What are the differential diagnoses for vertigo and light‑headedness with tachycardia (~100 bpm) in an adult?

Differential Diagnosis for Vertigo, Light-Headedness, and Heart Rate 100 bpm

In an adult presenting with vertigo, light-headedness, and tachycardia (~100 bpm), the differential diagnosis must distinguish between peripheral vestibular disorders (most commonly BPPV, vestibular neuritis, or Ménière's disease), cardiovascular causes (orthostatic hypotension, arrhythmia, medication effects), and central etiologies (posterior circulation stroke, vertebrobasilar insufficiency, vestibular migraine), with the tachycardia suggesting either a compensatory response to volume depletion/orthostatic stress or a primary cardiac arrhythmia rather than a vestibular disorder alone. 1, 2

Algorithmic Approach to Diagnosis

Step 1: Characterize the Timing and Triggers

Duration of episodes:

• Seconds (<1 minute): BPPV is the most likely diagnosis, accounting for 42% of all vertigo cases 1, 3
• Minutes to hours: Consider vestibular migraine (14% of cases) or Ménière's disease (10% in general practice, up to 43% in specialty settings) 1, 3, 4
• Days to weeks (continuous): Vestibular neuritis (41% of peripheral vertigo cases) or posterior circulation stroke (25% of acute vestibular syndrome, rising to 75% in high vascular risk patients) 1, 2, 3

Triggers:

• Specific head position changes: BPPV 1, 2
• Standing from supine: Orthostatic hypotension (cardiovascular, not vestibular) 2
• Spontaneous without trigger: Vestibular migraine, Ménière's disease, vertebrobasilar TIA 1, 4

Step 2: Assess for Associated Symptoms

Auditory symptoms:

• Fluctuating hearing loss + tinnitus + aural fullness: Ménière's disease 1, 3, 4
• No hearing loss: BPPV, vestibular neuritis, vertebrobasilar insufficiency 1, 3
• Sudden unilateral hearing loss: Red flag requiring urgent neuroimaging 2

Migraine features:

• Headache, photophobia, phonophobia, visual aura during ≥2 episodes: Vestibular migraine 1, 2

Neurological symptoms:

• Dysarthria, dysmetria, dysphagia, diplopia, limb weakness, Horner's syndrome: Central vertigo (stroke, MS) requiring immediate MRI 1, 3

Step 3: Evaluate the Tachycardia Component

The heart rate of 100 bpm is critical context:

• Orthostatic hypotension causes brief dizziness (seconds to minutes) after standing, relieved by sitting/lying down, and may trigger compensatory tachycardia 4. Check orthostatic vital signs: measure BP and HR supine, then at 1 and 3 minutes after standing 2. A drop of ≥20 mmHg systolic or ≥10 mmHg diastolic with HR increase confirms orthostatic hypotension 2.

• Medication-induced dizziness is the most common reversible cause of chronic vestibular symptoms 2. Review antihypertensives (can cause both orthostatic hypotension and compensatory tachycardia), diuretics, sedatives, anticonvulsants (Mysoline, carbamazepine, phenytoin), and cardiovascular drugs 1, 2.

• Cardiac arrhythmia (atrial fibrillation, SVT) can present with light-headedness and palpitations 4. Obtain 12-lead ECG immediately 5.

• Panic disorder produces light-headedness via hyperventilation, accompanied by palpitations, tachycardia, tremor, choking sensation, and anxiety lasting minutes 2, 4. However, panic disorder can also coexist with genuine vestibular dysfunction 2.

• Compensatory tachycardia in response to severe vertigo, nausea, and vomiting is common in acute vestibular syndrome (vestibular neuritis, labyrinthitis, stroke) 1, 5.

Step 4: Perform Targeted Physical Examination

Orthostatic vital signs:

• Measure BP and HR supine, then at 1 and 3 minutes standing 2
• Positive if systolic BP drops ≥20 mmHg or diastolic ≥10 mmHg 2

Dix-Hallpike maneuver (bilateral):

• Positive: Torsional upbeating nystagmus with 5–20 second latency, crescendo-decrescendo pattern, resolves within 60 seconds, fatigues with repeat testing → BPPV 1, 2
• Atypical: Immediate onset, persistent, purely vertical without torsional component → central pathology requiring urgent MRI 1, 2

HINTS examination (if trained):

• Peripheral pattern: Abnormal head impulse test, unidirectional horizontal nystagmus, no skew deviation 2, 5
• Central pattern: Normal head impulse, direction-changing or vertical nystagmus, skew deviation present → stroke until proven otherwise 2, 5
• Critical caveat: HINTS has 100% sensitivity for stroke only when performed by trained neuro-otology specialists; emergency physicians do not achieve comparable accuracy, so obtain MRI for high-risk patients regardless of HINTS results 2

Neurological examination:

