G91.1 vs G93.2
G91.1 and G93.2 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 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
- Hydrocephalus › foramen Magendie block (acquired) (external) (internal) (malignant) (recurrent)
- Hydrocephalus › noncommunicating (acquired) (external) (internal) (malignant) (recurrent)
- Hydrocephalus › obstructive (acquired) (external) (internal) (malignant) (recurrent)
- 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 (acquired) (external) (internal) (malignant) (recurrent)
- Hypertension, hypertensive › benign, intracranial (accelerated) (benign) (essential) (idiopathic) (malignant) (systemic)
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