M04.2

HCC Category Mapping

What This Code Means

A rare genetic condition caused by mutations in the NLRP3 gene that leads to recurrent fever, inflammation, and joint pain.

Coding Tips

• •CAPS (Cryopyrin-Associated Periodic Syndromes) includes FCAS, MWS, and NOMID; document the specific type if known
• •This is a serious autoinflammatory condition requiring specialized treatment; ensure proper documentation for medical necessity and insurance authorization

Clinical Significance

This represents cryopyrin-associated periodic syndromes (CAPS), a specific group of rare genetic autoinflammatory conditions caused by NLRP3 gene mutations. These conditions include familial cold autoinflammatory syndrome, Muckle-Wells syndrome, and neonatal-onset multisystem inflammatory disease, requiring specialized treatment with IL-1 inhibitors.

Documentation Requirements

• ✓Documentation of cryopyrin-associated periodic syndrome diagnosis
• ✓Evidence of characteristic clinical features (fever, rash, joint pain)
• ✓Genetic testing confirmation of NLRP3 mutations when available
• ✓Documentation of cold-triggered symptoms if applicable
• ✓Evidence of systemic inflammation and inflammatory markers
• ✓Exclusion of other periodic fever syndromes
• ✓Assessment for complications (hearing loss, amyloidosis, CNS involvement)
• ✓Response to IL-1 antagonist therapy if initiated

Commonly Confused Codes