A 65-year-old man arrives at the emergency department after complaining of headaches in the right temporal region for three days. The headaches are accompanied by blurred vision in both eyes on and off. He has also been fatigued for the past week, with shoulder and hip stiffness. The temperature is 37.5 degrees Celsius, according to the examination (99.5 F). As shown in the illustration, there is tenderness on palpation of the right temporal region, with enlargement of the underlying artery. Funduscopic examination reveals edematous optic discs in both eyes. The patient has limited active abduction of the shoulder joints bilaterally. Laboratory studies show an erythrocyte sedimentation rate of 115 mm/hr. Which of the following is the most important mediator of this patient's current condition?

Question

A 65-year-old man arrives at the emergency department after complaining of headaches in the right temporal region for three days. The headaches are accompanied by blurred vision in both eyes on and off. He has also been fatigued for the past week, with shoulder and hip stiffness. The temperature is 37.5 degrees Celsius, according to the examination (99.5 F). As shown in the illustration, there is tenderness on palpation of the right temporal region, with enlargement of the underlying artery.  Funduscopic examination reveals edematous optic discs in both eyes.  The patient has limited active abduction of the shoulder joints bilaterally.  Laboratory studies show an erythrocyte sedimentation rate of 115 mm/hr.  Which of the following is the most important mediator of this patient's current condition?

Quizplus · Accepted Answer

Eductional Objective: This patient has giant cell arteritis ([GCA] temporal arteritis) with associated polymyalgia rheumatica, with headaches, visual and muscular symptoms, an enlarged temporal artery, and an elevated erythrocyte sedimentation rate. GCA is the most common systemic vasculitis in people of Northern European descent, and it almost always affects people over the age of 50.
Although both humoral and cellular immune mechanisms have been linked to GCA pathogenesis, cell-mediated processes are more important. Lymphocytes (predominantly CD4-positive T cells) and macrophages make up the inflammatory infiltrate in affected vessels, which frequently contains multinucleated giant cells. The production of cytokines, particularly interleukin-6 (IL-6), appears to be closely related to the severity of the disease; tocilizumab, a monoclonal antibody against IL-6, is effective in treating GCA.

A 65-Year-Old Man Arrives at the Emergency Department After Complaining