ICD-10 Guide

A81.83

Fatal familial insomnia

BILLABLE STATUSYes

IMPLEMENTATION DATEOctober 1, 2015

LAST UPDATED09/05/2025

Code Description

ICD-10 A81.83 is a billable code used to indicate a diagnosis of fatal familial insomnia.

Key Diagnostic Point:

Fatal familial insomnia (FFI) is a rare genetic disorder characterized by a progressive inability to sleep, leading to severe neurological decline and ultimately death. It is caused by a mutation in the PRNP gene, which encodes the prion protein. The condition typically manifests in middle adulthood and is marked by insomnia, cognitive decline, and autonomic dysfunction. Patients may experience a range of symptoms including hallucinations, ataxia, and dysautonomia. As the disease progresses, individuals may develop severe neurological complications such as dementia and motor disturbances. The pathophysiology involves the accumulation of misfolded prion proteins in the brain, leading to neurodegeneration. Diagnosis is primarily clinical, supported by genetic testing and brain imaging, which may show atrophy in specific regions. Due to its genetic nature, family history plays a crucial role in diagnosis and management. FFI is distinct from other prion diseases, such as Creutzfeldt-Jakob disease, and requires careful differentiation in clinical settings.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

Requires understanding of genetic conditions and prion diseases.
Differentiation from other similar neurological disorders.
Documentation of family history and genetic testing results.
Potential for misdiagnosis with other sleep disorders.

Audit Risk Factors

Inadequate documentation of genetic testing.
Failure to document family history.
Misclassification with other sleep disorders.
Lack of detailed clinical notes on neurological symptoms.

Specialty Focus

Medical Specialties

Neurology

Documentation Requirements

Detailed neurological examination findings, family history, and genetic test results.

Common Clinical Scenarios

Patients presenting with insomnia, cognitive decline, and neurological symptoms.

Billing Considerations

Ensure comprehensive documentation of all neurological assessments and family history.

Genetics

Documentation Requirements

Genetic testing results and family pedigree charts.

Common Clinical Scenarios

Patients with a family history of prion diseases or unexplained neurological symptoms.

Billing Considerations

Accurate recording of genetic mutations and inheritance patterns.

Coding Guidelines

Inclusion Criteria

Use A81.83 When

Follow official ICD
10 coding guidelines for neurological disorders
Ensure accurate documentation of symptoms, family history, and genetic testing results

Exclusion Criteria

Do NOT use A81.83 When

Exclude other prion diseases and sleep disorders unless clearly differentiated

Related CPT Codes

81233CPT Code

Genetic testing for prion diseases

Clinical Scenario

Used when genetic testing is performed to confirm FFI.

Documentation Requirements

Document the reason for testing and results.

Specialty Considerations

Genetic specialists should ensure accurate family history documentation.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of prion diseases, enhancing the ability to track and manage rare conditions like FFI.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of prion diseases, enhancing the ability to track and manage rare conditions like FFI.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of prion diseases, enhancing the ability to track and manage rare conditions like FFI.

Resources

Clinical References

•
National Prion Disease Pathology Surveillance Center

Coding & Billing References

•
National Prion Disease Pathology Surveillance Center

Frequently Asked Questions

What is the primary cause of Fatal familial insomnia?

FFI is primarily caused by a genetic mutation in the PRNP gene, leading to the accumulation of misfolded prion proteins in the brain.

How is Fatal familial insomnia diagnosed?

Diagnosis is based on clinical symptoms, family history, and confirmation through genetic testing for PRNP mutations.

ICD-10 A81.83 is a billable code used to indicate a diagnosis of fatal familial insomnia.