Mitral stenosis

 

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Mitral stenosis is a valvular heart disease  characterized by the narrowing of the orifice of the mitarl valve of the heart.

Aeitiology:

  1. Rheumatic heart disease (99%). Almost all mitral stenosis is due to Rheumatic heart disease. At least 50% of sufferers have H/O Rh. Fever & single most common valve lesion due to Rh-F is pure mitral stenosis.
  2. Congenital (1%).

Pathophysiology: In rheumatic mitral valve orifice is slowly reduced by progressive fibrosis calcification of valve leaflets, and fusion of the cusps and subvalvular apparatus. When the normal mitral valve orifice of 5 c reduced to 1 c or less severe mitral stenosis occure. Blood flow from left atrium to left ventricle is therefore restricted & left atrial pressure rises and ultimately hypertrophy and dilatation occur. Consequently pulmonary venous, pulmonary arterial & right heart pressure rise. Pulmonary may cause pulmonary oedema, RVH and RHF. Due to progressive dilatation of the left atrium atrial fibrillation is very common.

Cause: Almost all cases of mitral stenosis are due to disease in the heart secondary to rheumatic fever and the consequent rheumatic heart disease. Uncommon causes of mitral stenosis are calcification  of the mitral valve leaflets, and as a form of congenital heart disease. However, there are primary causes of mitral stenosis that emanate from a cleft mitral valve. It is the most common valvular heart disease in pregnancy . Other causes include infective endocarditis   where the vegetations may favor increase risk of stenosis.

Clinical features:

Symptoms:

  1. Breathlessness (Due to pulmonary congestion).
  2. Fatigue (Due to cardiac output).
  3. Oedema & ascites (Due to RHF).
  4. Palpitation (Due to atrial fibrillation).
  5. Haemoptysis (Due to pulmonary congestion & embolism).
  6. Cough (Due to pulmonary congestion).
  7. Chest pain (Due to pulmonary hypertension).
  8. Thromboembolic complications (e.g. stroke, ischaemic limb)

Signs:

  1. Appearance: Mitral facies (malar flush); a bilateral, cyanotic or dusk pink discoloration of upper checks.
  2. Pulse: Normal/low volume.
  3. BP: Usually normal but reduced in sever stenosis.
  4. JVP: Normal/raised if RHF.
  5. Precordium:

a) Inspection: Visible apex beat.

b) Palpation:

  • Apex beat: Tapping in character & shift to left 5th intercostals space.
  • Left parasternal heave: Present if RVH.
  • Palpable (if pulmonary hypertension).
  • Thrill: Diastolic at the apex.

c) Auscultation:

  • Loud first heart sound.
  • Opening snap.
  • Mid diastolic murmur.
  1. Signs of raised pulmonary capillary pressure:

a) Bilateral basal crepitations.

b) Pulmonary oedema.

  1. Signs of pulmonary hypertension: RV heave, loud.

Investigations:

  1. Chest X-ray P/A view:
  • Enlarged LA and appendage.
  • Signs of pulmonary venous congestion.
  1. ECG:
  • P mitral or atrial fibrillation.
  • RVH: Tall R waves in -.
  1. Echo:
  • Thickened immobile cusps.
  • Reduced valve area.
  • Reduced rate of diastolic filling of LV.
  • Enlagred LA.
  1. Doppler:
  • Pressure gradient across mitral valve.
  • Pulmonary artery pressure.
  • Left ventricular function.
  1. Cardiac catheterization:
  • Coronary artery disease.
  • Mitral stenosis and regurgitation.
  • Pulmonary artery pressure.

Management of MS: Patient with minor symptoms should be treated medically, but the definitive treatment of mitral stenosis is surgical.

Medical treatment for patients with minor symptoms:

  1. No exertion.
  2. Anticoagulants: To reduce the risk of systemic embolism.
  3. Diagoxin (0.125-0.25 mg/day) and β-blocker: to control the ventricular rate in atrial fibrillation.
  4. Antibiotic for prophylaxis against infective endocarditis.

Definitive treatment:

[A] Mitral balloon valvulopasty: Treatment of choice, if the following criteria are fulfilled-

  • Significant symtopms.
  • Isolated mitral stenosis.
  • No mitral regurgitation.
  • Mobile non-calcified valve apparatus on echo.
  • Left atrium free of thrombus.

[B] Mitral valvotomy: Closed or open mitral valvotomy, if facilities or expertise for vulvulo-plasty are not available.

[C] Mitral valve replacement: It’s necessary if there is mitral regurgitation or if the valve is valve is rigid and calcified.

Complications:

  1. Atrial fibrillation.
  2. Systemic embolisation.
  3. Pulmonary hypertension.
  4. Pulmonary infraction.
  5. Chest infection.
  6. Tricuspid regurgitation.
  7. Right ventricular failure.

Reference:

  1. Davidson’s Principles and Practice of Medicine, 21st edition.
  2. Kumar and Clark, Clinical medicine, 7th edition.
  3. Wikipedia the free encyclopedia.

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