Polymyalgia Rheumatica - Nova Clinical Services

Transcription

Polymyalgia Rheumatica - Nova Clinical Services
Polymyalgia Rheumatica:
Diagnosis and Treatment Pearls
Dr. Kimberly A. Northcott
1. The proposed EULAR/ACR scoring algorithm serves as classification criteria 1. It was designed as a
research tool and was not intended for diagnostic purposes, although may serve as a guide:
REQUIRED CRITERIA:
≥ 50 years old
Bilateral shoulder aching
Abnormal CRP and/or ESR
SCORING ALGORITHM:
Morning stiffness duration >45 minutes
Hip pain or limited range of motion
Absence of RF or CCP Ab
Absence of other joint involvement
At least 1 shoulder with subdeltoid bursitis and/or biceps
tenosynovitis and/or glenohumeral synovitis and at least 1
hip with synovitis and/or trochanteric bursitis
Both shoulders with subdeltoid bursitis, biceps
tenosynovitis, or glenohumeral synovitis
Points without US (0-6)
2
1
2
1
NA
Points with US (0-8)
2
1
2
1
1
NA
1
A score of 4 or more is categorized as PMR without ultrasound (sensitivity 68%, specificity 78%)
A score of 5 or more is categorized as PMR with ultrasound (sensitivity 66%, specificity 81%)
2. PMR is almost exclusively a disease of adults over 50 years old. 50 years of age or older is considered
criterion for diagnosis.
3. A normal ESR and normal CRP have a high negative predictive value. Only 1.5% of patients have a
normal ESR and CRP (defined as <20mm/h and <10mg/L, respectively) 2. PMR can be diagnosed with
normal inflammatory markers if there is a classic clinical picture and response to steroids, and other
etiologies have been excluded appendix 1.
4. Response to corticosteroids is assumed to be a cardinal feature of PMR. There is little evidence to
substantiate this. Reevaluating the risk score model for patient response to corticosteroids did not
change the odds ratio1. A “steroid response” is outlined as achieving at least 70% global improvement in
one week and normal acute phase reactants in 3-4 weeks on prednisone 15-20mg 3. One study showed
3 weeks after starting prednisone 15mg po daily, only 55% had a complete response 4. Another study
reported a complete response at 4 weeks in 71% of patients and sustained in 78% at 26 weeks 1.
5. Imaging studies reveal inflammation of bursas and periarticuar structures. Bilateral subacromial /
subdeltoid bursitis and biceps tenosynovitis on ultrasound have moderately high diagnostic specificity 1.
The need for imaging arises when there is diagnostic uncertainty.
6. Initial glucocorticoid doses of 20-30mg po qd have a lower relapse rate at 2 months than 10- 20mg po
qd as reported in 1 high quality level of evidence randomized controlled trial. Induction therapy using a
minimal dose of prednisone between 12.5-25mg po qd for typically 1-2 months to remit myalgias,
stiffness and constitutional symptoms seems to balance benefit against harm. It is strongly advised not
to use >30mg of prednisone based on uncontroversial external evidence of harm from long term high
dose glucocorticoids and lack of future benefit of a high dose regimen5.
7. There is no consistent evidence for an ideal steroid tapering regimen suitable for all patients. The
approach to treatment must be flexible and tailored. Current guidelines recommend tapering by 1020% q 2 -4 weeks until 10 mg po qd is achieved ideally within 4-8 weeks and maintained 4-6 weeks. The
taper is subsequently slowed by 1mg q4 weeks or by using an alternate day regimen (eg. 10mg / 7.5mg
q4-8 weeks) until discontinued assuming remission is maintained 3,5,6.
8. Usually 1-2 years of treatment is needed. Some patients require small doses of steroid beyond this.
The need for treatment exceeding 2 years may prompt consideration for an alternate diagnosis (eg. coexisting osteoarthritis or rotator cuff tears) 7.
9. Disease flares are common with a relapse rate of >50% during glucocorticoid tapering8. On average,
relapses can occur 1-2 X/year6. An isolated rise in the ESR or CRP, without recurrence of PMR
symptoms, should not automatically trigger intensification of steroid therapy. Glucocorticoid doses
should not be increased to lower acute phase reactants 8.
10. Disease flares often respond to a 10-20% increase in the steroid dose 6,9. Guidelines suggest
increasing to the pre-relapse dose, and then tapering gradually over 4-8 weeks to the dose at which the
relapse occurred1,5.
