mitral stenosis

Question 1

Mitral stenosis causes

Answer 1

Mitral stenosis

Commonest causes of mitral stenosis are rheumatic fever, rheumatic fever and rheumatic fever. [90%)

_Rarer cause_s that may be seen in the exam include:

• congenital mitral stenosis,
• SLE,
• RA,
• endocarditis,
• atrial myxoma

Question 2

s/s

Answer 2

Features

• rumbling mid-late diastolic murmur (best heard in expiration) - radiates to axilla
• nb: graham steele murmur [high pitched early diastolic murmur associated w/ pulm regurg]
• loud S1, opening snap [due to lincreased L atrial pressure cos of valve narrowing] ]
• loud P2 - from pulm HTN/pulm oedena [due to increased L atrial pressure]
• palipitations- AF [due to atrial hypertrophy]
• L parasternal heave [from RVH]
• raised JVP, oedema, ascites [from RHF]
• low volume pulse- thready, irreg irreg
• malar flush [due to decreased CO thus decreased perfusion of pain= get compensatory cutaneous vasodilation due to vasodilator substances]
• apex- tapping + undisplaced, palpable
• dyspnoea, fatigue, chest pain haemoptysis [due to rupture of bronchial veins]

atrial fibrillation

Features of severe MS

• length of murmur increases
• opening snap becomes closer to S2

Question 3

ix

Answer 3

Bloodz: FBC, U+E, LFTs, glucose, lipids

Chest x-ray

• left atrial enlargement may be seen

Echocardiography

• the normal cross sectional area of the mitral valve is 4-6 sq cm. A ‘tight’ mitral stenosis implies a cross sectional area of < 1 sq cm

ECG:

• p-mitrale
• atrial fibrillation in 60-70% of patients

cardiac catheterization: assess severity of HF/CAD

• quantifies the gradient across the mitral valve
• permits measurement of cardiac output and right heart pressures
• severe stenosis is indicated by a gradient of more than 10 mmHg across the stenotic valve

Question 4

mx

Answer 4

• prevention of recurrent rheumatic fever:
  
  • penicillin is given for 5 years after the last attack of rheumatic fever or until the age of 20.
• anticoagulation:
  
  • this is to prevent thrombo-embolism.
  • some say should be started before the onset of atrial fibrillation.
• control of tachycardia:
  
  • digoxin, if necessary aided by a beta-blocker
• diuretics - lessen pulmonary venous pressure.
• balloon valvuloplasty:
  
  • best results are obtained when the valve shows commissural fusion, is pliable, is not heavily calcified, and has little or no disease of the subvalvular apparatus
• surgical mitral valvotomy or valve replacement

Question 5

complications

Answer 5

• atrial fibrillation
• thrombo-embolism - this can originate from the left atrium or appendage with atrial fibrillation
• pulmonary hypertension
• infective endocarditis - this condition is rare in pure mitral stenosis

Question 6

prognosis

Answer 6

• Many patients with mitral stenosis survive to the age of 60, or even into old age in mild cases.
• Thromboembolism is the most serious complication.
• The condition may be more severe if there are further attacks of rheumatic fever.
• significantly worse prog if PHTN/RHF develops