Causes of abdominal obstruction and its management, Can intestinal blockage clear itself?

Abdominal obstruction (also called bowel obstruction) occurs when there is a blockage in the intestines that prevents food, fluids, and gas from passing normally through the digestive tract. This can be a partial or complete blockage and may occur in the small or large intestine.

Symptoms of Abdominal Obstruction

• Severe abdominal pain and cramping.
• Bloating and abdominal swelling.
• Nausea and vomiting.
• Constipation or inability to pass gas.
• Diarrhea (in partial obstructions).
• Loss of appetite.
• Fever (if infection is present).

Individual Causes of abdominal obstruction and its management:

1. Obstruction by Adhesions and Bands (most common cause of intestinal obstruction.

Mechanism of adhesion formation: Peritoneal irritation ⇒ local fibrin production ⇒ adhesions

Etiology of adhesive intestinal obstruction:

1. post-operative adhesions (most common cause of small bowel obstruction): As early as 4 weeks post laparotomy. The majority of patients present between 1-5 years (Colorectal Surgery 25%, Gynaecological 20% & Appendectomy 14%).
2. Bacterial peritonitis.
3. Radiotherapy.
4. Ischemic or Chemical injuries.
5. FB reaction.

Etiology of Band intestinal obstruction:

1. Congenital: e.g. obliterated vitello-intestinal duct.
2. Acquired: A string band following previous bacterial peritonitis.

Problems of adhesive intestinal obstruction:

1. Small intestinal obstruction (SBO).
2. 2ry female infertility.
3. Ectopic gestation.
4. Chronic abdominal and pelvic pain.
5. Hazardous re-operation.

Factors that limit adhesion formation:

1. Good surgical techniques.
2. washing of the peritoneal cavity with saline to remove clots, etc..
3. Minimize contact with gauze.
4. Cover anastomosis and raw peritoneal surfaces.
5. Seprafilm: Hyaluronic acid and Carboxy-methyl-cellulose.

Treatment of adhesive obstruction:

1. conservative treatment:

• include: Intravenous rehydration and Nasogastric decompression.
• indication: there are no signs of strangulation.
• should rarely continue conservative treatment for longer than 72 hours.

2. surgical treatment: Laparotomy, if required, to divide the causative adhesion.

Treatment of recurrent adhesive intestinal obstruction:

1. Repeat adhesiolysis alone (open/laparoscopic).
2. Adhesiolysis with seprafilm (decrease fibrin formation).
3. Noble’s intestinal plication.
4. Child-Phillips transmesenteric plication.
5. Baker intestinal intubation.

2. Acute intussusception:

definition: a condition in which one segment of the intestine becomes invaginated or telescoped inside another.

intussusception in child Vs adult:

• Child: 95% of all intussusception (Common in 1^st year of life). adult: Only 5% of all intussusception.
• Common after viral illness enlargement of Peyer’s patches. adult: Secondary to polyps, hematoma or tumors
  
• ileocolicis the most commonest. adult: Colocolic is the commonest.
• Mainly non operative (barium hydrostatic reduction). adult: Mainly surgical resection is always required.

clinical picture

• previously healthy infant presents with colicky pain and vomiting (milk then bile).
• Between episodes, the child initially appears well.
• Later, they may pass a red currant jelly’ stool.

treatment in the child: Barium reduction

• The head of the intussusception is at the hepatic flexure.
• Partial reduction.
• Free flow of contrast into the distal small bowel indicates a complete reduction.

3. Volvulus

definition: Twisting or axial rotation of a portion of the bowel about its mesentery. When complete it forms a closed-loop obstruction. The most commonly affected part of the intestines in adults is the sigmoid color with the cecum being the second most affected.

Clinical picture:

• Palpable tympanic lump (sausage shape) in the midline or left side of the abdomen.
• Constipation, abdominal distension (early & progressive).
  

Treatment:

• endoscopic Relieved by decompression per anum.
• Surgery is required to prevent or relieve ischaemia.

Large Bowel Obstruction (LBO):

treatment according to the site of obstruction:

1. Obstructing lesion in the cecum or ascending colon:

• Removable (resectable) → Right hemicolectomy with ileo-transverse anastomoses.
• Irremovable (irresectable) → proximal stoma (ileostomy) or ileo-transverse (bypass).

2. Obstructing lesion in the transverse colon → Transverse colectomy with anastomosis between the ascending and descending colons.

3. Obstructing lesion in the left colon→ left hemicolectomy:

One-stage procedure:

• Resection, on-table lavage, and primary anastomosis.
• Total colectomy with ileorectal anastomosis.

Two-staged procedure:

1. Harmann’s procedure.
2. Closure of colestomy.

Three-staged operation:

• Defunctioning colostomy.
• Resection and anastomosis
• Closure of colostomy.

4. Rectal cancer

Anterior resection (resection of the rectum through an abdominal approach).

• High anterior resection: Resection of distal sigmoid colon and upper rectum.
• Low anterior resection: For lesions in the upper & mid rectum.
• Extended low anterior resection: For lesions in the distal rectum.

Abdomino-perineal resection (APR): Excision of the rectum, anal canal & anus with a permanent colostomy.

