RHEUMATIC HEART DISEASE

· The greatest number of valvular lesions results from rheumatic fever

· Rheumatic fever is an autoimmune disease or allergic disease

· Disease is initiated by streptococcal toxin:

· Group A haemolytic streptococci infection

(eg: scarlet fever, sore throat, middle ear infection)

—> Streptococci release various proteins

—> Antibodies are formed against proteins

—> Immune complexes deposit in joints & small blood vessels of heart

—> Large haemorrhagic, fibrinous, bulbous lesions grow along inflamed edges of heart valves

· Mitral valve is most affected as receives most trauma during valvular action followed by aortic valve, and lastly pulmonic & tricuspid valves as are less subjected to mechanical stresses during valvular action

· If valve leaflet edge becomes affected

—> destruction & scarring of filmy edge

—> regurgitation

· If adjacent valve leaflets become affected

—> eventual fusion

—> stenosis