ICD-10 Code B26.84 – Mumps polyneuropathy (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B26.84 – Mumps polyneuropathy
What it is
B26.84 identifies polyneuropathy associated with mumps infection. Use it when documentation links mumps to widespread peripheral nerve involvement rather than a single focal nerve problem.
Clinical signs
Clinical features vary; refer to documentation. Typical neuropathy findings may include numbness, tingling, weakness, or reduced reflexes, and the record should support a polyneuropathy pattern with mumps as the cause.
When to use this code
Use B26.84 when the provider documents mumps with polyneuropathy, or clearly states that the neuropathy is due to mumps. It may appear in cases where neurologic complications develop during or after the infection. If the cause is unclear, check documentation before assigning this code.
Do not use for
Do not use this code for mumps without nerve involvement, or for neuropathy from another cause. If the chart only says “neuropathy” or “viral neuropathy” without a mumps link, check documentation.
Coding tip
Always confirm that both the mumps diagnosis and the polyneuropathy relationship are documented before coding B26.84.