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How not to miss polymyalgia rheumatica

Rheumatologists Dr Pravin Patil and Professor Bhaskar Dasgupta discuss the signs and pitfalls when identifying cases of polymyalgia rheumatica, and offer a diagnostic flow chart

Worst outcomes if missed

  • Persistent polymyalgia rheumatica (PMR) symptoms in an elderly person can cause disability and deterioration in mental and physical health, leading to depression.
  • If accompanied by giant cell arteritis (GCA), the patient may lose vision in one eye or, more rarely, in both eyes, especially if treatment is delayed. The risk of GCA occurring while PMR is being treated is approximately 10–20%.1
  • The worst outcomes arise when PMR is over-diagnosed and over-treated, resulting in misdiagnosis of serious pathology such as cancer, infection, GCA or inflammatory rheumatic diseases. Relatively benign conditions such as osteoarthritis and rotator cuff lesions may be treated as PMR and patients may be subjected to unnecessary side-effects of steroids.

Epidemiology

  • PMR is the most common inflammatory rheumatic disease in the elderly. Caucasian women over the age of 50 have the highest risk of developing PMR. The average age of onset is just over 70 years. PMR almost exclusively affects people over the age of 50.
  • The incidence of PMR increases markedly with advancing age.
  • Women are two to three times more likely to be affected than men.
  • PMR prevalence varies among different populations. Scandinavian people have the highest rate, and black and Asian people have the lowest rates. Caucasians are affected more than other ethnic groups.
  • Annual incidence of PMR in the UK population is around 80-100 per 100,000.

Symptoms and signs

  • Patients typically present with moderate to severe musculoskeletal pain and stiffness in the shoulder and pelvic girdle muscles. Difficulty in raising arms above the head and getting up from a chair are common complaints. Stiffness is most noticeable in the morning or after a period of inactivity, and typically lasts more than 45 minutes.
  • PMR may develop abruptly. In some people, it comes on literally overnight. 
  • Patients may also admit to experiencing flu-like symptoms, including fatigue, loss of appetite, fever, night sweats and weight loss.
  • The physical examination might show restricted range of movement in hips and shoulders. There may be swelling over both shoulders, tenderness of the upper arms and thighs and tenderness over the trochanteric and ischial bursae.
  • Less common presentations include:

– asymmetrical peripheral arthritis

– swelling of the hands and arthritis (remitting seronegative symmetrical synovitis with pitting oedema)

  • The temporal arteries should be examined for abnormalities such as swelling, tenderness and pulsations to helpexclude GCA.
  • A trial of steroids should not be used as an alternative to clinical evaluation of PMR. There is no evidence that steroid responsiveness is a specific feature of PMR. Responsiveness can vary within PMR patients and the classification criteria study failed to find it useful to distinguish PMR cases.2 That and another recent study showed that three to four weeks after starting prednisolone 15mg daily only 55% of patients show a complete response to therapy.3,4

Five key questions

  1. Is there any suggestion of co-existing GCA/large vessel vasculitis?
  2. How old is the patient? Those aged over 50 years tend to be most commonly affected. The younger the patient, the greater the chances of an alternate diagnosis.
  3. Does the patient have pain and stiffness of the shoulder and pelvic girdle muscles?
  4. Does the patient describe proximal early morning stiffness that lasts for longer than 45 minutes?
  5. Have any other mimicking conditions been excluded?

Differential diagnoses

Symptoms of PMR are shared by several medical conditions that affect older people. Patients can also present with non-classical features, sometimes in association with other common disorders.

Inflammatory arthritis

Swelling and early morning or inactivity stiffness of the peripheral joints should point towards inflammatory arthritis. Elderly-onset rheumatoid arthritis involves the large joints (most notably the shoulders) in 40% of patients.

GCA/large vessel vasculitis

Headache, visual symptoms and jaw claudication should be recognised as GCA (40% of GCA patients have polymyalgia at onset). Prominent systemic symptoms, limb claudication, arterial bruits and absence of peripheral pulses or difference in bilateral blood pressure would suggest a large vessel vasculitis.

Late-onset spondyloarthropathy

The characteristic features of late-onset spondyloarthropathy include lower back pain, oligoarthritis, constitutional symptoms and high ESR. Lumbar spine and sacroiliac joint MRI with fat-suppressed views can aid accurate diagnosis.

