea/constipation
145
tx for colorectal cancer
resection including lymph nodes
146
mc organ involved in distant colorectal metastases
liver
147
how are tumors of cecum and ascending colon tx
right hemicolectomy that includes resection of distal portion of ileum and colon to mid transverse colon with an ileo mid transverse colon anastomosis
148
tx cancers to right and left middle colic artery
right- extended right hemicolectomy
left-partial left colectomy
149
tx hepatic flexure lesions
extended right colectomy that includes resection to or beyond level ofmidtransverse colon
150
tx splenic flexure and left sided lesions
left hemicolectomy thats includes resection from level of mid transverse colon to sigmoid
151
tx sigmoid colon lesions
sigmoid resection
152
tx obstructing or perf tumors
resection, diverting colostomy, and hartmann's pouch or mucous fistula
153
what is folfox and what is it used for
- 5fu, leucovorin, oxaliplatin
| - tx metastatic colorectal cancer
154
tx rectal tumors
resection + radiation + 5fu
155
what is used to stage the depth of penetration of the tumor in the rectal wall
endorectal us or mri
156
TNM staging
```
tx= primary tumor not assessed
to= no evidence prim tumor
tis= carcinome in situ; intraepithelial tumor or invasion of lamina propria
t1= submucosa
t2= muscularis propria
t3= muscularis propria into subserosa or into nonperitonealized pericolic or perirectal tissues
t4= organs or structures or perf visceral peritoneum
```
```
nx= nodes not assessed
no=no regional nodes
n1= 1-3 pericolic or perirectal nodes
n2=>4 pericolic or perirectal nodes
n3= any node along course of vascular trunk or to >1 apical node
```
```
mx= no distant metastasis assessed
mo= no distant metastasis
m1= distant metastasis
```
157
frequent follow up visits
3m for 2 yrs then 6m for 3 yrs then yearly until 10yr post resection
colonoscoy 1-2 yr postop then every 2-3yr
158
when do most recurrences happen
18-24 months
159
what is the most sensitive test to detect widespread metastases in colorectal cancer
positron emission tomography (PET)
160
rectal prolapse
intussessception of a full thickness portion of rectum through the anal opening
161
mucosal prolapse
eversion of 2-3cm of rectal mucosa through anal opening but which is not full thickness
162
difference between rectal prolapse and mucosal/hemorrhoidal prolapse
rectal has concentric, circumferential mucosal folds where mucosal has radial pattern of folds
163
rectal pain/pressure with mild bleeding, incontinence, mucous discharge and wet anus
rectal prolapse
164
tx rectal prolapse
intra abdominal procedure including sigmoid resection (redundant bowel) w rectopexy (suturing the bowel wall to the pre sacral fascia to immobilize it)
165
tx mucosal or hemorrhoidal prolapse
three column hemorrhoidectomy
166
what are the 3 positions in which hemorrhoids are normally found
left lateral
right anterior
right posterior
167
location of internal vs external hemorrhoids
internal- originate above dentate line
ext- below dentate line
168
degree of internal hemorrhoidal prolapse
1st- int hem do not prolapse
2nd- int hem prolapse w defecation and return spont. to anatomic position
3rd- int hem prolapse w defecation and require manual reduction
4th- not reducible
169
what is recommended in tx of hemorrhoids
bulk forming agents (psyllium derivatives) and avoidance of constipation
170
1st degree int hem def and tx
- bulge in anal canal lumen; doesn't protrude outside of lumen
- asym= bulking agents, no constipation, inc water intake
- symp= same asym, rubber band ligation, infrared coag
171
2nd degree int hem def and tx
- protrudes w defecation reduces spont
| - conservative man or rubber band ligation
172
3rd degree int hem def and tx
- selected cases= rubber band ligation
| - mixed= surgical hemorrhoidectomy
173
4th degree int hem def and tx
- protrudes, permanently incarcerated
| - surgical hemorrhoidectomy
174
how long do thromboses ext hem last
self limited and resolves progressively over 7-10d
175
how are most anorectal abscesses start
obstruction of the perianal glands located between internal and external sphincters; as it inc in size and spreads it becomes a perianal abscess
176
what are the mc perirectal abscesses
perianal and ischiorectal
177
tx of rectal abscess
drainage
178
after drainage of a perirectal abscess what does a pt have a 50% chance of having
chronic fistula-in-anu- abnorm communication between anus at level of dentate line and perirectal skin through the bed of previous abscess
179
intersphincteric fistulae is result of
perianal abscess
180
transsphincteric fistulae is result of
ischiorectal abscess
181
supresphincteric fistulae result of
suprelevator abscess
182
chronic drainage of pus and sometimes stool from the skin opening
fistula
183
Goodsall's rule
imaginary line drawn from right lateral to left lateral position at level of anus
184
tx of fistula
fistulotomomy- unroofing the fistula tract, allowing to heal slowly by secondary intention
185
mc cause of severe localized anorectal pain
anal fissure- linear tears in lining of anal canal below level of dentate line
186
where do most anal fissures occur
