Propriospinal Myoclonus in a Child

A 6-year-old girl was experiencing repetitive involuntary and massive jerks immediately involving limbs and trunk. The first motor events appeared approximately at 1 year old and only 5 months after a back trauma. Myoclonus became progressively more frequent and more violent, causing episodes of falls. Neurological examination showed jerks characterized by upper limb abduction, lower limb abduction, and head-body hyperextension. Apart from these motor events, the neurological examination was normal. The results of vitamin B-12 and folate, antinuclear antibody, anti-DNA, anti-Tiroglobulin, anti-thyroid peroxidase antibody, lupus anticoagulant, anti-cardiolipin antibody, rheumatoid factor, and C3 and C4 were unexceptional. Electroencephalography and brain and spinal magnetic resonance imaging were unremarkable. Electromyographic records with surface electrodes showed that duration of myoclonic jerks was ranging from 100 to 300 ms. We thought she had propriospinal myoclonus because of presence of the spreading through the shoulder, upper limbs, and lower limbs in addition to thoracolumbar paraspinal muscles.