Tests
1st tests to order
clinical diagnosis
Test
Diagnosis is usually clinical, based on the history and physical examination alone.
Classic features include sudden-onset (<72 hours) unilateral facial paralysis, severe ear/facial pain, and a vesicular rash, including blisters, involving the ear. However, note that many patients do not present with all three classic symptoms as these do not always develop at the same time; vesicles can precede, coexist with, or follow facial palsy. The most suggestive symptom of Ramsay Hunt syndrome is unilateral peripheral facial palsy.
Result
classic features include sudden-onset (<72 hours) unilateral facial paralysis, severe ear/facial pain, and a vesicular rash involving the ear
varicella zoster virus (VZV) polymerase chain reaction (PCR)
Test
If there is uncertainty regarding the etiology, vesicular lesions, if present, can be swabbed directly for confirmation by PCR. VZV PCR has nearly 100% sensitivity and specificity.[1]
Result
positive for VZV DNA
Tests to consider
electroneurography (evoked electromyography)
Test
Consider in acute patients who present with near-complete or complete facial paralysis (i.e., House-Brackmann scale V or VI) to quantify their degree of neural degeneration.[14]
Result
>90% decrease in the amplitude of compound muscle action potential (CMAP) on the affected side compared with the healthy side is an indication for further testing or surgical intervention
MRI head and neck with contrast
Test
Indicated in patients with unilateral facial palsy and any red flag sign/symptoms to rule out cerebrovascular accident (CVA) and malignancy. Red flags include gradual onset weakness, other cranial or peripheral neuropathies, uneven distribution of weakness across facial zones, and prior history of ipsilateral facial weakness.
Result
CVA: lesion seen along the course of the facial nerve
serology for Borrelia burgdorferi
Test
Indicated in all patients with recent travel to a Lyme disease-endemic area.
Result
negative
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