Single Episode of Vomiting with Acid Reflux, Headache, and Fatigue
This presentation most likely represents a self-limited viral gastroenteritis or migraine-associated gastroesophageal reflux, and requires only symptomatic management with oral rehydration and observation unless warning signs develop.
Initial Assessment and Red Flags
Immediately evaluate for warning signs that would indicate urgent pathology requiring further investigation 1, 2:
- Bilious vomiting (suggests malrotation/volvulus—surgical emergency) 2
- Severe abdominal pain or tenderness (suggests acute abdomen) 1, 2
- Hematemesis or blood in stool 1
- Fever, lethargy, or altered mental status 1
- Severe headache with visual changes or neurologic signs (suggests increased intracranial pressure) 2
- Signs of severe dehydration 2
If any warning signs are present, proceed immediately to diagnostic imaging or specialist consultation 1, 2.
Most Likely Diagnosis
In the absence of warning signs, a single bout of vomiting followed by reflux symptoms, headache, and fatigue most commonly represents 3, 4, 5:
- Viral gastroenteritis (most common cause of acute vomiting lasting <7 days) 6, 4, 5
- Migraine-associated gastroesophageal reflux (20-30% of patients with cyclic vomiting have migraine history; single episodes can occur) 7, 8
- Food-borne illness 4
- Medication adverse effect 4
The combination of headache and fatigue following vomiting suggests either a viral prodrome or post-vomiting dehydration and electrolyte shifts 4.
Immediate Management
Symptomatic Treatment
Oral rehydration is the cornerstone of management 6, 9:
- Small, frequent sips of electrolyte-rich fluids (sports drinks) 7, 4
- Avoid solid foods initially; advance diet as tolerated 4
- Rest in a quiet, dark environment if headache persists 7
Antiemetic Consideration
For a single episode that has already resolved, antiemetics are typically not necessary 6, 4. However, if nausea persists:
- Ondansetron 8 mg sublingual can be considered if vomiting recurs 7, 9
- Dimenhydrinate 50 mg may be used for nausea 10
Acid Reflux Management
For transient reflux symptoms following vomiting 11, 3:
- Calcium carbonate (antacid) for immediate symptom relief 11
- Avoid lying flat for 2-3 hours after the episode 1
- Small, frequent meals if appetite returns 4
When to Seek Further Evaluation
Return immediately or seek emergency care if 1, 2, 4:
- Vomiting recurs and becomes persistent (>24 hours) 2
- Unable to tolerate oral fluids 6, 4
- Signs of dehydration develop (decreased urination, dizziness, dry mucous membranes) 6, 4
- Severe or worsening headache with neurologic symptoms 2
- Abdominal pain becomes severe or localized 1, 2
- Fever develops 1
Consider outpatient follow-up if 2, 7, 8:
- Episodes become recurrent (≥3 episodes in a year with stereotypical pattern suggests cyclic vomiting syndrome) 7, 8
- Reflux symptoms persist beyond 7 days (requires upper endoscopy to exclude peptic ulcer disease or malignancy) 2
- Headaches become frequent or severe (evaluate for migraine disorder) 7
Important Clinical Caveats
Do not routinely order diagnostic testing for a single, self-limited episode 1, 6, 4. The history and physical examination in the absence of warning signs are sufficient 1.
Gastroesophageal reflux commonly occurs with vomiting due to transient lower esophageal sphincter relaxation and is not pathologic in this context 1, 3.
Headache and fatigue are expected sequelae of vomiting due to fluid loss, electrolyte shifts, and the physical stress of emesis 4.
If cannabis use is present (≥4 times weekly for >1 year), consider cannabinoid hyperemesis syndrome if episodes recur, though a single episode does not establish this diagnosis 7, 8.