Clinical Reasoning: Adult Patient Presenting With Spine Pain Following a Motor Vehicle Accident.

A 52-year-old woman with a complex medical history, including a history of consanguinity, developed refractory uncontrollable spine pain after a motor vehicle accident 2 years before presentation. There were no well-defined findings on clinical examination. She was found to have mildly elevated serum creatine phosphokinase levels, and spine imaging revealed fatty replacement and atrophy affecting predominantly lumbar paraspinal muscles. Initial EMG sampling of multiple limb muscles was normal. However, a follow-up concentric needle examination sampling paraspinal and trunk muscles showed abundant myotonic discharges, fibrillations and positive sharp waves, and myopathic motor unit action potential changes. This pattern of neurophysiologic abnormalities prompted the search for a myopathic disorder, which was ultimately confirmed with additional studies. This case highlights the critical role of neurophysiologic evaluation of paraspinal and other trunk muscles in the disambiguation of clinical and imaging data, helping to establish the diagnosis of a rare but treatable myopathy at early disease stages.