G91.9
BillableHydrocephalus, unspecified
Hydrocephalus, unspecified
Coding Notes
Includes
Conditions included under this code
- acquired hydrocephalus
Excludes 1
Codes that cannot be used together with this code (mutual exclusion)
Excludes 2
Conditions not included here, but the patient may have both
- •certain conditions originating in the perinatal periodP04-P96
- •certain infectious and parasitic diseasesA00-B99
- •complications of pregnancy, childbirth and the puerperiumO9A)O00
- •congenital malformations, deformations, and chromosomal abnormalitiesQ00-Q99
- •endocrine, nutritional and metabolic diseasesE00-E88
- •injury, poisoning and certain other consequences of external causesS00-T88
- •neoplasmsC00-D49
- •symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classifiedR00-R94
Related Codes(6)
ICD-11 Equivalents(1)
ICD-11 Equivalents
View full mappingCorresponding ICD-11 codes from the WHO crosswalk mapping
Also Known As / Clinical Terms(62)
SNOMED CT
- Acquired hydrocephalus4088009
- Arrested hydrocephalus4113009
- Aqueduct of Sylvius anomaly25397008
- CSF - Cerebrospinal rhinorrhea85638002
- CSF - Cerebrospinal rhinorrhoea85638002
- Cerebrospinal fluid rhinorrhea85638002
- Cerebrospinal fluid rhinorrhoea85638002
- Cerebrospinal rhinorrhea85638002
- Cerebrospinal rhinorrhoea85638002
- Internal hydrocephalus128431009
- Hydrocephalus230745008
- Hydrocephaly230745008
- External hydrocephalus253132009
- Hydrocephalus with anomaly of aqueduct of Sylvius253133004
- Acquired hydrocephalus of newborn782432008
- Cerebrospinal fluid rhinorrhea due to hydrocephalus1259109009
- Cerebrospinal fluid rhinorrhoea due to hydrocephalus1259109009
- Cranial cerebrospinal fluid leak due to hydrocephalus1259542001
- Leak of cranial cerebrospinal fluid due to hydrocephalus1259542001
- Cranial cerebrospinal fluid fistula1259545004
- Cranial cerebrospinal fluid leak1259545004
- Leak of cranial cerebrospinal fluid1259545004
UMLS
- HydrocephalusC0020255
- Hydrocephalus (disorder)C0020255
- Hydrocephalus NOSC0020255
- Hydrocephalus, unspecifiedC0020255
- HydrocephalyC0020255
- Nonsyndromal hydrocephalusC0020255
- Too much cerebrospinal fluid in the brainC0020255
- Water on the brainC0020255
- hydrencephalusC0020255
- hydrencephalyC0020255
- hydrocephalusC0020255
- hydrocephalyC0020255
Clinical Terms
- Acquired hydrocephalus
- Cerebrospinal rhinorrhoea
- Nonsyndromal hydrocephalus
- Water on the brain
- Arrested hydrocephalus
- Hydrocephalus with anomaly of aqueduct of Sylvius
- Cerebrospinal fluid rhinorrhea
- Hydrocephaly
- Acquired hydrocephalus of newborn
- CSF - Cerebrospinal rhinorrhoea
- Aqueduct of Sylvius anomaly
- External hydrocephalus
- Cranial cerebrospinal fluid leak
- Too much cerebrospinal fluid in the brain
- Cerebrospinal fluid rhinorrhea due to hydrocephalus
- CSF - Cerebrospinal rhinorrhea
- Cranial cerebrospinal fluid leak due to hydrocephalus
- Cranial cerebrospinal fluid fistula
- hydrencephaly
- Cerebrospinal fluid rhinorrhoea
- Leak of cranial cerebrospinal fluid due to hydrocephalus
- Hydrocephalus NOS
- Cerebrospinal rhinorrhea
- Hydrocephalus (disorder)
- hydrencephalus
- Cerebrospinal fluid rhinorrhoea due to hydrocephalus
- Internal hydrocephalus
- Leak of cranial cerebrospinal fluid
Frequently Asked Questions
What is the ICD-10 code for hydrocephalus, unspecified?
The ICD-10-CM code for hydrocephalus, unspecified is G91.9. The full clinical description is "Hydrocephalus, unspecified". G91.9 is a billable/specific code that can be used on insurance claims and medical billing.
What does ICD-10 code G91.9 mean?
ICD-10-CM code G91.9 represents “Hydrocephalus, unspecified”. It is classified under Chapter 6: Diseases of the Nervous System and is a billable/specific code that can be used on a claim.
Is G91.9 a billable code?
Yes, G91.9 is a billable/specific ICD-10-CM code and can be used to indicate a diagnosis on a medical claim.
What chapter is G91.9 in?
G91.9 is in Chapter 6: Diseases of the Nervous System (codes G00-G99).
What codes cannot be used with G91.9?
G91.9 has Excludes1 notes indicating codes that cannot be used together with it, including: Arnold-Chiari syndrome with hydrocephalus (Q07.-); congenital hydrocephalus (Q03.-); spina bifida with hydrocephalus (Q05.-).
What SNOMED CT codes does G91.9 map to?
G91.9 maps to 12 SNOMED CT concepts: 4088009, 782432008, 25397008, 4113009, 85638002, and 7 more. SNOMED CT is a clinical terminology used in electronic health records.
What are the UMLS CUIs for G91.9?
G91.9 is linked to 1 UMLS Concept Unique Identifier: C0020255. The UMLS (Unified Medical Language System) integrates multiple biomedical vocabularies maintained by the U.S. National Library of Medicine.
How does G91.9 relate to ICF functioning codes?
ICF (International Classification of Functioning, Disability and Health) codes describe how conditions like hydrocephalus, unspecified affect a person's functioning — body functions, activities, participation, and environmental factors. AutoICD provides ICF Core Sets for 12+ conditions and can map clinical text to ICF categories automatically. Browse the ICF directory to explore functioning codes.
What is the ICD-11 equivalent of G91.9?
G91.9 maps to the ICD-11 code: 8D64.Z (Hydrocephalus, unspecified).
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Includes SNOMED Clinical Terms® (SNOMED CT®) used by permission of SNOMED International. Includes content from the UMLS Metathesaurus, courtesy of the U.S. National Library of Medicine.