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Figure 16.26 Rheumatic valvulitis. A, Location of vegetations on the valves
of the left heart. The location of vegetations on mitral valve (left upper diagram) is
shown as viewed from the left atrium, while the vegetations on aortic valve (left
lower diagram) are shown as seen from the left ventricular surface. B, Opened up
chambers and valves of the left heart show irregularly scarred mitral valve leaving
a fish-mouth or buttonhole opening between its two cusps (black arrow). The free
surface and margin of the mitral valve shows tiny firm granular vegetations (white
arrow).

support to the role of mechanical pressure on the valves polymorphs. Occasionally, Aschoff bodies with central
in the pathogenesis of vegetations. foci of fibrinoid necrosis and surrounded by palisade of
The chronic stage of RHD is characterised by cardiac histiocytes are seen, but more often the cellular CHAPTER 16
permanent deformity of one or more valves, especially infiltration is diffuse in acute stage of RF. Vegetations
the mitral (in 98% cases alone or along with other valves) present at the free margins of cusps appear as eosinophilic,
and aortic. The approximate frequency of deformity of tiny structures mainly consisting of fibrin with
various valves is as under: superimposed platelet-thrombi and do not contain
Mitral alone = 37% cases. bacteria (Fig. 16.27, A).
Mitral + aortic = 27% cases. ii) In the healed (chronic) stage, the vegetations have
Mitral + aortic + tricuspid = 22% cases. undergone organisation. The valves show diffuse The Heart
Mitral + tricuspid = 11% cases. thickening as a result of fibrous tissue with hyalinisation,
Aortic alone = 2%. and often calcification. Vascularisation of the valve cusps
Mitral + aortic + tricuspid + pulmonary = less than may still be evident in the form of thick-walled blood
1% cases. vessels with narrowed lumina (Fig. 16.27, B). Typical
Thus, mitral valve is almost always involved in RHD. Aschoff bodies are rarely seen in the valves at this stage.
Gross appearance of chronic healed mitral valve in RHD RHEUMATIC MURAL ENDOCARDITIS. Mural endo-
is characteristically ‘fish mouth’ or ‘button hole’ stenosis. cardium may also show features of rheumatic carditis
Mitral stenosis and insufficiency are commonly combined though the changes are less conspicuous as compared to
in chronic RHD; calcific aortic stenosis may also be found. valvular changes.
These healed chronic valvular lesions in RHD occur due Grossly, the lesions are seen most commonly as
to diffuse fibrocollagenous thickening and calcification of MacCallum’s patch which is the region of endocardial
the valve cusps or leaflets which cause adhesions between surface in the posterior wall of the left atrium just above
the lateral portions, especially in the region of the the posterior leaflet of the mitral valve. MacCallum’s patch
commissures. Thickening, shortening and fusion of the appears as a map-like area of thickened, roughened and
chordae tendineae further contribute to the chronic wrinkled part of the endocardium (see Fig. 16.25).
valvular lesions (Fig. 16.26, B). Microscopically, the appearance of MacCallum’s patch
Microscopically, the inflammatory changes begin in the is similar to that seen in rheumatic valvulitis. The affected
region of the valve rings (where the leaflets are attached area shows oedema, fibrinoid change in the collagen, and
to the fibrous annulus) and then extend throughout the cellular infiltrate of lymphocytes, plasma cells and
entire leaflet, whereas vegetations are usually located on macrophages with many Anitschkow cells. Typical
the free margin of the leaflets and cusps. Aschoff bodies may sometimes be found.
i) In the early (acute) stage, the histological changes are
oedema of the valve leaflet, presence of increased number 2. RHEUMATIC MYOCARDITIS. Grossly, in the early
of capillaries and infiltration with lymphocytes, plasma (acute) stage, the myocardium, especially of the left
cells, histiocytes with many Anitschkow cells and a few ventricle, is soft and flabby. In the intermediate stage, the