🩺 Nausea and Vomiting

Nausea and vomiting are non-specific symptoms arising from the stimulation of the vomiting centre in the medulla, either via the chemoreceptor trigger zone (CTZ), the vestibular system, or visceral afferents from the GI tract. While often benign and self-limiting (e.g., viral gastroenteritis), they can be the presenting features of life-threatening emergencies such as bowel obstruction, intracranial hypertension, or metabolic crises. Management focuses on rehydration, electrolyte correction, and targeting the specific pathway with appropriate anti-emetic therapy.

Distinguish between nausea (the urge) and vomiting (the act). Ask about timing: early morning (raised ICP, pregnancy, uraemia), or shortly after eating (gastric outlet obstruction, bulimia). Note the content: bile-stained (post-pulpyloric obstruction), blood-stained (Mallory-Weiss tear or ulcer), or undigested food (achalasia/diverticula). Associated symptoms are crucial: abdominal pain, fever (infection), headache/photophobia (meningitis), or vertigo (vestibular). Medication history should include opioids, digoxin, and recent chemotherapy.

Begin with an assessment of hydration status (mucous membranes, skin turgor, heart rate, blood pressure). The abdominal exam is vital: look for distension, scars (previous surgery/adhesions), herniae (an incarcerated hernia can cause obstruction), and bowel sounds (high-pitched/tinkling in obstruction vs absent in ileus). Focus on signs of peritonism (guarding/rebound). A neurological exam (fundoscopy for papilloedema, cranial nerves) should be performed if a central cause or raised ICP is suspected. Pregnancy testing (hCG) is mandatory in all females of childbearing age.

Gastroenteritis, Bowel Obstruction, Peptic Ulcer Disease, Cholecystitis/Biliary colic, Appendicitis, Diabetic Ketoacidosis (DKA), Raised Intracranial Pressure (ICP), Migraine, Labyrinthitis, Drugs (opioids/chemo).

Haematemesis, faeculent vomiting, focal neurological deficits, papilloedema, severe 'boards-like' abdominal pain, weight loss, or persistent symptoms in those >55 (cancer risk).

First-line bloods include FBC (infection), U&Es (evidence of dehydration or electrolyte derangement like hypokalaemia), CRP, LFTs, and Amylase (to exclude pancreatitis). Capillary blood glucose and ketones are essential if DKA is a possibility. Urinalysis and hCG are standard. Imaging depends on suspicion: Erect CXR (if perforation suspected), Abdominal X-ray (if obstruction suspected), or CT Abdomen if there are signs of an acute abdomen. If a central cause is suspected, a CT Head is required. Gastroscopy (OGD) is the primary investigation for recurrent GI-related vomiting.

Vomiting of 'coffee-ground' material indicates upper GI bleeding where blood has been altered by gastric acid. Faeculent vomiting is a late and specific sign of distal small bowel or colonic obstruction. In patients with sudden onset nausea and 'the worst headache of their life', think of subarachnoid haemorrhage, not GI disease. Diabetic ketoacidosis (DKA) frequently presents with severe vomiting and abdominal pain—always check capillary blood glucose in these patients. Morning sickness (hyperemesis) is common in pregnancy, but persistent vomiting requires ruling out molar pregnancy or UTIs.

Aligned with the MLA content map 'Nausea and Vomiting'. Focus on the 'surgical' causes of vomiting (obstruction/perforation) versus 'medical' (DKA/Addison's) and 'neurological' (meningitis/ICP). Be aware of the metabolic consequence of persistent vomiting: hypochloraemic, hypokalaemic metabolic alkalosis. Practice the NICE pathways for dyspepsia and suspected GI cancer.