Temporal Artery Biopsy vs ULtrasound in Diagnosis of GCA (TABUL)

Giant Cell Arteritis (GCA) causes inflammation and narrowing of blood vessels and can cause blindness in one third of patients. It is important that a prompt, accurate diagnosis of GCA is made and treatment given as steroids for two or more years. Currently there is no 100% accurate test for GCA. Patients usually have new headache and scalp tenderness, typically with an abnormal blood test. However, it can be difficult to distinguish non-serious forms of headache from GCA; infection produces similar abnormal blood results. If there is a suspicion of GCA, treatment with steroids is started straight away. To confirm a diagnosis, the patient will need a biopsy of a temporal artery (a minor procedure performed under local anaesthetic to remove a sample of one of the scalp arteries). However, up to 44% of patients will have a normal biopsy. Therefore it is difficult to know if a patient with a normal biopsy does or does not have GCA. Withdrawing steroid treatment may increase the risk of blindness. Continuing treatment in a patient without GCA increases the risk of side effects (e.g., weight gain, infection risk, osteoporosis and fracture risk, high blood pressure, diabetes, cataracts). It is important to improve diagnostic tests for GCA. Another test to help in diagnosing GCA is an ultrasound scan of the arteries in the side of the head and under the arms. Ultrasound does not involve surgery; it is a simple test which can be performed as an out patient. Gel is applied to both sides of the head and under each arm. A sound probe is placed over the artery at each site to produce the scan. The investigators' study will examine the role of ultrasound in diagnosis of 402 patients with suspected GCA. All patients will have an ultrasound examination in addition to biopsy within a week of starting steroids. Patients will be treated according to usual practice. After six months, the investigators will reassess the diagnosis. The investigators will look at the accuracy of ultraso