2026 ICD-10-CM Diagnosis Code Q03.9Congenital hydrocephalus, unspecified

ICD-10-CM Codes›Q00-Q99›Q00-Q07›Q03

ICD-10-CM Q03.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q03.9 is a billable ICD-10-CM diagnosis code for congenital hydrocephalus, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nervous system congenital anomalies.

Code Identity

ICD-10-CM Code
Q03.9
Billable Status
Yes — Valid for Submission
Code Describes
Congenital hydrocephalus, unspecified
Short Description
Congenital hydrocephalus, unspecified
Same as the full description in the CMS dataset.
Parent Code
Q03
Congenital hydrocephalus

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ00-Q07Congenital malformations of the nervous system
CategoryQ03Congenital hydrocephalus
This CodeQ03.9Congenital hydrocephalus, unspecified

Present on Admission (POA)Billing

Q03.9 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal blue sclerae
  • Agenesis of cerebellum
  • Aqueduct of Sylvius anomaly
  • Arrested hydrocephalus
  • Beemer Ertbruggen syndrome
  • Central obesity
  • Cerebellum agenesis with hydrocephaly
  • Cerebral degeneration due to congenital hydrocephalus
  • Cerebrospinal fluid rhinorrhea
  • Cerebrospinal fluid rhinorrhea due to hydrocephalus
  • Congenital anomaly of sclera
  • Congenital deformity of lumbosacral region
  • Congenital elevation of scapula
  • Congenital endocardial fibroelastosis
  • Congenital hydrocephalus
  • Congenital hydrocephalus, low insertion of umbilicus syndrome
  • Congenital hypoplasia of cerebral hemisphere
  • Congenital hypoplasia of cerebral white matter
  • Congenital kyphosis
  • Congenital kyphosis of thoracic spine
  • Congenital malformation of the meninges
  • Congenital obstructive hydrocephalus
  • Congenital stenosis of aqueduct of Sylvius
  • Cranial cerebrospinal fluid leak
  • Craniosynostosis with Dandy-Walker malformation and hydrocephalus syndrome
  • Dandy-Walker syndrome
  • Endocardial fibroelastosis
  • External hydrocephalus
  • Game Friedman Paradice syndrome
  • Hydrocephalus
  • Hydrocephalus associated with congenital aqueduct stenosis
  • Hydrocephalus with endocardial fibroelastosis and cataract syndrome
  • Hydrocephalus with obesity and hypogonadism syndrome
  • Hydrocephalus, blue sclera, nephropathy syndrome
  • Hydrocephalus, costovertebral dysplasia, Sprengel anomaly syndrome
  • Hydrocephalus, tall stature, joint laxity syndrome
  • Hypoplasia of corpus callosum
  • Internal hydrocephalus
  • Kyphosis of thoracic spine
  • L1 syndrome
  • Leak of cranial cerebrospinal fluid due to hydrocephalus
  • Macroencephaly
  • Mega cisterna magna
  • Megalencephaly, polymicrogyria, postaxial polydactyly, hydrocephalus syndrome
  • Obstructive hydrocephalus
  • Port-wine nevi, mega cisterna magna, hydrocephalus syndrome
  • Port-wine stain of skin
  • Thoracic dysplasia and hydrocephalus syndrome
  • VACTERL syndrome with hydrocephalus
  • X-linked hydrocephalus syndrome

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Absence(of) (organ or part) (complete or partial)
      • skull bone (congenital)
        • with
          • hydrocephalus
    • Agenesis
      • skull (bone)
        • with
          • hydrocephalus
    • Anomaly, anomalous(congenital) (unspecified type)
      • bone
        • skull
          • with
            • hydrocephalus
    • Anomaly, anomalous(congenital) (unspecified type)
      • skull
        • with
          • hydrocephalus
    • Deformity
      • skull (acquired)
        • congenital
          • with
            • hydrocephalus
    • Degeneration, degenerative
      • brain (cortical) (progressive)
        • in
          • congenital hydrocephalus
    • Distortion(s) (congenital)
      • skull bone (s) NEC
        • with
          • hydrocephalus
    • Hydrocephalus(acquired) (external) (internal) (malignant) (recurrent)
      • congenital (external) (internal)
    • Hydrocephalus(acquired) (external) (internal) (malignant) (recurrent)
      • newborn
    • Hypoplasia, hypoplastic
      • skull (bone)
        • with
          • hydrocephalus
    • Imperfect
      • closure (congenital)
        • skull
          • with
            • hydrocephalus

