Vertigo with Size Distortion: Diagnostic and Treatment Approach
Immediate Clinical Recognition
Vertigo with size distortion (micropsia or macropsia) suggests skew deviation from central vestibular pathology affecting the brainstem or cerebellum, requiring urgent neurological evaluation rather than standard BPPV treatment. 1
This presentation differs fundamentally from benign paroxysmal positional vertigo (BPPV), which causes rotational vertigo without visual size distortion. 1
Key Diagnostic Features
Clinical Presentation Distinguishing Central from Peripheral Causes
Skew deviation presents with vertical diplopia, head tilt (torticollis), and subjective tilting of the perceived visual world—size distortion falls within this spectrum of visual perceptual abnormalities. 1
The acute to subacute onset with size distortion warrants immediate evaluation for serious etiologies including demyelination, ischemia, or mass lesions affecting vestibular supranuclear pathways in the brainstem and cerebellum. 1
Associated neurologic features help localize the lesion: look for nystagmus, internuclear ophthalmoplegia (INO), hemiparesis, sensory loss, ataxia, and Horner's syndrome. 1
Critical Examination Elements
Perform a complete three-step test and consider the upright-supine test (though this may not reliably distinguish acute skew deviation from superior oblique palsy). 1
Check specifically for other neuro-ophthalmic signs: Horner's syndrome, cranial nerve palsies, INO, nystagmus, and hearing loss. 1
Fundus examination must assess for papilledema or optic atrophy, and visual field testing may provide additional etiologic information. 1
Note that abnormalities in the rostral pons and midbrain result in contralateral hypotropia and head tilt, whereas abnormalities in the vestibular periphery, medulla, and more caudal pons result in ipsilateral hypotropia and head tilt. 1
Treatment Approach
Immediate Management
Do NOT treat this presentation as BPPV with canalith repositioning procedures—the size distortion indicates central pathology requiring different management. 1
Vestibular suppressant medications (meclizine 25-100 mg daily in divided doses) may provide short-term symptomatic relief for severe vertigo and nausea, but should not be used as definitive treatment. 2, 3
Meclizine should be prescribed with caution in patients with asthma, glaucoma, or prostate enlargement due to anticholinergic effects. 3
Be aware that meclizine causes drowsiness, cognitive deficits, and increased fall risk, particularly in elderly patients. 2, 3
Definitive Management
Immediate referral to neurology or neuro-ophthalmology is essential for patients presenting with vertigo and size distortion, as this indicates potential stroke, demyelination, or mass lesion. 1
Treatment targets the underlying etiology rather than the vertigo itself—control of disabling diplopia and perceived tilt of the subjective visual vertical are the primary outcome goals. 1
For vestibular neuronitis (if confirmed as the etiology), symptoms may be self-limiting and respond to medical intervention, but size distortion makes this diagnosis less likely. 1
Vestibular Rehabilitation
Once the acute phase resolves, vestibular rehabilitation (self-administered or therapist-directed) is indicated for persistent dizziness, chronic imbalance, or incomplete recovery from any vestibular cause. 2, 4
Patients should be reassessed within 1 month after initial treatment to document resolution or persistence of symptoms. 1, 2
Critical Pitfalls to Avoid
Never assume BPPV based solely on "vertigo"—the presence of size distortion is a red flag for central pathology that requires imaging and neurological consultation. 1
Do not obtain routine vestibular testing or radiographic imaging for typical BPPV, but size distortion is an "additional sign inconsistent with BPPV that warrants imaging." 1
Avoid prolonged use of vestibular suppressants, as they can interfere with central compensation mechanisms and increase fall risk without addressing the underlying pathology. 2, 4
Risk factors vary by etiology: cardiovascular risk factors (hypertension, diabetes, hyperlipidemia, smoking) suggest stroke in older adults, while younger patients with size distortion should raise suspicion for demyelination or trauma. 1