Pathophysiology
Summary
Vasculitides are predominantly immune-mediated, often categorized as type II antibody-mediated, type III immune complex-mediated, or type IV cell-mediated with granulomas. Systemic inflammatory diseases frequently manifest with recurrent fever, weight loss, and arthralgias. Diagnostic indicators include elevated levels of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Treatment strategies across vasculitic conditions often involve immunosuppression, most commonly with corticosteroids.
Giant cell arteritis predominantly affects women over 50, with a peak incidence ~70. This condition causes a range of symptoms including jaw claudication, headache, and severe visual changes due to the involvement of the ophthalmic artery. Up to half of patients also have polymyalgia rheumatica. Diagnosis is confirmed via a temporal artery biopsy, which reveals CD4+ helper T cell inflammation and macrophages accumulating in the media, among other histological features.
In contrast, Takayasu arteritis classically impacts younger individuals, often women under 40, but can affect people of all ages and backgrounds. It affects the aortic arch and its branches, leading to various symptoms including limb claudication, severe renovascular hypertension, and aortic regurgitation. Both Takayasu arteritis and GCA exhibit similar histology, including T-cell infiltrate of the tunica media and internal elastic lamina, granulomas, and intimal thickening.
Polyarteritis nodosa (PAN) is a systemic vasculitis that involves multiple organs and is strongly associated with hepatitis B and C. PAN features a non-granulomatous mixed inflammatory infiltrate of the entirety of the vessel wall and is marked histologically by segmental, transmural necrotizing inflammation leading to microaneurysm formation, as well as fibrinoid necrosis in vessels. PAN often spares the pulmonary vasculature but frequently involves the renal vessels, leading to hypertension, renal infarction, AKI, and chronic kidney disease. Skin and peripheral nerve involvement are also common.
Kawasaki disease mainly occurs in children and presents with symptoms like conjunctival injection, strawberry tongue, desquamative rash, cervical adenopathy, and erythema and swelling of the hands and feet. It often presents with a high-spiking fever lasting at least five days and increases the risk of coronary artery aneurysms, predisposing to thrombosis and myocardial infarction. Treatment consists of a combination of IVIG and high-dose aspirin.
Thromboangiitis obliterans is strongly associated with tobacco use and leads to thrombus formation causing distal ischemia. It involves a granulomatous lymphocytic infiltrate with microabscess leading to vessel obliteration. This condition can also lead to superficial phlebitis and neuropathy. Smoking cessation is a cornerstone of its treatment and is integral for symptom relief and disease management.
Lesson Outline
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FAQs
Systemic inflammatory diseases such as vasculitis often present with symptoms like recurrent fevers, weight loss, and arthralgia. Elevated inflammatory markers, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), are usually observed. A definitive diagnosis requires correlating clinical signs with these elevated markers and may include specialized tests like biopsies, depending on the suspected subtype of vasculitis.
Giant cell arteritis predominantly affects the cranial branches of the carotid artery, especially the temporal artery. Common among women over 50, its symptoms include headaches, temporal area tenderness, visual disturbances, and jaw claudication. Confirmation of diagnosis involves a temporal artery biopsy.
Takayasu arteritis frequently occurs in women under 40 and targets the aortic arch and its proximal branches. Symptoms may include disparate blood pressures in the limbs, vascular bruits, and neurological manifestations like vertigo and visual changes. Although it shares histological features with giant cell arteritis, Takayasu arteritis is distinct in the specific arteries it impacts.
Polyarteritis Nodosa (PAN) is a multi-organ vasculitis involving medium to small-sized vessels, often linked to hepatitis B and C infections. It manifests as acute flares and chronic inflammation, causing lesions of varying age and severity. Its etiology is not fully elucidated, but is likely related to a type III hypersensitivity reaction, and is marked by a segmental, transmural necrotizing inflammation on histology. Common symptoms may involve hypertension, cutaneous manifestations, and motor or sensory loss. Notably, PAN usually spares the pulmonary vasculature.
Thromboangiitis obliterans, also known as Buerger’s disease, has a strong correlation with tobacco use. The disease is marked by thrombus formation, which results in vessel obliteration and distal ischemia. Pathologically, it is characterized by granulomatous lymphocytic infiltration accompanied by microabscesses and thrombi. Clinical features may extend to superficial vein inflammation or peripheral nerve involvement, leading to neuropathy. Patients with TO often suffer from Raynaud phenomenon and intermittent claudication. Smoking cessation is a cornerstone of its treatment.
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