I67.7 vs M30.1
I67.7 and M30.1 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
Cerebral arteritis, not elsewhere classified
- Chapter 9
- Diseases of the circulatory system
- Section
- I60-I69
- Granulomatous angiitis of the nervous system
- Angiitis › nervous system, granulomatous
- Arteritis › brain
- Arteritis › cerebral
- Endarteritis › brain (bacterial, subacute) (infective)
- Endarteritis › cerebral or cerebrospinal (bacterial, subacute) (infective)
Polyarteritis with lung involvement [Churg-Strauss]
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M30-M36
- Allergic granulomatous angiitis
- Eosinophilic granulomatosis with polyangiitis [EGPA]
- Churg-Strauss syndrome
- EGPA (eosinophilic granulomatosis with polyangiitis)
- Angiitis › allergic granulomatous
- Granulomatosis › eosinophilic, with polyangiitis [EGPA]
- Syndrome › Churg-Strauss
These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027