An 18-year-old, left-handed North Indian man presented with a 2-year history of wasting and weakness of the left more than right hands. He was unable to lift heavy objects, but he could button his clothes and hold cups. His medical history was significant only for a remote motor vehicle accident, without head trauma or subsequent neck pain. There was no family history of neurologic disease.
On examination, tone was normal. There was moderate atrophy and weakness of the intrinsic hand (interossei worse than abductor pollicis brevis) and forearm muscles, but the bulk of the brachioradialis muscles was preserved bilaterally. The left-sided muscles were more severely affected. Muscle strength was normal in all upper extremity muscle groups proximal to the elbows and the lower extremities. The left triceps and finger flexor reflexes were absent, but all other reflexes were normal and symmetric, and plantar reflexes were flexor. Pain and vibration sensation were intact throughout. Coordination testing was normal.
The results for CSF immunoglobulin G index and oligoclonal bands, CSF Venereal Disease Research Laboratory, antinuclear antibodies, neuromyelitis optica antibody, SSA/SSB antibodies, rheumatoid factor, and erythrocyte sedimentation rate were unremarkable. GM1 antibodies were not checked. EMG of the bilateral upper and left lower extremities showed evidence of severe, subacute, partial denervation of muscles innervated by bilateral C7, C8, and T1 nerve roots. MRI of the spinal cord revealed T2-hyperintense lesions at T1–T2 and C4–C5 (, A and B). Additional images in attempted neck flexion revealed no dynamic changes of the spinal cord (not shown), but the degree of flexion was limited by the head coil.
MRI and CT of the cervical spine
In an effort to assess vascular and anatomic changes with full neck flexion, CTV was performed with the neck in both neutral and maximally flexed positions. For each scan, helical axial acquisition from the skull base to the T8 level in the late arterial/venous phase was performed following bolus IV injection of 70 mL Omnipaque-350 contrast. In between scans, he was allowed to recover and ambulate. Multiple sagittal and coronal reformations were performed.
CTV was normal in the neutral position (, C and D). In the maximally flexed position, however, there was anterior displacement of the cord and thecal sac along with engorgement of intraspinal epidural veins from C4 to T2 (, E and F). In both flexed and neutral position, the right jugular vein was diminutive, with no visualized filling between the jugular bulb and C2–C3 (not shown). The dominant left internal jugular vein demonstrated moderate focal narrowing at the level of the mid sternocleidomastoid muscle, which worsened with flexion. The epidural venous system was noted to communicate with posterior muscular veins via the foramina of the lower cervical spine.
In an attempt to limit disease progression, the patient was told to wear a soft collar at night to limit the extent of neck flexion. Over the past year, his muscle weakness and atrophy have remained stable.