Ongoing enthesitis in successfully treated Psoriatic Arthritis (PsA) with anti-TNF agents

This case illustrates how physicians dont fully recognise the importance of ongoing enthesitis in patients that have apparently responded to anti-TNF agents.

Mr X a 36 year old man had a long history of psoriasis with scalp and nail disease. He developed a severe polyarthritis and spinal disease in 2008 and also had associated clinically evident peripheral enthesitis.

He had pain, stiffness and swelling of his hands and knees.

He initially had a rough course and failed to respond to methotrexate and was switched to leflunomide. Following ongoing disease activity adalimumab was added in 2010. This resulted in a dramatic improvement and the patient returned to work.

His laboratory markers of inflammation showed that his CRP fell from 90mg/l to normal.

His managing physician was happy with his progress as he had no visible joint swelling and his CRP remained normal.

He sought a second opinion and reported early moring stiffness in his chest, neck, pelvis, hands and feet lasting for one hour each morning. Clincally he had enthesitis on the anterior brim of his pelvis and had chest wall discomfort. He also had right sided Achilles tenderness but no evident swelling.

This case illustrates that patients on anti-TNF may have ongoing enthesitis which is not recognised by physicians.

Management

Regular anti-inflamamtory drugs may help.

Some response to intramuscular steroids can be noted.

Increasing the frequency of the injections of anti-TNF can be contemplated.

Consider switching to another anti-TNF agent.

Lessons

Patients with Psoriatic Arthritis that have resolution of swelling and normalisation of inflammatory markers may still have active enthesitis. This needs to be recognised and attempts to treat it undertaken.

On a postive note the absence of swelling and the normalistion of inflammatory markers are reassuring that the patient will not develop progressive destructive arthritis.