Objective:

Lyme disease presenting with encephalomyelitis is rare. It often presents with non-localizing symptoms like confusion or personality changes. Focal symptoms can include hemiparesis, aphasia or ataxia. Acute brachial diplegia due to Lyme disease, although rare, has been previously reported. Our case offers additional insight into the underlying mechanisms of brachial diplegia.

Background:

A 73 year old man presented with mild upper thoracic back pain followed by progressive left greater than right arm weakness. Physical exam revealed a flicker of contraction in the left upper extremity and right thenar muscles. Mild proximal right arm weakness was noted. Lower extremity sensorimotor exam was normal. He was hyporeflexic in bilateral upper extremities and hyperreflexic in the lower extremities. He developed intermittent episodes of confusion, hyponatremia and a neurogenic bladder over the following week. His wife later reported he had a bulls-eye rash on his calf one month prior to presentation.

Design/Methods:

A work up for compressive myelopathy and cerebrovascular etiologies was negative. EMG revealed a demyelinating, predominantly motor neuropathy limited to the upper extremities, prompting treatment with IVIg. Serum Lyme PCR was positive. Cerebrospinal fluid showed lymphocytic pleocytosis, elevated protein and positive Lyme antibody. Diffuse nerve root edema was noted on brachial plexus MRI.

Results:

The patient was treated with intravenous ceftriaxone for 4 weeks. At his 4 week follow-up, left arm strength was at least 4/5 in all muscles. Right arm strength was normal proximally and at least 4/5 in all distal muscles. He reported paresthesia in his hands. He continues to require self-catheterization twice daily for ongoing urinary retention.

Conclusions:

This case illustrates that brachial diplegia in the setting of Lyme disease can be a result of radiculitis and proximal demyelination without significant motor axon loss. Radiculitis can precede encephalomyelitis. Early identification of the disease is crucial as treatment with antibiotics leads to marked improvement.