Synopsis
Assess vomiting by physiology and timing, correct dehydration and electrolyte danger, recognise obstruction and extra-abdominal emergencies, and investigate persistent gastric retention without premature prokinetic treatment.
- Clarify whether material is gastric, bilious, bloody, coffee-ground or faeculent and whether nausea precedes it; effortless regurgitation and rumination have different mechanisms from forceful vomiting.
- Early morning headache or neurological change, chest pain, pregnancy, drugs, cannabis, alcohol withdrawal, sepsis and metabolic disease must remain in the differential even when abdominal symptoms dominate.
- Postprandial fullness, early satiation and late vomiting of recognisable food suggest impaired gastric emptying or outlet obstruction, but structural narrowing must be excluded before diagnosing gastroparesis.
- Repeated vomiting commonly causes volume depletion, hypochloraemic metabolic alkalosis, hypokalaemia and kidney injury; diarrhoea or ketoacidosis may alter the acid-base pattern.
- Check capillary glucose, ketones, renal function, electrolytes, magnesium and an ECG when illness is severe or QT-prolonging antiemetics are being considered.
- Pregnancy testing belongs early in any relevant presentation. Hyperemesis is a diagnosis after assessing severity and excluding other obstetric, medical and surgical causes.
- Nasogastric decompression can reduce vomiting and aspiration in significant obstruction, but insertion requires an indication, safe position confirmation and ongoing loss replacement.
- Give thiamine before carbohydrate loading to a severely malnourished or prolonged-vomiting patient at risk of deficiency, using the local refeeding protocol.
- Antiemetics should be selected by likely mechanism, comorbidity, interactions, pregnancy and QT or extrapyramidal risk, then reviewed for response rather than stacked automatically.
Key red flags
Progressive early satiation, epigastric fullness, weight loss, dehydration and large-volume late postprandial vomiting suggest retention proximal to the pylorus or duodenum. Malignancy must be excluded promptly, particularly with short progressive history.
Colicky abdominal pain, distension, vomiting and reduced stool or flatus, especially after surgery or with a hernia, support mechanical obstruction. Constant pain, guarding, fever or acidosis raises strangulation.
Vomiting with thirst, polyuria, dehydration, deep breathing, abdominal pain, hyperglycaemia and ketonaemia indicates a metabolic emergency. Abdominal tenderness can improve with correction and should not conceal coexisting surgical disease.
Investigation priorities
Identify diabetic ketoacidosis, starvation ketosis, hypoglycaemia and acid-base consequences of vomiting.
Management branches
Vomiting is persistent, severe or associated with physiological abnormality.
- Assess airway and aspiration risk, breathing, circulation, mental state and abdominal signs; obtain venous access, bedside glucose and ketones and relevant bloods.
- Provide monitored crystalloid and electrolyte replacement based on losses and comorbidity, keep nil by mouth when obstruction or procedure is plausible, and measure urine output.
- Select one mechanism-appropriate antiemetic after ECG and interaction review where indicated, rather than giving several QT-prolonging agents simultaneously.
- Escalate haematemesis, peritonism, DKA, neurological signs, pregnancy instability or obstruction to the relevant acute specialty while resuscitation continues.