Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) are distinct yet related inflammatory conditions primarily affecting older adults. Both disorders involve an overactive immune system, leading to inflammation. While sharing similarities, they present unique characteristics and potential complications.
Understanding Polymyalgia Rheumatica
Polymyalgia rheumatica (PMR) is an inflammatory condition characterized by muscle pain and stiffness, predominantly in the shoulders, neck, and hips. Symptoms often appear suddenly or develop over days to weeks. The discomfort is bilateral, worse in the morning or after inactivity, and often lasts more than 30 minutes.
The stiffness can be severe enough to make everyday tasks challenging, such as dressing, reaching, or getting out of bed. PMR primarily affects individuals over 50, with an average onset around 70. Women are more frequently affected than men, and people of Northern European descent have a higher prevalence. About one-third of patients may also experience systemic symptoms like fatigue, loss of appetite, weight loss, or a low-grade fever.
Understanding Giant Cell Arteritis
Giant cell arteritis (GCA), also known as temporal arteritis, is an inflammatory condition affecting the lining of arteries, particularly those in the head like the temporal arteries. This inflammation can cause arteries to swell and narrow, restricting blood flow and potentially damaging tissues due to lack of oxygen and nutrients. GCA affects individuals over 50, with a mean age of onset around 70 years.
Symptoms of GCA include new onset of persistent, severe headaches, often localized to the temples, and scalp tenderness. Patients may also experience jaw pain, or claudication, when chewing or opening their mouth wide, which arises from insufficient blood flow to the jaw muscles. Vision changes, such as temporary or sudden, permanent loss of vision in one or rarely both eyes, or double vision, are concerning symptoms. This vision loss is often painless and can be irreversible if not treated promptly. GCA is considered a medical emergency due to the risk of irreversible complications like permanent blindness, stroke, or aortic aneurysms.
The Connection Between Polymyalgia Rheumatica and Giant Cell Arteritis
Polymyalgia rheumatica and giant cell arteritis, while distinct, are closely related inflammatory disorders that frequently occur together. Approximately 50% of individuals diagnosed with GCA also experience PMR symptoms. Conversely, about 10% to 20% of PMR patients may develop GCA.
This strong association suggests they share common underlying inflammatory processes and risk factors, such as age and genetic predispositions. Both conditions are thought to be triggered by a combination of genetic and environmental factors, potentially including viral infections. Given this overlap, a diagnosis of one condition often prompts monitoring for the other, as GCA in a PMR patient necessitates a different, more urgent treatment approach.
Diagnosis and Treatment Approaches
Diagnosing polymyalgia rheumatica and giant cell arteritis involves a comprehensive assessment, beginning with a physical examination and a detailed review of symptoms and medical history. Blood tests are standard for both conditions. Key inflammatory markers, such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), are elevated, indicating inflammation. While these markers are often elevated, a normal ESR or CRP does not completely rule out GCA, especially if clinical suspicion remains high.
For GCA, a temporal artery biopsy is considered the gold standard for confirmation. A small segment of the artery from the temple is removed and examined under a microscope for signs of inflammation and abnormally large cells called giant cells. This procedure is often performed on an outpatient basis. Imaging techniques also play an important role in diagnosing GCA. Doppler ultrasound can identify a “halo sign,” suggestive of arterial inflammation, while magnetic resonance angiography (MRA) and positron emission tomography (PET) scans can detect inflammation in larger blood vessels, such as the aorta.
Treatment for both conditions involves corticosteroids, such as prednisone, which are effective in reducing inflammation and alleviating symptoms. For GCA, prompt initiation of high-dose corticosteroids is important, often starting before biopsy confirmation, to prevent irreversible complications like permanent vision loss. The dosage is tapered gradually over time as symptoms improve and inflammatory markers decrease. In some cases, especially for GCA or when corticosteroid side effects are severe or prolonged, other immunosuppressant medications like methotrexate or tocilizumab may be considered as steroid-sparing agents.
Living with Polymyalgia Rheumatica and Giant Cell Arteritis
Living with polymyalgia rheumatica and giant cell arteritis often involves long-term management and careful monitoring. Ongoing medical follow-up is important to assess disease activity, detect potential relapses, and manage side effects associated with prolonged corticosteroid use. Corticosteroids, while effective, can lead to various complications over time, including bone density loss (osteoporosis), increased susceptibility to infections, weight gain, high blood pressure, and mood changes.
Patients are encouraged to adhere to their prescribed treatment plans and attend regular appointments with their healthcare providers. Strategies to mitigate corticosteroid side effects may include calcium and vitamin D supplementation for bone health, monitoring blood pressure and blood sugar, and maintaining a balanced diet and active lifestyle. Open communication with the healthcare team about any new symptoms or concerns is important for optimizing long-term outcomes and maintaining quality of life.