11. Consider intramuscular methylprednisolone as an alternate to oral glucocorticoids especially in
patients with mild disease or high risk comorbid conditions. The treatment regimen is
methylprednisolone 120mg IM q 3-4 weeks, then reduce by 20mg q2-3 weeks until discontinued 9. One
randomized controlled trial showed an equivalent remission rate at week 12, a lower cumulative
glucocorticoid dose and lower weight gain in the IM group5.
12. There is no data showing benefit of divided steroid dosing. This increases physiological side effects
from the HPA axis. This would only be considered in patients with severe night pain or unresolving
extensive morning stiffness despite single day dosing5.
13. Up to 86% of patients will have steroid-related side effects (3-fold risk of diabetes, 5-fold risk of hip
fracture)8. Additional immunomodulatory therapy is considered after 2 relapses.
14. There is moderate – high level of evidence based on randomized controlled trials that methotrexate
increases remission rates (RR 5.2), reduces relapses, facilitates more rapid discontinuation of steroids,
and reduces glucocorticoid cumulative dose. Bone density scores were better at 12 months in the
methotrexate group5.
15. There are no recommendations for the use of hydroxychloroquine based on the low level of
evidence for efficacy based on an observational study only.
16. A small case series found leflunomide effective at preventing relapses in difficult to treat cases, but
prospective, randomized, controlled trials are required 10.
17. A small, randomized, controlled trial with azathioprine 2mg /kg/d modestly reduced requirements
for glucocorticoid treatment in patients with polymyalgia rheumatica11.
18. There is no role for TNF – inhibitors in the management of PMR.
19. Individuals with a high fracture risk (eg. age ≥ 65 years old and prior fragility fracture) require a
bisphosphonate with calcium and vitamin D. Other individuals require calcium and vitamin D, and a
bone density, with a bone-sparing agent if the t-score is ≤ -1.5 3.
20. PMR is recognized as a chronic condition. Often inflammatory markers remain abnormally elevated
even after a 2 year treatment course. It is not clear how to manage this post-acute phase. More
immunosuppression does not necessarily improve outcomes 6.
21. Elevated plasma fibrinogen may more accurately indicate persistent disease activity. It has a
superior positive predictive value and likelihood ratio for identifying persistent disease than either the
ESR or CRP 12. However, fibrinogen is not yet recommended as part of laboratory monitoring.
REFERENCES:
1. Dasgupta B. et al. 2012 Provisional classification criteria for polymyalgia rheumatica. A European
League Against Rheumatism / American College of Rheumatology Collaborative Initiative. Arthritis
Rheum. 2012, 64 (4): 943-54.
2. Myklebust G. A prospective study of 287 patients with PMR and TA: clinical and laboratory
manifestations at onset of disease and at time of diagnosis. Br J Rheum. 1996; 35(11):1161.
3. Dasgupta B. et al. BSR and BHPR guidelines for management of polymyalgia rheumatica.
Rheumatology, 2009; 1-5.
4. Hutchings A. et al. Clinical outcomes, quality of life, and diagnostic uncertainty in the first year of
PMR. Arthritis Rheum. 2007;57: 803-9.
5. Dejaco C. Polymyalgia rheumatica: Grading the evidence. ACR Scientific Meeting 2014, Boston MA.
6. Weyand C. Giant cell arteritis and polymyalgia rheumatica. NEJM. 2014; 371:50-7.
7.Kyle V. Treatment of polymyalgia rheumatica and giant cell arteritis. II. Relation between steroid
dosing and steroid associated side effects. Ann Rheum Dis. 1989; 48: 662-6.
8. Dasgupta B. Polymyalgia rheumatica: What is it? ACR Scientific Meeting 2014, Boston MA.
9. Dasgupta B. et al. An initially double-blind controlled 96 week trial of depot methylprednisolone
against oral prednisolone in the treatment of polymyalgia rheumatica. Brit J.Rheumatol.1998;37:189-95.
10. Adizie T. et al. Efficacy and tolerability of leflunomide in difficult-to-treat polymyalgia rheumatica
and giant cell arteritis: a case series. Int J Clin Prac, 2012; 66(9): 906-9.
11. De Silva M. et al. Azathioprine in giant cell arteritis/polymyalgia rheumatica: a double-blind study.
Ann Rheum Dis, 1986;45:136-8.
12. McCarthy EM. et al. Plasma fibrinogen better identifies persistent disease activity in polymyalgia
rheumatica than either ESR or CRP (abstract). Arthritis Rheum, 2012; 64 suppl 10: 2348.
Appendix 1: