Temporal arteritis (TA)

Temporal arteritis (also known as giant cell arteritis: GCA) is a vasculitis of unknown cause that affects medium and large-sized vessels arteries. It occurs in those over 50 years old, with a peak incidence in patients who are in their 70s.

It requires early recognition and treatment to minimize the risk of complications such as permanent loss of vision. Hence, when temporal arteritis is suspected, treatment must be started promptly with high-dose prednisolone as well as urgent referral for assessment by a specialist.

There is an overlap between temporal arteritis and polymyalgia rheumatica (PMR) - around 50% of patients will have features of PMR.

Pathogenesis:

Although Cell-mediated processes plays a major role, both humoral and cellular immune mechanisms are implicated;

The inflammatory infiltrate usually contains CD4+ T cells and macrophages as well as multinucleated giant cells.

The production of cytokines, in particular IL-6, appears to closely correlate with the severity of the disease;

Features

• typically patient > 60 years old
• usually rapid onset (e.g. < 1 month)
• headache (found in 85%)
• jaw claudication (65%)
• vision testing is a key investigation in all patients
  • anterior ischemic optic neuropathy accounts for the majority of ocular complications. It results from occlusion of the posterior ciliary artery (a branch of the ophthalmic artery) → ischaemia of the optic nerve head. Fundoscopy typically shows a swollen pale disc and blurred margins
  • may result in temporary visual loss - amaurosis fugax
  • permanent visual loss is the most feared complication of temporal arteritis and may develop suddenly
  • diplopia may also result from the involvement of any part of the oculomotor system (e.g. cranial nerves)
• tender, palpable temporal artery
• around 50% have features of PMR: aching, morning stiffness in proximal limb muscles (not weakness)
• also lethargy, depression, low-grade fever, anorexia, night sweats

Investigations