Atypical presentation of motor neurone disease: a case of Mills’ syndrome – progressive spastic hemiparesis

<h3></h3> A 55-year-old man presented to Neurology clinic with weakness in his right arm and leg. He was otherwise fit and well, with no relevant family history. Approximately three years ago, he felt some discomfort in his right leg whilst running and noticed his gait progressively deteriorated. Over the last 18 months, his right arm became weak – now struggling to lift this above his head. His left arm and leg were normal. There were no speech or swallowing difficulties, and sphincter function was intact. Cranial nerve examination was normal, except for a brisk jaw jerk. There was right- sided spasticity associated with pyramidal weakness, unilaterally brisk reflexes and an upgoing plantar. No fasciculation or focal muscle wasting was observed and he remained independently mobile. Sensory examination was normal. He had been previously investigated for suspected primary progressive multiple sclerosis. MRI appearances of the brain were normal, with only mild degenerative changes in the lower cervical spine without significant neural compression. Cord signal was normal throughout. His EMG revealed evidence of fibrillation potentials and positive sharp waves in the right triceps, right thoracic and lumbar paraspinal muscles and right medial gastrocnemius. He was diagnosed with Mills’ syndrome, a rare progressive spastic hemiparesis.