1. Giant cell arteritis can affect many arteries throughout the body, producing symptoms and signs which mimic many other medical and surgical conditions:

1. Systemic symptoms—flu like with fever.
2. Myalgic symptoms.
3. Arteritis—local inflammation, partial or complete occlusion.

2. Temporal arteritis a clinical syndrome due to giant cell arteritis localized to the region of the temporal artery.
3. Polymyalgia rheumatica is due to giant cell arteritis and causes a clinical syndrome of proximal, symmetrical extremity pain and stiffness.

Both B and C are diseases of elderly people. They may coexist or appear separately.
Diagnosis is largely by clinical history, a substantially raised sed rate, exclusion of other conditions and confirmatory biopsy evidence.
Sudden painless loss of vision in one eye due to arterial occlusion is a dreaded complication of arteritis.
"Temporal artery biopsy samples are positive in 60-80% of patients with giant cell arteritis, but in only 15-20% of patients with polymyalgia rheumatica, in whom biopsy for polymyalgia alone is not justified."
Corticosteroids are essential for the treatment of polymyalgia rheumatica and temporal arteritis. They rapidly relieve the incapacitating symptoms and reduce the incidence of blindness. Response to steroids is dramatic.
The need for long-term steroid therapy causes concern. Titrating a gradual reduction in dose guided by the clinical picture and the sed rate is reasonable. Most studies indicate that between 1/3 and 1/2 of patients can stop steroids after 2 years. The risk of relapse must be balanced against steroid related side effects.
"Polymyalgia rheumatica and temporal arteritis are among the most rewarding diseases for a clinician to diagnose and treat because the unpleasant symptoms and serious consequences can be rapidly prevented with corticosteroids.
BMJ May 3, 1997; 312: 1329-32 Clinical review from Notingham City Hospital, UK