G83.1 vs I69

G83.1 and I69 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 G83.1

monoplegia of lower limbs due to sequela of cerebrovascular disease (I69.04-, I69.14-, I69.24-, I69.34-, I69.84-, I69.94-)

G83.1

Monoplegia of lower limb

Not billable

Chapter 6: Diseases of the nervous system
Section: G80-G83

Use when the record says

Paralysis of lower limb

Indexed under

Monoplegia › lower limb
Paralysis, paralytic › leg (complete) (incomplete)

I69

Sequelae of cerebrovascular disease

Not billable

Chapter 9: Diseases of the circulatory system
Section: I60-I69

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