or swollen optic disc or retinal artery occlusion. A swinging afferent papillary defect can also occur.
Investigation An elevated ESR greater than 50 is one American Society of Rheumatology classification criterion (see box), but it should be noted that lower ESRs can occasionally occur. Temporal artery biopsy is thought to be the most sensitive test and does have a high negative predictive value. However, the lesions are not confluent and if GCA is still strongly clinically suspected aſter a first negative biopsy a second may be performed.
Treatment Tis is a common treatable cause of blindness. If there is a strong clinical suspicion of GCA, immediate treatment with glucocorticoids is indicated. Many laboratories will do an urgent ESR which will be available the same day, which may help to confirm clinical suspicions. If ESR is normal the glucocorticoid prescription can be reviewed. An urgent referral to a specialist centre with the aim of performing a temporal artery biopsy within the first week is advised. Local services vary and it is important to be aware of the relevant receiving specialty as it can be either ophthalmology, rheumatology or vascular surgery. Temporal artery biopsy is important because a positive result will have prognostic implications and confirms the need for long-term glucocorticoid therapy. If it is uncomplicated GCA (no visual change or jaw
CLASSIFICATION
The American College of Rheumatology (ACR) classification criteria for GCA
• Age at disease onset >50 years: development of symptoms or findings beginning at the age of >50 years
• New headache: new onset of or new type of localised pain in the head
• Elevated ESR: ESR>50 mm/h by the Westergren method arteriosclerosis of cervical arteries
• Abnormal artery biopsy: biopsy specimen with artery showing vasculitis characterised by a predominance of mononuclear cell infiltration or granulomatous inflammation, usually with multinucleated giant cells
Patients require three out of these five criteria to fulfill a diagnosis of GCA by these guidelines
• Temporal artery abnormality: temporal artery tenderness to palpation or decreased pulsation, unrelated to
Prominent artery with arteritis on the temple of a 76- year-old woman
claudication), 40-60 mg of prednisolone per day is advised until symptoms resolve and inflammatory markers decline. If there is evidence of evolving visual loss, an in-patient assessment may be required and i.v. methyl prednisolone is recommended for three days. If there is established unilateral visual loss, 60mg once daily of prednisolone should be prescribed to protect the other eye. At initial presentation inflammatory markers and chest X-
ray (if possible) should be performed. Te CXR is to assess if there is involvement of the thoracic aorta. Consideration should also be given to starting aspirin (some evidence to support reduction in visual loss), as well as calcium, vitamin D and bisphosphonate and gastroprotection, particularly in those over 65 years of age. A suggested steroid tapering regimen is 40-60mg
prednisolone continued for four weeks (until resolution of symptoms and laboratory abnormalities), then dose reduced by 10mg every two weeks to 20mg, then by 2.5mg every two to four weeks to 10mg, then by 1mg every one to two months provided there is no relapse. Recording the ESR within the case records and ensuring
that the symptoms do resolve on glucocorticoids treatment is vital. As always it is recommended that the clinician keeps good legible notes of the consultation and these will be essential should any subsequent medico-legal issues arise. A relapse is considered if there is a rise in ESR to greater or equal to 40 and recurrence of symptoms. Most patients will require glucocorticoids for two to three years and should have their ESR monitored throughout this time.
Conclusion As with many clinical emergencies it is oſten the initial clinical assessment of GCA that is the most important factor in determining the long-term outcome. As detailed above there are a number of pitfalls in the diagnosis, particularly in the atypical presentations. However, an awareness of the condition and current guidelines outlined, coupled with a careful history and examination makes falling into these pitfalls much less likely. In short, the prompt diagnosis of giant cell arteritis and appropriate action will in a good proportion of presentations of this condition save sight.
nDr Rajan Madhok is a consultant physician and rheumatologist at the Centre for Rheumatic Diseases at the Glasgow Royal Infirmary
nDr Nicola Alcorn is a physician at the Centre for Rheumatic Diseases at the Glasgow Royal Infirmary
SUMMER 2012 17
PHOTOGRAPH: SCIENCE PHOTO LIBRARY
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