Valvular Disorders - Pathoma

RHD = Rh heart disease    
IE = Infective endocarditis    
NBTE = Nonbacterial thrombotic endocarditis
  • sterile
  • aortic valve > mitral valve > tricuspid valve > pulmonary valve
    • ie in order of pressure gradients
  • e.g. hyper coag [states inc malignancy esp mucin producing adenocarcinomas like pancreatic, gastric; SLE...]  and trauma)      
LSE = Libman-Sacks Endocarditis (in 10% SLE)

Acute Rheumatic Fever
  • Systemic complication of pharyngitis
  • Due to group A β-haemolytic streptococci
    • Streptococcus pyogenes
    • Lancefield A
    • Gram +ve
    • M protein - virulence - and mimicry
    • T antigen - surface
    •  erythrogenic toxin
    • Other complications
      • toxic shock syndrome
      • NB diff strain causes scarlet fever than causes RhF
      • Rheumatic fever
      • Post-streptococcal glomerulonephritis
  • 2-3 weeks after pharyngitis/tonsilitis
  • M protein
    • Causes molecular mimicry
  • Jones Criteria to Dx Rh Fever
    • Evidence of prior strep pyogenes infection
      • anti-DNA
      • Anti-Streptolysin -O titre
      • anti-DNAse B titre
    • Minor criteria
      • Fever
      • Elevated ESR
      • Prolonged PR interval
    • Major
      • J - joints - migratory polyarthritis - pain, swelling of one large joint, resolves, moves to other large joint
      • O - pancarditis - endo, peri [fibrinous] and myocarditis
        • Endocarditis - causes vegetations especially on valves, especially on mitral - poss also aortic as well
          • Thus mitral valve regurg, maybe aortic too
        • Myocarditis - Aschoff bodies
          • Chronic inflammation with giant cells, essentially a granuloma
          • Fibrinoid - degenarated collagen
          • High risk of death in acute phase
          • Anitschkow cells
            • Macrophages with thin hairy nucleus
          • Pericarditis - friction rub
          • If survive acute phase, progress to chronic
            • Repeat strep pyogenes infection may cause acute relapse
            • Inc risk for chronic Rh valvular disease
      • N - nodules - subcutaneous
      • E - erythema marginatum - redder at margins
      • S - Sydenham's Chorea
  • Chronic disease almost always involves mitral valve
    • Thicken chordae tendineae, cusps
      • Fish mouth appearance
    • Occasionally aortic too - fusion of commissures
      • Causes stenosis
      • If have this, will undoubtedly also have mitral involvement
      • Can see best on the top and left of this pic:
    • Other valves rarely involved
    • Complication of damaged valve = endocarditis
Aortic Stenosis
  • Opening should be 4cm2 - when stenosed, less than 1cm2
    • Severe:
      • mean gradient >40 mmHg (>45 replace)
      • aortic valve area (AVA) <1 cm2 (replace if <0.6)
      • peak aortic jet velocity >4.0 m/s
  • Usually due to fibrosis and calcification
    • Also poss due to chronic Rh Fever
      • But if don't have mitral disease, then not Rh as always hits mitral first
      • & Don't get commissure fusion in "wear and tear" aortic stenosis
  • Presents
    • Late adult - >50yo
  • Bicuspid valve inc risk, more rapid progression
    • Turner's syndrome
    • >50% of pts with coarctation or interruption of the aorta
    • William's syndrome (7q) - supravalvular stenosis too
    • PDA
    • Cystic medial necrosis (AD - not the cystic medial degen in Marfan's!)
  • Get compensation
    • Prolonged, aSx stage
    • LV hypetrophies to get past inc resistence
    • Ejection systolic click as valve opens
    • Crescendo-decrescendo systolic murmur
  • Complications
    • Concentric left ventricular hypertrophy
    • Angina, syncope with exercise
      • Limited capacity to increase CO
    • Microangiopathic haemolytic anaemia
      • RBCs rutpure when forced passed stenotic valve!
  • Rx
    • Replacement if Sx
Aortic regurgitation
  • Backflow from aorta to LV during diastole
  • Due to
    • Isolated aortic root dilatation - most common cause
      • "pulls" on valves
      • so open up a bit
      • May be due to syphilitic aneurysm - tree bark aortic root
    • Valve damage
      • Infective endocarditis
  • Presents
    • Early, blowing diastolic murmur
                        
    • Low diastolic pressure
      • As lose pressure when blood falls back through aortic valve
    • Inc systolic
      • as inc SV as more blood regurged back in
    • so Widened pulse pressure
    • Hyperdynamic circulation
      • Collapsing pulse
        • Watson's water hammer pulse in upper limb
        • Corrigan's pulse - rapid up and collapse of carotid pulse
      • Pulsating nailbed - Quincke's sign
      • Head nodding - De Musset's sign - Musset nods his mullet
      • 'pistol shot' systolic sound heard over the femoral artery  - Traube's sign 
      • Uvula pulsation - Muller's sign
      • Retinal vessel pulsation - Becker's sign
      • Diatolic drop> 15mmHg when raise arms 
    • Volume overload
      • LV dilatation
      • Eccentric hypertrophy
        • ie doesn't involve entire ventricle, only part
  • Rx
    • valve replacement once get LV impairment

Mitral Valve Prolapse
  • Ballooning of mitral valve into left atrium during systole
  • Due to myxoid degeneration of valve - makes floppy
    •  dermatan sulfate accumulation
  • ? aetiology - get in
    • Idiopathic
    • Marfan's syndrome
    • Ehlers-Danlos Syndrome,
    • Polycystic Kidney Disease
    • Graves' disease
      • (also main cause of myxoeddema - proteoglycan etc build up!)
    • Pectus excavatum
    • Pts tend to be lean, low BMI
  • Presents
    • Hear a mid systolic click
    • Some regurg, not always
    • Most aSx
  • Complications
    • Infective edocarditis
    • Arryhthmia
    • Severe mitral regurg
    • These are rare
  • Rx
    • Valve replacement
Mitral regurgitation
  • Reflux blood from LV to LA during systole
  • Usually complication of mitral valve prolapse
  • Other causes
    • LV dilatation - stretch - eg dilated cardiomyopathy
    • Infective endocarditis - damage leaflets
    • Acute Rh heart disease - vegetations
    • Papillary muscle rupture post MI - can't hold leaflets in
  • Presents
    • Holosystolic blowing murmur
      • Louder on squatting - inc peripheral resistance so more "back pressure" through LV and thus mitral valve
      • Expiration - inc blood coming to LV from lungs - so more blood to regurge
Mitral stenosis
  • Narrowing
  • Usually chronic Rh valve disease (cf acute causes regurg)
  • Presents
    • Opening snap
    • Diastolic mumble
  • Complication
    • Volume overload of LA
    • Dilates LA
    • Pulmonary congestion - back up pressure from LA to lungs
      • Thus pulm oedema
      • and pulm HTN
      • and capillary haemorrhage so haemosiderin laden macrophages (heart failure cells)
      • and maybe thus cor pulmonale
    • Atrial fibrillation
      • due to dilatation of LA
      • mucks up conducting system
      • Get areas of stasis and thus risk of mural thrombosis

Robbins Basic Pathology, Robbins Pathologic Basis of Disease, Robbins Review of Pathology (MCQs - very path-y), Robbins Flash Cards, Baby Robbins, Robbins Atlas - some exact same images come up in the exam, 100 Cases in ClinicalPathology - possibly the best Qbank for the practical