INTESTINAL OBSTRUCTION

Lecture 2

د. كريم الاعرجي

Investigations

The diagnosis of IO is a clinical i.e.: Colicy abdominal pain with exaggerated bowel sounds during the attacks of colic .Investigations are done to assess the general condition of the patient and to confirm diagnosis.

  1. Plain abdominal X-rays ( Erect &Supine ) :It may show distended bowel loops with gases or presence of air-fluid levels of more than three .It confirms diagnosis of IO and helps in localization of IO whether small or large bowel. Small bowel obstruction is suggested by presence of Air-fluid levels which appear later than gas shadows , straight and centrally located (‘stepladder pattern ) . No gas is seen in the colon . Jejunum is characterized by the presence of valvulae conniventes, which completely pass across the width of the bowel and are regularly spaced, giving a ‘concertina’ or stepladder appearance .The Ileum is featureless .Caecum – a distended caecum is shown by a rounded gas shadow in the right iliac fossa .Large bowel shows peripheral gas shadows ( Picture frame appearance ) with haustral folds, which are spaced irregularly, do not cross the whole diameter of the bowel and do not have indentations placed opposite one another .
  2. Laboratory investigations : Hb% , WBC Count , BU , FBS according to the general condition of the patient .
  3. Abdominal CT Scan in cases of colonic tumours .
  4. Contrast study ( Water-soluble gastrografin ) in the form of Barium enema for large bowel obstruction or follow through (with caution ) to differentiate between mechanical obstruction and ileus .

Treatment of acute intestinal obstruction (drip and suck )

  1. Gastrointestinal drainage :By passage of NG Tube .It facilitates decompression of intestine proximal to the obstruction, reduce the risk of subsequent aspiration during induction of anaesthesia .
  2. Fluid and electrolyte replacement : Hartmann’s solution or normal saline. The volume required is determined by clinical , haematological and biochemical criteria.
  3. Antibiotics are not mandatory but indicated for all patients undergoing small or large bowel resection
  4. Relief of obstruction : Surgical treatment is necessary for most cases of intestinal obstruction but should be delayed until resuscitation is complete, provided there is no sign of strangulation or evidence of closed-loop obstruction . (‘the sun should not both rise and set’ on a case of unrelieved acute intestinal obstruction )

Indications for early surgical intervention

■ Obstructed or strangulated external hernia

■ Intestinal strangulation

■ Acute obstruction with sudden onset .

Volvulus : It implies twisting or torsion of a bowel around its axis or mesentery . It occurs in sigmoid , caecum and small bowel .

Clinical features of sigmoid volvulus : It affect mainly elderly patients . The patient usually presents with sudden onset of abdominal pain , vomiting , absolute constipation and prominent distension . Erect abdominal x-ray shows a hugely distended bowel loop which is located diagonally across the abdomen from right to left . It is treated by untwisting of the volvulus by introduction of rectal flatus tube through flexible or rigid sigmoidoscopy if patient comes early and surgery during the same admission or surgical resection in late cases and with the presence of peritonitis .

Postoperative intestinal obstruction : The presence of obstruction should be considered if symptoms of intestinal obstruction occur after the initial return of bowel function or if bowel function fails to return within the expected 3 to 5 days after abdominal surgery.

Adynamic Intestinal obstruction (No mechanical obstruction ) : It includes :

Paralytic ileus: It is a state of atony of the intestine and characterized by abdominal distention , vomiting , absence of colicy pain and absolute constipation

Causes

  1. Postoperative
  2. Peritonitis
  3. Metabolic :Hypocalaemia , Diabetes and uraemia .
  4. Drug induced : Morphine , Anticholinergic
  5. Reflex :Spinal fracture , pelvic fracture ,ureteric colic , retroperitoneal haemorrhage etc.

Differentiation between ileus and mechanical obstruction

Ileus is usually painless , the abdomen is distended without marked tenderness .The bowel sounds are diminished or silent abdomen .Abdominal x-ray shows generalized gaseous distension of both small and large bowels .

Treatment of paralytic ileus

  1. Prevention and treatment of underlying causes
  2. Correction of fluids and electrolytes disturbances
  3. Nasogastric suction
  4. Stimulation of GIT motility by metoclopromide
  5. Pain and discomfort relief

Pseudo-obstruction : It is an obstruction, mainly the colon in the absence of a mechanical cause or acute intraabdominal disease. It is diagnosed by exclusion of a mechanical cause .

Mesenteric vascular occlusion : It is due to embolism , thrombosis or venous thrombosis . It is characterized by severe abdominal pain , shock and bloody diarrhea with predisposing factor such as cardiac disease .Mesenteric Doppler and angiography may be useful . It is treated by intestinal resection and initiation of anticoagulant therapy . Embolectom or vascular repair have very limited place .