Giant cell arteritis (GCA) is a form of vasculitis that affects large and medium sized arteries. Vasculitis means inflammation of blood vessels. GCA is also known as temporal arteritis as it often affects the temporal arteries. GCA mainly affects older people and is very rare under the age of 50. Polymyalgia rheumatica is present in around 50% of people who develop GCA and it is thought that they are different spectrums of the same disorder. It tends to only occur in those over the age of 50, and the risk increases with increasing age. People of northern European descent are more likely to get the disorder suggesting a genetic predisposition.
- New onset persistent headaches which can be very severe.
- Pain and aching in the jaw muscles when chewing. The pain gets worse the more you chew due to reduced blood supply to the muscle.
- Tender scalp and/or tenderness over the temporal arteries.
- Fevers, night sweats or weight loss.
- Visual disturbance including double vision or visual loss.
- Aching in a limb with activity (limb claudication).
- Polymyalgia symptoms (aching and stiffness in the neck, shoulder girdle and hip girdle which is worse in the morning).The cause of GCA is not known but seems to start more commonly in spring and summer suggesting an environmental trigger. It occurs in about 25% of people who have polymyalgia rheumatica.
Diagnosis is based on the symptoms, findings of raised inflammatory markers in the blood (CRP or ESR) and confirmation of vasculitis with either a biopsy of the temporal artery or an ultrasound of the temporal and/or axillary arteries showing inflammation.
Delay in diagnosis and treatment can lead to permanent blindness or stroke. We offer a fast-track clinic where you are seen within 10 days of referral. As part of this consultation Dr Suppiah will ultrasound the temporal, carotid and axillary arteries to help make the diagnosis. A decision on appropriate therapy is made based on symptoms, blood tests and the findings on ultrasound. In most cases having an ultrasound will remove the need for a temporal artery biopsy. Fast-track pathways such as this have been shown to reduce visual loss, reduce over treatment and reduce cost in studies done overseas.
The current standard of therapy for GCA is high dose steroids (prednisone) and aspirin. Treatment is usually required for 2-3 years and this can result in lots of side effects due to the cumulative dose effect of prednisone. Management of these side effects such as preventing bone loss is also required.
In the case of visual threatening disease, disease refractory to standard therapy, or where there has been stroke or transient ischaemic events occurring then intravenous methylprednisolone and/or cyclophosphamide can be used to try and bring the vasculitis under control.
Other steroid sparing agents such as methotrexate, leflunomide, and mycophenolate can be considered to reduce the dose of prednisone required for treatment. However, the overall benefit from these medications have not been tested in a proper clinical trial. Tocilizumab is an expensive biologic medication that has been shown to be effective in the treatment of GCA including prevention of relapse whilst on treatment. It is not currently Pharmac funded for this indication in New Zealand but is available.