Worsening myelopathy masked by peripheral nerve disorders

Peripheral nerve disorders--whether due to peripheral nerve entrapment or to polyneuropathy--can alter the signs of myelopathy, masking both the sensory loss and distal hyperreflexia. Diagnosis of worsening myelopathy may be missed when there is a coexisting peripheral nerve disorder.

This study is a case description and analysis of 3 consecutive cases identified over 2 years.

Three cases were identified in which the diagnosis of worsening myelopathy was missed and treatment was delayed because neurologic decline was attributed to a coexisting peripheral nerve disorder. This report describes 2 cases of posttraumatic syringomyelia masked by superimposed peripheral nerve entrapments and 1 case of cervical myelopathy due to cervical spinal stenosis from ossification of the posterior longitudinal ligament masked by diabetic polyneuropathy.

It is important to continually question whether the working diagnosis of peripheral nerve disorder explains the clinical findings, given neurologic decline; or whether a superimposed worsening myelopathy may coexist. Early diagnosis of worsening myelopathy is important, because prompt treatment of syringomyelia and myelopathy due to cervical spinal stenosis may yield better outcomes. Early diagnosis is aided by (a) considering alternative and multiple diagnoses, (b) assessing spinothalamic as well as posterior column sensation and assessing these sensory modalities for proximal as well as distal limbs, (c) assessing tendon hyperreflexia of proximal as well as distal limb muscles, and (d) utilizing electrodiagnostic tests that can identify myelopathy.