GIANT CELL ARTERITIS (GCA)

Dr. Vivek Rajagopal MD, MRCP

Consultant Rheumatologist

WestSuffolkHospital, Bury St Edmunds, UK

Giant cell arteritis (Temporal Arteritis) is a type of vasculitis characterised by granulomatous inflammation in the wall of medium and large sized arteries. The extra cranial branches of the carotid artery and branches of ophthalmic arteries are preferentially involved.

Epidemiology

GCA is the most common systemic vasculitis in western countries.

There is a slight geographic variation in incidence. Incidence is 7/100,000 in Italy; 29/100,000 in Norway.The epidemiology of GCA is similar to that of PMR. It is 7 times more common in white than in black people.

It is rare before the age of 50 and the mean age of onset is 70 years.

It is three times more common in women.

Between 20 – 40% of patients with GCA develop PMR at some stage in their illness.

Clinical Features

Symptoms

  • Headache is the main symptom and seen in 70% of patients at presentation. The pain is severe and usually localised to the temple, but it can be occipital or diffuse in some instances.
  • Scalp tenderness and Jaw claudication (cramps in the jaw especially while chewing) are specific symptoms that are uncommon in other causes of headache.
  • Visual disturbances – permanent or partial loss of vision is seen in up to 20% of patients and can be an early symptom. If untreated, the second eye can be affected within 1 – 2 weeks and hence urgent treatment is required.

Systemic features – Most people may experience fever, night sweats,weight loss and depression. Symptoms of PMR can be seen in 20 – 40% of patients with GCA.

Signs

  • Scalp tenderness occurs in about 50%.
  • Abnormal temporal arteries – thickening, nodularity or lack of pulsation can be seen in up to 75% of people. The overlying skin may be red.
  • Peripheral arthritis and peripheral oedema – can be seen in 25%. Swelling is prominent over the dorsum of the hands, ankle and feet.

Differential Diagnosis

Other causes of headache such as migraine or tension headache are much more common than GCA.

Raised intracranial pressure can cause chronic headache. But this is usually worse in the morning with nausea, abnormal fundoscopy or neurological deficits.

Atherosclerotic ischemic optic neuropathy is ten times more common than GCA and also presents as painless loss of vision. These patients do not experience headache and have normal inflammatory markers.

Diagnosis

There are no diagnostic tests that can be routinely done in primary care to diagnose GCA. However, the following may support the diagnosis.

  • Inflammatory markers
  • ESR more than 50mm/hr is seen in 90 – 95% of patients at diagnosis. This is usually accompanied by a raised CRP. High ESR with normal CRP is unlikely in GCA and is usually due to other causes.
  • Normocytic normochromic anaemia with high platelets is common.
  • About a third of patients have abnormal LFTs, usually an elevated alkaline phosphatase.

The diagnostic test is a temporal artery biopsy which has a sensitivity of 90%.

A positive test is confirmatory, but a negative test does not rule it out as `skip lesions’ can occur along the temporal artery.

Biopsy should be performed within 2 weeks of starting corticosteroids.

Recently Ultrasound Doppler of the temporal arteries has been used as a diagnostic tool and also to localise the site of biopsy.

Treatment

Steroids are the mainstay of management and should be initiated in primary care for patients with typical clinical features and elevated inflammatory markers. All patients should be referred for specialist review to confirm the diagnosis as the condition is very rare and few primary care physicians would have developed sufficient experience to manage these patients.

For patients presenting with visual symptoms, prednisolone 60mg daily is the preferred starting dose and they should be referred for urgent ophthalmology review.

For patients with headache and no visual symptoms, prednisolone 40mg daily is sufficient. All patients should be reviewed after 48 hours of starting steroids to assess response and nonresponders should be referred for rheumatology opinion urgently. Steroids are continued for 18 to 24 months to prevent relapses. A significant proportion of patients may become steroid dependant and steroids sparers such as methotrexate, azathioprine and leflunomide may be required.

All patients should be given low dose aspirin (75mg daily) along with a PPI as these patients have an increased risk of cerebrovascular disease. Osteoporosis prophylaxis should be prescribed as per local guidelines.

Prognosis

Most patients remain in remission after completing a course of steroids. 10 to 20 % percent may require low dose prednisolone or a steroid sparing agent to maintain remission. Steroid related adverse effects such as osteoporosis, cataracts, glaucoma and diabetes affect a significant proportion of patients and cause considerable morbidity. An increased incidence of strokes and thoracic aneurysms are long term complications which can be minimised by early recognition and treatment of Giant Cell Arteritis.