Surgery - Lower GI Flashcards
What can cause failure of fascia closure in ab surgery?
Infection in abdomen
Can have hernia w/ fascia open – need to go to OR to fix ASAP
Most common causes of lower GI bleeding
1) Diverticulosis
2) Andiodysplasia
Ischemic colitis
Happens in setting of
- hypoTN
- vasculitis
- atherosclerosis
Present w/:
- ab pain (pain out of proportion of PE)
- —usually pain after eating –> wt loss
- fever
- vomitting
Bleed b/c of ischemia of watershed areas of the colon
Acute mesenteric thrombosis
Ab pain out of proportion of physical findings
N/V
Bloody diarrhea b/c mucosal sloughing
Numerous athero risk factors
Usually SMA is occluded –> distal duodenum –> transverse colon
Common causes of pelvic abscesses
- male
- female
Male
- appendicitis
- rupture of appendix –> form pelvic abscess from fluid draining into rectovesical pouch
Fem:
- gyn issues
Drain these abscesses!
Pelvic abscess vs anorectal abscess
Pelvic
- tender fluctuant mass palpable only w/ tip of examing finger on rectal
- painful defecation
- diarrhea
Anorectal
- perineal pain
- fluctuant mass palpable on perineum
- pain w/ ambulation + defecation
- urinary retention
Rovsing sign
RLQ pain w/ deep palpation of LLQ
Sign of Appendicitis
How do you dx appendicitis?
CLinically!
Don’t need further imaging to confirm dx if classic signs, sx, and lab data are present
Get CT if person has suspected appendicitis w/ atypical presentation
Need surgery ASAP
Give Abx pre and postop
Isolated duodenal hematoma
Mostly in kids after BAT
Usually have blood b/n submucosal and muscular layers of duodenum –> obstruction
Most will resolve by itself in 1-2 wks
Tx:
- nasogastric suction w/ TPN
- if need surgery, can do laparotomy or laparoscopic procedure
Uncomplicated vs complicated diverticulitis
- tx?
Uncomplicated
- colonic diverticular inflamamation
- tx: outpt, bowel rest, oral abx, observation
Complicated
- diverticulitis + abscess, perf, obstruct, or fistula formation
- if fluid collection < 3 cm, tx w/ IV abx
- if fluid > 3cm, CT guided drainage
- surgery (drainage + debridement) if drainage does not fix
Ab aorta operations - what is an early complication?
Bowel ischemia and infarction
How long do you give a pt who went under ab surgery that is now third spacing?
48-72 hrs
At this time, they will reabsorb edema and pee it all out
Pathophys of dumping syndrome
Rapid emptying of hypertonic gastric content into duodenum + SI
causes fluid shift from intravascular space –> SI
Then release intestinal vasoactive polypeptides and stimulation of autonomic reflexes
When do you use technetirum-99 labeled RBC scintigraphy?
IN cases of lower GI bleeding where source can’t be ID’d by colonoscopy
Mesenteric ischemia
inflammation and injury of the small intestine result from inadequate blood supply
Different severities of hernias
Reducible
Incarcerated = not reducible
Strangulated = not reducible + ischemic
Minimize post op infection for elective colonic surgery
What can you use to decrease bacterial load in bowel before GI surgery?
Mechanical cleansing
Oral Abx
Periop parenteral abx (anaerobes and aerobes)
Oral nonabsorbable abx
- neomycin
- erythromycin
Risk factors associated with colorectal cancer
Strong risk
- advanced age
- country of birth (eg Korea, Scandanavians)
- FAP/HNPCC
- long standing UC
Moderate risk
- previous adenoma or cancer
- 1st degree relative w/ adenoma or cancer
- pelvic irradiation
Protector factors assoc w/ colorectal cancer
Moderate
- physical activity
- aspirin/NSAIDs (Nurses study)
- high Ca intake (Nurses study)
Genetics of colon cancer - what can be mutated?
Tumor suppressors
- APC
- Chr 18
- p53
Oncogenes
- k-ras
DNA repair genes
- hMLH1
- hMSH2
Where do adenocardionmas of colon come from?
Glandular tissue of mucosa (#1)
Familial adenomatous polyposis
APC gene mutation
Chromosome 5 location
AD inheritance
100% colon cancer risk
Total proctocolectomy in early 20s
- ileostomy
- or J pouch (ileoprocto anastamoses)
Still early death b/c more susceptible to other adenomas, esp in duodenum
What is double contrast barium enema?
2 contrasts:
- Barium
- Air
Air to disperse barium
Gardner’s syndrome
Osteomas
variant of FAP
Classic for peutz-jegher’s?
