CMT1B Presenting with Hemifacial Spasm and Multiple Cranial Nerve Enhancement
Background:
Charcot Marie Tooth (CMT) disease is a group of hereditary motor and sensory neuropathies that are characterized by progressive distal weakness, sensory loss, and foot deformities. Here, we present a case of genetically confirmed CMT1b presenting with refractory hemifacial spasm and multiple cranial nerve enlargement and enhancement on magnetic resonance imaging, with only mild and nearly asymptomatic exam findings of distal symmetric neuropathy.
Results:
A 46 year old male presented to our neurology clinic for second opinion evaluation of bilateral hemifacial spasms. He reported four years of left-sided hemifacial spasm, and two years of right-sided hemifacial spasm. He received botulinum toxin treatment as well as left-sided microvascular decompression, however symptoms remained refractory. Prior workup included brain MRI with diffuse thickening and enhancement of bilateral third, sixth, seventh, eighth, ninth, and tenth cranial nerves. Spinal MRI showed diffuse thickening and enhancement of the lower thoracic, lumbar, and cauda equina nerve roots. CSF studies for infectious, infiltrative, and immune etiologies were unremarkable. On our evaluation, he denied lower extremity sensorimotor symptoms. His exam was notable for bilateral hemifacial spasm, high arches, hammer toes, minimal distal sensory loss, preserved strength, and diffuse areflexia. EMG/NCS showed a sensorimotor demyelinating polyneuropathy, with uniform demyelination that favored inherited neuropathy. Genetic testing confirmed a pathogenic variant in MPZ, consistent with CMT1b.
Conclusions:
This case highlights a unique clinical presentation and imaging findings of a patient with CMT1b. Hemifacial spasm and trigeminal neuralgia have been associated with CMT, however our case in conjunction with prior case series suggest hemifacial spasm may be a unique phenotype to CMT1b. Additionally, we review the differential and clinical reasoning of cranial nerve and root enhancement with a demyelinating neuropathy.
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