Polymyalgia Rheumatica (PMR) is an inflammatory disease whose main characteristic is pain and stiffness in the waist, shoulders, hips and neck. Although it is related to other pathologies or presents similar symptoms, it is important that both the patient and the rheumatologist know the differences.
Giant Cell Arteritis and Polymyalgia Rheumatica
Symptoms of Giant Cell Arteritis (GCA), such as headache, temporal artery tenderness, jaw pain, evidence of cerebral ischemia or vision loss, are not usually present in PMR. If so, it is important for the rheumatologist to monitor these symptoms on an ongoing basis.
Rheumatolide Arthritis and Polymyalgia Rheumatica
Patients with rheumatoid arthritis (RA) usually have symmetrical polyarthritis in the small joints of the hands and feet, which is persistent and partially responsive to low doses of prednisone, a corticosteroid drug. These symptoms are different from those of PMR, in which there are not as many swollen joints and it usually responds to low doses of prednisone.
RS3PE and Polymyalgia Rheumatica Syndrome
The symptoms of RS3PE syndrome (remitting seronegative symmetrical seronegative synovitis with pitting edema) can be easily confused with PMR. The main features of RS3PE syndrome that differentiate it from PMR are:
- Abrupt onset of polyarthritis.
- It affects more people over 50 years of age.
- Lack rheumatoid factor (abnormal globulin that appears in the blood serum).
- Symptoms are usually more prominent at the distal level.
- Some patients respond to treatment with low doses of glucocorticoids.
- It can be considered a variant of PMR with significant edema.
Spondyloarthropathy and polymyalgia rheumatica.
In late-onset spondyloarthropathy (SpA) constitutional symptoms may appear, such as fever, weight loss and anorexia, along with an elevated erythrocyte sedimentation rate (rate at which red blood cells “fall”). But other symptoms that are not normally present in PMR also appear, such as inflammation of muscles, ligaments, fingers, toes, sacroiliac joints (where the lumbar spine connects to the pelvis), and an increased prevalence of HLA-B27 positive.
Hypothyroidism and Polymyalgia Rheumatica
Patients with hypothyroidism may present with joint pain and stiffness, but the differential factor is altered thyroid hormones, which would give the diagnosis.
Fibromyalgia and Polymyalgia Rheumatica
Although clinically it may present similarly, patients with fibromyalgia have a normal erythrocyte sedimentation rate, hematocrit, and protein C, unlike PMR.
Tendinitis, Bursitis and Polymyalgia Rheumatica
Symptoms in shoulders with PMR can be similar to those of subdeltoid bursitis (under the deltoid, the shoulder muscle responsible for lifting the arm) or rotator cuff tendinitis (the set of muscles that give stability to the shoulder). However, unlike PMR, patients with bursitis or tendonitis do not have constitutional symptoms, i.e., weight loss, fatigue and anorexia. They also do not have an elevated erythrocyte sedimentation rate or anemia.
Malignant Tumors and Polymyalgia Rheumatica
There is no relationship between the occurrence of PMR and malignant tumors. However, some cancer patients may have muscle and joint pain similar to PMR, but in this case they do not respond to prednisone.
Infective Endocarditis and Polymyalgia Rheumatica
This and other infectious diseases may be confused with PMR, but the symptoms that differentiate endocarditis from PMR are heart murmurs, persistent fever, vegetations on a heart valve (formation of lumps of tissue within the heart), and positive blood cultures.
Inflammatory Myopathy and Polymyalgia Rheumatica
Muscle diseases such as polymyositis or dermatomyositis often present with symmetrical proximal muscle weakness, but the pain is not as severe as in PMR. Other differential factors include abnormal electromyography, elevated muscle enzyme levels, or evidence of myositis on muscle biopsy.