Workup for a Single Episode of Nausea
For a single, isolated episode of nausea without alarm features, minimal or no workup is needed—focus on supportive care and empiric antiemetic therapy if symptoms persist. 1, 2
Initial Assessment
Determine if this is truly acute, isolated nausea or part of a pattern:
- Acute nausea lasting less than 48 hours typically has an evident trigger (viral illness, food poisoning, medication) and requires only supportive management without extensive testing 3, 4
- A single episode lasting less than 7 days is considered acute and generally does not warrant investigation unless alarm features are present 2
Red Flags Requiring Immediate Workup
Proceed with diagnostic testing only if any of these alarm features are present:
- Severe, persistent vomiting with inability to tolerate oral intake 1
- Signs of dehydration or severe metabolic abnormalities 4
- Acute abdominal pain suggesting surgical pathology 1
- Neurologic symptoms (headache, focal deficits, altered mental status) 5
- Hematemesis or signs of gastrointestinal bleeding 1
Basic Laboratory Evaluation (Only if Indicated)
If alarm features exist or symptoms persist beyond 48 hours, obtain:
- Complete blood count, serum electrolytes, glucose, liver function tests, and lipase 5
- Urinalysis to exclude urinary tract infection or pregnancy 5
- Check blood levels of potentially causative medications: digoxin, phenytoin, carbamazepine, tricyclic antidepressants 5, 6
Medication Review
Always review current medications as a primary cause:
- Common culprits include opioids, antibiotics, NSAIDs, chemotherapy agents, and antidepressants 1, 2
- Consider recent medication changes or dose adjustments 6
- Cannabis use patterns should be assessed, particularly if episodes are recurrent 5
Empiric Treatment Approach
For a single episode without alarm features, treat symptomatically:
- First-line antiemetic: Ondansetron 8 mg sublingual or oral every 4-6 hours 5, 6, 7
- Alternative dopamine antagonists: Prochlorperazine 5-10 mg every 6-8 hours or promethazine 12.5-25 mg every 4-6 hours 5, 6
- Ensure adequate hydration with electrolyte-rich fluids 6
- Small, frequent meals at room temperature rather than large, hot meals 6
When to Avoid Extensive Testing
Do not pursue imaging or endoscopy for:
- Single, self-limited episodes without recurrence 5
- Absence of alarm symptoms or physical examination abnormalities 1, 2
- Symptoms that resolve within 24-48 hours with supportive care 3, 4
Important Caveats
- Gastric emptying studies should not be ordered for acute, isolated nausea 5
- Repeated upper endoscopy or imaging is not indicated for single episodes 5
- Most acute episodes are self-limited and resolve without identifying a specific cause 3, 4
- If symptoms become recurrent (≥4 episodes per year), consider cyclic vomiting syndrome and pursue prophylactic therapy 5