How is polymyalgia (PMR) diagnosed?
Your GP may be able to diagnose polymyalgia rheumatic straight away if you're over 60 and have the following symptoms:
- shoulder pain on both sides
- morning stiffness that lasts at least 45 minutes
- high levels of inflammation measured by blood tests
- new hip pain on both sides
- no swelling in the small joints of the hands and feet
- no evidence of rheumatoid arthritis, such as swollen joints or positive blood tests.
However, you may be referred to a rheumatologist if there's any doubt about the diagnosis or if there are complicating factors – for example, if the symptoms don't improve with steroid treatment or if you have side-effects from the treatment.
There's no specific test for PMR, but you may have blood tests to check for inflammation. There are three tests that could be used:
- erythrocyte sedimentation rate (ESR)
- plasma viscosity (PV)
- C-reactive protein (CRP)
Inflammation alone isn't enough to confirm a diagnosis of PMR as it's also a feature of many other conditions, including infections and rheumatoid arthritis. You may therefore have tests – for example, for rheumatoid factor or anti-CCP antibodies – to help rule out these other conditions and confirm the diagnosis of PMR.
Different types of imaging may be used to help in the diagnosis of PMR and to help rule out other conditions. Ultrasound of the shoulders and hips may be used and can often show inflammation in the tissues. Other forms of imaging, such as magnetic resonance imaging (MRI) and positron emission tomography (PET) scans, may occasionally be requested by a rheumatologist.
Anaemia (a lack of red blood cells) is quite common in PMR so your doctor may test for this, but this can also occur in other conditions.
If your doctor suspects you have GCA, a biopsy of a small piece of artery may be taken from your scalp and examined under a microscope.