Late-onset neuromuscular disorders in the differential diagnosis of sarcopenia.

In geriatric patients with a focal or asymmetrical muscular weakness and atrophy, sarcopenia assessment should be extended with patient's history of disease course. Furthermore, concomitant diseases, analysis of serum creatine kinase, electrophysiological examination, and in selected patients muscle biopsy and gene analysis is needed to rule out a late-onset neuromuscular disorder.