Background/Purpose:

The cryopyrin-associated periodic syndrome (CAPS) is a rare inherited inflammatory disease associated with a mutation in the NLRP3 gene. Articular symptoms are often described in CAPS, but their frequency has been poorly investigated. Our objective was to describe the type and frequency of articular symptoms present in a cohort of pediatric and adult patients followed for a CAPS in France.

Methods:

We conducted a retrospective study concerning articular manifestations (articular symptoms bone and muscle) in patients with CAPS [the familial cold autoinflammatory (FCAS), the Muckle-Wells syndrome (MW), and the neonatal-onset multisystem inflammatory disorder (NOMID or chronic infantile neurologic, cutaneous and articular syndrome (CINCA)] by contacting their referring physicians in the adults or paediatrician departments. Medical data were collected using a standardized questionnaire and radiographs were analyzed when present in the records.

Results:

88 patients were included (16 FCAS, 55 MW, 12 CINCA / NOMID and 5 unclassified). 50% were women, 56 patients were adults (mean age 33 ± 18.4 years) and 32 children (10.8 ± 4.4 years). The onset age is on average about 4.35 ± 7.8 years, and age of diagnosis is delayed to 20 ± 16 years. The first symptoms are usually: a cutaneous manifestation (68%), fever (26%), articular (22%) or neurological manifestation (11%). 65 patients (74%) have a family history of CAPS and 11 patients have a CAPS without genetic mutation. During follow-up, only 17 patients (23%) showed no joint symptoms. 53 patients (60%) had arthralgia and 55 patients (63%) had synovitis. The most affected joint were respectively: knees (65%), ankles (60%), wrist (47%), hands (40%) and feet (20%). Tendinopathy occurred in 13 patients (15%) and myalgia in 29 cases (33%). Only two patients had arthropathy with a typical non-inflammatory enlargement of the growth plates and epiphyses of long bones. Contractures and joint limitations (2%) or synovial masses are rare (2%). 24/88 (27%) were treated with anakinra and 55/88 (62.5%) with canakinumab.When reported delay in statural growth was -2DS for children before anti-IL1 treatment.

Conclusion:

Articular symptoms encountered in CAPS are very common and found in 82% of patients with arthralgia and synovitis in knees and ankles. These symptoms are considered predominant for 20% but rarely explored by imaging. Pseudo tumor are rare. Delay of growth is frequent. Most patients benefit from treatment with anakinra or Canakinumab which allows almost complete regression of joint symptoms.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/articular-symptoms-in-cryopyrin-associated-periodic-syndrome-retrospective-french-study/