What is the differential diagnosis (Dx) and workup for a patient presenting with lightheadedness and headache?

Differential Diagnosis and Workup for Lightheadedness with Headache

The combination of lightheadedness and headache requires immediate assessment for life-threatening secondary causes before considering primary headache disorders; your workup must prioritize ruling out intracranial pathology, cardiovascular causes, and infection based on specific red flag features in the history and examination.

Initial Assessment: Red Flags Requiring Urgent Investigation

Your first priority is identifying features that mandate immediate neuroimaging or other urgent testing 1, 2:

• Recent head or neck trauma 1
• New, worse, worsening, or abrupt onset ("thunderclap") headache 1, 3
• Headache triggered by Valsalva maneuver or cough 1
• Age >50 years with new-onset headache 1, 2
• Abnormal neurological examination findings 4, 1
• Fever or systemic signs suggesting infection 1, 2
• History of cancer or HIV infection 1
• Rapidly increasing headache frequency 4
• History of syncope accompanying the headache 4

Differential Diagnosis by Category

Life-Threatening Secondary Causes (Rule Out First)

Intracranial pathology:

• Subarachnoid hemorrhage (abrupt onset, "worst headache of life") 1, 3
• Cerebral venous thrombosis (progressive headache, may have focal deficits) 4
• Intracranial mass or hemorrhage 4, 2
• Meningitis/encephalitis (fever, neck stiffness, altered mental status) 1, 2
• Spontaneous intracranial hypotension (orthostatic headache, may have dural enhancement on MRI) 4

Cardiovascular causes of presyncope:

• Orthostatic hypotension 5, 6
• Cardiac arrhythmias 5
• Medication-induced presyncope 5

Primary Headache Disorders (After Excluding Secondary Causes)

Migraine with associated dizziness:

• Unilateral, pulsating, moderate-to-severe pain lasting 4-72 hours 4
• Aggravated by routine physical activity 4
• Accompanied by nausea/vomiting and/or photophobia and phonophobia 4
• May have brainstem aura symptoms including vertigo 4
• Family history often positive 4

Tension-type headache:

• Bilateral, pressing/tightening quality, mild-to-moderate severity 7
• Not aggravated by routine activity 7
• Lacks prominent nausea or both photophobia and phonophobia 7

Cluster headache:

• Strictly unilateral, severe orbital/supraorbital/temporal pain lasting 15-180 minutes 8, 9
• Ipsilateral autonomic symptoms (lacrimation, conjunctival injection, nasal congestion, ptosis) 8, 9
• Frequency of 1-8 attacks per day 8

Medication-overuse headache:

• Headache ≥15 days/month with regular overuse of acute medications >3 months 4
• Non-opioid analgesics ≥15 days/month or other acute medications ≥10 days/month 4

Peripheral Vestibular Causes

Benign paroxysmal positional vertigo (BPPV):

• Episodic vertigo triggered specifically by head position changes 5, 6
• May have associated headache 5, 6

Vestibular neuritis/labyrinthitis:

• Episodic vertigo not associated with specific triggers 6
• May have unilateral hearing loss if labyrinthitis 5

Meniere disease:

• Vertigo with unilateral hearing loss 5, 6

Diagnostic Workup Algorithm

Step 1: Focused History

Characterize the headache:

• Onset (sudden vs gradual), duration, frequency, location, quality 4, 1
• Severity and impact on daily activities 4
• Associated symptoms (nausea, vomiting, photophobia, phonophobia, autonomic features) 4, 8
• Triggers and aggravating/relieving factors 4
• Medication use (especially analgesics) 4
• Family history of migraine 4

Characterize the lightheadedness:

• Timing and triggers (positional, exertional, spontaneous) 5, 6
• Associated symptoms (hearing loss, tinnitus, palpitations) 5, 6
• Relationship to headache (concurrent vs separate) 5, 6

Step 2: Physical Examination

Vital signs:

• Orthostatic blood pressure measurements (lying, sitting, standing) 5, 6
• Temperature (to assess for infection) 1

Complete neurological examination:

• Mental status, cranial nerves, motor/sensory function, reflexes, coordination, gait 4, 1
• Assessment for nystagmus 5, 6
• Dix-Hallpike maneuver if BPPV suspected 5, 6
• HINTS examination (head-impulse, nystagmus, test of skew) if acute vestibular syndrome 6

Assess for autonomic features during attack if possible 8

Step 3: Neuroimaging Indications

Obtain MRI brain (preferred) or CT if:

• Any red flag features present 4, 1
• Abnormal neurological examination 4, 8
• Atypical headache features 8
• Headache worsened by Valsalva 8, 1
• Headache awakening patient from sleep 4, 8
• New-onset headache in older patients 8, 1
• Progressively worsening headache 8, 1

MRI is preferred over CT for most nonacute presentations 4, 1. CT is appropriate for acute presentations concerning for hemorrhage 1.

Step 4: Additional Testing When Indicated

Lumbar puncture if:

• Suspected subarachnoid hemorrhage with negative CT 1
• Suspected meningitis/encephalitis 1
• Suspected intracranial hypotension or high-pressure syndromes 4, 1

Laboratory testing:

• Generally not helpful for routine headache evaluation 5, 6
• Consider if systemic illness suspected (CBC, metabolic panel, ESR/CRP in older patients) 1, 2

Cardiac evaluation if presyncope suspected:

• ECG, Holter monitoring, echocardiography as indicated 5

Critical Clinical Pitfalls

Do not assume primary headache disorder without excluding secondary causes - approximately 20% of dizziness cases remain undiagnosed, and missing a secondary headache can be catastrophic 5, 3.

Do not rely solely on symptom quality - patients have difficulty accurately describing dizziness quality, but can more consistently identify timing and triggers 6.

Do not skip neuroimaging in patients with red flags - the U.S. Headache Consortium emphasizes that history and examination findings should guide imaging decisions, and abnormal findings significantly increase likelihood of significant intracranial pathology 4.

Do not overlook medication-overuse headache - only 20% of patients meeting criteria for chronic migraine are properly diagnosed, and medication overuse is a common contributor 4.

Consider cerebral venous thrombosis in patients with progressive headache and dizziness - this can present with non-specific symptoms and may be precipitated by conditions like spontaneous intracranial hypotension 4.