Q04.5 ICD-10-CA code: Megalencephaly
Q04.5 is the ICD-10-CA code for “Megalencephaly” in CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026.
Official description
Q04.5Megalencephaly
ICD-10-CA · Canada · Also written Q045
Notes for Q04.5
As CIHI prints them, with any note Q04.5 takes from the headings above it.
Excludes
Conditions classified elsewhere.
- Cyclopia (Q87.0)macrocephaly (Q75.3)From Q04 Other congenital malformations of brain
- Inborn errors of metabolism (E70-E90)From Chapter 17: Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
Where Q04.5 sits
- 1ChapterChapter 17: Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- 2Block Q00-Q07Congenital malformations of the nervous system
- 3Category Q04Other congenital malformations of brain
- 4Valid code Q04.5Megalencephaly
Source and release
- Data release
- ICD-10-CA · FY 2026–2027
- Effective date
- Apr 1, 2026
- Publisher
- CIHI
This page is built from the ICD-10-CA catalog that Vero Codes reads when it suggests codes: Canadian Institute for Health Information’s FY 2026–2027 release, imported from the publisher’s file and checked against it. The description, notes and structured data come from the same record.
Frequently asked questions
What does ICD-10-CA code Q04.5 mean?
Q04.5 is the ICD-10-CA code for “Megalencephaly” in CIHI’s ICD-10-CA FY 2026–2027 release.
Where is Q04.5 in ICD-10-CA?
Q04.5 sits under Q04 Other congenital malformations of brain, within Q00-Q07 Congenital malformations of the nervous system, within Chapter 17: Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99).
What coding notes apply to Q04.5?
ICD-10-CA lists Excludes notes for Q04.5, including those from the headings it sits under. They are listed on this page with where each one comes from.
Which ICD-10-CA release does this page use?
It uses CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026 to Mar 31, 2027. It is a reference: confirm the code against the current list and the payer’s rules before you submit it.