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ICD-10 Guide
ICD-10 CodesG91.9

G91.9

Billable

Hydrocephalus, unspecified

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/05/2025

Code Description

ICD-10 G91.9 is a billable code used to indicate a diagnosis of hydrocephalus, unspecified.

Key Diagnostic Point:

Hydrocephalus is a condition characterized by an abnormal accumulation of cerebrospinal fluid (CSF) within the ventricles of the brain, leading to increased intracranial pressure. This condition can occur at any age and may be congenital or acquired. Symptoms can vary widely depending on the age of onset and the underlying cause. In infants, signs may include an enlarged head, irritability, vomiting, and developmental delays. In older children and adults, symptoms may include headaches, nausea, vision problems, cognitive difficulties, and gait disturbances. Hydrocephalus can result from various factors, including obstruction of CSF flow, overproduction of CSF, or impaired absorption. The unspecified designation indicates that the specific type or cause of hydrocephalus has not been determined, which can complicate treatment and management. Diagnosis typically involves neuroimaging techniques such as MRI or CT scans to visualize the ventricles and assess for any obstructions or abnormalities. Treatment often involves surgical intervention, such as the placement of a shunt to drain excess fluid and relieve pressure on the brain.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variety of potential underlying causes
  • Need for precise documentation of symptoms
  • Differentiation from other neurological disorders
  • Potential for co-existing conditions

Audit Risk Factors

  • Inadequate documentation of symptoms
  • Failure to specify the type of hydrocephalus
  • Lack of supporting imaging studies
  • Misalignment between diagnosis and treatment codes

Specialty Focus

Medical Specialties

Neurology

Documentation Requirements

Detailed neurological examination findings, imaging results, and treatment plans.

Common Clinical Scenarios

Patients presenting with headaches, cognitive decline, or developmental delays.

Billing Considerations

Ensure that all neurological assessments and imaging studies are documented to support the diagnosis.

Pediatrics

Documentation Requirements

Growth charts, developmental assessments, and parental observations.

Common Clinical Scenarios

Infants with increased head circumference or developmental delays.

Billing Considerations

Document any family history of neurological disorders and the child's developmental milestones.

Coding Guidelines

Inclusion Criteria

Use G91.9 When
  • Follow the official ICD
  • CM coding guidelines, ensuring that the diagnosis is supported by clinical documentation
  • Include any relevant imaging studies and treatment plans in the patient's medical record

Exclusion Criteria

Do NOT use G91.9 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

62230CPT Code

Insertion of ventricular catheter

Clinical Scenario

Used in cases of acute hydrocephalus requiring immediate drainage.

Documentation Requirements

Document the indication for the procedure and any imaging studies performed.

Specialty Considerations

Neurosurgery should provide detailed operative notes.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of hydrocephalus, improving the ability to capture the nuances of the condition and its management. G91.9 serves as a catch-all for unspecified cases, but coders should strive for specificity when possible.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of hydrocephalus, improving the ability to capture the nuances of the condition and its management. G91.9 serves as a catch-all for unspecified cases, but coders should strive for specificity when possible.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of hydrocephalus, improving the ability to capture the nuances of the condition and its management. G91.9 serves as a catch-all for unspecified cases, but coders should strive for specificity when possible.

Resources

Clinical References

  • •
    Hydrocephalus Association

Coding & Billing References

  • •
    Hydrocephalus Association

Frequently Asked Questions

What are the common causes of hydrocephalus?

Common causes include congenital malformations, infections such as meningitis, tumors, and traumatic brain injuries that obstruct CSF flow.