What Are the Most Common Polymyalgia Rheumatica Causes?

Rheumatic polymyalgia (PMR) is a painful disease unrelated to other diagnosed rheumatic diseases, infections, and tumors. It is common in the elderly and is accompanied by increased erythrocyte sedimentation. PMR is a clinical syndrome characterized by muscle pain in the limbs and proximal trunk, and is sensitive to low-dose hormone therapy. It usually manifests as pain and stiffness in two or more parts of the neck, scapula, and pelvic girdle muscles, lasting 30 minutes or more, not less than 1 month, and older than 50 years. The diagnosis should exclude chronic rheumatoid arthritis, myositis, and malignancies.

Basic Information

English name

polymyalgia arteritica, poly-myalgia rheumatica

Visiting department

Division of Rheumatology

Multiple groups

Older women

Common locations

Proximal limbs and trunk muscles

Common causes

unknown

Common symptoms

Morning stiffness, sore joints and muscle pain

Causes of rheumatic polymyalgia

The exact etiology of PMR is unknown, and age, environmental and genetic factors may play a role. PMR has a family aggregation phenomenon, which is related to the HLA-DR4 gene.

Clinical manifestations of rheumatic polymyalgia

Systemic symptoms

More than half of the patients have systemic symptoms such as fatigue, low fever, weight loss, and may be the first symptoms. Patients with PMR without giant cell arteritis (GCA) rarely experience peak fever.

2. Proximal bone and joint muscle pain and morning stiffness

PMR is characterized by symmetry of pain and soreness of the proximal joints and muscles and morning stiffness. It is most prominent in the shoulder, neck and pelvic girdle muscles, and is often symmetrically distributed. Sometimes distal muscle groups and joints can be affected. In more than 70% of patients, scapular pain first occurs, and then progresses to the proximal parts of the limbs, neck, chest, buttocks, etc., which directly affects the patient's life. The above symptoms can suddenly or conceal the onset for several weeks to several weeks. month. Pain and morning stiffness increase in the morning and during exercise. The above symptoms may be severe and restrict the patient's daily activities so that he cannot turn over and breathe deeply. Muscles can develop tenderness, affect activity and cause atrophy, and muscle contractures can occur. Muscle strength is usually normal.

3. Joint symptoms

PMR arthropathy is mainly tendinitis and synovitis. Multicenter studies have shown that PMR mild to moderate synovitis mainly affects the proximal joints, spine, and limb bands, such as the shoulder joints are most commonly affected; another 15% to 50% develop peripheral synovitis, with the knee joint and The wrist joint is most common. Radionuclide bone scans revealed abnormalities in 96% of PMR patients, with 80% of shoulder joints and 16% of hand, wrist, and knee joints increasing radionuclide uptake. Magnetic resonance (MRI) examination also showed that PMR subacromial / deltoid synovitis is the most common injury of the shoulder. MRI examination showed that the external joint and soft tissue of the knee joint capsule of PMR patients were swollen, and the incidence (50%) was significantly higher than Rheumatoid Arthritis.

4. Relationship between PMR and GCA

A large body of evidence suggests that PMR and GCA are related and that they should be different manifestations of the same disease process. PMR can coexist with GCA. 10% to 15% of simple PMR temporal artery biopsies are positive. On the other hand, 30% to 50% of GCA patients have PMR.

Rheumatic polymyalgia examination

1. ESR and C-reactive protein (CRP)

The most significant laboratory change in PMR was a significant increase in the levels of the acute-phase reactants, ESR and C-reactive protein (CRP). ESR is usually> 50mm / h, even exceeding 100mm / h. CRP rises within a few hours of the onset of PMR, and CRP also increases in patients with normal erythrocyte sedimentation. After effective treatment, CRP generally decreases to normal within 1 week and ESR declines slowly, which takes 1 to 2 months or longer. ESR and Elevated CRP often indicates repeated illness. If other clinical features of PMR are typical, even a normal ESR cannot rule out a diagnosis. Approximately 50% of patients with PMR can develop anemia of positive cells, positive pigment, and decreased platelets. This is related to the degree of inflammation. Rheumatoid factor antinuclear antibodies and other autoantibodies have higher titers than normal peers. Complement levels were normal, with no rise in cryoglobulin and monoclonal globulin. Muscle enzymes (creatine kinase, aldolase) are normal. Elevated serum amyloid A level is an indicator of PMR disease activity. If its level remains high or decreases after it rises, it indicates that the disease activity or repetitive, so the determination of serum amyloid A is useful for guiding clinical glucocorticoids. Medication has a certain value.

2. Imaging examination

X-rays, radionuclide scans, MRI, and ultrasound have some value in determining joint involvement in PMR.

3. Temporal Artery Biopsy

If the PMR patient has symptoms and signs suggestive of GCA, or does not respond to 15 mg of prednisone per day, then a temporal artery biopsy should be considered.

4. Other

There were no abnormal findings in the EMG examination, which had no diagnostic significance for PMR. There were no characteristic changes in the histology of the muscle biopsy specimens of PMR, and non-specific type II muscle fiber atrophy was seen when the muscle was discarded. Synovial fluid and synovial examination showed that the white blood cell count of synovial fluid was between 1 × 10 ⁹ 8 × 10 ⁹ / L. Monocyte-based synovial biopsy showed mild synovial cell proliferation with slight lymphocyte infiltration. . The above tests are of little significance and are rarely performed clinically.

Diagnosis of rheumatic polymyalgia

The diagnosis of PMR mainly depends on clinical manifestations. There are 6 diagnostic criteria: age of onset> 50 years; neck, scapular and pelvic girdle at least 2 muscle pain and morning stiffness time 1 week; ESR and / or CRP rise High; low-dose hormones (prednisone 15mg / day) effective; no muscle loss or muscle atrophy and muscle redness and fever; exclude other similar PMR manifestations such as RA, myositis tumors and infections.

If you meet the above 6 can be diagnosed as PMR.

Differential diagnosis of rheumatic polymyalgia

The following diseases should be excluded: atherosclerosis (especially carotid atherosclerosis), fever of unknown cause of myositis, infective endocarditis, non-Hodgkin's lymphoma, multiple myeloma, rheumatoid arthritis , Systemic lupus erythematosus, arteritis, tuberculosis, etc., in addition to thyroid myopathy. PMR with peripheral arthritis and RA with PMR-like symptoms as the first episode are easily misdiagnosed.

Rheumatic polymyalgia treatment

Non-steroidal anti-inflammatory drugs (NSAIDs) can alleviate some symptoms. Low-dose glucocorticoids (prednisone 10-20mg / day) can receive good results, can make the pain and stiffness of the musculoskeletal system quickly (usually within one day) and significantly improve, and erythrocyte sedimentation and CRP levels gradually recover normal. Can both relieve symptoms and prevent vascular complications. In order to reduce the amount of glucocorticoids, some people have used methotrexate for short-term (3 months) and long-term (2 years) observations, but no positive effect has been seen. Hormones need to be slowed down, maintained for a long time, and relapses are common, requiring increased doses to achieve symptomatic relief.

Rheumatic polymyalgia prevention

PMR is generally a two-year self-limiting disease and rarely develops into GCA.

Quitting smoking is an important measure for prevention. Clinical observation found that smoking cessation can relieve pain, stabilize the condition, and worsen the symptoms of smoking again.