- Clinical or known evidence of associated systemic diseases that might cause neuropathy, including but not limited to connective tissue disease, HIV infection, hepatitis, Lyme disease, cancer (with the exception of benign skin cancer), Castleman's disease and systemic lupus erythematosus, diabetes mellitus (defined as a history of type 1 or type 2 diabetes with fasting plasma glucose ≥ 7.0 mmol/L), a malignant plasma cell dysplasia, immunoglobulin M (IgM) paraproteinemia, and amiodarone therapy.