Intestinal obstruction Flashcards
Definition
Intestinal obstruction
mechanical - physical barrier that impeded progress of intestinal contents from mouth to anus
simple or complicated
Functional - eg. Paralytic ileus is a neurogenic failure of peristalsis
eg. post surgery, pus in peritoneum
Etiology
Small bowel adhesions hernias neoplasms intussusception volvulus, foreign bodies gallstone ileus IBD (chrons) strictures - ischemic or anastomotic
Large bowel
colorectal cancer
diverticular disease (chronic causes inflammation, strictures while acute causes edema leading to acute obstruction
volvulus (most likely sigmoid colon)
Complications/Sequelae
Strangulation,
pressure in the lumen increases due to inability of the bowel to decompress. This overcomes venous pressure and decreases venous return. eventually the arterial pressure is overcome and this leads to ischemia and necrosis. mechanical obstruction likely to strangulate
closed loop obstruction, both ends are obstructed
Presentation
vomiting
distension
obstipation/constipation
abdominal pain
mechanical obstruction is a colicky intermittent pain due to peristalsis of bowel trying to overcome the obstruction
pain in ileus is more a dragging distension like pain
abdominal distension is more marked in large bowel as it has greater propensity to distend
Workup SBO
Clinical diagnosis Examination -
dehydration due to third spacing and vomitiong ie fluid sequestered into the lumen from the extracellular space specifically intravascular space
features of strangualtion - ie, fever, peritonitis , tendernedd, reobound, decompression. patient with simple obstrution should not be
Plain radiograph, SUPINE AND ERECT
supine- multiple dilated loops of bowel
erect - multiple air fluid levels (>4)
Small bowel - central with plicae circularis - lines that go from one wall to the other - strainght across
Large bowel when dilated have haustrtions which do not go directly across the bowel (partial lines)
CT scan : gives you etiology closed vs open loop mass likelihood of of
Managemetnt SBO
CBC, WBC, Xmatch, U&E, urine output I/O
FLuid resucitatoion- isotonic fluids
Ucat - monitor resuscitattion
NG decompression - record losses and replace 1:1
Management of SBO - partial vs complete
NO PRIOR SURGERY - Laparotomy
PRIOR SURGERY: depends on whether complete or partial
partial:
gastrograffin test- contrasts placed in and x ray done (6hrs post) if seen in colon we know obstruction is partial and they can have non operative manangement but keep checking WBC, NG output and abdominal exams - NG output must be falling for you to keep them on non operative. gastro graffin is therapeutic as it pulls water into the lumen as well
Complete obstruction - surgery asap
if non adhesive then both partial and complete need surgery
obstruction resolution
passage of flatus and stool
low NG output
establish diet
Investigations LBO
CT scan
single contrast enema (NO AIR should be included so cant do double) to see if obstruction is functional or mechanical
functional obstruction if barium goes up to the caecum its a functional obstruction. mechanical if barium stops and progresses no further.
Management LBO
1 stage: resection + primary anastamosis (ideal but not done often)
2 stage : resection and stoma , reversal (most common)
3 stage : loop stoma then resection and anastomoses then closure of stoma\
stent can be passed by anal canal using guide wire. Very useful in improving outcomes in LBO .
Management of Intussusception
Telescoping of bowel into another segment leading to obstruction
in adults we do not try and reduce intussusception as the lead point may be due to a cancer and we do not want to disseminate this cancer during reduction
Management of volvulus
Volvulus is a twisting of large or small intestine on itself to form an obstructive loop.
If there are no features of strangulation, decompress the volvulus and decompress the obstruction using sigmoidoscopy, add a flatus tube to prevent reblocking of volvulus and when stable head to surgery
O’GIlvies syndrome
This is a colonic pseudoobstruction usually related to underliying conditions namely antipsychotics, opiods, bedridden, multiple comorbidities, electrolyte imbalances (hypokalemia), sepsis / ICU
ceacum is most susceptible to rupture/perforation due to laplas law - if ceacal diameter >10cm then colonoscopy is necessary to decompress
MANANGEMENT
Colonoscopy - pass to ceacum and suck air out
neostigmine - parasymptathetic system jump start, may cause bradycardia so must be done in resusitation ready conditions
caecostomy - rarely done as there are many surgical complications
