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Abstract
Atrophy of paraspinal muscles has been reported with ageing, spinal disorders and various neuromuscular conditions. There are no reports describing atrophy of paraspinal muscles in myotonic dystrophy. We describe a case of striking paraspinal muscle atrophy in a patient with myotonic dystrophy type I. A 47-year-old warehouseman was referred to the Greater Manchester Neuro ICAT for assessment of nonradiating lumbar spine pain. He was triaged to MRI scan of the lumbosacral spine. This demonstrated marked atrophy of paraspinal muscles and he was reviewed in neurology clinic (Abstract POC04 Figures 1 and 2). He gave a 2-year history of progressive low backache which was aggravated on bending forwards. There were no upper limb symptoms and no sensory, bulbar or sphincter problems. There was no significant developmental or past history of note. Examination revealed frontal balding with bilateral partial ptosis and mild weakness of eye closure. The upper limbs were normal. There was wasting of calf, thigh and paraspinal muscles. Sensation and co-ordination were normal. Plantars were flexor and there was marked percussion myotonia. EMG showed myotonic discharges with mild myopathic features distally. The clinical phenotype and the neurophysiological changes were consistent with myotonic dystrophy type I, which was confirmed by genetic analysis. This case identifies atrophy and fatty replacement of paraspinal muscles as an unrecognised feature of myotonic dystrophy.