• Assess for dysarthria, dysmetria, dysphagia, limb weakness, truncal ataxia, diplopia, Horner's syndrome 1, 3

Step 5: Identify Red Flags Requiring Urgent MRI

Immediate MRI brain without contrast is mandatory for: 1, 2

• Severe postural instability with falling
• New-onset severe headache with vertigo
• Any focal neurological deficits
• Downbeating or purely vertical nystagmus without torsional component
• Direction-changing nystagmus without head position change
• Baseline nystagmus without provocative maneuvers
• Sudden unilateral hearing loss
• Inability to stand or walk
• Failure to respond to appropriate peripheral vertigo treatments
• Age >50 with vascular risk factors (hypertension, diabetes, atrial fibrillation, prior stroke), even with normal neurologic exam (11–25% have posterior circulation stroke) 2

CT head has <1% diagnostic yield for isolated dizziness and misses most posterior circulation infarcts; MRI with diffusion-weighted imaging is mandatory when stroke is suspected. 2

Specific Differential Diagnoses

Peripheral Vestibular Disorders

Benign Paroxysmal Positional Vertigo (BPPV):

• Episodes <1 minute, triggered by head position changes 1, 3
• No hearing loss, tinnitus, or aural fullness 1, 3
• Positive Dix-Hallpike with characteristic nystagmus 1, 2
• Treat immediately with Epley maneuver (80% success after 1–3 treatments, 90–98% with repeat maneuvers) 1, 2

Vestibular Neuritis:

• Acute onset severe rotational vertigo lasting 12–36 hours, then 4–5 days of decreasing disequilibrium 1, 3
• No hearing loss 1, 3
• Unidirectional horizontal nystagmus 1
• Treat with vestibular suppressants (acute phase only) followed by early vestibular rehabilitation 2

Ménière's Disease:

• Episodes 20 minutes to 12 hours 1, 3, 4
• Fluctuating low-to-mid frequency sensorineural hearing loss, tinnitus, aural fullness 1, 3, 4
• Requires audiometry to document fluctuating hearing loss 2
• Treat with salt restriction, diuretics, oral corticosteroids for acute attacks 2, 6

Cardiovascular Causes

Orthostatic Hypotension:

• Brief dizziness (seconds to minutes) after standing, relieved by sitting/lying 4
• Compensatory tachycardia common 2
• Positive orthostatic vital signs 2
• Review medications (antihypertensives, diuretics) 1, 2

Cardiac Arrhythmia:

• Palpitations, light-headedness, syncope 4
• Obtain 12-lead ECG 5

Medication Side Effects:

• Most common reversible cause of chronic dizziness 2
• Review antihypertensives, cardiovascular drugs, anticonvulsants, sedatives 1, 2

Central (Neurologic) Causes

Posterior Circulation Stroke:

• 25% of acute vestibular syndrome overall, 75% in high vascular risk patients (age >50, hypertension, diabetes, atrial fibrillation, prior stroke) 1, 2, 7
• 75–80% present without focal neurologic deficits 2
• Severe postural instability with falling is a key distinguishing feature 1, 3
• Requires immediate MRI with diffusion-weighted imaging 2

Vertebrobasilar Insufficiency:

• Episodes <30 minutes without hearing loss 1, 3, 4
• May precede stroke by weeks to months 1, 3
• Gaze-evoked nystagmus that does not fatigue 1
• Severe postural instability 1

Vestibular Migraine:

• 14% of all vertigo cases, lifetime prevalence 3.2% 1, 3
• Episodes 5 minutes to 72 hours 1
• Requires migraine symptoms (headache, photophobia, phonophobia, visual aura) during ≥2 episodes 1, 2
• Stable or absent hearing loss (distinguishes from Ménière's) 1, 2
• Treat with migraine prophylaxis and lifestyle modifications 2

Psychiatric Causes

Panic Disorder:

• Episodes lasting minutes with palpitations, tachycardia, tremor, choking, anxiety 2, 4
• Light-headedness from hyperventilation 2
• Can coexist with genuine vestibular dysfunction 2

Common Pitfalls to Avoid

• Do not rely on patient descriptions of "spinning" versus "light-headedness"; focus on timing, triggers, and associated symptoms 2
• Do not assume a normal neurologic exam excludes stroke; 75–80% of posterior circulation strokes present without focal deficits 2
• Do not order CT head for isolated dizziness; it has <1% diagnostic yield and misses most posterior circulation infarcts 2
• Do not rely on HINTS examination in the emergency department unless performed by a trained neuro-otology specialist; obtain MRI for high-risk patients regardless 2
• Do not overlook medication side effects as the most common reversible cause of chronic dizziness 2
• Do not miss vestibular migraine, which is extremely common but under-recognized, especially in young patients 1, 2
• Do not prescribe vestibular suppressants for BPPV; they prevent central compensation and delay recovery 1, 2