Large Vessel Vasculitis (LVV) is a disorder where the immune system mistakenly attacks blood vessel walls. This condition is a form of vasculitis, defined as the inflammation of blood vessels. LVV specifically targets the largest arteries, including the aorta and its major branches that supply blood to the head, neck, and limbs. Inflammation in these main arteries can quickly lead to widespread health issues.
Understanding the Condition
LVV is an autoimmune inflammatory response affecting the arterial wall structure. Immune cells, such as T-lymphocytes and macrophages, infiltrate the artery wall layers, causing chronic, granulomatous inflammation. This persistent attack damages the vessel lining, leading to thickening.
This pathology causes two primary mechanical problems that disrupt blood flow. The first is stenosis, where thickening and scarring cause the artery to narrow, restricting blood flow. This reduced flow can lead to ischemia, a lack of oxygen and nutrients in the supplied tissues.
The second consequence is the weakening of the artery wall, resulting in an aneurysm. An aneurysm is a balloon-like bulge that develops due to the damaged vessel wall. These bulges carry a risk of rupture or dissection, which are medical emergencies.
The Two Primary Forms
Large Vessel Vasculitis is primarily composed of two distinct diseases: Giant Cell Arteritis (GCA) and Takayasu Arteritis (TA). While both involve large artery inflammation, they affect different patient populations and vascular territories. GCA, also known as temporal arteritis, is the most common form of vasculitis in adults, found almost exclusively in individuals over 50.
GCA frequently involves the arteries of the head and neck, such as the temporal and ophthalmic arteries, but can also affect the aorta and its major branches. Up to half of GCA patients experience symptoms of Polymyalgia Rheumatica (PMR), which causes pain and stiffness in the shoulders and hips. GCA inflammation is characterized by patchy, segmental involvement, which can make diagnosis challenging.
Takayasu Arteritis (TA) is sometimes called the “pulseless disease” and typically presents in a younger demographic, often women under 40. TA primarily affects the aortic arch and its branching arteries, including the subclavian, carotid, and renal arteries. This condition is observed more frequently in individuals of Asian descent.
The inflammation in TA tends to be more diffuse, often leading to severe narrowing or occlusion of the affected vessels. Damage caused by TA can manifest as decreased or absent pulses and measurable differences in blood pressure between the arms.
Recognizing the Symptoms
LVV symptoms are separated into systemic and localized categories. Systemic symptoms are generalized signs of inflammation, including unexplained fever, persistent fatigue, and unintended weight loss. These non-specific signs often precede localized symptoms, making early diagnosis difficult.
In Giant Cell Arteritis, localized symptoms involve the head and neck. The most common complaint is a new-onset, severe headache, typically felt around the temples. Patients may also experience jaw claudication, which is pain in the jaw muscles when chewing and is highly suggestive of GCA.
Sudden visual disturbance is a serious symptom of GCA, ranging from transient loss of vision to permanent blindness. This occurs when inflammation affects the ophthalmic artery and requires immediate medical intervention to prevent irreversible damage. Other localized signs include scalp tenderness, making activities like combing hair painful.
Localized symptoms of Takayasu Arteritis result from reduced blood flow to the limbs and organs. Patients may notice claudication, which is cramping or pain in the arms or legs during exercise. Artery narrowing can lead to measurable differences in blood pressure between the arms, a hallmark sign. If renal arteries are affected, reduced blood flow to the kidneys can cause new high blood pressure.
Diagnosis and Treatment Strategies
Diagnosis requires clinical evaluation, laboratory tests, and advanced imaging. Blood tests check for elevated inflammatory markers, such as Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP), which are often increased in active disease. These markers can be normal in some cases, particularly in Takayasu Arteritis, so they are not definitive alone.
Advanced imaging is necessary for visualizing arteries and detecting inflammation. Modalities like CT angiography, magnetic resonance angiography (MRA), or Positron Emission Tomography (PET) scans show characteristic signs such as vessel wall thickening, narrowing, or aneurysms. For GCA, a temporal artery biopsy remains a standard method, where a small section of the artery is examined for signs of inflammation and giant cells.
Initial treatment for active LVV is the immediate administration of high-dose glucocorticoids, often prednisone, to rapidly suppress inflammation. This acute therapy is maintained until symptoms resolve and inflammatory markers normalize, typically over several weeks. Prompt treatment is important in GCA to prevent irreversible vision loss.
Long-term management focuses on maintaining remission while minimizing prolonged steroid side effects. Physicians introduce steroid-sparing agents, such as methotrexate, or biologic therapies. The biologic drug Tocilizumab, which targets the inflammatory cytokine interleukin-6, is frequently used as it has shown effectiveness in both GCA and TA. If the disease causes severe narrowing or aneurysm formation, surgical or endovascular procedures may be necessary to restore blood flow or repair the damaged vessel.