Paraneoplastic neuromyopathy and neuropathy

This code describes a neurological disorder characterized by muscle weakness (myopathy) and nerve damage (neuropathy) that arises as a remote effect of an underlying malignancy, not due to direct tumor invasion or metastasis. These paraneoplastic syndromes are typically immune-mediated, where the body's immune system attacks parts of the nervous system in response to cancer.

Assign this code when documentation explicitly states a diagnosis of paraneoplastic neuromyopathy or neuropathy. This typically occurs in patients with a known or suspected malignancy presenting with progressive neurological symptoms like muscle weakness, sensory disturbances, or autonomic dysfunction. Supporting documentation should include neurological exam findings, electromyography (EMG), nerve conduction studies (NCS), and often serological tests for paraneoplastic antibodies.

• Always sequence the underlying malignancy code first, as this is a manifestation of the cancer.
• Do not use this code for neurological complications directly caused by tumor compression, metastasis, or treatment side effects (e.g., chemotherapy-induced neuropathy).
• Ensure documentation specifies "paraneoplastic" to differentiate from other causes of neuromyopathy or neuropathy.