Synopsis
Recognise mechanical obstruction of the distal stomach or proximal duodenum, correct aspiration, volume and electrolyte threats, distinguish benign scarring from malignancy through imaging and biopsy, and select endoscopic or surgical relief with nutritional planning.
- Gastric outlet obstruction is a mechanical block at the antrum, pylorus or proximal duodenum; retained food and delayed emptying alone do not define its cause.
- Gastric, duodenal and pancreatic malignancy must be considered in an adult with new obstruction, especially with weight loss, anaemia, jaundice, a mass or progressive course.
- Benign causes include peptic-ulcer scarring, inflammatory oedema, Crohn's disease, pancreatitis or pseudocyst, bezoar and postoperative or anastomotic stenosis.
- Repeated vomiting depletes hydrochloric acid and volume, producing hypochloraemic, hypokalaemic metabolic alkalosis with paradoxical aciduria when depletion becomes severe.
- Contrast CT defines level, mural disease, extrinsic compression and metastases; upper-GI endoscopy after initial decompression directly inspects and biopsies the narrowing.
- A nasogastric tube can relieve distension and reduce aspiration risk but does not diagnose or definitively treat a tumour or fibrotic stricture.
- Benign peptic narrowing may improve as oedema settles with PPI and H. pylori treatment, while fixed stenosis can require graded balloon dilatation or surgery.
- Malignant obstruction is managed through an MDT using systemic or oncological treatment, duodenal stenting, surgical bypass or other expert techniques according to prognosis and goals.
Key red flags
Coughing, hypoxaemia, altered consciousness or copious supine vomiting signals airway danger. Sit upright, use suction and seek anaesthetic support before sedation or transfer.
Weakness, cramps, arrhythmia and reduced consciousness can accompany severe chloride, potassium and volume depletion. An apparently high bicarbonate should prompt urgent correction and ECG review.
Sudden severe pain, guarding, fever, lactate rise or free air suggests a complication beyond simple retention and needs emergency surgical management.
Investigation priorities
Quantify vomiting-related depletion and guide safe fluid replacement.
Management branches
Persistent vomiting, distension or imaging confirms a functionally important gastric outlet blockage.
- Keep nil by mouth, elevate the head, assess aspiration and insert venous access; use nasogastric decompression when indicated with position and output documented.
- Replace isotonic fluid, chloride, potassium and magnesium according to serial laboratory, ECG, urine output and renal findings rather than a fixed generic bag sequence.
- Give thiamine and plan controlled nutrition in major depletion, while arranging CT and an endoscopy strategy that accounts for the food-filled stomach and sedation risk.