Q. Illustrate Pathology?
Following rheumatic fever, over next few years to decades, the typical funnel shaped mitral valve assumes a fish mouth appearance. During rheumatic fever endocardium of the leaflets gets inflamed, edematous and develops pin head vegetations at the tips or along the line of closure. These heal with fibrosis resulting in thickening of the leaflets with limited mobility. Some times there may be calcific deposits over the leaflets. The commissures get fused and in diastole the larger anterior leaflet pulls the posterior leaflet anteriorly. This decreases the valve opening in diastole. Thickened and fused chordae further limit the opening of the valve. Subvalvular apparatus, i.e., the chordae may fuse to such an extent that a secondary orifice may develop below the mitral valve limiting the diastolic blood flow. The abnormal valvular flows due to initial valvulitis may further worsen the thickening and fibrosis of the leaflets progressively. The progression may be rapid in some patients due to repeated attacks of rheumatic carditis, genetic or hormonal factors or due to increased hemodynamic load as seen in manual laborers.