Large bowel obstruction

Large bowel obstruction

Causes

large bowel cancer accounts for up to 80-90% of cases of large bowel obstruction most occur at or distal to the splenic flexure

other causes include diverticular stricture diverticulitis
 involving small bowel ,volvulus and other rare causes incarcerated sliding hernia ,radiation or ishaemic and strictures

Colonic and rectal malignancies

 treatment depend on the condition of the patient ,condition of the bowel to be used in anastomosis and the skill of the surgeon .shock and circulatory instability of the patient and peritonitis may dictate  a staged procedure.as hartmann,s procedure like wise a staged procedure may be
indicated if there is potential tension of the anastomosis or surgeon,s in experience. obstructing right -sided lesions (proximal to the splenic flexure)are treated by resection with primary anastomosis unresectable tumours should be treated by internal bypass or a proximal stoma

Obstructing left-sided lesions including high rectal cancers are treated by resection with primary anastomosis with or without on - table antegrade colonic lavage with or without a covering stoma . alternatively a hartmann,s procedure or a subtotal colectomy with ileorectal anastomosis may be performed

 If the left -sided obstructing lesions present with caecal perforation this usually mandates a subtotal colectomy , unless it is not deemed safe for primary anastomosis in which case resection is carried out with the formation of a terminal ileostomy and a mucous fistula

Obstructing of lower rectal cancers may be treated most appropriately by diverting colostomy this allow time for preoperative radiotherapy as these lesions are usually locally advanced and also allows for a primary resection and anastomosis alternatively it may be possible to reestablish a lumen by means of laser to allow time before elective definitive treatment
 
 Sigmoid volvulus

Is predisposded to by the presence of a long narrow mesocolon and chronic constipation radiological appearance is characteristic plain abdominal X Ray is diagnostic in 70-80%of patients showing a massively dilated kidney -shaped single lop of bowel arising from the pelvis with its concavity towards the left iliac fossa . instant barium enema may show a characteristic tapered spiral twist or tayer shaped(brird,s beak)in cases when plain radiography is inconclusive it may also reduce the volvulus . Treatment initially should involve deflation using a rigid sigmoidoscope and the passage of a flatus tube this is succeeds in up to 90%of the patients the flatus tube should be left in situ for at least 48 hours otherwise early recurrence is common

 elective sigmoid colectomy is advisable before the patient discharged home if sigmoidoscopic deflation fails or if there are signs of bowel infarction perforation or peritonitis then emergency sigmoid colectomy with or without anastomosis (double-barrel colostomy )is the only option

Endoscopic sigmoidoplexy using a combined colonoscopy and percutaneous insertion of colostomy tubes to fix the sigmoid to the lateral abdominal wall has been successful in  unfit patient these may be changed to flatus tubes which are left in situ indefinitely to prevent recurrence 

Caecal volulus

Plain X Ray abdomen may show a large kidney or comma - shaped gas -filled loop of bowel with its concavity toward the left hypochondrium. the right iliac fossa is seen to be free of gas later on the small bowel becomes dilated wit fluid filled loops seen
Colonoscopic decompression and detorsion has been tried but rarely successful
Right hemicolectomy is the preferred treatment in many patients essential if the caecum is not viable Alternatively detorsion followed by caecopexy using nonabsorbable sutures to lateral peritoneum with tube caecostomy the tube is normally removed after 10 days and most close spontaneously afterwards

tags:bowel,large,obstruction