Definition
- Polymyalgia Rheumatica (PMR) = a rheumatic condition that causes pain, stiffness and
inflammation in the muscles around the shoulders, neck and hips
- Poly = many; Mya = muscles; Algia = pain; Rheumatica = joints and connective tissue
- Even though ‘mya’ means ‘muscle’, the actual pain comes from bursae and tendons
Epidemiology
- Age > 50 years (especially > 70 years)
- Women > men (women have 2-3 times higher risk)
- Race: more common among white people whose ancestors were from Scandinavia or
Northern Europe
- Average annual incidence is 52,5 cases per 100 000 persons > 50 years
Causes and risk factors
The cause of PMR is unknown, but it’s thought to be a combination of genetic and
environmental factors. It has been suggested to be caused by viruses, such as the Epstein-
Barr virus (EBV), but it hasn’t been confirmed yet. This is probably due to the process of
molecular mimicry, in which the immune cells mistake proteins of the body as antigens and
start an inflammatory process against them.
Changes in the following immune markers can be seen and may suggest the role of the
immune system in the pathogenesis:
- Increased IL-6, IgG4
- Decreased number of circulating B cells
- Decreased Treg cells and Th1 cells
- Increased Th17 cells
- Increased expression of TLR7 and TLR9 (Toll Like Receptors) in peripheral blood
monocytes
Symptoms
The main symptom is muscle stiffness in the morning that lasts longer than 45 minutes. Other
symptoms may include:
- Bilateral shoulder and hip pain
- Rapid onset of symptoms, usually from a day up to 2 weeks
- Extreme tiredness
- Loss of appetite
- Weight loss
- Depression
- Limited range of motion in affected areas
- Mild fever
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