Muscle wasting and atrophy, NEC, right upper arm

This code signifies a reduction in muscle mass and size, specifically affecting the right upper arm, that is not attributable to a neurological disease, disuse, or other classified conditions. It indicates a primary muscle disorder leading to diminished muscle tissue in this specific anatomical location.

Apply this code when documentation clearly states muscle wasting or atrophy of the right upper arm without an underlying neurological cause (e.g., stroke, nerve injury) or disuse atrophy. Supporting documentation should include physical exam findings noting decreased muscle bulk or strength in the right upper arm, often accompanied by diagnostic imaging (e.g., MRI) confirming muscle loss.

• Ensure documentation specifies "right upper arm" to justify laterality and anatomical site.
• Differentiate from disuse atrophy (M62.50, M62.58) or atrophy due to neurological conditions, which would be coded with a primary neurological diagnosis.
• Always look for an underlying cause; if identified, that condition should be coded first, and this code may be secondary if the atrophy is a manifestation.