What is Giant Cell Arteritis/ Temporal Arteritis?
This is a disease characterised by inflammation ("itis") of large and medium sized blood vessels ("arteries"), with infiltration of small and large blood cells ("giant cell"). An alternative name for this condition is "Temporal Arteritis" as the blood vessels in the temple area of the head are commonly affected.
Who are affected?
This condition is one of the commonest forms of vasculitis, affecting one or two persons per 10,000 people. This condition is more commonly seen in older patients, and is seldom diagnosed below the age of 50. For some unknown reason, this condition affects the white population almost exclusively.
What are the symptoms?
Symptoms of fatigue, loss of appetite, weight loss and fever are often found.
Headache is a prominent feature of this disease due to inflammation of the temporal vessels. Giant cell arteritis is closely associated with the "polymyalgia rheumatica syndrome", which causes general weakness, pai n and stiffness in muscles and joi nts. The weakness in the muscles can be quite debilitating and typically affects the upper arms and legs. Simple tasks such as brushing the hair, cooking, gardening, getting up and out of chairs or beds and walking may become difficult.
As this condition affects blood vessels with inflammation, a reduction in the oxygen supply (ischaemia) to different organs can result. Depending on the organ supplied by the diseased vessels, a great variety of symptoms can result.
A classic symptom of this condition is jaw and tongue pain due to lack of oxygen supply. In the heart, a heart attack can result and starving the brain of blood can lead to a stroke. Reduction in oxygen supply to the eyes can lead to blurred vision, or in some patients, blindness.
Aetiology /Cause
An infectious trigger has been suggested but no definite infectious organism has been found consistently in patients. The predominance in the white population, cluster of cases in some families and the association with some genes called HLA-DR4 favour an inherited predisposition to the disease.
Diagnosis
The inflammation in the blood will be reflected in certain blood markers. One such marker which is always raised in this condition is called an "ESR", and can be measured by taking a blood sample. Unfortunately other conditions such as infections can also cause an ESR rise and so diagnosis is not solely made on the basis of the ESR result.
The standard for diagnosis is a biopsy of the temporal artery. The inflammation in the blood vessels is not uniformly present and sections of the blood vessels can still be normal. Hence, a positive biopsy showing inflammation confirms disease but a negative biopsy does not exclude disease.
Treatment
The aim of treatment is to rei ieve patients of troublesome symptoms and prevent ischaemic symptoms due to lack of oxygen. Most symptoms resolve with treatment.
High dose oral steroids in the form of prednisolone is usually given and the dose is reduced slowly over months, using the ESR marker as a guide to response. Treatment with steroids is given for at least one to two years.
Does the treatment have adverse effects?
Yes. Steroids work by suppressi ng inflammation but also suppress the body's ability to fight infection. Steroids will accelerate the natural process of bone thinning, and fractures can occur. Steroids can also cause or aggravate indigestion, sugar diabetes, high blood pressure, thinning and bruising of the skin and weight gain. Although most patients will be taking steroids for years, the dose is reduced qu ickly to prevent side effects.
Patients will be seen regularly and the dose of steroids taken is not sufficient in most patients to cause these side effects.
Can this condition relapse?
Yes. In about 50% of patients, withdrawal of steroids can lead to a relapse of the symptoms. In such cases, the steroid is re-started and it is often sufficient to induce remission, the steroid dose can again be reduced. In most relapsed cases, the patient will be maintained on a small dose of steroid indefinitely.
Prognosis
Good, with correct early diagnosis and treatment.