Valvular disorders and cardiac murmurs

Rheumatic heart disease

Definition: multi-system, autoimmune inflammatory disorder affecting the heart, skin, joints, and brain

Aetiology: Genetic susceptibility + environmental factors + autoimmunity => ? + GAS infection + ADNase B

Pathogenesis: Autoimmunity against auto-antigens

Morphology:

Clinical Features:

  • Fever, pancarditis, large joint inflammation (migratory polyarthritis), subcut nodules on pressure points i.e. elbows (t-cell mediated), subcut inflammation known as erythema marginatum (gradually expanding), Sydenham’s chorea (inflammation in the brain), all of this due to T cell inflammation and all settle except for endocarditis whose severity increases with each subsequent attack of ARF
  • Cardiac failure: due to pancarditis, decreased function due to inflammation, => insufficient expulsion of blood => blood accumulates within heart => backlong to lungs => pulmonary oedema => bibasilar crackles
  • Pericarditis: severe fibrinous “bread & butter” pericarditis => pericardial rub; marked vasodilation
  • Endocarditis: vegetations => acute inflammation of the valves, antibodies are against collagen which is well covered by endocardial layer but valve edges develop small ulcers where the collagen is exposed allowing antiboacute-rheumatic-fever-mitral-valve-valvulitisdies to stick, hence valve free-edges are most exposed,
    • mitral valves exposed to the highest pressure hence most commonly involved in rheumatic fever
  • Myocarditis: Aschoff bodies
    • Macrophages form Giant cells and Caterpillar or Antishkow cells
    • This same reaction is occuring everywhere, from heart to CNS to skin and joint. The Anitshkow cells more prominent in the myocardium. Fibrinoid necrosis + T-lymphocytes + macrophages (Caterpillar/Anitschow cells) around the blood vessels = Ashcoff bodies

Complications

  • Arrhythmia
  • Cardiac hypertrophy
  • Heart Failure

RHD

Aetiology: recurrent attacks of ARF

Pathophysiology: thickening, opacity of valves, nodularity, irregularity, due to fibrosis, due to repeated inflammation and fibrosis process, angiogenesis => development of blood vessels within the valves

Morphology: thick fibrous scarred stenotic fixed valves with new blood vessels within the valves, inflammation extends to chordae tendinea: thick, nodular and fused; shrinkage => valve deformity, commisural fusion: fish mouth stenosis,

  • McCallum plaques: thickening due to jet of blood hitting an area of the endocardium due to stenosed mitral valve
  • Microscopic
    • Fibrosis and scarring
    • Neovascularisation
    • Calcification

Clinical Features:

  • Mitral stenosis and regurgitation
  • Mitral + aortic stenosis and regurgitation
  • Mitral facies: butterfly shaped erythema on face of mitral stenosis patient
    • This is due to chronic hypoxaemia and vasodilation

Complications:

  • Arrhythmia
  • Atrial fibrillation => thromboemolism
  • Infective endocarditis on abnormal valves
  • Heart failure due to severe obstruction => insufficient blood supply to body
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