Initial Screening Approach for Nausea and Vomiting in a 25-Year-Old Active Duty Male
Obtain complete blood count, serum electrolytes, glucose, liver function tests, lipase, urinalysis, and urine drug screen as your initial laboratory panel to exclude metabolic causes, assess for dehydration, and screen for cannabis use in this age group. 1
Critical History Elements to Obtain
- Cannabis use history is essential in this demographic, as Cannabis Hyperemesis Syndrome (CHS) should be suspected if heavy cannabis use preceded symptom onset 1
- Duration and frequency of symptoms to distinguish acute (≤7 days) versus chronic (≥4 weeks) presentation 2, 3
- Timing relative to meals, as postprandial symptoms suggest gastroparesis or gastric outlet obstruction 4
- Medication and supplement use, particularly recent initiations that commonly cause nausea 2, 5
- Associated symptoms including abdominal pain, headache, diarrhea, or neurologic changes 5
- Vomiting characteristics: differentiate true vomiting from regurgitation or rumination 4
Physical Examination Focus
- Assess for dehydration by checking mucous membranes, skin turgor, orthostatic vital signs, and mental status 5
- Abdominal examination to exclude acute surgical abdomen, organomegaly, or masses 5
- Neurologic examination if headache or altered mental status present 5
Initial Laboratory Screening Panel
The following tests should be ordered simultaneously 1:
- Complete blood count to assess for infection or anemia
- Serum electrolytes to detect hypokalemia, hypochloremia, and metabolic alkalosis from prolonged vomiting 1
- Glucose to exclude hyperglycemia or hypoglycemia
- Liver function tests to screen for hepatobiliary disease
- Lipase to exclude pancreatitis
- Urinalysis to assess for urinary tract infection or ketones
- Urine drug screen to identify cannabis use or other substances 1
Additional Testing Based on Clinical Context
- Urine pregnancy test if applicable (though less relevant for male patient) 5
- Thyroid-stimulating hormone if signs of thyroid dysfunction present 1, 5
- Calcium level to exclude hypercalcemia 1
- Morning cortisol if Addison's disease suspected based on hypotension, hyperpigmentation, or hyponatremia 1
Imaging Considerations
- One-time esophagogastroduodenoscopy (EGD) or upper GI imaging is recommended to exclude obstructive lesions, but avoid repeated endoscopy unless new symptoms develop 1
- Abdominal imaging (ultrasound, CT, or plain radiography) only if alarm features present such as severe abdominal pain, distension, or concern for obstruction 5
- Head CT only if acute intracranial process suspected based on severe headache, altered mental status, or focal neurologic deficits 5
Red Flags Requiring Urgent Evaluation
Watch for these alarm features that warrant immediate escalation 5:
- Signs of dehydration or metabolic acidosis
- Acute abdomen findings suggesting perforation or obstruction
- Severe headache with neurologic changes
- Hematemesis or melena
- Unintentional weight loss
Common Pitfalls to Avoid
- Never dismiss cannabis use history in young adults, as CHS is increasingly common and requires specific management 1
- Do not use antiemetics if mechanical bowel obstruction suspected, as this masks progressive ileus and gastric distension 1
- Avoid repeated imaging or endoscopy without new clinical developments 1
- Do not overlook medication adverse effects, particularly if any new medications started within the past month 2, 5
When Acute Gastroenteritis is Suspected
If history and examination suggest viral gastroenteritis or foodborne illness without alarm features 2, 6:
- Laboratory testing may be deferred if symptoms are mild and patient can maintain hydration
- Supportive care with oral rehydration is appropriate
- Antiemetic therapy can be initiated empirically
- Reassess if symptoms persist beyond 7 days or worsen