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ICD-10 Guide
ICD-10 CodesM05.479

M05.479

Billable

Rheumatoid myopathy with rheumatoid arthritis of unspecified ankle and foot

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/12/2025

Code Description

ICD-10 M05.479 is a billable code used to indicate a diagnosis of rheumatoid myopathy with rheumatoid arthritis of unspecified ankle and foot.

Key Diagnostic Point:

Rheumatoid myopathy is a condition characterized by muscle weakness and pain associated with rheumatoid arthritis (RA), an autoimmune disorder that primarily affects the joints. In this case, the unspecified ankle and foot involvement indicates that the specific joints affected are not detailed. Anatomically, the ankle consists of the tibia, fibula, and talus, while the foot comprises multiple bones including the metatarsals and phalanges. Pathophysiologically, RA leads to chronic inflammation, which can extend to the muscle tissue, resulting in myopathy. Clinically, patients may present with joint swelling, stiffness, and reduced range of motion, particularly in the ankle and foot, impacting ambulation and daily activities. The condition may also lead to muscle atrophy due to disuse and inflammation, further complicating the clinical picture.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Involvement of multiple anatomical structures (ankle and foot)
  • Overlap of symptoms between myopathy and arthritis
  • Need for detailed documentation of joint involvement
  • Potential for systemic manifestations affecting coding

Audit Risk Factors

  • Inadequate documentation of joint involvement
  • Failure to specify laterality when applicable
  • Misclassification of myopathy severity
  • Lack of supporting evidence for functional limitations

Specialty Focus

Medical Specialties

Orthopedics

Documentation Requirements

Orthopedic documentation should include imaging studies (X-rays, MRIs) to assess joint integrity and functional assessments to evaluate mobility and strength.

Common Clinical Scenarios

Common scenarios include surgical interventions for joint deformities or arthroplasties due to severe RA.

Billing Considerations

Joint-specific considerations include documenting the severity of joint damage and any surgical history.

Rheumatology

Documentation Requirements

Rheumatologic documentation should include laboratory tests for inflammation markers (e.g., ESR, CRP) and assessments of disease activity (e.g., DAS28 score).

Common Clinical Scenarios

Scenarios often involve managing systemic symptoms and adjusting DMARD therapy based on disease progression.

Billing Considerations

Considerations include monitoring for systemic involvement and potential comorbidities.

Physical Medicine

Documentation Requirements

Functional assessments should evaluate the patient's ability to perform daily activities and any need for assistive devices.

Common Clinical Scenarios

Rehabilitation scenarios may focus on restoring mobility and strength through physical therapy.

Billing Considerations

Mobility limitations should be documented, including the need for orthotics or other assistive devices.

Coding Guidelines

Inclusion Criteria

Use M05.479 When
  • Official coding guidelines require specificity in documenting laterality (if applicable), severity of the condition, and the type of encounter (initial, follow
  • up, etc
  • Coders should ensure that all relevant clinical information is captured to support the diagnosis

Exclusion Criteria

Do NOT use M05.479 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

97110CPT Code

Therapeutic exercises

Clinical Scenario

Used in physical therapy to improve strength and mobility in patients with rheumatoid myopathy.

Documentation Requirements

Document the specific exercises performed and the patient's response to therapy.

Specialty Considerations

Physical medicine specialists should focus on functional outcomes and progress.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for greater specificity in coding musculoskeletal conditions, enabling better tracking of disease prevalence and treatment outcomes. Coders must be familiar with the nuances of the new codes to ensure accurate billing and reporting.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for greater specificity in coding musculoskeletal conditions, enabling better tracking of disease prevalence and treatment outcomes. Coders must be familiar with the nuances of the new codes to ensure accurate billing and reporting.

Reimbursement & Billing Impact

billing and reporting.

Resources

Clinical References

  • •
    American College of Rheumatology Guidelines

Coding & Billing References

  • •
    American College of Rheumatology Guidelines

Frequently Asked Questions

What is the significance of specifying joint involvement in rheumatoid myopathy coding?

Specifying joint involvement is crucial as it impacts treatment decisions and the understanding of disease progression. Accurate documentation helps in assessing the severity of the condition and planning appropriate interventions.