Myopathy vs. Neuropathy

This is an important clinical distinction to make, but may not always be easy. 

Myopathy (Break down or inflammation of muscle) 

• Tends to affect (large) muscle groups (i.e Hips, Shoulders) causing proximal weakness.
• There will be a lack of sensory deficits (but they may complain of myalgias or tenderness to palpation (if myositis)). 
• Reflexes should be intact and no fasciculations should be seen. 

Neuropathy (Damage to your peripheral nerves)

• Tends to affect distal muscles first in a length dependent distribution. 
• Typically will have sensory findings (i.e paresthesia, dysesthesia).
• May have loss of reflexes (i.e Lower Motor Neuron pathology).
• Fasciculations may be present.

NOTE: Tests such as CK and NCS/EMG can help delineate the two etiologies should the clinical picture not be clear. 

REFERENCES

1. Saguil A. Evaluation of the patient with muscle weakness. Am Fam Physician. 2005 Apr 1;71(7):1327-36.
2. Paganoni, S., Amato, A. Electrodiagnostic Evaluation of Myopathies. Phys Med Rehabil Clin N Am. 24 (2013) 193–207.
3. Chawla, J. Stepwise Approach to Myopathy in Systemic Disease. Front Neurol. 2011; 2: 49.