FY2027
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Excludes1 pair

G91.1 vs G93.2

G91.1 and G93.2 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.

The official note, declared on G93.2
obstructive hydrocephalus (G91.1)
G91.1

Obstructive hydrocephalus

Billable
Chapter 6
Diseases of the nervous system
Section
G89-G99
Indexed under
  • Block, blocked › foramen Magendie (acquired)
  • Hydrocephalus › foramen Magendie block (acquired)
  • Hydrocephalus › noncommunicating
  • Hydrocephalus › obstructive
  • Obstruction, obstructed, obstructive › aqueduct of Sylvius
G93.2

Benign intracranial hypertension

Billable
Chapter 6
Diseases of the nervous system
Section
G89-G99
Use when the record says
  • Pseudotumor
Indexed under
  • Pseudohydrocephalus
  • Pseudotumor
  • Symond's syndrome
  • Hydrocephalus › otitic
  • Hypertension, hypertensive › benign, intracranial

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