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ICD-10 Guide
ICD-10 CodesG91.2

G91.2

Billable

(Idiopathic) normal pressure hydrocephalus

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

Code Description

ICD-10 G91.2 is a billable code used to indicate a diagnosis of (idiopathic) normal pressure hydrocephalus.

Key Diagnostic Point:

Idiopathic normal pressure hydrocephalus (NPH) is a neurological condition characterized by an accumulation of cerebrospinal fluid (CSF) in the brain's ventricles, leading to ventricular enlargement without an increase in intracranial pressure. This condition typically presents in older adults and is often associated with a classic triad of symptoms: gait disturbance, cognitive dysfunction, and urinary incontinence. The exact etiology of idiopathic NPH remains unclear, but it is thought to involve a combination of factors including age-related changes in CSF dynamics and potential neurodegenerative processes. Diagnosis is primarily clinical, supported by neuroimaging findings that reveal ventricular enlargement. Treatment often involves the surgical placement of a ventriculoperitoneal shunt to drain excess CSF, which can lead to significant improvement in symptoms if performed early. However, the response to treatment can vary, and not all patients experience the same degree of benefit.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Differentiation from other types of hydrocephalus
  • Need for comprehensive documentation of symptoms
  • Potential overlap with other neurological disorders
  • Variability in treatment response and follow-up care

Audit Risk Factors

  • Inadequate documentation of symptoms and clinical findings
  • Failure to include neuroimaging results in the medical record
  • Misdiagnosis due to symptom overlap with other conditions
  • Lack of follow-up documentation post-treatment

Specialty Focus

Medical Specialties

Neurology

Documentation Requirements

Detailed neurological examination findings, neuroimaging reports, and symptom progression.

Common Clinical Scenarios

Patients presenting with gait disturbances, cognitive decline, and urinary incontinence.

Billing Considerations

Ensure that all symptoms are documented clearly and that neuroimaging supports the diagnosis.

Neurosurgery

Documentation Requirements

Surgical notes, pre-operative assessments, and post-operative follow-up documentation.

Common Clinical Scenarios

Patients undergoing ventriculoperitoneal shunt placement for NPH.

Billing Considerations

Document the rationale for surgical intervention and any complications or outcomes.

Coding Guidelines

Inclusion Criteria

Use G91.2 When
  • According to ICD
  • 10 guidelines, G91
  • 2 should be used when the condition is idiopathic and not due to other identifiable causes
  • Documentation must support the diagnosis, including clinical findings and imaging results

Exclusion Criteria

Do NOT use G91.2 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

62223CPT Code

Insertion of a ventriculoperitoneal shunt

Clinical Scenario

Used for patients diagnosed with idiopathic NPH requiring surgical intervention.

Documentation Requirements

Surgical consent, pre-operative assessments, and post-operative follow-up notes.

Specialty Considerations

Neurosurgeons must document the rationale for surgery and any complications.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of idiopathic normal pressure hydrocephalus, improving the accuracy of data collection and reimbursement processes.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of idiopathic normal pressure hydrocephalus, improving the accuracy of data collection and reimbursement processes.

Reimbursement & Billing Impact

reimbursement processes.

Resources

Clinical References

  • •
    Normal Pressure Hydrocephalus: A Guide for Patients and Families

Coding & Billing References

  • •
    Normal Pressure Hydrocephalus: A Guide for Patients and Families

Frequently Asked Questions

What are the key symptoms of idiopathic normal pressure hydrocephalus?

The key symptoms include gait disturbance, cognitive decline, and urinary incontinence, often referred to as the classic triad.

How is idiopathic normal pressure hydrocephalus diagnosed?

Diagnosis is based on clinical evaluation, the presence of the classic triad of symptoms, and neuroimaging that shows ventricular enlargement without increased intracranial pressure.