Why This Station Is Tested
Nausea and vomiting are among the most common presenting complaints in both primary and secondary care. The OSCE tests your ability to generate a systematic, broad differential — from the benign (gastroenteritis, pregnancy) to the life-threatening (raised intracranial pressure, bowel obstruction, DKA) — and to elicit red flag features that demand urgent investigation.
Opening the Consultation
Introduce yourself, confirm patient identity, and establish rapport. A useful opening: "I understand you've been feeling sick and have been vomiting — can you tell me in your own words what's been happening?" Allow the patient to speak freely for 30–60 seconds before directing the history.
Systematic History Framework
Onset and Duration
Acute onset (hours): gastroenteritis, food poisoning, acute alcohol, medication side effect, MI, bowel obstruction, raised ICP. Chronic or recurrent (weeks–months): gastroparesis, pregnancy, metabolic (uraemia, hypercalcaemia, Addison's), psychological (functional dyspepsia, eating disorder), malignancy.
Character of the Vomit
| Vomit character | Differential |
|---|---|
| Undigested food | Oesophageal (achalasia, Zenker's) |
| Partially digested, sour | Gastric — gastritis, peptic ulcer |
| Bile-stained (green/yellow) | Post-pyloric obstruction or normal reflex |
| Faeculant (faecal smell) | Distal small bowel/large bowel obstruction |
| Blood (haematemesis) | Upper GI bleed — peptic ulcer, varices, Mallory-Weiss |
| Projectile, non-bile | Pyloric stenosis (infants) or raised ICP |
Associated Symptoms — Key Screen
- Abdominal pain: onset relative to vomiting (pain before = surgical; relief with vomiting = peptic ulcer)
- Headache + photophobia: meningitis, raised ICP, migraine
- Vertigo + tinnitus: vestibular causes (labyrinthitis, Ménière's, BPPV)
- Altered bowel habit + absolute constipation: bowel obstruction
- Polyuria/polydipsia + weight loss: DKA, hypercalcaemia
- Last menstrual period: always ask in women of reproductive age — hyperemesis gravidarum
- Fever: infection (gastroenteritis, cholecystitis, appendicitis, meningitis)
- Dysphagia + weight loss: oesophageal or gastric malignancy
Red Flags (Urgent)
⚠️ Red Flag
Red flags: projectile vomiting with severe headache (raised ICP — meningitis, subarachnoid haemorrhage, intracranial mass), haematemesis, absolute constipation + abdominal distension (obstruction), vomiting in a known diabetic (DKA), signs of dehydration/shock.
SOCRATES Applied to Vomiting
- Site — N/A (symptom, not pain), but where do they feel the nausea?
- Onset — sudden or gradual?
- Character — as above
- Radiation — N/A
- Association — as above
- Time course — continuous vs episodic; morning vs evening
- Exacerbating/relieving — does eating help or worsen? Position? Medications?
- Severity — how many times per day?
Medications
Metformin, opioids, NSAIDs, digoxin toxicity, chemotherapy, iron supplements, antibiotics (especially macrolides), and SSRIs are all common drug causes. Always ask about over-the-counter medications and supplements.
Social History
Alcohol excess, recent travel (food poisoning, tropical infections), contacts with similar symptoms (gastroenteritis cluster), stress and anxiety, dietary history.
Differential Diagnosis by System
| System | Differentials |
|---|---|
| GI | Gastroenteritis, peptic ulcer, GORD, bowel obstruction, appendicitis, cholecystitis, pancreatitis, gastroparesis, malignancy |
| Neurological | Raised ICP (tumour, bleed, meningitis), migraine, vestibular |
| Metabolic | DKA, hypercalcaemia, uraemia, Addison's, hyponatraemia |
| Endocrine | Pregnancy/hyperemesis gravidarum, hypothyroidism |
| Drugs/toxic | Medications, alcohol, food poisoning |
| Psychological | Functional, eating disorder, anxiety |
| Cardiac | Inferior MI (vagal), acute heart failure |
Completing the History
Past medical history (known GI disease, diabetes, renal failure, malignancy, previous surgery — adhesions), family history (coeliac, IBD, malignancy), drug allergies. Establish impact on daily life and ability to keep fluids down — dehydration risk assessment is a mark-scheme item.
💡 Tip
Always ask about the LMP in any woman of reproductive age — missing pregnancy as a cause of vomiting is a classic OSCE fail. In OSCEs, the pregnancy test result is often revealed when you ask this question.
Examiner Mark-Scheme Checklist
- ✓Explores onset, duration, and frequency
- ✓Asks about vomit character (blood, bile, faeculant)
- ✓Enquires about associated abdominal pain
- ✓Asks about red flag headache/neurological symptoms
- ✓Asks about LMP (women of reproductive age)
- ✓Explores medications
- ✓Asks about contacts and travel
- ✓Explores dehydration symptoms (thirst, dark urine, dizziness)
- ✓Summarises and offers a sensible differential
- ✓Proposes initial investigations (bloods, pregnancy test, imaging if indicated)
Frequently Asked Questions
"How do I differentiate between vomiting from raised ICP and vomiting from a GI cause in the OSCE?"
