According to the American College of Rheumatology, GCA presents after the age of 50, starts typically as a new headache or new localised pain in the head, and a blood test will show an erythrocyte sedimentation rate (ESR) of more than 50.It is usually accompanied by tporal artery tenderness or decreased pulses that are not related to atherosclerosis, and a biopsy shows a predominance of mononuclear or granulomatous inflammation, usually with giant cells.GCA has been associated with polymyalgia rheumatica (PMR), as 40% of GCA cases have PMR, while conversely, 10% of PMR cases develop GCA at some point. It is difficult to provide a definitive diagnosis of GCA, especially in the over 50 age group. {{quote-A:R-W:500-Q: It is usually accompanied by tporal artery tenderness or decreased pulses that are not related to atherosclerosis, and a biopsy shows a predominance of mononuclear or granulomatous inflammation, usually with giant cells. }}Symptoms include; a rapidly sequential, bilateral vision loss; transient visual obscurations, in the form of coloured, map-like subjective patterns; transient or persistent diplopia; and eye pain. Signs include a chalky white swelling of the optic disc.GCA must be considered in all patients over 50 who present with anterior ischaic optic neuropathy (AION), transient visual obscurations, central retinal artery occlusion (CRAO), posterior ischaic optic neuropathy, and diplopia or a cranial nerve palsy.Interestingly, the combination of a CRAO and cilioretinal artery occlusion is regarded as pathognomonic of GCA. Signs of ocular or orbital ischaia such as uveitis, corneal oeda, low IOP, or retinal cotton wool exudates are also possibilities.Systic symptoms include; jaw claudication – which can be revealed with a two-minute chewing gum test of one chew per sec – the recent onset of ‘different’ types of headaches, scalp tenderness, neck or ear pain, fatigue, fevers, or weight loss.However, up to 20% of cases will show none of those systic symptoms. Scalp ulceration, transient ischic attacks or strokes, and ischaias involving the myocardium or bowel are also possible.An early diagnosis is essential if irreversible vision loss is to be prevented but even then, correct treatment can still result in further deterioration of up to 30% in the affected eye and 10% in the fellow eye.GCA can blind or kill if not treated properly. According to one authority, the most useful information relates to jaw claudication, neck pain, and a C-reactive protein (CRP) test, which is considered more useful than ESR, as the latter can still be normal in a GCA case.Treatment is with intravenous methylprednisilone and most do not regain any lost vision. Oral steroids are used for general symptoms only and Fraser advised the audience to watch the patient take the tablets to enforce compliance. Published guidelines offer suggestion for tapering the dosage.A daily dose of aspirin is also recommended, as it inhibits cytokines in inflamed arterial walls, acts as a platelet aggregation inhibitor, and has a protective effect on cardiovascular and cerebrovascular events in GCA patients. A concurrent proton-pump inhibitor (PPI) was also recommended when a combination of a steroid and aspirin was used.While unpleasant, a tporal artery biopsy (minimum length 7 mm) is still regarded as the gold standard and ultrasound is not a substitute. However, a bilateral biopsy is unnecessary as well as unpopular.
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Associate Professor Clare Fraser specialises in neuro-ophthalmology, adult strabismus and visual electrodiagnostics. She is a consultant Visiting Medical Officer at both Sydney Eye Hospital and St Vincent’s Hospital, and is also in private practice in Sydney. At the University of Sydney, she holds the title of Associate Professor of Neuro-ophthalmology. |
