Q07.00 Arnold-Chiari syndrome without spina bifida or hydrocephalus

Billable ICD-10-CM code, FY2026. Exempt from present-on-admission (POA) reporting.

Applies from Q07 Other congenital malformations of nervous system

Excludes2 (not included here)

• congenital central alveolar hypoventilation syndrome (G47.35)
• familial dysautonomia [Riley-Day] (G90.1)
• neurofibromatosis (nonmalignant) (Q85.0-)

Applies from Q07.0 Arnold-Chiari syndrome

Applicable to

• Arnold-Chiari syndrome, type II

Excludes1 (never code together)

• Arnold-Chiari syndrome, type III (Q01.-)
• Arnold-Chiari syndrome, type IV (Q04.8)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 182 — Spinal Cord Disorders/Injuries
• CMS-HCC V22: HCC 72 — Spinal Cord Disorders/Injuries
• RxHCC V08: HCC 155 — Spinal Cord Disorders
• ESRD V24: HCC 72

MS-DRG index

Defines the logic of DRG(s) 091-093 in MDC 01.

Approximate ICD-9-CM (GEMs)

• 741.90 Spina bifida without mention of hydrocephalus, unspecified region (approximate)

Code annotations containing back-references to Q07.00

Back-references to Q07.0

• Type 1 Excludes: Q03 Congenital hydrocephalus ("Arnold-Chiari syndrome, type II (Q07.0-)")
• Type 1 Excludes: Q05 Spina bifida ("Arnold-Chiari syndrome, type II (Q07.0-)")

Back-references to Q07

• Type 1 Excludes: G91 Hydrocephalus ("Arnold-Chiari syndrome with hydrocephalus (Q07.-)")

Diagnosis Index entries for Q07.00

• Arnold-Chiari disease, obstruction or syndrome (type II)

Nearby codes

• Q07 Other congenital malformations of nervous system
• Q07.0 Arnold-Chiari syndrome
• Q07.00 Arnold-Chiari syndrome without spina bifida or hydrocephalus (this code)
• Q07.01 Arnold-Chiari syndrome with spina bifida
• Q07.02 Arnold-Chiari syndrome with hydrocephalus
• Q07.03 Arnold-Chiari syndrome with spina bifida and hydrocephalus
• Q07.8 Other specified congenital malformations of nervous system
• Q07.9 Congenital malformation of nervous system, unspecified