5. Hernia

1. Obstructed external Hernia:

Commonest:

1. Femoral hernia (the commonest hernia to strangulate).
2. Indirect inguinal hernia.
3. Umbilical hernia.
4. Others: incisional hernia.

Ischaemia occurs initially by venous occlusion, followed by edema & arterial compromise.

Strangulation is noted by:

1. local signs: tender (persistent pain), tense, discoloration, irreducible, and no impulse on cough.
2. Constitutional symptoms. e.g. fever.

2. internal hernia:

Definition: A portion of the small intestine becomes entrapped in one of the retroperitoneal fossae or into a congenital mesenteric defect.

Potential sites of internal herniation:

• The foramen of Winslow.
• hole in the mesentery or transverse mesocolon.
• Defects in the broad ligament.
• Congenital or acquired diaphragmatic hernia.
• Duodenal retro-peritoneal fossa, left para-duodenal & right duodeno-jejunal.
• Cecal/appendiceal retro-peritoneal fossae – superior, inferior & retro-cecal.
• Inter-sigmoid fossa.

Treatment of internal herniation:

• The standard R/ is to release the constricting agent by division.
• This should not be undertaken in cases of herniation involving the foramen of Winslow, mesenteric defects & the para-duodenal / duodeno-jejunal fossae, as major blood vessels run in the edge of the constriction ring.
• The distended loop in such circumstances must first be decompressed with minimal contamination & then reduced.

6. Enteric Stricture Causing small bowel obstruction:

causes:

1. Inflammatory stricture 2ry to TB or Crohn’s disease.
2. Malignant stricture: lymphoma is common, whilst carcinoma and sarcoma are rare.

clinical presentation: usually subacute or chronic

Standard surgical treatment: Resection & anastomosis.

In Crohn’s disease stricturoplastymay be considered in the presence of short multiple strictures without active sepsis.

7. Paralytic ileus:

Causes:

1. Post-operative.
2. Infection: Intra-abdominal sepsis, abscess, peritonitis.
3. Reflex ileus: following fractures of the spine or ribs, retro-peritoneal hemorrhage.
4. Metabolic: uremia, hypokalemia, hypo-thyroidism.
5. Medications: anticholinergics, opiates, calcium channel blockers.

Clinical Features: Distension, effortless vomiting, Absence of bowel sounds, No passage of flatus and Pain is not a feature.

diagnosis:

1. X-ray: gas-filled intestinal loops with multiple fluid levels.
2. CT scan is the test of choice.

Management of Paralytic ileus:

• Nasogastric suction.
• Fluid and electrolyte balance.
• Removal of the Iry cause.
• No place for the routine use of peristaltic stimulants.
• If the paralytic ileus is prolonged; laparotomy is performed to exclude a hidden cause and facilitate bowel decompression.

8. Pseudo-obstruction:

Definition: Obstruction, usually of the colon, in the absence of a mechanical cause or acute intra-abdominal disease. It is associated with a variety of syndromes where there is an underlying neuropathy &/or myopathy.

Small intestinal pseudo-obstruction:

1. Primary (i.e. sporadic or familial visceral myopathy, neuropathy).
2. Secondary (e.g. scleroderma, muscular dystrophy, spinal cord injury, viral infection).

Colonic pseudo-obstruction:

1. Acute form: Ogilvie syndrome.
2. Chronic form.

9. Mesenteric Ischemia:

Gut ischemia: important anatomical consideration:

• Marginal artery of Drummond.
• Marginal artery of Dwight.
• Griffiths point.
• The are of Riolan.

types:

1. acute mesenteric ischemia:

causes: Arterial or venous thrombosis, Embolism, Vasculitis, and Surgical trauma to vessels (e.g. aortic reconstruction).

Clinical features:

1. Sudden onset of severe abdominal pain in a patient with atrial fibrillation or atherosclerosis. Abdominal pain is classically out of proportion to the physical findings.
2. Persistent vomiting: defecation occurs early with subsequent passage of altered blood.
3. Hypo-volemic shock rapidly ensues.
4. examination: Mild abdominal tenderness initially and rigidity is a late feature.

investigations:

• Laboratory tests: Leucocytosis, acidosis, hyper-amylasemia.
• Imaging: Plain X-ray, angiography, CT scan.

Treatment:

• Full resuscitation.
• Massive resection of affected bowel. unless flow is restored within 6 hours.
• Second look laparotomy.
• In early cases: embolectomy or revascularization of the SMA by aorto-SMA bypass.
• Anti-coagulations early in the post-operative period.
• IV alimentation after extensive enterectomy.
• Small bowel transplantation in selected cases.

40% of patients receive no treatment or an -open & closed laparotomy.

Prognosis: Mortality rate = 60-85%.

2. Chronic Mesenteric Ischemia (Intestinal Angina):

• causes: insufficient blood flow to the bowel during periods of increased metabolic demand associated with digestion. Patients are in their 50s or 60s & have other evidence of generalized atherosclerosis.
• Clinical features: Recurrent postprandial pain, bloating, flatulence, constipation, or diarrhea, associated with weight loss and steatorrhea (50%).

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