Giant cell arteritis

In July 2013, a 64-year-old woman presented to her optometrist with a 4-day history of intermittent blurred vision in the left eye with a left-sided headache. The patient was unsure whether she had had jaw claudication or scalp tenderness. She had no previous ocular history except spectacles for hyperopia and presbyopia. She had been taking diclofenac, tramadol, omeprazole, alendronic acid, calcium sup plements, and glyceryl trinitrate spray. Her best corrected visual acuity was 6/6 in the right eye and 6/60 in the left eye. Pupil reactions indicated a positive left relative aff erent pupillary defect. A swollen optic disc was observed in the left eye, more severe in the superior region with a corresponding inferior visual fi eld defect. The patient was referred urgently to the local eye casualty department with the working diagnosis of arteritic anterior ischaemic optic neuropathy secondary to giant cell arteritis. The patient attended the eye casualty department a few hours later and her vision had reduced further to hand movements. A fundus photograph showed a mildly swollen left disc (fi gure A). The left superfi cial temporal artery was pulsatile and tender. She was given aspirin 75 mg. Full blood count test results were all normal except for the red cell distribution width, which was slightly high at 15·3% (normal range 11·0–14·8). C-reactive protein was 7 mg/L (local laboratory normal range 0–10) and the erythrocyte sedimentation rate was 14 mm/h (local laboratory normal range 0–20). Urea and electrolytes, glucose, and liver function test results were all normal. Although the usual treatment for patients with giant cell arteritis is initial intravenous methylprednisolone for 3 days then switching to oral prednisolone, because of the slightly atypical presentation with normal infl ammatory markers in our patient, treatment with oral prednisolone 60 mg daily was chosen and a temporal artery biopsy was scheduled. The biopsy was done 5 days later and showed features consistent with giant cell arteritis (fi gure B, C). The patient did not develop any ocular problems in the right eye. Giant cell arteritis is a granulomatous arteritis with a propensity for medium and large sized arteries. Common symptoms include visual loss, headache, scalp tenderness, and jaw claudication. The visual consequence is usually arteritic anterior ischaemic optic neuropathy, although other manifestations can occur. The clinical signs of arteritic anterior ischaemic optic neuropathy include a reduction in visual acuity, relative aff erent pupillary defect, swollen optic disc with or without peripapillary haemorrhages and cotton wool spots. Other clinical features can include polymyalgia rheumatica, a thickened and tender non-pulsatile temporal artery, aneurysms, CNS disease, and stroke. Diagnosis is usually made on clinical suspicion, high erythrocyte sedimentation rate and C-reactive protein and histologically, via a temporal artery biopsy. A prompt diagnosis of giant cell arteritis is essential to reduce the risk of bilateral blindness. C-reactive protein and erythrocyte sedimentation rate infl ammatory markers will usually aid diagnosis but—as in this case—results can be within normal reference ranges in about 4% of patients. Erythrocyte sedimentation rate and C-reactive protein can be aff ected by many factors including drugs. Clinicians should be aware that a normal erythrocyte sedimentation rate and C-reactive protein does not rule out giant cell arteritis. If giant cell arteritis is suspected on clinical grounds, a temporal artery biopsy should be done irrespective of the erythrocyte sedi mentation rate and C-reactive protein values.