How should a patient with a unilateral headache and hypotension (blood pressure 90/70 mmHg) be evaluated and managed?

Immediate Evaluation for Secondary Causes of Headache

A patient with unilateral headache and hypotension (BP 90/70 mmHg) requires urgent evaluation to exclude life-threatening secondary headache disorders, particularly spontaneous intracranial hypotension (SIH), cerebral venous thrombosis (CVT), or intracranial hemorrhage, before considering primary headache disorders like migraine.

Critical Red Flags Assessment

The combination of unilateral headache with hypotension is atypical and demands immediate attention to exclude secondary causes 1. Key red flags to assess include:

• Orthostatic component: Does the headache worsen when upright and improve when lying down? This is pathognomonic for intracranial hypotension 2, 3
• Onset pattern: Thunderclap (sudden, severe) versus gradual
• Neurological deficits: Focal weakness, visual changes, altered consciousness
• Recent procedures: Lumbar puncture, epidural, or spinal intervention within past weeks 3
• Associated symptoms: Neck stiffness, fever, nausea/vomiting, photophobia, phonophobia

Primary Diagnostic Considerations

1. Spontaneous Intracranial Hypotension (SIH)

The hypotension combined with headache raises concern for SIH, which presents with:

• Orthostatic headache (worsens upright, improves supine) 2, 4
• Neck pain, tinnitus, nausea, diplopia 5
• Can be unilateral 1
• Systemic hypotension may coexist

Immediate imaging: MRI brain AND complete spine without and with IV contrast to identify dural enhancement and locate CSF leak 2, 3. Do not delay imaging if SIH is suspected.

2. Cerebral Venous Thrombosis (CVT)

CVT can present with unilateral headache and may cause hypotension in severe cases:

• Progressive headache with neurological deterioration 6
• Risk factors: dehydration, oral contraceptives, infection, hypercoagulable states
• Can lead to hemorrhagic transformation 6

Immediate imaging: Non-contrast head CT followed by CT or MR venography 7. If hemorrhage detected, continue anticoagulation per AHA/ASA guidelines despite bleeding 6.

3. Intracranial Hemorrhage/Aneurysm

Thunderclap headache with hypotension suggests:

• Subarachnoid hemorrhage from ruptured aneurysm
• Subdural hematoma (can occur with SIH) 6

Immediate imaging: Non-contrast head CT (98% sensitivity for acute SAH) 7. If positive, proceed to CTA or conventional angiography 7.

Diagnostic Algorithm

Step 1: Characterize the headache

• Orthostatic? → Suspect SIH
• Thunderclap onset? → Suspect SAH/hemorrhage
• Progressive with focal deficits? → Suspect CVT or mass lesion

Step 2: Obtain appropriate imaging

• If orthostatic headache: MRI brain + complete spine with/without contrast 2, 3
• If thunderclap or acute severe: Non-contrast head CT immediately 7
• If progressive with deficits: MRI brain with contrast, consider MRV/CTV 1, 7

Step 3: Assess for recent procedures

• Dural puncture within 72 hours: Conservative management first, epidural blood patch if no improvement 3
• No recent procedure: Proceed with full imaging workup 2

Management Based on Diagnosis

If SIH Confirmed:

• Conservative: Bed rest, IV hydration, caffeine, NSAIDs 5
• Interventional: Epidural blood patch if conservative measures fail 2, 5
• Targeted therapy: If leak identified on imaging, directed patching or surgical repair 2

If CVT Confirmed:

• Anticoagulation: Initiate IV heparin immediately, continue even if hemorrhagic transformation occurs 6
• Supportive: Antiemetics, adequate hydration, seizure prophylaxis if indicated 6

If Primary Migraine (After Exclusion of Secondary Causes):

Only after imaging excludes secondary causes 1:

• Acute treatment: NSAIDs (ibuprofen, naproxen) first-line 8, 9
• Migraine-specific agents: Triptans if NSAIDs ineffective 8, 9
• Avoid: Ergotamines in setting of hypotension (contraindicated with cardiovascular compromise) 8, 9

Critical Pitfalls to Avoid

1. Do not attribute headache to migraine without imaging when red flags present 1
2. Do not withhold anticoagulation for CVT even with hemorrhagic transformation 6
3. Do not delay epidural blood patch beyond 72 hours if post-dural puncture headache not improving 3
4. Do not use vasoconstrictive migraine medications (triptans, ergots) until cardiovascular causes excluded and hemodynamics stabilized 8, 9
5. Do not assume hypotension is incidental—it may be part of the pathophysiology (SIH) or a complication (CVT with increased ICP) 6, 2

The hypotension in this case is not typical for primary migraine and mandates urgent evaluation for secondary causes, particularly SIH and CVT, before any migraine-specific treatment is initiated.