A87 vs B05.1
A87 and B05.1 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.
The official note, declared on A87
meningitis due to measles virus (B05.1)
B05.1
Measles complicated by meningitis
Billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- B00-B09
Use when the record says
- Postmeasles meningitis
Indexed under
- Meningitis › postmeasles (basal) (basic) (brain) (cerebral) (cervical) (congestive) (diffuse) (hemorrhagic) (infantile) (membranous) (metastatic) (nonspecific) (pontine) (progressive) (simple) (spinal) (subacute) (sympathetic) (toxic)
- Measles › with › meningitis (black) (hemorrhagic) (suppressed)
- Meningitis › in › measles (basal) (basic) (brain) (cerebral) (cervical) (congestive) (diffuse) (hemorrhagic) (infantile) (membranous) (metastatic) (nonspecific) (pontine) (progressive) (simple) (spinal) (subacute) (sympathetic) (toxic)
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