polymyalgia rheumatica

Question 1

definition of polymyalgia rheumatica

Answer 1

Polymyalgia rheumatica (PMR) is an inflammatory rheumatological syndrome that manifests as pain and morning stiffness involving the neck, shoulder girdle, and/or pelvic girdle in individuals older than age 50 years. Peripheral musculoskeletal involvement may also be present.[1][2] PMR occurs either as an isolated condition or associated with giant cell arteritis.

Question 2

risk factors

Answer 2

female
GCA (giant cell arteritis)
>50 y/o

Question 3

symptoms

Answer 3

shoulder/hip girdle pain and stiffness
acute onset
oligoarticular arthritis

constitutional symptoms:
malaise, anorexia, low grade fever, malaise, depression, asthenia (muscle weakness)

Question 4

signs

Answer 4

rapid response to cortiocosteroids

Question 5

investigations

Answer 5

1st investigations:
ESR => elevated
CRP => elevated
FBC (screen for myeloproliferative disease)
ultrasound => bursitis, joint effusions 

others:
TSH (screen for hypothyroid which has similar presentation)
MRI => bursitis, joint effusion
serum protein electrophoresis => normal in PMR (screen for myeloproliferative conditions)
IL-6 (emerging test) => elevated

Question 6

GCA and PMR

Answer 6

GCA: New-onset unilateral headache, jaw claudication associated with chewing tough foods, diffuse mandibular discomfort, dental discomfort, sinus pain and pressure, and/or tongue pain are associated with GCA. Blindness, diplopia, or blurry vision and an abnormally thickened, tender, erythematous, or nodular temporal artery are also found.

A positive temporal artery biopsy showing a granulomatous vasculitis confirms the diagnosis of GCA; however, results may be positive in PMR patients without GCA symptoms.

Question 7

late onset RA vs PMR

Answer 7

Presentation may be very similar to PMR; however, the absence of a prompt response to low-dose corticosteroids distinguishes the two. The peripheral musculoskeletal symptoms of late-onset RA do not respond rapidly.[5] Some with RA will respond to 10 to 20 mg of prednisolone.

investigations for RA: Elevated rheumatoid factor and persistently raised plasma viscosity.[28] Positive anti-CCP antibody assays.[3] Anti-CCP assays were 61.4% sensitive and 100% specific for the diagnosis of late-onset RA.

Question 8

hypothyroidism vs PMR

Answer 8

hypothyroidism: may show similar signs of muscle and joint pain, weakness in the extremities, and fatigue; however, delayed relaxation of deep tendon reflexes (a rare finding) is strongly suggestive of hypothyroidism.

An elevated TSH helps to differentiate hypothyroidism.[5] Creatine phosphokinase may also be elevated.

Question 9

fibromyalgia vs PMR

Answer 9

fibromyalgia pain tends to be more widespread and is not associated with shoulder/hip girdle stiffness. The pain does not typically improve with low-dose daily prednisolone as is characteristic of PMR.

ESR and CRP are normal in fibromyalgia

Question 10

paraneoplastic syndromes (e.g. lambert eaton) vs PMR

Answer 10

paraneoplastic syndromes are syndromes that are caused by chemicals/signalling molecules produced by cancer tumours. e.g. in lambert eaton which is associated with small-cell lung cancer, may cause proximal weakness that improves later in the day, a feature similar to the symptoms of PMR

May present with constitutional symptoms and proximal muscle pain easily confused with the shoulder and hip girdle stiffness found in PMR. Paraneoplastic syndrome symptoms usually do not respond to low-dose corticosteroid treatment. A thorough tumour work-up should be reserved for those unresponsive to low-dose glucocorticoid therapy. Removal of the tumour leads to a resolution of symptoms

basic cancer screen: CXR, an FBC, a chemistry panel, and urinalysis. Age-appropriate cancer screening tests should also be performed (i.e., faecal occult blood testing, colonoscopy, mammogram)

Question 11

overuse bursitis/tendonitis vs PMR

Answer 11

No systemic symptoms as in PMR. Typically unilateral shoulder involvement without bilateral involvement.

normal ESR

Question 12

treatment

Answer 12

1. corticosteroids - glucocorticoids (prednisone)
   + calcium (calcium carbonate), vit D (colecalciferol), bisphosphonates (aldendronate)
   ++ NSAID (naproxen or ibuprofen)
2. methotrexate and folic acid in some patients

Question 13

complications

Answer 13

due to corticosteroid use:
- osteoporosis, DM, skin changes, increased risk of infection, hypertension, muscle weakness, cataract formation, glacucoma

due to methotrexate use:

• myelosuppression
• oral suppression
• hepatotoxicity
• interstitial lung disease

related to PMR:

• vascular events
• chronic relapsing PMR (Characterised by frequent exacerbations of symptoms. May require treatment with higher doses of corticosteroids and the addition of a corticosteroid-sparing agent. The course of therapy may be prolonged.)
• giant cell arteritis (Patients who have PMR and GCA are at risk for blindness due to inflammation-induced vessel occlusion and ischaemia. Prompt treatment with high-dose corticosteroids is indicated to either prevent or limit visual impairment.)

Question 14

prognosis

Answer 14

The overall prognosis is good. Although response to treatment typically occurs within 24 to 72 hours, relapses or symptom exacerbations are common. Treatment also typically requires 2 to 3 years. Less commonly, there is a chronic relapsing course that may require a longer course of treatment. PMR may also be associated with giant cell arteritis (GCA) and, if present, the prognosis and treatment is directly related to GCA.[47][48]

Increased risk of relapse or prolonged therapy has shown association with female sex, high ESR (>40 mm/hour), and peripheral arthritis