[Isolated posterior cord syndrome in Lyme s disease: a clinico neurophysiological study]

Lyme disease, caused by spirochete Borrelia burgdorferi, is a multisystemic infectious disorder with prominent neurologic involvement, affecting both the peripheral and the central nervous system. Meningitis, cranial neuritis and radiculoneuritis are the usual manifestations in the acute phase, and peripheral neuropathy in the chronic phase. Other less common manifestations have been also described. Here we report one case of Lyme disease confirmed by PCR, with a previously undescribed neurological manifestation, and the neurophysiological studies performed before and after treatment.

Our patient showed a chronic and progressive clinical picture consisting of instability on walking and distal paresthesia of lower limbs, suggestive of posterior column disfunction. The neurophysiological exam performed prior to treatment with ceftriaxone revealed bilateral absence of lower limbs somatosensory evoked potentials (SEPs), without alterations in the distal nervous conduction or in upper limbs SEPs. The exam performed after treatment revealed a partial recovery of lower limb SEP with presence of an evoked response in SEP of left lower limb, coincident with a transitory clinical improvement of paresthesia in the same extremity.

Our findings reveal that posterior column disfunction can be a neurological manifestation of Lyme disease. Furthermore the neurophysiological study shows that this manifestation is partially reversible following treatment. Our study emphasize the importance of the neurophysiological tests for the diagnosis and follow up of neurological manifestations of Lyme disease.