Buccal pigmentation
HNPCC (Lynch syndrome)
AD inheritance
Not hundreds of adenomas like FAP but will still get polyps
Mismatch repair gene mutation
Higher risk for other cancers:
- stomach
- SI
- renal
- ovarian
- pancreatic
Where are most hereditary colon cancers?
R side
Watershed areas of Colon
Lives off collateralization of arteries for supplying area
Griffith’s point = splenic flexture
- Arch of Reiling
- SMA - marginal A branch of IMA
Sudek’s point
- superior hemorrhoidal A (IMA) - middle and inferior rectal A (internal iliac)
- mets to lung and liver for rectal cancer
Microsatellite instability
When 2 bases don’t line up, you get a break = MI
condition of genetic hypermutability that results from impaired DNA Mismatch Repair (MMR).
Microsatellite stable vs. unstable - which has better prognosis?
Microsatellite unstable cancer has better prognosis!
- less biologically active
But more resistant to 5-flurouracil chemo
Molecular pathogenesis of colorectal cancer
MIcrosatellite stable cancer:
Loss of APC gene –> k-ras mutation –> DCC deletion –> p53 deletion
Microsatellite unstable cancer:
MSH2/ MLH1 abnormality –> k-ras mutation –> DCC deletion –> p53 deletion
What do you look for in FOBT?
Iron!
THIS IS NOT SPECIFIC OR SENSITIVE!
Guiaic test:
- 3 separate stool samples collected by patients and tested for blood
Screening recommendations for CRC
- what tests do you do?
Annual FOBT + sigmoidoscopy / 5 years
Colonoscopy every 10 years
Double contrast barium enema every 10 years
Post op, when does bowel function come back?
SI - 4h
Stomach - 24h
Colon - 3d
Abx for GI surgery ppx if will cause significant trauma
Ampicillin + gentamicin
- fights enterococci
Intestinal atresia usually due to
vascular accidents in utero
Ileum #1 affected
Duodenum is a failure to recannalize rather than a vascular accident in utero
Whipple’s disease manifestations
PAS + macrophages (foamy)
Cardiac sympoms
Arthralgias
Neurologic symptoms
Diverticulosis
Most in sigmoid colon
- smaller diameter, more pressure
- more formed stool
Occur esp where vasa recta perforate muscularis externa
Volvulus
Twisting of portion of bowel around redundant mesentery in colon
Cecum (young)
Sigmoid (old)
Meconium ileus
- pathophys
- tx
In cystic fibrosis
Meconium plug obstructs intestine (terminal ileum) preventing stool passage at birth
Tx:
Gastrografin enema to dx
Gastrografin enema can also tx (draws fluids in and dissolves pellets of meconium)
NO SURGERY!
Necrotizing enterocolitis
- what is it?
- tx?
Necrosis of intestinal mucosa
Possible perf
Colon is usually involved
More common in preemies
- common when baby begins solids foods or formula
IVF + IV abx
Surgery if have pneumoperitoneum, ab wall erythema, air in portal v, or intestinal pneumotosis
Dx carcinoid
Tx carcinoid
Dx:
- urinary 5-hydroxyindoleacetic acid
- not blood levels b/c it is waxing and waning symptoms. levels only high at time of attack; otherwise, levels will be normal
Tx:
Tumor excision is 1st line
Use octreotide if can’t resect/too advanced
Bacterial overgrowth syndrome in intestine
- symptoms
- clinical manifestations
Sx: Ab pain Watery diarrhea Dyspepsia Wt loss
Severe: Tetany (hypo Ca b/c vit D deficiency) night blindness (vit A def) neuropathy (B12 def) dermatitis arthritis hepatic injury
PE: secussion splash (from fluid filled loops of bowels)
Upper GI w/ small bowel follow through to dx by showing hypomotility, partial obstruction, dilation w/ delayed GI motility
Usual Causes of ileus
UTI
PNA
Tx ogilvie’s syndrome
1st make sure there is no actual intestinal blockage
neostigmine + monitor cardiac function
Tx Volvulus
Dx volvulus
rigid sigmoid + rectal tube (keep from twisting on itself and do on a bowel perp) so you can do a sigmoid resection
Can dx w/ xray
Tx Gallstone ileus
go in and slit in the ileum and milk out the stone. Go back and fix the gallstone duodenum fistula later
Ab pain + high amylase + normal lipase
What happened?
Bowel can release amylase.
If have ab pain and only high amylase without corresponding rise in lipase, not pancreatitis and can be bowel ischemia
Most common causes of C Dif colitis
- when do you need surgery
CLindamycin
Cephalosporins
Surgery when WBC > 50, serum lacate > 5
Fissure or fistula that doesn’t heal well - what does this suggest?
Crohns
Anal area has good blood supply and usually these things heal. If not, suggests Crohns
Generally, GI bleeding is from where?
3/4 cases before ligament of Treitz (upper GI)
1/4 in colon or rectum
BRBPR in child - what is it most likely?
