Large vessel vasculitis (LVV) refers to a group of conditions characterized by inflammation of the body’s largest arteries. This inflammation affects the vessel walls, potentially leading to thickening, narrowing, or weakening of these important blood pathways. The aorta, which is the main artery carrying blood from the heart, and its primary branches are most commonly affected. This condition can restrict blood flow, impacting various organs and tissues throughout the body.
Types and Associated Symptoms
Large vessel vasculitis primarily encompasses two distinct conditions: Giant Cell Arteritis (GCA) and Takayasu’s Arteritis (TAK). These conditions differ significantly in the age groups they typically affect and their presenting symptoms.
Giant Cell Arteritis affects adults over 50, often around 70. It is more common in women and individuals of Northern European descent. Characteristic symptoms often include a new, persistent, severe headache, often in the temple. Patients may also experience jaw pain that worsens with chewing, scalp tenderness, and vision problems like blurred vision, double vision, or sudden vision loss. Other symptoms include fever, fatigue, and unintended weight loss.
Takayasu’s Arteritis, by contrast, affects younger individuals, usually women aged 20 to 40, and is more prevalent in people of East Asian and South Asian ancestry. Symptoms develop slowly and vary based on affected arteries. Early signs include malaise, fever, fatigue, and muscle or joint pain. As the disease progresses, reduced blood flow causes symptoms like pain or weakness in the arms or legs, often with activity (claudication). Differences in blood pressure between arms, dizziness, headaches, and bruits—whooshing sounds over narrowed arteries—are also observed.
Causes and Risk Factors
The precise cause of large vessel vasculitis is not fully understood, but it is recognized as an autoimmune condition. In autoimmune conditions, the immune system mistakenly attacks healthy tissues, targeting blood vessel walls in LVV. This immune system malfunction leads to inflammation that can damage the arteries.
Genetic predisposition plays a role, though specific genes are not yet isolated. Environmental triggers, such as infections like hepatitis B or C, or COVID-19, may initiate or worsen vasculitis. Other immune conditions, such as lupus or rheumatoid arthritis, may also increase the risk.
Specific risk factors differ for GCA and TAK. GCA affects individuals over the age of 50, with the risk increasing with age. It shows a higher incidence in those of Northern European descent. TAK, conversely, typically affects individuals under 40 years of age, between 20 and 40 years. It is more prevalent in women and among people of East Asian and South Asian ancestry.
The Diagnostic Process
Diagnosing large vessel vasculitis involves an evaluation combining patient history, physical examination, and medical tests. Doctors discuss symptoms, medical background, and perform a physical exam to check for signs like scalp tenderness, diminished pulses, or bruits over arteries.
Blood tests are routinely conducted to detect markers of inflammation. Elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are common indicators of active inflammation, though normal levels do not exclude a diagnosis. These tests help to suggest the presence of an inflammatory condition.
Imaging studies visualize large arteries and assess for inflammation or structural changes. Doppler ultrasound evaluates blood flow and detects thickening in arteries close to the skin, like the temporal arteries. Computed Tomography Angiography (CTA) and Magnetic Resonance Angiography (MRA) provide detailed images of the aorta and its major branches, revealing vessel wall thickening, narrowing (stenosis), or bulging (aneurysms). Positron Emission Tomography (PET) scans, often combined with CT (PET/CT), identify active inflammation in arterial walls, even in early stages.
For Giant Cell Arteritis, a temporal artery biopsy is a standard diagnostic method. This procedure involves surgically removing a small segment of the temporal artery for microscopic examination. Specific inflammatory cells within the artery wall confirm GCA.
Treatment Approaches
Treatment goals for large vessel vasculitis are to control inflammation, prevent further blood vessel damage, and manage symptoms. Medications are the main approach.
High-dose corticosteroids, like prednisone, are first-line treatment. These medications rapidly suppress the immune system and reduce inflammation. The initial dose is high, often 40-60 mg per day, maintained until symptoms improve and inflammatory markers normalize. This intensive treatment aims to induce remission and prevent complications, particularly vision loss in GCA.
Once inflammation is controlled, the corticosteroid dose is slowly tapered over months to minimize side effects. To reduce corticosteroid reliance and manage the condition long-term, “steroid-sparing” agents or other immunosuppressants may be introduced. Methotrexate is a common example, used to decrease the overall steroid dose and maintain remission. Biologic drugs, like tocilizumab, target specific immune system pathways and reduce relapses and cumulative steroid dosage, particularly in GCA. These medications work by modulating the immune response to prevent the immune system from attacking the blood vessels.
Potential Complications
Uncontrolled large vessel vasculitis can lead to long-term complications due to persistent inflammation and arterial wall damage. These complications involve structural changes to affected arteries.
Stenosis, or artery narrowing, is a common complication. This narrowing can restrict blood flow to organs and tissues, causing symptoms from reduced oxygen supply. Conversely, inflammation can weaken artery walls, leading to aneurysms—abnormal bulges. Aneurysms carry a life-threatening rupture risk.
These vascular complications can result in health events. In GCA, untreated inflammation can lead to permanent vision loss. Both GCA and TAK can increase the risk of cardiovascular events, including stroke or heart attack. Peripheral vascular disease, characterized by reduced blood flow to the limbs, is also a potential outcome.