Temporal arteritis, also called giant cell or cranial arteritis, is a systemic inflammatory vasculitis of medium and large-sized arteries occurring most frequently in adults. This results in an ischemic optic neuropathy with irreversible or significant visual loss on the affected side with possible contralateral involvement. Left untreated, it can result in many systemic, neurologic, and ophthalmologic complications. Although the temporal artery is most commonly involved, other arteries may certainly be affected. These include the aorta and the subclavian, iliac, ophthalmic, occipital, and vertebral arteries. Although not necessary, the disease is commonly associated with polymyalgia rheumatica.
While TA generally occurs in people over the age of 50, the average age of onset is 75. Women are more commonly affected, almost four times more than men. It is a relatively rare disease, occurring in about 10 to 20 people over the age of 50 per year, depending on the nationality of the patient. It is more commonly found in people of European descent but may present in a patient of any ethnicity.
As GCA is a disease characterized by cell-mediated immunity, the pathophysiology is thought to involve the body's inappropriate response to vascular endothelial injury. The initial insult to the vascular wall causes a massive release of cytokines, in turn attracting macrophages and multinucleated giant cells. This inflammatory cascade causes activation of CD4 helper T cells, causing further inflammation and hyperplasia. 
The biopsy of the artery will usually reveal the following features:
The patient will usually present with complaints of a headache, painless vision loss, jaw claudication, fatigue, fever, anorexia, or temporal artery tenderness. Patients may state that their headache has been occurring for a duration of 2 to 3 months and worsens with exposure to cold and at night when the pressure of the pillow causes pain to the artery. On physical exam, the temporal artery may be thickened, painful, nodular, or erythema may occur on the overlying skin. It is important to realize that the physical exam of the temporal artery may be inconclusive. In addition, the temporal artery may not necessarily be the artery involved which further complicates the diagnosis. Many patients will present with signs or symptoms of TIA or stroke. The ophthalmologic exam will generally be benign, although if the circulation of the optic nerve is involved, the patient may display an afferent pupillary defect. Because of the inconsistencies regarding the history and physical, temporal arteritis is often a difficult disease to diagnose in the emergency setting.
The American College of Rheumatology has developed a set of criteria for the diagnosis of temporal arteritis. Three of the five criteria must be present to make the diagnosis. These include:
Due to the patchy nature of the disease in the affected artery, a biopsy may yield a false negative if not taken of adequate length. The recommended length is at least 1 cm, with 1.5 cm to 3 cm showing a sensitivity of 85% to 90%, to achieve a successful biopsy. An elevated CRP, although not required for diagnosis, may also be helpful. Although imaging has generally not been indicated in the diagnosis of temporal arteritis in the past, recent studies show ultrasound as a useful adjunct. If a dark halo is seen around the vessel, sensitivity approaches 80% to 100%. High-resolution 3T MRI has also been shown to be effective in some studies. Although the clinical picture may be helpful in the diagnosis, it is important to note that only a biopsy of the affected artery can give a definitive diagnosis.
The timing of treatment is critical in these patients to prevent vision loss. Steroids should be started immediately upon suspicion of temporal arteritis. Although there is no consensus among physicians regarding the amount of steroid therapy to begin, 60 milligrams of prednisone PO or 1 mg/kg daily can be used as a general guideline. This may be required for 1 to 2 years. The patient should be followed by their primary care physician with frequent ESR draws. If acute vision loss is present, the patient may be started on 250 mg to 1000 mg of intravenous (IV) steroids for 3 days. Low-dose aspirin should also be started daily. A rheumatologist should be consulted immediately upon starting steroid treatment and before performing a biopsy. An ophthalmologist should also see the patient to perform a full eye exam to rule out other serious causes of vision loss. If strong clinical suspicion is present, the biopsy may be performed by either a neurosurgeon, ophthalmologist, plastic surgeon, or general surgeon. Treatment with steroids must be started when the disease is suspected, rather than while awaiting biopsy results. Biopsy results may still be positive a week after beginning steroids. Patients may be safely discharged on oral steroids with close follow-up without hospital admission. Symptoms warranting admission include the inability of the patient to care for themselves or severe symptoms.
Remember, the temporal artery may be normal on physical exam. This may be due to early disease or involvement of a vessel other than the temporal artery. During the physical exam, checking the intraocular pressure should be performed to rule out acute glaucoma. In a patient with a new headache and an elevated ESR, GCA should be considered. Hints to temporal artery tenderness include pain from wearing glasses or a hat. Transient episodes of recurring blurriness in one eye is usually an indicator of reversible disease, but once total monocular vision loss occurs, this is usually permanent. Temporal arteritis is a diagnosis that is seldom made in the emergency department. Patients who present to the ED with headaches and improve after analgesia are often discharged home and are misdiagnosed. Palpation of the temporal artery should become apart of every provider's physical exam on patients who present with a headache.
The management of temporal arteritis is with a multidisciplinary team that consists of an internist, neurologist, rheumatologist, ophthalmologist, a nurse, pharmacist and surgeon. Education is the most important step as patients need to know the complications of this disorder and the need for close monitoring. All patients should be urged to follow up with an ophthalmologist to ensure that vision loss is not occurring. Anyone with weakness, loss of vision, difficulty with gait, dysphagia or speech problems should immediately seek medical assistance. The pharmacist should educate the patient on corticosteroid compliance and the potential side effects. All patients should be told that despite treatment they may develop problems with other blood vessels in the future. (Level V)
For the majority of patients, who get prompt treatment, there is a complete recovery. Symptomatic improvement occurs in 2-4 days after treatment. To avoid the adverse effects of the corticosteroids, tapering is recommended after 4-6 weeks. Blindness from temporal arteritis is very rare today. However, the course of the disease does vary from patient to patient and may last 3 months to 5 years. The biggest problem with the treatment of temporal arteritis today is the morbidity associated with the corticosteroids. Individuals likely to require prolonged treatment with steroids include females, older age, and those with a higher baseline ESR. For those who are untreated, the prognosis is poor; these individuals may suffer from blindness, develop a stroke or an MI. Overall, about 1-3% of patients with temporal arteritis die from a stroke or an MI. (Level V)