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MAL004
Nervous system congenital anomalies
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Dandy-Walker Syndrome

    a congenital abnormality of the central nervous system marked by failure of the midline structures of the cerebellum to develop, dilation of the fourth ventricle, and upward displacement of the transverse sinuses, tentorium, and torcula. clinical features include occipital bossing, progressive head enlargement, bulging of anterior fontanelle, papilledema, ataxia, gait disturbances, nystagmus, and intellectual compromise. (from menkes, textbook of child neurology, 5th ed, pp294-5)

  • Hydrocephalus

    excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, intracranial hypertension; headache; lethargy; urinary incontinence; and ataxia.

  • Hydrocephalus, Normal Pressure

    a form of compensated hydrocephalus characterized clinically by a slowly progressive gait disorder (see gait disorders, neurologic), progressive intellectual decline, and urinary incontinence. spinal fluid pressure tends to be in the high normal range. this condition may result from processes which interfere with the absorption of csf including subarachnoid hemorrhage, chronic meningitis, and other conditions. (from adams et al., principles of neurology, 6th ed, pp631-3)

  • Walker-Warburg Syndrome

    rare autosomal recessive lissencephaly type 2 associated with congenital muscular dystrophy and eye anomalies (e.g., retinal detachment; cataract; microphthalmos). it is often associated with additional brain malformations such as hydrocephaly and cerebellar hypoplasia and is the most severe form of the group of related syndromes (alpha-dystroglycanopathies) with common congenital abnormalities in the brain, eye and muscle development.

  • Endocardial Fibroelastosis

    a condition characterized by the thickening of endocardium due to proliferation of fibrous and elastic tissue, usually in the left ventricle leading to impaired cardiac function (cardiomyopathy, restrictive). it is most commonly seen in young children and rarely in adults. it is often associated with congenital heart anomalies (heart defects congenital;) infection; or gene mutation. defects in the tafazzin protein, encoded by taz gene, result in a form of autosomal dominant familial endocardial fibroelastosis.

  • Cerebrospinal Fluid Rhinorrhea

    discharge of cerebrospinal fluid through the nose. common etiologies include trauma, neoplasms, and prior surgery, although the condition may occur spontaneously. (otolaryngol head neck surg 1997 apr;116(4):442-9)

  • Congenital Hydrocephalus

    hydrocephalus that is present at birth.

  • External Hydrocephalus

    abnormal increase of cerebrospinal fluid in the subdural space of the brain.

  • Endocardial Fibroelastosis

    a rare disorder characterized by diffuse thickening of the endocardium. it presents with unexplained heart failure.

  • TAFAZZIN wt Allele|BTHS|Barth Syndrome Gene|CMD3A|Cardiomyopathy, Dilated 3A (X-Linked) Gene|EFE|EFE2|Endocardial Fibroelastosis 2 Gene|G4.5|LVNCX|TAZ|TAZ1|Tafazzin, Phospholipid-Lysophospholipid Transacylase wt Allele|Taz1

    human tafazzin wild-type allele is located in the vicinity of xq28 and is approximately 10 kb in length. this allele, which encodes tafazzin protein, plays a role in phospholipid metabolism, including cardiolipin remodeling. mutations in the gene are associated with barth syndrome, dilated cardiomyopathy (dcm), hypertrophic dcm, endocardial fibroelastosis and left ventricular noncompaction.

  • Congenital Kyphosis

    an abnormally increased curvature of the thoracic portion of the spine that is present at the time of birth.

  • Cerebrospinal Fluid Rhinorrhea

    discharge of cerebrospinal fluid through the nose.

Patient EducationClinical

Hydrocephalus

Hydrocephalus is the buildup of too much cerebrospinal fluid in the brain. Normally, this fluid cushions your brain. When you have too much, though, it puts harmful pressure on your brain.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert Q03.9 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
742.3 Congenital hydrocephalus
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About Q03.9Overview

Is Q03.9 (Congenital hydrocephalus) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report congenital hydrocephalus, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is Q03.9 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for congenital hydrocephalus, unspecified on inpatient claims.

What is the ICD-9 equivalent of Q03.9?

Under the General Equivalence Mappings, congenital hydrocephalus, unspecified converts to ICD-9-CM 742.3 (congenital hydrocephalus). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.