Features

1. Pain: colicky
   • Epigastrium / umbilical = small bowel
   • Suprapubic = large bowel
2. Vomiting
   • Consequences: dehydration, metabolic alkalosis/respiratory acidosis - hypoxia
   • More distal lesions, later the vomiting
   • Contents: pyloric = watery; high = bilious; low = faeculent
3. Distension
   • Depends on level of obstruction
4. Constipation
5. Pyrexia, septicaemia

Causes

1. Luminal
   • Intussuception
2. Mural
   • Malignancy
   • Inflammatory bowel disease
3. Extra-mural
   • Hernia
   • Adhesions

Frequency of causes

1. Adhesions - 60%
2. Herniae - 15%
3. Malignancy - 6%
4. IBD
5. Ischaemic bowel

Pathophysiology

1. Bowel dilatation proximal to obstruction
   • Results in gas / fluid accumulation with bowel wall and lumen (proximally)
   • Impairs resorption
2. Mucosal oedema impairs venous / arterial flow
   • Bowel becomes strangulated
3. Ischaemia leads to haemorrhagic infarction
   • Further dilation leads to bowel perforation
4. Bacterial translocation leads to sepsis

Principles of Management

1. History
   • Previous operations
   • Abdominal diseases
   • Previous obstruction
2. Examination
   • Previous scars
   • Presence of hernia
   • Bowel sounds: tinkling / hyperactive
3. Investigations
   • Plain AXR - distended bowel loops (and level of obstruction) - small plicae circulares; large haustrae
   • Plain CXR - exclude free air
   • FBC: WCC, anaemia
   • Electrolytes
   • ABG: Lactate / acidosis
4. Resuscitation
   • IV crystalloid
   • Correct acid-base
   • NGT
   • Catherise
   • Analgesia

Indications for surgery

1. Absolute
   • Peritonitis
   • Perforation
   • Incarcerated hernia
2. Relative
   • Palpable mass
   • Virgin abdomen
   • Failure of conservative treatment

Surgical options in Large bowel disease

1. One stage (medially optimised patient)
   • resection of tumour/lesion, decompression of bowe, lavage with primary anastamosis
2. Two stage (unwell patients who may be optimised)
   
   • Hartmann's procedure with resection of tumour
   • Later reversal of colostomy
3. Three stage (sick patients/moribund/advanced disease)
   
   • Emergency defunctioning colostomy (until patient fit for further operation)
   • resection of tumour and anastamosis in 2nd operation
   • Final closure