Vomiting
Differential Diagnosis
Common Diagnoses
- Gastroenteritis
- Acute Vestibular Neuronitis (and Some Other Causes of Acute Vertigo) 480
- Upper Respiratory Tract Infection (URTI) (in Children, Especially with Marked Coughing)
- Pregnancy
- Appendicitis and Other Causes of the Acute Abdomen
Occasional Diagnoses
- Hyper- and Hypoglycaemia
- Intestinal Obstruction
- Pyelonephritis
- Ureteric Calculus
- Migraine
- Medication (e.g. Antibiotics and Cytotoxics)
Rare Diagnoses
- Gastroduodenal Disease (e.g. Pyloric Stricture or Stenosis, Du, Carcinoma)
- Meningitis
- Cerebral Haemorrhage
- Bulimia Nervosa
- Severe Constipation
- Raised Intracranial Pressure (e.g. Tumour)
- Renal Failure
- Acute Glaucoma
Ready Reckoner
Key distinguishing features of the most common diagnoses
| Gastroenteritis | Vestibular Neuronitis | URTI (Child) | Pregnancy | Acute Abdomen | |
|---|---|---|---|---|---|
| Mainly Mornings | No | No | No | Yes | No |
| With Diarrhoea | Yes | No | Possible | No | Possible |
| Nystagmus | No | Yes | No | No | No |
| Bowel Sounds Increased? | Yes | No | No | No | Possible |
| Tender Abdomen? | Possible | No | Possible | No | Yes |
Possible Investigations
Likely:None.
Possible:Urinalysis, MSU, pregnancy test, blood glucose, FBC, U&E.
Small Print:Lumbar puncture, abdominal X-rays, renal imaging, OGD, CT scan.
- Urinalysis: High specific gravity suggests dehydration; glucose and ketones indicate hyperglycaemia; blood, pus cells and nitrites suggest UTI (confirm with MSU); blood alone might indicate a renal stone.
- Pregnancy test: To confirm or reveal pregnancy.
- Blood glucose: Will confirm hypo- or hyperglycaemia.
- U&E: May be deranged by vomiting; may also reveal underlying renal failure.
- FBC: Raised WCC suggests underlying infection or inflammation. Haemoglobin (Hb) may be reduced in malignancy. Raised platelets associated with oesophageal or stomach cancer.
- Lumbar puncture, renal imaging, abdominal X-rays, OGD and CT scans: Required in a few cases depending on the clinical picture and invariably arranged by the relevant specialist.
Top Tips
- Vomiting in children tends to be presented early, when it may be difficult to give a definite diagnosis. Be honest about this and make sure that parents know to call you again if the symptom doesn’t settle or other ‘alarm’ symptoms develop – or arrange a definite time for follow-up.
- Remember to look for both the cause (i.e. the aetiology) and the effect (i.e. possible dehydration) – especially in the very young and the very old, when the history may be difficult to obtain and the effects of fluid loss more marked.
- Check to see if the patient is on any medication. This may be causing the vomiting, or it may have serious implications for management (e.g. steroids).
- Don’t forget pregnancy as a cause – the patient may be ‘ignoring’ the possibility.
Red Flags
- Unless the diagnosis is obviously migraine, beware the patient with vomiting and a headache – think of meningitis, subarachnoid haemorrhage or raised intracranial pressure.
- Do not treat empirically with anti-emetics – these may mask the true diagnosis or cause diagnostic confusion via side effects.
- Have a low threshold for admitting diabetics. Whatever the cause of the vomiting, their diabetes is liable to become uncontrolled.
- Look for acid dental erosion as a clue to bulimia in recurrent vomiting.
- Gastroenteritis should cause increased bowel sounds. In the patient with abdominal pain and vomiting, if bowel sounds are absent or scanty, the diagnosis is likely to be an acute abdomen.