A young female patient came for routine examination. On examination a mid systolic click was found. There is no history of RHD. The histopathological examination is most likely to show:
Ans. a. Myxomatous degeneration and prolapse of the mitral valve (Ref: Robbins 9/e p556)The clinical picture mentioned in the question is suggestive of Mitral valve prolapse syndrome (MVP). The histopathological examination in MVP is most likely to show myxomatous degeneration and prolapse of the mitral valve.Mitral Valve Prolapse Syndrome (MVP)MVP is also termed as systolic click murmur syndrome. Barlow's syndrome, Floppy-valve syndrome, and bellowing mitral leaflet syndromeIn MVP, one or both mitral valve leaflets are "floppy" and prolapse, or balloon back, into the left atrium during systole.Common in young womenInheritance in familial cases is autosomal dominantQ.Morphology:Characteristic anatomic change in MVP: Interchordal ballooning (hooding) of the mitral leaflets or portions thereof.Affected leaflets are often enlarged, redundant, thick and rubbery.The associated tendinous cords may be elongated, thinned, or even ruptured, and the annulus may be dilated.The tricuspid, aortic, or pulmonary valves may also be affected.Elongated, redundant or ruptured chordae tendinae (patients with ruptured chordae tendinae are usually symptomatic with significant regurgitation - MR)Dysfunction and Ischemia of papillary musclesProgressive dilatation and calcification of mitral valve annulusHistologically, there is attenuation of the collagenous fibrosa layer of the valve, on which the structural integrity of the leaflet depends, accompanied by marked thickening of the spongiosa layer with deposition of mucoid (myxomatous) material.Key histologic change in MVP: Myxomatous degeneration.Clinical Features:Most patients are asymptomaticDiscovered incidentally by detection of a mid-systolic click on physical examination.Associated with a systolic murmurMajority of patients with MVP have no untoward effectsClinical course is usually benignPatients may present with non-specific chest pain, dyspnea, fatigue and palpitationsQAuscultatory findings are characteristic and most importantCharacteristic mid systolicQ or late systolic non ejectionQ clicks which may be multipleQLate systolic ejection murmurQ (Often but not always)Accentuation of findings by Valsalva and standingQDiminished by squatting and isometric exercisesQComplications of MVP (seen in 3% of cases)Infective endocarditisQMitral insufficiencyQ, sometimes with chordal ruptureArrhythmiasQ, both ventricular and atrial.Transient ischemic attackSudden deathQStroke or other systemic infarcts, resulting from embolism of leaflet thrombi.Diagnosis:Diagnosis is confirmed by echocardiographyQ.ECG is normal in most casesQRHD is characterized principally by deforming fibrotic valvular disease, particularly mitral stenosis, of which RHD is virtually the only causeQ.Morphology:During acute RF, focal inflammatory lesions are found in various tissues.Distinctive lesions occur in the heart, called Aschoff bodies, which consist of foci of lymphocytes (primarily T cells), occasional plasma cells, and plump activated macrophages called Anitschkow cells (pathognomonic for RF).These macrophages have abundant cytoplasm and central round to ovoid nuclei in which the chromatin is disposed in a central, slender, wavy ribbon (hence the designation "caterpillar cells"), and may become multinucleatedQ.During acute RF, diffuse inflammation and Aschoff bodies may be found in any of the three layers of the heart, causing pericarditis, myocarditis, or endocarditis (pancarditis)Q.Inflammation of the endocardium and the left-sided valves typically results in fibrinoid necrosis within the cusps or along the tendinous cords.Overlying these necrotic foci are small (1-2 mm) vegetations, called verrucae, along the lines of closureQ.Subendocardial lesions, perhaps exacerbated by regurgitant jets, may induce irregular thickenings called MacCallum plaques, usually in the left atriumQ.The cardinal anatomic changes of the mitral valve in chronic RHD are leaflet thickening, commissural fusion and shortening, and thickening and fusion of the tendinous cordsQ.Fibrous bridging across the valvular commissures and calcification create "fish mouth''' or "buttonhole" stenosesQ.
Myxomatous degeneration and prolapse of the mitral valve
Fibrinous deposition on the tip of papillary muscle
Rupture of chordae tendinae
Aschoff nodule on the mitral valve
C.V.S