Fibromyalgia

Patients do not describe true inflammatory stiffness and have prominent depressive symptoms, poor sleep and multiple trigger points on examination.

Inflammatory/metabolic myopathy

Painless muscle weakness might suggest an inflammatory polymyositis. Look for features of Cushing’s syndrome on inspection of the patient. Discoid or photosensitive rashes might suggest systemic lupus erythematosus.

Cancer and infection

These conditions may present in a similar manner to PMR and may also improve in the early stages with steroids. A careful history and physical examination cannot be over-emphasised in the assessment of patients with PMR.

Non-inflammatory/degenerative conditions

The absence of systemic and lower limb symptoms indicates local shoulder pathology, such as bilateral adhesive capsulitis or OA.

Investigations

A diagnosis of PMR is based primarily on history and physical examination. No single test can definitively diagnose PMR. The most typical finding is an elevated ESR or CRP. Baseline tests should also include FBC, U&Es, LFTs, bone profile, rheumatoid factor, anti-CCP antibodies and urine dipstick (to exclude infection).

As several medical disorders can mimic PMR symptoms, the following investigations should be considered:

  • anti-nuclear antibody test
  • serum and urine protein electrophoresis
  • TSH
  • creatine kinase
  • chest X-ray if patient has significant constitutional symptoms. Result to be reviewed before starting steroids.
  • early ultrasonography of shoulders/hips, peripheral joints and temporal arteries is necessary if there is a diagnostic dilemma, or if GCA is suspected.

Five red herrings

  1. Polymyalgic syndrome can herald the onset of large vessel vasculitis and inflammatory arthritis in the elderly.
  2. Although a trial of steroids is common medical practice, there is no evidence that steroid responsiveness is a specific feature of PMR.
  3. Non-response, partial response  and need for prolonged high-dose steroid therapy should prompt a reconsideration of the PMR diagnosis.
  4. Unlike with GCA, steroids can be delayed (for a couple of weeks) to allow full assessment. However, if the patient does present with symptoms suggestive of GCA, urgent institution of high-dose steroid therapy is needed, as well as urgent assessment by rheumatology or ophthalmology.5
  5. Refer for consideration of alternative  diagnoses if:
  • the patient is aged under 50 at  onset
  • onset is chronic
  • there is peripheral arthritis
  • there is spinal involvement
  • there are severe constitutional symptoms
  • acute phase markers are very raised or normal
  • shoulders are not involved
  • steroid response is poor, partial or non-sustained.

Dr Pravin Patil is rheumatology research fellow at Southend University Hospital. Professor Bhaskar Dasgupta is consultant rheumatologist and honorary professor at Essex University and Southend University Hospital

References

  1. Salvarani C, Cantini F, Boiardi L et al. Polymyalgia rheumatica and giant cell arteritis. N Engl J Med 2002;347:261–71
  2. Dasgupta B, Cimmino M, Kremers HM et al. Provisional classification criteria for polymyalgia rheumatica: A European League Against Rheumatism/American College of Rheumatology collaborative initiative. Arthritis Rheum 2012;64:943–54
  3. Matteson EL, Maradit-Kremers H, Cimmino MA et al. Patient-reported outcomes in polymyalgia rheumatica. J Rheumatol 2012;39:795–803
  4. Hutchings A, Hollywood J, Lamping DL et al. Clinical outcomes, quality of life, and diagnostic uncertainty in the first year of polymyalgia rheumatica. Arthritis Rheum 2007;57:803–9
  5. Dasgupta B, Borg F, Hassan N et al. BSR and BHPR guidelines for the management of polymyalgia rheumatica. Rheumatology 2010;49:186–90

Primary Care Rheumatology Society Annual Conference

York, 21-23 November 2013

The PCR Society is inviting GPs with a special interest in musculoskeletal medicine and other GPs keen to update their skills to attend its annual meeting.

A huge range of topics  is covered over two days, including pain management, fibromyalgia, spine problems, knee pain, osteoporosis and foot and ankle problems.

A keynote lecture on  the first day will provide advice on medicolegal pitfalls in primary care musculoskeletal medicine.

For further details:

pcrsociety.org

contact@pcrsociety.org

01609 774794

Readers' comments (1)

  • My Mother had this & our family had never heard of it however suspect there was giant cell arteritus too which wasn't picked up as had severe multi infart dementia not being able to speak .Surely non diagnosis is not being used as cost cutting measure?

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