What is the recommended evaluation and management for a 14‑week pregnant woman with new‑onset headache, recent oseltamivir (Tamiflu) treatment for influenza A two weeks ago, and hyperemesis gravidarum?

Approach to New-Onset Headache at 14 Weeks Gestation with Recent Influenza A and Hyperemesis Gravidarum

This patient requires urgent evaluation to exclude preeclampsia, as any new headache with hypertension in pregnancy should be considered preeclampsia until proven otherwise, even at 14 weeks gestation. 1, 2

Immediate Assessment Priorities

Critical Red Flags to Evaluate Immediately

• Check blood pressure immediately – new-onset headache with hypertension is preeclampsia until proven otherwise, regardless of gestational age 1, 2
• Assess for focal neurological deficits, visual changes, altered consciousness, or seizures – any of these require urgent neuroimaging 1
• Evaluate for signs of severe dehydration from hyperemesis gravidarum: orthostatic hypotension, decreased skin turgor, dry mucous membranes 3
• Check for signs of malnutrition including weight loss >5% of prepregnancy weight and muscle wasting 3

Essential Laboratory Evaluation

• Comprehensive metabolic panel to assess electrolyte imbalances and renal function related to hyperemesis gravidarum 3
• Liver function tests – elevated in 40-50% of severe hyperemesis gravidarum cases 3
• Complete blood count to evaluate for anemia or infection 3
• Urinalysis with protein quantification if hypertension is present to evaluate for preeclampsia 1
• Thyroid function tests – hyperthyroid disorders are associated with hyperemesis gravidarum 3

Differential Diagnosis Framework

Primary Considerations at 14 Weeks

Hyperemesis gravidarum-related headache is likely given the recent diagnosis, as symptoms typically peak at 8-12 weeks and can persist beyond 14 weeks in some patients 3. However, this is a diagnosis of exclusion after ruling out dangerous causes.

Preeclampsia must be excluded first despite the early gestational age – check blood pressure and urinalysis immediately 1, 2

Post-viral headache from recent influenza A is possible, though oseltamivir treatment was completed 2 weeks ago 3, 4

Migraine – pregnancy can trigger new-onset migraines or change existing migraine patterns 2

Life-Threatening Causes to Exclude

• Cerebral venous thrombosis – pregnancy is a hypercoagulable state; requires neuroimaging if focal deficits, seizures, or non-positional severe headache 1
• Intracranial hemorrhage – requires urgent neuroimaging if sudden onset, "thunderclap" quality, or neurological changes 1
• Meningitis/encephalitis – check for fever, neck stiffness, photophobia 3

Management Algorithm

If Blood Pressure is Elevated (≥140/90 mmHg)

1. Treat as preeclampsia until proven otherwise – this requires antihypertensive management and magnesium sulfate, not simple analgesics 1
2. Obtain urgent obstetric consultation 1
3. Do not discharge with simple analgesics without excluding preeclampsia 1

If Blood Pressure is Normal and No Red Flags Present

Acute Headache Treatment (Pregnancy-Safe)

• First-line: Acetaminophen 1000 mg every 4-6 hours (maximum 4 g/day) – safest option throughout pregnancy 1, 2, 5
• Second-line: Ibuprofen 400-800 mg every 6 hours – ONLY during second trimester (safe at 14 weeks, but avoid in third trimester) 1, 2
• For migraine-associated nausea: Metoclopramide 10 mg orally or IV – excellent safety profile throughout pregnancy with no significant increase in congenital defects 2, 5

Critical Medications to AVOID

• Never use opioids (meperidine, butorphanol) – risk of dependency, medication-overuse headache, and eventual loss of efficacy 1, 2
• Never use butalbital-containing medications – habit-forming with rebound headache risk 2
• Avoid ergotamine derivatives and dihydroergotamine – contraindicated throughout pregnancy due to oxytocic properties 2
• Avoid NSAIDs in third trimester – but acceptable at 14 weeks 2

Ongoing Hyperemesis Gravidarum Management

Since symptoms can persist beyond 14 weeks in 10% of patients 3:

Antiemetic Therapy

• First-line: Doxylamine-pyridoxine 10 mg/10 mg combination – FDA-approved for nausea/vomiting in pregnancy 3, 5
• Alternative: Vitamin B6 (pyridoxine) 10-25 mg every 8 hours if not already on combination therapy 3, 5
• Second-line: Metoclopramide 5-10 mg every 6-8 hours – safe throughout pregnancy and treats both nausea and headache 5
• H1-receptor antagonists (promethazine, dimenhydrinate) are safe first-line options 3

Hydration and Nutritional Support

• IV fluid resuscitation if signs of dehydration persist 3
• Thiamine supplementation 100 mg daily for minimum 7 days to prevent Wernicke encephalopathy in prolonged vomiting 5
• Small, frequent, bland meals (BRAT diet: bananas, rice, applesauce, toast) 3
• High-protein, low-fat meals 3

Lifestyle Modifications for Headache Prevention

• Maintain adequate hydration with regular fluid intake 2
• Ensure regular meals to avoid hypoglycemia triggers 2
• Secure consistent, sufficient sleep patterns 2
• Identify and avoid specific migraine triggers 2

When to Consider Preventive Therapy

Preventive migraine medications should be avoided during pregnancy unless headaches are frequent (≥2 attacks/month causing disability for ≥3 days/month) and disabling 2

If preventive therapy becomes necessary:

• Propranolol 80-160 mg daily in long-acting formulations has the best safety data 1, 2
• Contraindicated: Topiramate, candesartan, sodium valproate – teratogenic effects 2, 5

Common Pitfalls to Avoid

• Missing preeclampsia by attributing headache solely to hyperemesis gravidarum or post-viral syndrome – always check blood pressure first 1
• Prescribing opioids or butalbital as first-line therapy instead of acetaminophen and NSAIDs 1, 2
• Discharging without excluding secondary causes – ensure red flags are evaluated 1
• Forgetting thiamine supplementation in prolonged hyperemesis gravidarum – critical to prevent Wernicke encephalopathy 5
• Using ondansetron as first-line antiemetic – reserve for refractory cases due to small teratogenic risks 5

Follow-Up Considerations

• Monitor for resolution of hyperemesis gravidarum symptoms – 50% improve by week 16,80% by week 20 3
• Weekly monitoring if symptoms persist to assess for complications 3
• Ultrasound evaluation to assess fetal growth and rule out multiple or molar pregnancy if not already performed 3
• If headaches persist or worsen, consider neuroimaging to exclude structural causes 1