Acute Intestinal Obstruction

Causes

Peritoneal adhesions

Bands of fibrous tissue developed after inflammation and fibrin exudation

Hernias

A protrusion of a loop of bowel through a weak point in the wall of the abdominal cavity

Intussuception

Occurs in children, usually at the junction between large and small intestine. A segment of small bowel is dragged by peristaltic contraction into the large bowel. A telescoping.

Volvulus

A twist

Paralytic ileus

Damage to nerve cells in the wall of the intestine by handling or infection caused by drugs or post operatively

Thrombosis

Involving the mesenteric artery

Neoplasm

Faecal impaction

Stenosis

Uraemia

SCI

Hypokalaemia

Classification of cause may be;

Extramural, Mural Intraluminal

(from outside) (wall) (within)

Pathophysiology

Normal peristaltic waves above obstruction become more vigorous

Build up of pressure - build up of gas and fluid

Distal bowel will be empty

Veins in the wall of the intestine are closed

No blood can leave effected area of bowel

Area becomes oedematous and congested with blood

Increased intravascular resistance stops the arterial perfusion after an hour or so

Cells in the intestinal wall die, necrosis develops

Bacteria from the bowel escape through the dead wall causing peritonitis

Peritonitis may lead to overwhelming systemic infection and death

Small intestine effected more commonly than the large

Effected bowel is distended with digestive juices leading to possible systemic hypovolaemia, (8 -10 litres of juices are secreted into the digestive tract per day, all except 100 mls are reabsorbed).

Electrolyte imbalance

Haemorrhage into bowel

Absorption of toxins from strangulated segments - toxaemia, (endotoxic shock may be a principle cause of death, In chronic cases there may be hypertrophy)

Clinical features

Acute intermittent colicky pain, (small bowel 2-20 minutes, large bowel every 30 minutes)

Absolute constipation, (early in large bowel, later in small bowel obstruction)

Vomiting, (quality depends on level of obstruction, a late feature in large bowel obstruction)

Abdominal distension, (the lower the site of obstruction the more bowel there is to distend)

Increased bowel sounds

Shock

Collapse

Hypovolaemia

Oliguria

Absent flatus

Investigations

Physical examination Plain XR

Serum electrolytes Blood count

Treatment

Patient stabilisation

Decompression

Remove cause

Surgical relief of the obstruction

Application of warm towels to effected bowel to see if circulation can be restored

If not resection and anastamosis

Treatment in paralytic ileus is usually medical

Drip and suck

Prevent aspiration FBC

Nursing assessment

TPR BP Pain

Character of vomit and stools Any respiratory restriction due to distension

Nursing goals

Passes flatus normally

Normal bowel movements

Normal urinary output

Improved breathing ability

Takes diet and fluids normally

No vomiting or diarrhoea

No pain

Appears relaxed and claims to feel better

Chronic Intestinal Obstruction

Usually in the large bowel

Usually caused by tumour

A partial obstruction occurs

Alternating constipation and diarrhoea

Upstream bowel distension with hard faecal material, megacolon may occur

Megacolon also occurs in Hirschsprung`s disease, occurring in infants and young children due to a congenital absence of nerves in the rectum

Typical features include obstruction, persistent vomiting, dehydration and hypokalaemia.