M33.91

Billable

Dermatopolymyositis, unspecified with respiratory involvement

This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).

What This Code Means

A rare autoimmune disease with features of both dermatomyositis and polymyositis, with respiratory system involvement such as lung inflammation.

Coding Tips

•Document respiratory manifestations including dyspnea, pulmonary function test results, or imaging findings
•Consider additional coding for interstitial lung disease or other specific respiratory conditions

Clinical Significance

Unspecified dermatopolymyositis with respiratory involvement represents a serious combination requiring immediate aggressive treatment and pulmonology consultation. The respiratory complication significantly worsens prognosis and increases mortality risk.

Documentation Requirements

✓Evidence of inflammatory myopathy with skin involvement
✓Documentation of respiratory system involvement
✓Pulmonary function testing showing impairment
✓Chest imaging demonstrating lung changes
✓Documentation that specific myositis subtype is unclear
✓Treatment plan addressing respiratory complications
✓Monitoring plan for lung function
✓Coordination between rheumatology and pulmonology

Commonly Confused Codes

M33.11 — Use when dermatomyositis is specifically diagnosed M33.21 — Use when polymyositis is specifically diagnosed J84.10 — Use for idiopathic lung disease, not myositis-related M33.90 — Use when respiratory involvement is not documented

Code Hierarchy

└M33Dermatopolymyositis └M33.9Dermatopolymyositis, unspecified └M33.91Dermatopolymyositis, unspecified with respiratory involvement

└M33.91Dermatopolymyositis, unspecified with respiratory involvement