Myalgia in 30 Patients with Suspected Myopathy

Background: In patients with neuromuscular disorder, only little data of myalgia frequency and characterization exists. To date, only a weak correlation between pain intensity and pressure pain threshold has been found, and it remains enigmatic whether high pain intensity levels are equivalent to high pain sensitivity levels in neuromuscular disorders. Methods: 30 sequential patients with suspected neuromuscular disorder and myalgia were analyzed with regard to myalgia characteristics and clinical findings, including symptoms of depression and anxiety and pain- threshold. Results: A neuromuscular disorder was diagnosed in 14/30 patients. Muscular pain fasciculation syndrome (MPFS) without evidence for myopathy or myositis was diagnosed in 10/30 patients and 6/30 patients were diagnosed with pure myalgia without evidence for a neuromuscular disorder (e.g., myopathy, myositis, MPFS, polymyalgia rheumatica). Highest median pain scores were found in patients with pure myalgia and polymyalgia rheumatica. Pressure pain threshold measurement showed a significant difference between patients and controls in the biceps brachii muscle. Conclusion: Only a weak correlation between pain intensity and pressure pain threshold has been suggested, which is concordant with our results. The hypothesis that high pain intensity levels are equivalent to high pain sensitivity levels was not demonstrated.