A few months ago, a new patient, SR, came into our office with a long and varied history of rheumatic disease. A 34-year-old Caucasian male with a nearly 20-year history of plaque, scalp, and nail psoriasis, SR was diagnosed with psoriatic arthritis (PsA) a decade ago. He was initially treated with a variety of topical agents to manage his psoriasis, but progressed to more aggressive therapies such as therapeutic aspirations and injections after developing recurrent knee effusions starting in 2004. SR’s rheumatologist diagnosed him with PsA in 2006 and initiated etanercept monotherapy (because of a history of alcoholism, methotrexate was not an option).
SR’s medical record showed that he was successfully managed with etanercept for several years until his psoriasis and joint disease began to flare. He was then switched to adalimumab monotherapy, again with a good response for several years until flaring in both knees. Instead of switching to another biologic, SR’s rheumatologist prescribed a quick taper of prednisone. This had limited success, with SR’s bilateral feet and knees flaring every few weeks, requiring a series of short prednisone bursts. He was subsequently switched to ustekinumab monotherapy.
After another series of knee effusions, SR was finally referred for ultrasound-guided aspiration and therapeutic injections. His synovial fluid was analyzed and showed monosodium urate crystals, a negative culture, and a cell count of 8,000 cells/μL. The laboratory evaluation was perhaps most notable for a high uric acid level of 11.3 mg/dL, which was suggestive of a concomitant diagnosis of gout. Based on these results, SR received bilateral intra-articular methylprednisolone acetate injections in his knee, followed by allopurinol after his latest PsA-related flare had resolved. SR continued receiving allopurinol regularly until his uric acid reached a level of <6.0 mg/dL.
Concomitant PsA and gout is not unusual. Studies have shown that patients with PsA have a 5-fold greater risk of developing gout than patients with psoriasis alone (although even patients with psoriasis alone are at greater risk of developing gout than the general population).1-3 One recent study also showed that a dual diagnosis of gout and PsA is more common in men than women.2
Being aware of the relationship between psoriasis/PsA and gout is important when monitoring patients with PsA, especially in patients undergoing arthrocentesis for a flare. It should be routine practice in these patients to send synovial fluid for evaluation of urate crystals. Patients with PsA should also be assessed for potential hyperuricemia from time to time to gauge their risk of developing gout. As with SR, including a possible differential diagnosis of a crystal-associated arthropathy should be considered in patients with PsA whose disease remains uncontrolled for a significant period of time.
A few weeks after starting on allopurinol in addition to his ustekinumab, SR was feeling somewhat better and achieved relief of his joint pain, although on exam there was still considerable psoriasis, nail findings, and a few tender and swollen joints. This led his rheumatologist to discontinue ustekinumab and switch to secukinumab. He continued to receive allopurinol to prevent further attacks of gout.
“In addition to inflammatory arthritis, patients with psoriasis, PsA, hyperuricemia, and/or gout are all at higher risk of developing metabolic syndrome and cardiovascular risk compared to the general population.2,3”
It’s been approximately 1 year since this latest adjustment in treatment. SR quickly achieved remission of his PsA and has had no further gout exacerbations in the last year.
Identifying the presence of gout in addition to SR’s PsA seems to have been key to managing his disease, but it’s something we’ll certainly need to monitor on a regular basis. In addition to inflammatory arthritis, patients with psoriasis, PsA, hyperuricemia, and/or gout are all at higher risk of developing metabolic syndrome and cardiovascular disease compared to the general population.2,3 The fact that SR has been diagnosed with all of these conditions heightens our need to evaluate and then treat potential risk factors for cardiovascular disease. Now that we know what we are treating, our approach to the future care of SR will hopefully be smoother. He’s a complex patient for sure, but someone who should be treatable over the long-term basis with our current regimen of available medications.
References
- Kelly JC. Gout risk high in those with psoriasis, psoriatic arthritis. Medscape Medical News. March 28, 2014.
- Merola JF, Wu S, Han J, Choi HK, Qureshi AA. Psoriasis, psoriatic arthritis and risk of gout in US men and women. Ann Rheum Dis. 2015:74(8):1495-500.
- Hu SC, Lin CL, Tu HP. Association between psoriasis, psoriatic arthritis and gout: A nationwide population-based study. J Eur Acad Dermatol Venerol. 2018 Oct 14 [Epub ahead of print].
AUTHOR PROFILE: Eileen Lydon works at the New York University Langone Orthopedic Hospital in New York, New York and is the Chapter Development Chair of the Rheumatology Nurses Society.