Wednesday, January 12, 2011

Rheumatic fever.

Immunologic mulitsystem inflammatory disease following Group A β hemolytic Streptococcus( GABHS) throat infection or skin infection

If not treated in time, can progress to RHD( Rheumatic Heart Disease) with multivalvular lesions

Modified duckett jones criteria:

Major –

carditis,
Migratory polyarthritis,
chorea,
erythema marginatum,
subcutaneous nodules

Minor –

previous RHD,
arthralgia, fever,
elevated ESR,
ECG changes( PR prolongation)

Essential criteria

h/o scarlet fever or sore throat in the past
Throat swab culture positive for GABHS
2 major criteria or 1 major and 2 minor criteria should be fulfilled for diagnosis

RF Pathogenesis:

Heart valve glycoproteins cross-react with hyaluronate capsule of strep

Cross reactivity between cardiac muscle and strep cell wall M proteins

Cytotoxic T cells sensitized to strep antigens lyse heart cells

Immunoglobulins and complement attach to cardiac myocytes and Aschoff nodules are formed

“licks the joints and bites the heart”

Bacteria are themselves absent from the lesion in the heart.

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