posteroanterior plane because pelvic muscular support is weakest along axis
187
classic triad assoc w anal fissures
- ext skin tag
- fissure exposing internal sphincter fibers
- hypertrophied anal papilla at level of dentate line
188
tx anal fissures
- acute= conservative tx, avoid d/c, bulk laxatives, mild nonnarcotic analgesic; sits baths; topical agents (procainamide, nitroglycerin) relax sphincter
- fails or is chronic=surgery= partial lateral internal sphincterotomy
189
two types of anal cancers
- epidermoid carcinoma (generic type includes squamous cells, basaloid, cloacogenic, mucoepidermoid, transitional carcinomas)
- malignant melanoma
190
tx anal cancers
chemo and radiation using protocol of pelvic radiation w infusion of 5fu and mitomycin c
191
mc anorectal infx affecting homosexual men
anal condylomas- pink/white papillary lesions, cauliflower like, bleed easily, pain
192
tx anal condylomas
- topical= bichloracetic acid, poco-phyllin
| - local destructive= electrocoag, cryo, laser
193
rectal symptoms including tenesmus and pain, hematochezia, ulcer
chlamydia- friable, ulcerating erythematous mucosa
194
tx chlyamydia
tetracycline or doxycycline
195
pruritus, tenesmus, hematochezia w thick yellow mucopurulent discharge
neisseria gonorrhea
196
tx n gonorrhea
ceftriaxone w tx for chlamydia (tetra or doxy)
197
A 57-year-old man comes to clinic with complaints of foul-smelling urine and two urinary tract infections treated with antibiotics by his primary care physician over the past 6 weeks. He has no pain at this time. Two months ago, he was seen in the emergency department with 2 days of left lower quadrant pain and constipation and was treated with oral antibiotics for diverticulitis. His past history is otherwise negative. His only medication Is ciprofloxacin. He is afebrile and vital signs are normal. A urine sample is cloudy with sediment. What is the next best step In diagnosis?
CT scan remains the most sensitive test for diagnosis of enterovesical fistula and location of the portion of the intestinal tract involved. Plain radiographs may show air in the bladder, but not the etiology. Ultrasound has no role. Barium enema Identifies the fistula
198
A 62-year-old woman is seen in the emergency department with dark red rectal bleeding and hypotension. Initial hemoglobin is 7.2. She is given intravenous fluids and two units of packed red blood cells but continues to have large amounts of bloody stools. Nasogastric tube effluent is clear bilious fluid. The best choice for Identification of the bleeding site at this time is .
mesenteric angiography
While rigid proctoscopy may be done, it Is unlikely to identify a source of massive bleeding. The patient is unlikely to be sufficiently stable for the colonoscopy prep or the time required for it. Tagged RBC scan Is more sensitive than angiography for Identifying active bleeding, but much less specific for identifying the source of bleeding and is not as useful in massive bleeds. Diagnostic laparoscopy would not elucidate the bleeding source. Mesenteric angiography Is much more specific for identifying the source and offers the potential for therapy (angiographic embolization) to control bleeding as well in selected cases.
199
An 85-year-old male nursing home resident is brought to the emergency department with 3 days of painless abdominal distention and obstipation. He appears to be in no pain, but his abdomen is massively distended and tympanitic. Plain abdominal films show a kidney-bean-shaped air-filled structure suspicious for cecal volvulus. The best management at this point is .
right colon resection
Observation occurs In Ogllvle’s, not volvulus. Contrast enema decompression Is not useful in cecal volvulus. Colonoscopic detorsión is useful for sigmoid volvulus, but considered unwise in cecal volvulus due to associated risks. Cecopexy carries a high rate of revolvulus.
200
A 41 -year-old man Is seen In clinic with bright red rectal bleeding, seen on the toilet tissue intermittently over the last several months. He is an insurance agent, exercises regularly, and eats a well-balanced diet. He denies changes In bowel habits. Family history is unremarkable. His vital signs are normal. His abdomen exam is normal. Digital rectal exam is normal, and blood is Identified on the examining finger. Anoscopy shows no other pathology. What is the next best step in diagnosis?
colonoscopy
In the absence of an obvious source in the anus or distal rectum, further evaluation of the colon Is needed. Fecal occult blood test (FOBT) Is irrelevant with a history of visible rectal bleeding. CBC is unlikely to be helpful. Flexible sigmoidoscopy only examines part of the colon. While barium enema may Identify an abnormality anywhere In the colon, It Is not as specific as colonoscopy.
201
A 24-year-old woman is seen In clinic with anal pain. Examination shows a fissure in the anterior midline of the anal canal. Digital rectal exam cannot be performed due to pain. The next step in management should be .
sitz baths, bulking agents, reassurance
The presentation is classic for traumatic anal fissure. Fissures off the midline generally prompt evaluation for other etiologies.
