LARGE BOWEL OBSTRUCTION Causes Colorectal cancers Volvulus sigmoid

LARGE BOWEL OBSTRUCTION

Causes • Colorectal cancers • Volvulus- sigmoid colon, caecum • Diverticular disease of colon • Faecal impaction • Inflammatory disease- Crohn’s disease, ulcerative colitis • Vascular – ischaemic colitis • Hernia • Adhesions • Pseudo obstruction(Ogilvie’s syndrome)

Clinical features • Classical symptoms- Obstipation, pain abdomen, significant abdominal distention. Vomiting- late feature. • Closed loop obstruction- a surgical emergency. Due to carcinoma colon with competent ileocaecal valve, volvulus. Increased risk of perforation at the site of pathology or proximally at the thin caecal wall( Laplace’s law- T= PD where T is caecal wall tension, P is intraluminal pressure, D is diameter of the organ).

• On examination- marked abdominal distension, usually without any tenderness or discomfort on palpation. Dilated bowel loops may be palpable. Bowel sounds increase initially but decrease gradually with continued obstruction. • Digital rectal examination- empty rectum, ballooning of rectum. Look for faecal impaction, rectal growth.

Investigations • Serum electrolytes • Blood urea, serum creatinine • Plain x ray abdomen- erect film • Multi detector CT scan with intravenous and rectal contrast • Barium/ water soluble contrast enema-

Management • Usually requires emergency operation. • Fluid and electrolyte resuscitation • N G tube insertion, urinary catheterisation, • Perioperative broad spectrum antibiotics • DVT prophylaxis. • Arrange adequate blood. • Lithotomy position

• Laparotomy- midline incision. • Inspect the abdomen for the site of obstruction and the pathology, assess the viability of the involved bowel. Decompress the bowel if there is massive dilatation of the bowel.

• Obstructing right colon cancer- Primary right colectomy with immediate anastomosis for most of the patients. If the patient is unstable/ intraperitoneal sepsis/ bowel is of doubtful viability- tumour resection, end ileostomy, closure of proximal end of transverse colon or it is brought out as mucous fistula.

• Obstructing left colon cancer- 3 stage procedure- 1. colostomy. 2. tumour resection. 3. re establishment of continuity of bowel. Not commonly practiced nowadays.

2 stage operation- 1. resection of tumour, colostomy and closure of distal end of bowel. (Hartmann operation). 2. re establishment of bowel continuity.

Tumour resection with end colostomy and mucous fistula.

One stage procedure- segmental resection with primary anastomosis.

• Intestinal bypass or loop ileostomy- for patients with large, fixed tumours with extensive local invasion. • Other options- Endoscopic Metallic Stent(SEMS), trans anal rectal tube insertion.

• Management of sigmoid volvulus- Endoscopic detorsion- temporary. Laparotomy- Resection and primary anastomosis or Hartmann operation( resection of sigmoid colon, proximal end colostomy, closing the distal end).

Acute colonic pseudo obstrucion • Ogilvie’s syndrome • Symptoms and signs of large bowel obstruction without any mechanical obstruction • Affects mainly the caecum and right colon. • If not treated promptly may result in caecal perforation, peritonitis and death.

Causes • Primary- familial visceral myopathy, disorder in the innervation of large bowel smooth muscles. • Secondary- metabolic disturbances(K+, Mg+), cardiovascular diseases( MI), post operative state ( orthopedic, urologic, transplant), neurological diseases, endocrine (myxoedema), inflammatory diseases(pneumonia). • Drugs- opiates, psychotropics, anticholinergics, chemotherapy agents.

Clinical features • Acute massive dilatation of caecum and right colon. • Acute or gradual progressive abdominal distension and discomfort. • Sluggish bowel sounds

Management • Plain x ray abdomen- gaseous distension of colon. Caecal diameter of >10 cm. requires immediate decompression. • Colonoscopy- to rule out any cause of mechanical obstruction and decompression of colon. • Neostigmine therapy- under close supervision • Laparotomy- for perforation or ischaemia of bowel. Closure of perforation and exteriorisation of bowel. Tube caecostomy.