Page 248 - Concise Pathology for Exam Preparation ( PDFDrive )

10 Blood Vessels 233

Q. Write briefly about Kawasaki disease.

Ans. Kawasaki disease was originally reported in Japan and is the foremost cause of heart
disease affecting children.

Salient Features
• Self-limiting acute febrile illness of childhood (majority patients are less than 4 years)
• Affects large- to medium-sized to small arteries

Pathogenesis
Unknown; infectious agents are thought to trigger the disease in genetically predisposed
individuals

Clinical Features
• Conjunctival and oral erythema, erythema of palms and soles
• Oedema of hands and feet
• Desquamative rash and cervical lymph node enlargement (mucocutaneous syndrome)
• Commonly involves the coronary arteries to form aneurysms which may rupture
resulting in acute myocardial infarction

Pathology

• Transmural inflammation like PAN; however, less fibrinoid necrosis
• Most changes in cardiovascular system. Segmental erosion with weakening of arterial
wall may cause aneurysmal dilation, thrombosis or localized rupture.

Q. Write briefly about microscopic polyangiitis.
Ans. Microscopic polyangiitis is a necrotizing vasculitis also known as hypersensitivity or
leukocytoclastic vasculitis.

Salient Features

• Characterized by inflammatory involvement of venules, capillaries and arterioles
• Skin, mucous membrane, lungs, brain, heart, GIT, kidneys and muscles are commonly affected
• Necrotizing glomerulonephritis and pulmonary capillaritis are particularly common
(feature differentiating it from PAN; also, microscopic polyangiitis affects smaller vessels
and all its lesions are in the same histopathological stage, unlike PAN)
• Typically, presents as palpable purpura, haemoptysis, arthralgias, abdominal pain,
haematuria, proteinuria, muscle pain or weakness

Pathogenesis

Thought to be due to an immunologic response to an antigen that may be bacteria
(streptococci), viruses, malarial parasite, drugs (penicillin) and chemicals. Antibodies
are formed leading to immune complex formation or development of secondary ANCA-
associated immune responses.

Clinical Features

Depending on the vessel involved, patient may present with:
• Haemoptysis, albuminuria and haematuria
• Abdominal pain and melena
• Muscle pain and weakness
• Palpable purpura
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