Mitral Stenosis (MS)

Question 1

Definition of MS

Answer 1

• Narrowing of the mitral valve orifice

Question 2

Aetiology of MS

Answer 2

• Rheumatic fever
• Infective endocarditis
• Congenital abnormalities of the valve
• Carcinoid syndrome
• Ergot and/or serotogenic drugs
• SLE
• Mitral annular calcification
• Amyloidosis

Question 3

Signs and Symptoms of MS

Answer 3

• Mid-diastolic, low pitched ‘rumbling’ murmur with a loud S1 (due to thick valves requiring large force to shut)
• Signs/symptoms include history of rheumatic fever, dyspnoea, orthopnoea, malar flush and neck vein distension.
• Risk factors include streptococcal infection and female sex.

Question 4

Pathophysiology of MS

Answer 4

• As the orifice becomes reduced, flow between the LA and the LV is progressively impeded and pressure in the LA remains higher than the LV
• This increased LA pressure is referred to the lungs causing congestion, AF, pulmonary HTN and secondary right heart dilatation
• The restricted orifice also limits filling of the LV, limiting cardiac output

Question 5

Investigation of MS

Answer 5

• ECG
  
  • AF
  • Left atrial enlargement
  • LV hypertrophy
• CXR
  
  • Double right heart border indicating enlarged LA
  • Prominent pulmonary artery
  • Kerley B lines
• ECHO
  
  • Hockey stick shaped mitral deformity