Medicine – Essential Features of Vasculitis

Vasculitis refers to a group of disorders characterised by inflammation and damage of blood vessel walls. The resulting vascular injury may cause narrowing, occlusion, thrombosis, haemorrhage, or aneurysm formation, leading to tissue ischaemia and organ damage. Vasculitides are commonly classified according to the predominant size of the affected vessels into large-vessel, medium-vessel, and small-vessel vasculitis.

Large-Vessel Vasculitis

1. Takayasu’s Arteritis

Takayasu’s arteritis is a chronic, progressive inflammatory disease affecting the aorta and its major branches. Inflammation of the arterial walls can cause progressive thickening, stenosis, and eventual occlusion of affected vessels. It occurs predominantly in young women, particularly those younger than 40 years of age.

Vascular involvement may result in ischaemia or aneurysm formation within the aorta or its major branches. A characteristic presentation is arm claudication, in which patients develop pain or fatigue in the upper limbs during activity because of reduced arterial blood flow. Peripheral pulses may become weak or absent, giving rise to the description “pulseless disease.” Differences in blood pressure between the arms and vascular bruits may also occur.

Diagnosis is based primarily on vascular imaging, traditionally angiography, which demonstrates stenosis, occlusion, dilatation, or aneurysmal changes in the affected arteries. Treatment aims to control vascular inflammation and prevent further arterial damage. Corticosteroids and other immunosuppressive drugs are commonly used, while surgical or endovascular intervention may be necessary when severe vascular obstruction or aneurysm formation develops.

2. Giant Cell Arteritis

Giant cell arteritis is a large-vessel granulomatous vasculitis that commonly affects branches of the carotid artery, particularly the temporal arteries, although larger vessels may also be involved. Arterial inflammation causes narrowing of the lumen and reduced blood supply to affected tissues. It is especially important because it is a treatable cause of irreversible visual loss in older adults.

Patients usually have a markedly elevated erythrocyte sedimentation rate (ESR) and other evidence of systemic inflammation. Diagnosis is supported by temporal artery biopsy, although a negative biopsy does not completely exclude the condition because inflammation may occur in discontinuous segments of the artery.

The typical clinical presentation includes a new unilateral throbbing headache, often associated with scalp tenderness. Jaw claudication, in which pain develops during chewing, is particularly suggestive of the disease. Visual manifestations include amaurosis fugax, diplopia, and permanent visual loss resulting from ocular ischaemia. Approximately half of affected patients may also experience symptoms of polymyalgia rheumatica, such as prominent shoulder and hip girdle pain and morning stiffness.

Giant cell arteritis responds well to high-dose corticosteroid therapy. When the condition is strongly suspected, treatment should be started promptly rather than delayed while awaiting biopsy because early corticosteroid treatment can help prevent permanent blindness.

Medium-Vessel Vasculitis

1. Polyarteritis Nodosa (PAN)

Polyarteritis nodosa is a systemic necrotising vasculitis that predominantly affects medium-sized arteries. The inflammatory process can cause arterial narrowing, thrombosis, tissue ischaemia, and the development of small aneurysms. An important association is hepatitis B virus infection, although many cases occur without an identifiable infectious trigger.

Clinical manifestations vary according to the organs affected. Constitutional symptoms such as fever, malaise, and significant weight loss may occur. Skin involvement can produce livedo reticularis, while vascular inflammation involving the testes may cause testicular pain or tenderness. Musculoskeletal manifestations include myalgia and leg tenderness, and peripheral nerve involvement may produce mononeuropathy or polyneuropathy.

Features used in classification criteria include weight loss greater than 4 kg, livedo reticularis, testicular pain, myalgia or leg tenderness, mono- or polyneuropathy, evidence of hepatitis B infection, characteristic arteriographic abnormalities, and compatible biopsy findings. Angiography may reveal abnormalities such as aneurysms or arterial occlusions, while biopsy of affected tissue can demonstrate vasculitis.

2. Kawasaki Disease

Kawasaki disease is an acute systemic vasculitis that primarily affects young children, particularly those under five years of age. It predominantly involves medium-sized arteries and is especially important because of its potential effects on the coronary circulation.

