Giant Cell Arteritis

Definition

Definition of Giant Cell Arteritis
Giant cell arteritis (GCA) is an inflammation of the lining of your arteries - the blood vessels that carry oxygen-rich blood from your heart to the rest of your body. Most often, it affects the arteries in your head, especially those in your temples. For this reason, giant cell arteritis is sometimes called temporal arteritis or cranial arteritis.

Symptoms

Symptoms of Giant Cell Arteritis
The most common symptoms of giant cell arteritis are head pain and tenderness - often severe - that usually occurs in both temples. Some people, however, have pain in only one temple or in the front of the head.

Signs and symptoms of giant cell arteritis can vary. For some people, the onset of the condition feels like the flu - with muscle aches throughout the body (myalgia), fever and fatigue, as well as headaches.

Causes

Causes of Giant Cell Arteritis
Your arteries are pliable tubes with thick, elastic walls. Oxygenated blood leaves your heart through your body's main artery, the aorta. The aorta then subdivides into smaller arteries that deliver blood to all parts of your body, including your brain and internal organs.

With giant cell arteritis, some of these arteries become inflamed, causing them to swell. Just what causes these arteries to become inflamed isn't known.

Although almost any large or medium-sized artery can be affected, swelling most often occurs in the temporal arteries in your head, which are located just in front of your ears and continue up into your scalp. In some cases, the swelling affects just part of an artery, with sections of normal vessel in between.

Diagnosis

Diagnosis of Giant Cell Arteritis
Physical Exam:

1. Palpation of the head reveals prominent temporal arteries with or without pulsation.
2. The temporal area may be tender.
3. Decreased pulses may be found throughout the body.
4. Evidence of ischemia may be noted on fundal exam.

Laboratory Tests:

1. LFTs, liver function tests, are abnormal particularly raised ALP- alkaline phosphatase
2. Erythrocyte sedimentation rate, an inflammatory marker, >60 mm/hour (normal 1–40 mm/hour).
3. C-reactive protein, another inflammatory marker, is also commonly elevated.
4. Platelets may also be elevated.

Biopsy:

1. 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. Unilateral biopsy of a 1.5–3 cm length is 85-90% sensitive (1 cm is the minimum). So, a negative result does not definitely rule out the diagnosis. Thus, currently biopsy is only considered confirmatory for the clinical diagnosis, or one of diagnostic criteria.

Imaging Studies:

1. Radiological examination of the temporal artery with ultrasound yields a halo sign. Contrast enhanced brain MRI and CT is generally negative in this disorder. Recent studies have shown that 3T MRI using super high resolution imaging and contrast injection can non-invasively diagnose this disorder with high specificity and sensitivity.

Treatment

Treatment of Giant Cell Arteritis
Treatment for GCA consists of high doses of a corticosteroid drug such as prednisone. Because immediate treatment is necessary to prevent vision loss, your doctor is likely to start medication even before confirming the diagnosis with a biopsy.

You should start feeling better within just a few days, but you may need to continue taking medication for one to two years or longer. After the first month, your doctor may gradually begin to lower the dosage until you reach the lowest dose of corticosteroids needed to control inflammation as measured by sed rate and CRP tests. Some of your symptoms may return during this tapering period.

Prognosis

Prognosis of Giant Cell Arteritis
Most people make a full recovery, but long-term treatment (for 1 to 2 years or longer) may be needed. The condition may return at a later date.

Prevention

Prevention of Giant Cell Arteritis
There is no known prevention.