Having isolated the disease to that of a chronic/subacute process of the cervical spinal cord, the differential diagnosis of this case should include:

• ALS - similar motor signs are found as in this case (weakness, atrophy, fasciculations), however, with no sensory loss; therefore unlikely

• MS - mimics any CNS disease, and thus should always be in the differential; early MS has a clinical picture similar to this case, albeit one of a remitting course with signs and symptoms of more than one lesion; early atrophy of hand muscles is not seen. Loss of spinothalamic tracts bilaterally in a suspended distribution would be unusual.

• Subacute combined degeneration - the motor signs are usually limited to legs and lead to ataxic or ataxic/spastic gait. Both motor and sensory findings are usually symmetrical with mental signs commonly observed. In addition, impairment of the vibration sense is consistently found, particularly in the lower limb. None of these findings are evident in this patient.

• Intramedullary spinal cord space-occupying lesion  (tumour, vascular malformation) - similar clinical signs of cord enlargement and chronic course

• Cervical spondylosis - chronic cord compression (sensory loss in arms, pyramidal signs in legs) also confuses diagnosis. Pain in the neck region is an associated symptom, but it is not seen in this patient.

• Syringomyelia - classical loss of bilateral spinothalamic function in a suspended distribution with preservation of posterior columns results in dissociated sensory loss. Involvement of distal corticospinal tracts with resulting upper motor neuron signs depends on how lateral the syrinx extends

The clinician must now choose appropriate investigations and tests to differentiate amongst the above for the best possible diagnosis.