Life Science Encyclopedia

Temporal arteritis, also called giant cell arteritis (GCA) is an inflammatory disease of blood vessels (most commonly large and medium arteries of the head). It is therefore a form of vasculitis. The name comes from the most frequently involved vessel (temporal artery which branches from the external carotid artery of the neck). The alternative name (giant cell arteritis) reflects the type of inflammatory cell that is involved (as seen on biopsy).

The disorder may coexist (in one quarter of cases) with polymyalgia rheumatica (PMR), which is characterized by sudden onset of pain and stiffness in muscles (pelvis, shoulder) of the body and seen in the elderly. Other diseases related with temporal arteritis are systemic lupus erythematosus, rheumatoid arthritis and severe infections.

Symptoms

It is more common in females than males by a ratio of 2:1. The mean age of onset is about 70 years and is rare at less than 50 years of age.

Patients present with:

• fever
• headache
• tenderness and sensitivity on the scalp
• jaw claudication (pain in jaw when chewing)
• reduced visual acuity (blurred vision)
• acute visual loss (sudden blindness)

The inflammation may affect blood supply to the eye and blurred vision or sudden blindness may occur. In 76% of cases involving the eye, the ophthalmic artery is involved causing anterior ischemic optic neuropathy.^[1] Loss of vision in both eyes may occur very abruptly and this disease is therefore a medical emergency.

Diagnosis

Physical exam

Palpation of the head reveals sensitive and thick arteries with or without pulsation.

Laboratory tests

Sedimentation rate is very high in most of the patients, but may be normal in approximately 20% of cases.

Biopsy

The gold standard for diagnosing temporal arteritis is biopsy, which involves removing a small part of the vessel and examining it microscopically for giant cells infiltrating the tissue. Since the blood vessels are involved in a patchy pattern, there may be unaffected areas on the vessel and the biopsy might have been taken from these parts. So, a negative result does not definitely rule out the diagnosis.

Radiology

Radiological examination of the temporal artery with ultrasound yields a halo sign. Contrast enhanced brain MRI and CT is generally negative in this disorder.

Treatment

Corticosteroids must be started as soon as the diagnosis is suspected (even before the diagnosis is confirmed by biopsy). Steroids do not prevent the diagnosis later being confirmed by biopsy, although certain changes in the histology may be observed towards the end of the first week of treatment and are more difficult to identify after a couple of months.^[2]

References