Calcium pyrophosphate deposition disease
ICD-10 M11.8 · ICD-11 FA26.0

Chronic CPP Crystal Inflammatory Arthritis After Hydroxychloroquine Failure

Chronic CPP crystal inflammatory arthritis is a persistent inflammatory oligoarthritis or polyarthritis that can closely resemble rheumatoid arthritis. When first-line hydroxychloroquine therapy does not achieve adequate joint control, a next-line protocol defines the appropriate course of action.

Clinical scenario

This protocol applies to patients with chronic CPP crystal inflammatory arthritis — a form of calcium pyrophosphate deposition disease characterised by sustained synovitis affecting multiple joints. Presentation may be mistaken for RA due to overlapping features of chronic joint inflammation.

Previous treatment — inadequate response

The preceding treatment line used Hydroxychloroquine, targeting at least a 30% reduction in the number of swollen and tender joints. This protocol is indicated when that threshold is not reached — representing a confirmed inadequate response requiring escalation.

Next-line treatment approach

The escalated regimen involves a disease-modifying agent that has been specifically investigated for refractory CPPD and is endorsed by EULAR for severe cases. Full dosing parameters, monitoring, and the complete algorithm are contained within the structured protocol.

Treatment goals

Success is defined by a meaningful decrease in VAS pain scores, reduction in swollen and tender joint counts, and lowering of inflammatory markers including erythrocyte sedimentation rate and CRP. Symptom improvement is expected within a window of 4 to 16 weeks.

Instant Access to Structured Evidence-Based Regimens

References

DOI: 10.3389/fmed.2024.1327715

A subset of patients with CPP arthritis may present with symptoms of chronic joint inflammation that can be mistaken for RA.

Chronic CPP crystal arthritis, on the other hand, is a chronic inflammatory oligoarthritis or polyarthritis.

Methotrexate (MTX) has been investigated as a potential treatment for CPPD in several studies.

Based on these positive outcomes, EULAR recommended MTX as a treatment for severe refractory CPPD.

In a case series of five patients, MTX resulted in a significant decrease in VAS pain (p < 0.001), number of swollen and tender joints (p < 0.001) and a decrease in erythrocyte sedimentation rate and CRP.

The mean time to symptom improvement was 7.4 weeks (range 4–16 weeks).

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