Introduction: Psoriatic arthritis (PsA) is chronic inflammatory arthritis affecting 30% of patients with skin psoriasis. We present an case of PsA who has encountered recurrent insufficiency fractures.
Case description: A 59 year old female diagnosed with PsA 22 years ago mainly presented as enthesitis of the knees and ankles. Her background includes skin psoriasis with nail changes, allergic to penicillin, ex-smoker with COPD and Emphysema, working in a Morrisons supermarket garage living with her daughter. She was initially treated with Methotrexate(MTX) and Sulphasalazine. The later was not tolerated due to nausea. She had similar problems with MTX but gastrointestinal side effects responded to increase in folic acid. Her inflammatory arthritis was poorly controlled requiring recurrent intra-articular steroids as well as occasional intramuscular steroids for persistent ankle and knee symptoms. Due to persistent joint inflammation and dactylitis she was commenced on Adalimumab along with the MTX. Progression: She had developed E coli 0157 diarrhoea requiring to withhold anti- TNF and MTX to restart after infection settles. She had developed persistent foot and ankle pain with MRI revealing insufficiency fractures at multiple sites including distal tibial metaphysis, the navicular, heads of 4th and 5th metatarsals, medial and intermediate cuneiforms and the calcaneum at the point of Achilles tendon insertion. There were sclerotic areas at both proximal tibia and femoral condyle consistent with insufficiency fractures. This required moon boots, non weight bearing with crutches impacting on her quality of life and her occupation. She had 3-4 courses of IV Ibandronate switched to Denosumab with good reduction in bone turn over markers. A subsequent bone scan revealed severe vertebral osteoporosis T score of -4.5 and -2.9 at the femoral neck. Recurrent immobilisation due to insufficiency fractures possibly contributing to further bone loss. Currently she is planned to continue Adalimumab and MTX and commence Tereparatide after the anti resorptive effective of Denosumab has subsided.
Discussion: Chronic psoriatic arthritis is a debilitating condition if not well controlled can impact on quality of life. Recurrent systemic and intra-articular steroids though rare may result in steroid induced osteoporosis. Thus we present a lady with skin psoriasis and related chronic inflammatory arthritis who had encountered either side effects with her arthritis treatment or complications including infection, osteoporosis resulting in multiple insufficiency fractures. Challenging question for the experts: What is the future treatment of the osteoporosis and insufficiency fractures in our patient and how to assess it's efficiency and effectiveness?
Key Learning points: 1) Our patient initially presented with foot pain and mono-arthritis unlike rheumatoid arthritis which is poly articular. Hence was initially treated as flare though the differentials to consider would be sepsis and as in this case fracture. 2) Patients with psoriasis and PsA have increased incidence of fracture risk and osteoporosis compared to general population and rheumatoid arthritis patients depending on severity of the condition. Most of the data available for osteoporosis management are from rheumatoid arthritis cohort rather than PsA patients. 3) There is delay in diagnosis of osteoporotic fracture as often plain films are normal and patient needs MRI to aid diagnosis. 4) Treatment of insufficiency fracture is non weight bearing which in turn could result in rapid progression of bone mineral density. Weight bearing is extremely painful. 5) Management of our patient included constant vigilance for any further insufficiency fractures.