Raised ICP vomiting classically occurs without preceding nausea, is often projectile, and is accompanied by headache (worse on waking, coughing, or straining — features of raised ICP), visual disturbance, papilloedema, or altered consciousness. It may be worse in the morning when recumbent ICP is highest. GI causes typically produce nausea before vomiting, are often relieved by vomiting, and are associated with GI symptoms (pain, altered bowel habit, bloating). In the OSCE, the key questions to distinguish these are: "Did the vomiting come on suddenly without warning?" and "Do you have a headache — can you describe it?" Any patient with vomiting and a new, severe headache requires urgent neurological assessment. Always ask about neck stiffness and photophobia to screen for meningitis.
"What investigations would you request first for a patient presenting with acute nausea and vomiting?"
First-line investigations depend on your clinical suspicion after history and examination. For most acute presentations: urine dipstick and pregnancy test (beta-hCG) in women of reproductive age, blood glucose (DKA), full blood count (infection, anaemia), CRP and white cell count, U&E (dehydration, uraemia, hyponatraemia), LFTs (hepatitis, cholecystitis), amylase (pancreatitis), and calcium (hypercalcaemia). If bowel obstruction is suspected: erect chest X-ray (free air under diaphragm) and supine abdominal X-ray (dilated loops, air-fluid levels). If raised ICP is suspected, do NOT perform lumbar puncture before CT head. Venous blood gas rapidly identifies metabolic acidosis (DKA, sepsis) or alkalosis (persistent vomiting). In the OSCE, presenting a logical, staged investigation plan scores highly.
"What are the causes of vomiting without nausea and why is this clinically important?"
Vomiting without preceding nausea — so-called projectile vomiting — is a red flag symptom that points to conditions bypassing the normal chemoreceptor trigger zone pathway. In adults, the key concern is raised intracranial pressure: brain tumour, intracranial haemorrhage (especially subarachnoid — "thunderclap" headache), encephalitis, or meningitis. Posterior fossa lesions (cerebellum, brainstem) are particularly associated with sudden vomiting without nausea. In infants aged 2–6 weeks, projectile non-bilious vomiting after feeding is the classic presentation of pyloric stenosis — the pyloric mass may be palpable as an "olive" in the right upper quadrant. In the OSCE, if a patient describes vomiting suddenly without feeling sick first, ask immediately about headache, visual changes, and consciousness level, and raise the possibility of a neurological emergency in your differential.
"How do I take a medication history relevant to nausea and vomiting?"
Ask about all prescribed medications, noting dose and when started — nausea is often a new drug side effect. Key offenders include: opioids (direct chemoreceptor trigger zone stimulation — dose-related), metformin (GI irritation — should be taken with food), NSAIDs and aspirin (gastric mucosal irritation — peptic ulceration), digoxin (toxicity presents with nausea, vomiting, and yellow-green visual halos), chemotherapy agents (especially cisplatin — highly emetogenic), macrolide antibiotics (erythromycin is a motilin agonist causing nausea), iron supplements, SSRIs and SNRIs (especially on initiation), and antiretrovirals. Also ask about over-the-counter medications, herbal remedies, and alcohol. In the OSCE, proposing an antiemetic (e.g., ondansetron, metoclopramide, cyclizine) appropriate to the suspected cause demonstrates good management knowledge.
"What is gastroparesis and how would a patient with it present in a history OSCE?"
Gastroparesis is delayed gastric emptying without mechanical obstruction, caused by autonomic neuropathy affecting the vagus nerve. The most common cause is long-standing type 1 or type 2 diabetes mellitus (diabetic gastroparesis); other causes include post-surgical vagotomy, Parkinson's disease, systemic sclerosis, and hypothyroidism. The classic history is a patient with poorly controlled diabetes who reports nausea, vomiting of undigested food (sometimes many hours after eating), early satiety, abdominal bloating, and significant weight loss. Vomiting typically worsens after meals and the patient may notice fluctuating blood glucose control. The OSCE history should specifically explore: duration, relationship to meals, food content of vomit, diabetes history and duration, HbA1c control, and symptoms of other diabetic complications. Diagnosis is confirmed with a gastric emptying scintigraphy study.
"What are the key safety-netting points to cover at the end of a nausea and vomiting history?"
Safety-netting is a mark-scheme item that demonstrates clinical responsibility. Cover: instructions to seek immediate help if vomiting blood or passing black tarry stools (haematemesis/melaena — upper GI bleed), if unable to keep any fluids down for more than 24 hours (dehydration risk), if developing severe worsening headache or neck stiffness (raised ICP/meningitis), if abdominal pain becomes severe and constant, or if developing fever above 38°C with rigors. In a pregnant patient, advise to return if symptoms of dehydration develop (unable to keep fluids down — risk of hyperemesis gravidarum requiring IV fluids and antiemetics). Provide written information where possible. In the OSCE, conclude by stating: "I would give the patient clear advice on when to seek urgent medical attention" — this demonstrates you are a safe practitioner.
Related guides: Abdominal History OSCE · Abdominal Examination OSCE · Upper GI Bleeding OSCE · DKA Management OSCE · Headache History OSCE