What do you do next?
Meckel’s diverticulum
Technetium scan looking for ectopic gastric mucosa
Omphalocele vs. gastroschisis repair
Omphalocele = reduce day by day
Gastrochisis = need TPN b/c bowel will not work for about 1 mo
Tx imperforate anus in newborn
If there is a fistula, can delay until before potty training time
If no fistula, do colostomy for high rectal pouches or do primary repair asap
Find where blind pouch is with xrays taken upside down
Dx Hirschsprung disease
Full thickness bx of rectal mucosa
Manometrics usually for older kids
SCC of anus
more common in HIV+ and homosexuals
fungating mass growing out of anus
tx:
nigro chemorad (90% success)
surgery if there is residual
All hernias should be electively repaired except
umbilical hernias in kids < 2-5 yo
esophageal sliding hernia
Anal fissure
Usually in young women
lots of pain w/ defecation + blood streaks covering stools
Can get constipated because fear defecation
Tx:
- stool softners
- topical nitro
- local botox
- forceful dilatation
- CCB (dilitazem)
Thumb print sign on KUB/Ab XRAY
Bowel wall edema
On an unremarkable abdominal radiograph of a patient with normal colon wall thickness, you see only the inner wall of the bowel because it is outlined by the gas in the lumen of the bowel; you don’t normally see outer wall of normal bowel wall.
If the bowel wall is thickened, it protrudes into gas-filled lumen, and on radiographs, these protrusions appear as focal areas of soft tissue thickening along the colon wall that look like somebody is pressing a thumb into the air-filled lumen
SBO in man w/o previous ab surgeries + aerobilia - what do you suspect?
Aerobilia = air in the biliary tract
This is gallstone ileus!!!
Tx: ileotomy + extraction; later cholecystectomy
- do not operate on the biliary fistula now
Tx Hirschprung’s disease
Initial = colostomy decompression
Wait for definite repair until nutritional status is ok and nontdistended bowel
Umbilical hernia in newborn + no incarceration - tx?
Wait
Most close by age 4
Is more water absorbed in R or L colon?
Both same!
How best to stage rectal wall and pararectal lymph nodes in rectal cancer?
US
Do you do a resection for rectal cancer if it invades muscularis mucosa?
Not needed - if taking out cancer has clear gross adn microscopic margins, tumor is well differentiated, and stalk not invaded
Ach - + or - motility of GI?
Causes motility!!
Anything that simulates PSNS activity stimulates motility
Places where hemorrhoids arise
L lateral
R anterior
R posterior
Tx external hemorrhoids, thrombosed
If < 72 hrs old - remove clot
If > 72 hrs old - don’t do anything, warm bath. body is resorbing the clot
Where do you cut to do I&D for anal abscess?
Near anus as possible b/c may make fistula so want to go as close to opening as possible
anal fissure characteristics
Will have a skin tag usually with it
Coincentric rings indicative of
Rectal prolapse
Causing anal pain
Abscess
Herpes
Fissure
Thrombosed external hemorrhoids
Mass on outside of anus/abnormalities around anus that are not painful
Skin tags
Internal hemrrhoids
Pruritus ani
Tumor
Crohns vs regular fissure
Crohns usually lateral
Conventional fissures usually posteriorly
Howship Romberg sign
Obturator neuralgia from nerve compression by obturator hernia
Thigh extension, adduction and medial rotation
.Fat absorption
Short _ medium chain = transport directly from jejunal mucosa –> portal venous system
Larger triglycerides –> chylomicrons –> lymphatics
Regional enteritis aka crohns in kid can mimic appendicitis - what do you do when you do surgery and the appendix looks normal?
Appendectomy if cecum at base of appendix is not involved
Anal cancer 1st therapeutic approach should be
Radiation + chemo
Surgery has been shown to have not great results
Indications for surgery in crohns
Free perforation
Stricture if it compromises nutritional status
Fistula w/ symptoms
Carcinoid tumor in appendix tx
< 2 cm - appendectomy
> 2cm - R hemicolectomy
Tx complicated diverticulitis
- abscess
- perforation
- obstruction
- fistula formation
Abscess:
CT guided percutaneous drainage –> if doesn’t resolve, surgical drainage and debridement
Fistula, perforation, peritonitis, obstruction, recurrent attacks:
- sigmoid resection
GI complaints followed by periorbital edema + myositis + eosinophilia + splinter hemorrhages
Trichinellosis!!!
What should you always look for as a source of constipation?
Hyper Ca
Watch out for MM, cancers causing this, esp if pt has bone pain
Difference between ileus vs pseudoobstruction
ileus has NO BS
- will have both SI and colon distention
Pseudoobstruction has hyperactive bowel sounds
- most colon distention w/o much SI distention
