Tetralogy of Fallot

Tetralogy of Fallot

the commonest cause of cyanotic congenital heart disease
clinical features
1. 4 cardinal anatomical features
  1. large VSD
  2. overriding of aorta wrt ventricular septum
  3. subpulmonary stenosis
    1. causing right ventricular outflow obstruction
  4. right ventricular hypertrophy
2. Sx
  1. classical description
    1. severe cyanosis
    2. hypercyanotic spells
      1. rapid increase in cyanosis
        assoc w/ irritability or inconsolable crying
        due to severe hypoxia
        assoc w/ breathlessness and pallor
        due to acidosis
      2. short murmur during spell
      3. complications
        myocardial infarction
        cerebrovascular accidents
        death
    3. squatting on exercise
    4. develops in late infancy
    5. rare in developed countires
3. signs
  1. in older children
    1. clubbing: fingers & toes
  2. loud harsh ejection systolic murmur
    1. at left sternal edge
      1. from day 1 of life
    2. murmur will shorten & cyanosis will increase
      1. with increasing right ventricular outflow tract obstruction
        mostly muscular and below pulmonary valve
diagnosed
1. antenatally
2. detection of murmur in 1st 2 months of life
  1. cyanosis at this stage may not be obvious
Ix
1. CXR
  1. relatively small heart
  2. uptilted apex (boot shaped)
    1. due to right ventricular hypertrophy
  3. right sided aortic arch
  4. pulmonary artery bay
    1. classic feature
    2. concavity on left heart border
      1. where convex-shaped main pul a & right ventricular outflow tract would normally be profiled
  5. decreased pulmonary vascular markings
    1. due to reduced pulmonary blood flow
2. ECG
  1. normal at birth
  2. right ventricular hypertrophy when older
    1. upright T wave in V1, no S wave (pure R wave)
3. Echo
  1. cardinal features shown
    1. but cardiac catherisation needed to show anatomy of coronary aa
Mx
1. initially medical
  1. then surgery @ 6 months old
    1. close VSD
    2. relieve right ventricular outflow obstruction
      1. sometimes w/ artificial patch going across pulmonary valve
2. neonates who are very cyanosed
  1. need shunt to increase pulmonary blood flow
    1. surgically done
      1. modified Blalock-Taussig shunt
        surgical placement of artificial tube btw subclavian a and pulmonary a
      2. balloon dilatation of right ventricular outflow tract
3. hypercyanotic spells
  1. usually self-limitig
  2. followed by period of sleep
  3. if prolonged (>15 mins) require prompt Rx
    1. sedation & pain relief
      1. morphine
    2. iv propanolol or an alpha adrenoceptor agonist
      1. works as peripheral vasoconstrictor
      2. relieves subpulmonary muscular obstruction that causes reduced pulmonary blood flow
    3. iv volume adminstration
    4. bicarbonate
      1. correct acidosis
    5. muscle paralysis and ventilation
      1. to reduce metabolic O2 demand
right to left shunt

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	Criado por v.djabatey quase 11 anos atrás