ICD-10 Code G58.9 – Mononeuropathy, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G58.9 – Mononeuropathy, unspecified
What it is
G58.9 identifies a disorder of a single peripheral nerve when the specific nerve is not named in the record. Use it when documentation supports mononeuropathy but does not specify the nerve or exact cause.
Clinical signs
Clinical features vary; refer to documentation. Common findings in mononeuropathy include localized numbness, tingling, pain, weakness, or reduced reflexes in the distribution of one nerve.
When to use this code
Use this code when the provider documents mononeuropathy, neuropathy of one nerve, or an isolated peripheral nerve disorder without further detail. It is appropriate when the affected nerve cannot be identified from the note. If laterality, nerve name, or cause is documented, code the more specific option.
Do not use for
Do not use G58.9 for polyneuropathy, radiculopathy, or generalized neuropathic symptoms affecting multiple nerves. Check documentation if the record names a specific entrapment neuropathy or traumatic nerve injury.
Coding tip
Code G58.9 only after confirming the note lacks a named nerve or more specific mononeuropathy diagnosis.