- Age: GCA almost exclusively affects people over the age of 50, with the average age of onset around 70.
- Sex: Women are about two to three times more likely to develop GCA than men.
- Genetics: There appears to be a genetic predisposition, as GCA is more common in people of Northern European descent.
- Polymyalgia Rheumatica (PMR): A significant percentage of people with PMR either have or will develop GCA, and vice versa.
- Environmental factors: Some research suggests that infections or other environmental triggers might play a role in initiating the condition in genetically susceptible individuals, but no specific trigger has been definitively identified.
- Persistent, severe headache: Often localized to the temples, but can be on one or both sides of the head, or in the back of the head. The pain may be throbbing or sharp.
- Scalp tenderness: Pain or tenderness when touching the scalp, especially over the temporal arteries.
- Jaw pain (jaw claudication): Pain or cramping in the jaw muscles that worsens with chewing.
- Vision problems: Sudden, temporary, or permanent loss of vision in one or both eyes (often described as a "curtain coming down"), double vision, or blurred vision. This is a medical emergency.
- Fatigue: General tiredness and weakness.
- Fever: Low-grade fever is common.
- Weight loss: Unexplained weight loss.
- Loss of appetite.
- Muscle aches and stiffness: Similar to polymyalgia rheumatica, affecting the shoulders, neck, and hips.
- Medical history and physical examination: The doctor will ask about your symptoms, especially headaches, jaw pain, and vision changes. They will also examine your temporal arteries, which may be tender, swollen, or have a reduced pulse.
- Blood tests:
- Erythrocyte Sedimentation Rate (ESR): A significantly elevated ESR is a strong indicator of inflammation.
- C-reactive protein (CRP): Another marker of inflammation that is typically high in GCA.
- Other blood tests may be done to rule out other conditions.
- Temporal artery biopsy: This is often considered the gold standard for diagnosis. A small sample of the temporal artery is surgically removed and examined under a microscope for signs of inflammation (giant cells).
- Imaging tests:
- Ultrasound: High-resolution ultrasound of the temporal arteries can show signs of inflammation (e.g., "halo sign").
- MRI or CT angiography: May be used to visualize larger arteries and assess for inflammation or narrowing.
- PET scan: Can sometimes identify inflammation in large arteries throughout the body.
- High-dose corticosteroids:
- Oral corticosteroids (e.g., prednisone) are the cornerstone of treatment and are started immediately, often even before a biopsy confirms the diagnosis, especially if vision changes are suspected.
- The initial dose is high to rapidly control inflammation and protect vision.
- The dose is gradually tapered over many months to years, as GCA is a chronic condition that requires long-term management.
- Immunosuppressants:
- In some cases, other immunosuppressive medications (e.g., methotrexate, tocilizumab) may be added to allow for a lower corticosteroid dose, reduce side effects, or manage refractory disease.
- Aspirin: Low-dose aspirin may be recommended to help prevent blood clots and reduce the risk of stroke or heart attack.
- Bone-preserving medications: Calcium, Vitamin D, and bisphosphonates are often prescribed to counteract the bone-thinning side effects of long-term corticosteroid use.
- Monitoring: Regular follow-up with your doctor is essential to monitor symptoms, inflammation markers (ESR, CRP), and adjust medication dosage. Close monitoring for potential complications is also crucial.