Giant cell arteritis risks

Giant cell arteritis is a serious condition that cannot always be immediately diagnosed, with potential medico-legal repercussions. Consultant ophthalmologist Mr Paul Riordan-Eva reviews the risks

Giant cell (temporal or cranial) arteritis (GCA) can cause rapid severe visual impairment in both eyes. Permanent visual loss occurs in 20-50% of cases. Among patients who have developed visual loss in one eye, without treatment almost 90% will develop visual loss in the other eye and 25-50% will develop bilateral blindness. The period from involvement of one eye to involvement of both eyes is usually less than five days.

Incidence

GCA almost always presents after age 50 and predominantly in caucasians, particularly those of Scandinavian descent. In the UK, there are approximately 7,000 newly diagnosed cases each year.

Presentation

Patients with GCA may present not only to GPs, rheumatologists, ophthalmologists and neurologists, but to many hospital departments including A&E, general medicine, healthcare for the elderly, cardiology, vascular surgery, general surgery, gastroenterology, ENT, oral medicine and maxillofacial surgery, as well as to dentists.

Symptoms and signs

Typical non-visual symptoms of GCA include headache, which characteristically localises to the temporal region but may localise to the occipital region or to the face (leading to misdiagnosis of sinusitis), scalp tenderness, systemic malaise and weight loss. Jaw claudication is highly specific but often overlooked. About 15% of patients have a history of polymyalgia rheumatica (PMR). 

Less common non-visual manifestations include fever, altered mental state, stroke, angina, myocardial infarction, pericarditis, limb claudication, abdominal pain, facial pain and/or swelling, tongue pain and/or swelling or necrosis, ear pain, cough and hoarseness. 

GCA may cause transient visual loss that is usually unilateral but may affect both eyes simultaneously or, more commonly, at different times. There may also be transient or persisting double vision. Any transient visual symptoms are harbingers of permanent visual loss. About 20% of patients with visual loss due to GCA have no non-visual symptoms ('occult GCA').

The superficial temporal arteries may be tender, thickened, or pulseless. (GCA is associated with potentially fatal aortic aneurysm, especially affecting the thoracic aorta.)

Diagnosis

Clinical diagnosis is confirmed initially in most cases by markedly elevated erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP), which together have greater sensitivity than either test alone. Individually they are normal in up to 15% of cases, whereas they are both normal in less than 5% of cases but both may be suppressed by steroid treatment. Anaemia, thrombocytosis, leucocytosis and elevated serum alkaline phosphatase are common in untreated GCA.

The gold standard for diagnosis of GCA remains temporal artery biopsy, which should be performed without undue delay but not necessarily within a few days of starting systemic steroid treatment. It is important that a specimen of at least 2cm and preferably 3cm is obtained. In some cases a negative biopsy warrants a second (contralateral) biopsy.

Treatment

It is crucial to start systemic steroid treatment as soon as a clinical diagnosis of GCA has been made, especially when permanent or transient visual loss has already occurred. It should result in rapid resolution of headache, scalp tenderness, jaw claudication, general malaise, PMR and transient visual symptoms, followed by normalisation of ESR and CRP.

Intravenous treatment should be considered, especially in patients presenting with bilateral visual symptoms or progressive visual loss despite oral treatment.

Paul Riordan-Eva, MB BChir, is a consultant ophthalmologist at King's College Hospital, London and an MDU Council member.

Case studies

The following fictionalised cases, based on actual cases, highlight the pitfalls of diagnosing GCA.

1. A 62-year-old woman consulted her dentist about jaw pain on chewing that was ascribed to temporomandibular joint dysfunction. She had also consulted her GP about recent onset occipital headaches. GCA was not diagnosed until she presented to hospital with sudden loss of vision in her left eye.
2. An 85-year-old man on oral steroid treatment for PMR presented to A&E with sudden loss of vision in his right eye. He was assessed by an ophthalmologist and a neurologist who agreed a diagnosis of ischaemic optic neuropathy. There was no history of headache and ESR and CRP were normal so GCA was thought to be unlikely. Three days later on waking he was completely blind (no perception of light) in both eyes. Temporal artery biopsy was positive for GCA.
3. A 71-year-old woman with fever, general malaise and weight loss was found to have markedly elevated ESR and CRP. She denied any headache or scalp tenderness. Before temporal artery biopsy could be performed, she developed sudden loss of vision in her left eye due to central retinal artery occlusion. Once started on systemic steroids she reported rapid resolution of neck and shoulder pain that she had ascribed to her age.

Learning points

1. The mean age at diagnosis of GCA is over 70 years, but GCA needs to be considered in any patient over 50 with new onset headache or symptoms potentially due to arterial insufficiency including sudden visual loss.
2. GCA especially needs to be considered in patients with a history of PMR and older caucasians of Scandinavian descent.
3. Jaw pain in older patients may be a manifestation of GCA.
4. ESR and CRP are usually elevated but may be normal in GCA.
5. The most definitive diagnostic test for GCA is temporal artery biopsy.
6. Once GCA is suspected, systemic steroid treatment needs to be started urgently, or as an emergency if there are visual symptoms.
7. In the early period following initiation of steroid treatment, patients with GCA need to be regularly reviewed to ensure that treatment is adequate.

This article originally appeared in the printed edition of the MDU journal April 2013 entitled "Giant cell arteritis"

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