Other giant cell arteritis

This code represents a systemic inflammatory vasculitis affecting medium and large arteries, specifically when the clinical presentation or pathological findings do not fully meet the criteria for classic temporal arteritis or Takayasu arteritis, but still demonstrate features of giant cell arteritis. It encompasses atypical or less common manifestations of giant cell arteritis.

Use this code for patients diagnosed with giant cell arteritis that doesn't fit the more specific categories of temporal arteritis (M31.5) or Takayasu arteritis (M31.4). Documentation should clearly indicate a diagnosis of giant cell arteritis with atypical features or involvement of vessels other than the temporal arteries, without meeting criteria for other specified forms.

• Ensure documentation specifies "giant cell arteritis" and explicitly rules out or does not meet criteria for M31.4 or M31.5.
• Do not use this code if the documentation clearly indicates temporal arteritis; use M31.5 instead.
• Consider sequencing this code as a primary diagnosis if it's the main reason for the encounter, or as a secondary diagnosis if it's a comorbidity impacting treatment.