One of the most serious complications is the development of coronary artery aneurysms or other coronary lesions. Severe coronary involvement can result in thrombosis, myocardial ischaemia, myocardial infarction, sudden cardiac death, or papillary muscle dysfunction. The risk of coronary complications makes early recognition and treatment particularly important.

Standard treatment consists of intravenous immunoglobulin (IVIG) together with aspirin. IVIG significantly reduces the likelihood of coronary artery abnormalities, while aspirin is used for its anti-inflammatory and antiplatelet effects depending on the phase of illness.

Small-Vessel Vasculitis

1. Churg–Strauss Syndrome

Churg–Strauss syndrome, now known as eosinophilic granulomatosis with polyangiitis (EGPA), is a systemic small-vessel vasculitis strongly associated with asthma and eosinophilia. Patients typically have a history of asthma or allergic disease before developing systemic manifestations of vasculitis.

The combination of asthma, marked peripheral blood eosinophilia, and systemic vasculitis is highly characteristic. Multiple organs may become involved, including the lungs, skin, peripheral nerves, gastrointestinal tract, and heart. Corticosteroids are an important component of treatment, with additional immunosuppressive or targeted therapy used in more severe disease.

2. Wegener’s Granulomatosis

Wegener’s granulomatosis, now called granulomatosis with polyangiitis (GPA), is a necrotising granulomatous systemic vasculitis that mainly affects small and medium-sized vessels. It characteristically involves the upper respiratory tract, lungs, and kidneys.

The disease is strongly associated with cytoplasmic antineutrophil cytoplasmic antibodies (c-ANCA), particularly antibodies directed against proteinase 3 (PR3). However, ANCA testing supports the diagnosis and should be interpreted together with the clinical findings rather than being used alone.

Upper respiratory tract involvement is very common and may present with recurrent epistaxis, purulent or bloody nasal discharge, and chronic sinusitis. Lower respiratory tract disease may produce pulmonary infiltrates, nodules, cough, breathlessness, or pulmonary haemorrhage, with haemoptysis occurring in severe cases.

Renal involvement is another major feature and can cause proteinuria and haematuria. More aggressive renal disease may progress to rapidly progressive glomerulonephritis and renal failure. Other systemic manifestations include polyarthralgia and a vasculitic skin rash.

3. Henoch–Schönlein Purpura

Henoch–Schönlein purpura, currently known as IgA vasculitis, is an IgA-mediated small-vessel leukocytoclastic vasculitis. It is one of the most common systemic vasculitides occurring in children. The disease is characterised by the deposition of IgA-containing immune complexes, particularly within small vessels of the skin and kidneys.

The illness frequently develops following an upper respiratory tract infection. Its most characteristic manifestation is a palpable purpuric rash, particularly over dependent areas such as the lower limbs and buttocks. The purpura occurs without thrombocytopenia and reflects inflammation of small dermal vessels.

Other important manifestations include arthralgia or arthritis, particularly involving the lower-limb joints. Renal involvement may cause haematuria, proteinuria, or glomerulonephritis. Gastrointestinal vasculitis can result in colicky abdominal pain and gastrointestinal bleeding. In children, bowel involvement may occasionally lead to intussusception, which is an important acute complication.

Treatment of Vasculitis

Treatment depends on the type of vasculitis, severity of disease, and organs involved. Severe systemic vasculitis, particularly when there is major renal, pulmonary, neurological, or other organ-threatening disease, may require aggressive immunosuppression.

Induction of Remission

The initial objective in severe vasculitis is to achieve rapid control of active vascular inflammation and induce remission. High-dose corticosteroids are commonly used, and severe disease may require intravenous pulsed methylprednisolone. Additional immunosuppressive therapy, such as cyclophosphamide, may be required for life-threatening or organ-threatening disease.

Maintenance of Remission

Once remission has been achieved, treatment is usually changed to a less intensive maintenance regimen to reduce the risk of relapse while limiting the adverse effects of prolonged powerful immunosuppression. Depending on the specific type of vasculitis, maintenance therapy may include corticosteroids together with drugs such as azathioprine or other steroid-sparing immunosuppressive agents.

Plasma Exchange

Plasma exchange has historically been used in selected patients with particularly severe vasculitis. Its role depends on the specific disease and clinical situation and is more limited in current practice than older treatment schemes suggest. It may still be considered in selected severe presentations where removal of circulating pathogenic antibodies or immune components is clinically indicated.