L. Bowel Obstruction Flashcards
Definition
Surgical emergency where a mechanical interruption (either complete or partial) occurs to the flow of intestinal contents, with multiple potential causes
Prevalence & patient demographics
Uncommon, M>F
Causes
Malignant colorectal disease Colonic volvulus: sigmoid/caecal Benign stricture Adhesions Hernia Foreign body Pelvic abscess Gynae neoplasm, endometriosis
Risk factors
Female Colorectal Ca Prev abdo surgery Elderly Institutionalisation Mental illness megacolon Low/high fibre diet IBD Laxative abuse Diabetes Prev colorectal resection
Clinical Presentation
Colicky abdo pain
Abdo distension
Change in bowel habits: hard faeces, rectal bleeding, tenesmus, no passing of faeces or flatus
Signs
Tympanic abdo, abnormal bowel sounds, palpable abdo mass, positive faecal occult blood test
Differentials
Acute Colonic pseudo-obstruction Chronic/ idiopathic megacolon Toxic megacolon Endometriosis Pseudomembranous colitis
Investigations
Bloods: FBC (elevated WBC & anaemia), serum electrolytes, renal function (elevated urea & creatinine), serum amylase/lipase (elevated), coag studies (prolonged PT, PTT, INR)
Erect CXR: Free air under the diaphragm
Plain abdo X-ray: Gaseous distension of L.bowel, coffee bean volvulus
Consider: biopsy, flexible/rigid endoscopy, CT abdo/pelvis, contrast enema
Management in acute obstruction?
Supportive: IV fluids, supplementary O2, blood transfusion (if anaemic), Abx pre-op (amoxicillin, metronidazole)
NG decompression: Initial management of any cause, decompress the intenstinal tract & reduce flow of gastric contents/air
Emergency surgery: Mandatory in patients w/colonic perforation due to obstruction
Prognosis
Colorectal Ca=Moderate morbidity & mortality, likely to have adverse effects on long-term prognosis & reduced 5-year survival
Colonic volvulus= Without surgery high recurrence & morbidity & mortality
Rare causes= underlying process dictates long-term outcome
Complications
Dehydration Electrolyte imbalance Death Bowel perforation Sepsis
Pathophysiology
Colon proximal to obstruction dilates thus inc colonic pressure leading to reduced mesenteric flow producing mucosal oedema w/transudation of fluid & electrolytes into colonic lumen. With progression arterial supply is compromised w/ mucosal ulceration & full thickness necrosis & perforation occur.
What are the types of benign stricture?
diverticular, inflammatory, ischaemic, radiation-induced, or anastomotic
Management of obstruction due to volvulus?
Flexible/rigid sigmoidoscopy: Endoscopic detorsion. May relieve obstruction, performed immediately after diagnosis, rectal tube inserted
Surgery: Extra-peritonealisation of the colon, mesosigmoidoplasty, laproscopic fixation. If peritonitis/mucosal gangrene= emergency midline laparotomy
