What are the differential diagnoses for an elderly male presenting with sudden onset bilateral hearing loss and blurred vision that occurred overnight?

Sudden Bilateral Hearing Loss with Blurred Vision: Critical Differential Diagnoses

This presentation of sudden bilateral hearing loss with blurred vision in an elderly male demands immediate consideration of brainstem stroke, autoimmune inner ear disease, or meningitis, with urgent MRI being mandatory to exclude life-threatening central nervous system pathology. 1, 2

Life-Threatening Diagnoses Requiring Immediate Evaluation

Brainstem/Cerebellar Stroke

• Bilateral temporal lobe strokes (hemorrhagic or ischemic) can present with acute bilateral hearing loss and visual disturbances 3
• The combination of bilateral hearing loss with visual symptoms (diplopia, blurred vision) strongly suggests brainstem involvement and mandates immediate neuroimaging 1, 2
• Look for accompanying focal neurologic findings: dysarthria, hemiataxia, encephalopathy, severe headaches, focal weakness, or nystagmus (downbeating or gaze-evoked) 1
• Anterior inferior cerebellar artery (AICA) territory infarction classically causes unilateral hearing loss but can be bilateral, often with facial numbness, facial palsy, and cerebellar ataxia 4
• Elderly males with vascular risk factors (atrial fibrillation, hypertension, diabetes) are at highest risk 3, 4

Meningitis (Infectious, Inflammatory, or Neoplastic)

• Presents with bilateral sudden hearing loss, headache, fever, and altered mental status 5
• Associated with abnormal cerebrospinal fluid and possible other cranial nerve palsies 5
• Bacterial and viral meningitis are well-established causes of bilateral sensorineural hearing loss 5

MELAS (Mitochondrial Encephalopathy)

• Presents with confusion, elevated lactate, MRI white matter changes, and bilateral hearing loss 5
• Consider in patients with encephalopathy and stroke-like episodes 5

Autoimmune/Inflammatory Causes

Autoimmune Inner Ear Disease (AIED)

• Presents with fluctuating bilateral hearing loss, often with vertigo 5
• Rapidly progressive bilateral symptoms suggest this diagnosis 2
• High-dose corticosteroids (prednisone 1 mg/kg/day) are first-line therapy 2

Cogan Syndrome

• Causes nonsyphilitic interstitial keratitis (eye pain, redness, lacrimation, photophobia), bilateral hearing loss, and vertigo 1, 5
• The combination of concurrent eye symptoms with bilateral hearing loss is highly suggestive 1

Toxic/Metabolic Causes

Ototoxic Medications

• Aminoglycosides and cisplatin cause bilateral sensorineural hearing loss, often with concurrent vestibular loss and oscillopsia 5
• Review medication history for recent exposure 6, 7

Traumatic Causes

Severe Head Trauma

• Basal skull or temporal bone fractures can cause bilateral hearing loss 5
• Recent significant head trauma should be identified in history 1

Immediate Diagnostic Workup Algorithm

Step 1: Distinguish Sensorineural from Conductive Hearing Loss

• Perform otoscopic examination to rule out cerumen impaction, middle ear fluid, otitis media, or tympanic membrane perforation 1
• Weber and Rinne tuning fork tests (256 or 512 Hz) to differentiate conductive from sensorineural loss 1
• Patients with sensorineural hearing loss will have normal otoscopic examination 1

Step 2: Assess for Red Flag Features

• Focal neurologic symptoms (weakness, dysarthria, ataxia, diplopia, severe headache) 1, 2
• Eye symptoms (pain, redness, lacrimation, photophobia) suggesting Cogan syndrome 1
• Vertigo with oscillopsia suggesting bilateral vestibular loss 1
• Encephalopathy or confusion suggesting MELAS or meningitis 5

Step 3: Obtain Urgent MRI

• MRI with gadolinium is mandatory for bilateral sudden hearing loss with visual symptoms to exclude stroke, autoimmune disease, or structural lesions 2, 4, 7
• The American College of Radiology rates MRI as "usually appropriate" for this presentation 2

Step 4: Confirm with Audiometry

• Pure tone audiometry must be performed to confirm sensorineural hearing loss and identify patterns (isolated low-frequency trough suggests Ménière's disease) 2
• Diagnosis requires 30-dB hearing loss at 3 consecutive frequencies 1

Critical Pitfalls to Avoid

• Do not assume idiopathic sudden sensorineural hearing loss when bilateral hearing loss occurs with visual symptoms—this combination demands exclusion of central pathology 1, 2, 3
• Do not delay MRI in elderly patients with vascular risk factors presenting with bilateral symptoms 3, 4
• Do not miss cerumen impaction—it must be removed before establishing diagnosis 1
• Missing cerebrovascular pathology leads to significant morbidity and mortality 3