ICD-10-CM 2027
ICD-10 code for Arnold-Chiari disease
From the official ICD-10-CM alphabetic index entry “Arnold-Chiari disease, obstruction or syndrome (type II)”. Page updated September 29, 2026.
About coding Arnold-Chiari disease
The ICD-10-CM code for Arnold-Chiari disease is Q07.00 (Arnold-Chiari syndrome without spina bifida or hydrocephalus). The official index lists 5 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on Q07.00.
Within Q07.0, choose Q07.00 (without spina bifida or hydrocephalus) only when documentation doesn't support a more specific option: with spina bifida (Q07.01), with hydrocephalus (Q07.02) and with spina bifida and hydrocephalus (Q07.03).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 091 (Other Disorders of Nervous System with MCC, relative weight 1.7046), DRG 092 (Other Disorders of Nervous System with CC, relative weight 1.0239), DRG 093 (Other Disorders of Nervous System without CC/MCC, relative weight 0.7783), DRG 791 (Prematurity with Major Problems, relative weight 4.1075) and DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), in MDC 01 (Diseases and Disorders of the Nervous System) and MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific Arnold-Chiari disease codes (official index)
- with
- hydrocephalus Q07.02 — Arnold-Chiari syndrome with hydrocephalus
- with spina bifida Q07.03 — Arnold-Chiari syndrome with spina bifida and hydrocephalus
- spina bifida Q07.01 — Arnold-Chiari syndrome with spina bifida
- with hydrocephalus Q07.03 — Arnold-Chiari syndrome with spina bifida and hydrocephalus
- type III
- type IV Q04.8 — Other specified congenital malformations of brain
Common questions about Arnold-Chiari disease ICD-10 codes
What is the ICD-10 code for Arnold-Chiari disease?
- Q07.00 — Arnold-Chiari syndrome without spina bifida or hydrocephalus. More specific codes apply when the documentation supports them: Q07.02, Q07.03, Q07.01, Q07.03 and others below.
What is the ICD-10 code for type iv arnold-chiari disease?
- Q04.8 — Other specified congenital malformations of brain.
Is Q07.00 billable?
- Yes. Q07.00 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q07.00 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q07.00 as a principal diagnosis.
Is Q07.00 a CC or MCC?
- No. Q07.00 is neither a CC nor an MCC under MS-DRG v44.0.