What causes vertigo that occurs or worsens when lying down, and how should it be diagnosed and treated?

Vertigo When Lying Down: Diagnosis and Management

Benign paroxysmal positional vertigo (BPPV) is the most likely diagnosis when vertigo occurs with lying down, and you should immediately perform the Dix-Hallpike maneuver to confirm posterior canal involvement and the supine roll test to identify lateral canal involvement. 1

Understanding the Clinical Presentation

BPPV causes brief episodes of intense spinning vertigo lasting seconds to less than 1 minute, triggered specifically by head position changes such as lying down, rolling over in bed, looking up, or bending forward. 1, 2 The condition accounts for 42% of vertigo cases in primary care settings and is the single most common cause of triggered episodic vertigo. 2

Key distinguishing features:

• Episodes are brief (seconds to <1 minute), not constant 1, 2
• Symptoms are triggered by obligate head position changes 2
• BPPV does NOT cause hearing loss, fainting, or constant severe dizziness 1, 2
• Patients may experience residual unsteadiness for hours after an acute episode 2
• Nausea and disorientation are common during episodes 1

Diagnostic Algorithm

Step 1: Perform Bedside Positional Testing

The Dix-Hallpike maneuver is essential for diagnosing posterior canal BPPV (85-95% of cases): 1

• Rotate the patient's head 45° to one side while seated 1
• Rapidly move the patient to supine position with head extended 20° off the bed edge 1
• Look for characteristic torsional (rotatory) upbeating nystagmus 1, 3
• Note a latency period of 5-20 seconds before nystagmus onset 1
• Nystagmus should crescendo then resolve within 60 seconds 1

The supine roll test must also be performed to avoid missing lateral canal BPPV (5-15% of cases): 1, 2

• With patient supine, rapidly turn head 90° to each side 1
• Geotropic nystagmus (beating toward ground) indicates the stronger side is affected 3
• Apogeotropic nystagmus (beating away from ground) indicates the opposite ear is affected 3

Step 2: Identify Red Flags Requiring Neuroimaging

Obtain MRI of the brain (not CT) if any of these features are present: 2, 4

• Downbeat nystagmus without torsional component 3, 2
• Persistent nystagmus that does not decay within 60 seconds 4
• Direction-changing nystagmus that doesn't follow typical BPPV patterns 3
• Cerebellar signs (ataxia, dysmetria, dysdiadochokinesia) 3
• Failure to respond to appropriate BPPV treatment maneuvers 2
• Associated neurological symptoms 2

Common pitfall: CT scans are inadequate for evaluating posterior fossa structures and should not be used as the primary imaging modality. 2, 4

Treatment Approach

For Posterior Canal BPPV (Most Common)

The Epley maneuver is the gold standard treatment with 90-98% success rates when repeated if necessary: 2

• Can be performed immediately after diagnostic Dix-Hallpike maneuver 1
• Success rates reach 70-90% with just 1-3 treatments 2
• Brief distress from vertigo and nausea during the maneuver is expected 1

For Lateral Canal BPPV

The barbecue roll maneuver or Gufoni maneuver are moderately effective for geotropic lateral canal BPPV with success rates of 81-93%: 2

Post-Treatment Expectations

Patients may experience residual motion sensitivity and mild unsteadiness for a few days to weeks after successful treatment. 1, 2 This does not indicate treatment failure but rather normal resolution of symptoms.

When Treatment Fails

If symptoms persist after 2-4 treatment attempts, reassess for: 2

• Persistent BPPV in a different canal 2
• Canal conversion (posterior to lateral canal BPPV can occur during repositioning) 3, 2
• Coexisting vestibular conditions (Ménière's disease, vestibular neuritis, superior canal dehiscence) 2
• Central nervous system disorders requiring neuroimaging 2

Alternative Diagnoses to Consider

Other peripheral vestibular causes: 2

• Vestibular neuritis (constant vertigo, not positional) 2
• Ménière's disease (associated hearing loss, tinnitus, aural fullness) 2
• Superior canal dehiscence syndrome 2

Central causes mimicking positional vertigo: 2

• Vestibular migraine 2
• Posterior circulation stroke or TIA 2
• Demyelinating diseases 2
• Vertebrobasilar insufficiency 2

Non-vestibular causes: 2

• Postural hypotension (check orthostatic vital signs) 2
• Medication side effects 2

Critical Management Points

Do NOT routinely order: 5

• Brain imaging for typical BPPV 5
• Vestibular suppressant medications like meclizine (ineffective for BPPV) 5
• Laboratory testing 5

DO emphasize: 1, 2

• Immediate bedside diagnosis and treatment 5
• Fall precautions, especially for elderly patients 1, 2
• Seniors should seek professional help quickly as untreated BPPV significantly increases fall risk 2

Common diagnostic pitfall: Failing to perform both Dix-Hallpike and supine roll testing potentially misses lateral canal BPPV in up to 30% of cases. 2