B26.85

HCC Category Mapping

What This Code Means

Inflammation of the joints (arthritis) caused by the mumps virus, occurring as a complication of mumps infection.

Coding Tips

• •Document which joints are affected and whether symptoms are symmetric or asymmetric
• •Mumps arthritis is typically self-limited; specify if monoarticular or polyarticular involvement

Clinical Significance

Mumps arthritis is an uncommon but recognized complication of mumps virus infection, occurring in approximately 0.4% of mumps cases. It typically presents as a migratory polyarthritis affecting large joints and is usually self-limited, resolving within weeks. In the era of widespread MMR vaccination, this condition is rare but may be seen during outbreaks.

Documentation Requirements

• ✓Confirmed mumps infection (positive mumps IgM or viral PCR)
• ✓Joint involvement documented: specific joints affected, symmetry, duration
• ✓Timeline of arthritis relative to parotitis or other mumps symptoms
• ✓MMR vaccination history
• ✓Clinical course documentation: onset, peak, resolution

Commonly Confused Codes