outflow obstruction in sick infant

coarctation of the aorta
1. due to arterial tissue encircling aorta @ point of insertion of duct
  1. when duct closes, aorta constricts
    1. -> severe obstruction to left ventricular outflow
2. commonest cause of collapse due to left outflow obstruction
3. clinical features
  1. 1st day of life
    1. examination: normal
  2. neonates age: 2 days
    1. acute circulatory collapse
      1. duct closes day 2 of life
  3. physical signs
    1. sick baby
      1. w/ severe heart failure
    2. absent femoral pulses
    3. severe metabolic acidosis
4. Ix
  1. CXR
    1. cardiomegaly
      1. from heart failure & shock
  2. ECG
    1. normal
5. Mx
  1. surgical repair soon after diag
  2. as for all obstructed left outflow tract
interruption of aortic arch
1. uncommon
2. no connection btw prox aorta & distal to arterial duct
  1. so cardiac output dependent on R to L shunt via the duct
3. VSD usually present
4. presentation
  1. shock in neonatal period
  2. absent pulses
    1. femoral
    2. left brachial
5. Mx
  1. complete correction within 1st few days of life
    1. closure of VSD
    2. repair of aortic arch
6. assoc w/ DiGeorge syn
  1. 22q11.2 gene microdeletion
  2. absent thymus
  3. palatal defects
  4. immunodef
  5. hypocalcaemia
hypoplastic left heart syn
1. underdevelopment of entire left side of heart
  1. small/atretic mitral valve
  2. diminutive left ventricle
  3. aortic valve atresia
  4. small asc aorta
  5. nearly always coarctation of aorta
2. all peripheral pulses absent
3. circulatory collapse
4. clinical features
  1. detected @ antenatal US screening
    1. allows for effective counselling
    2. prevents child getting sick after birth
  2. if presenting @ birth
    1. are the sickest neonates w/ duct-dependent sys circulation
    2. no flow through left side of heart so ductal constriction->
      1. rapid cardiovascular collapse
      2. cos no flow through left side of heart
      3. profound acidosis
5. Mx
  1. Norwood procedure
    1. difficult neonatal op
    2. fb Glenn or hemifontan op
      1. at 6 months old
      2. fb Fontan op
        at 3 years old
clinical features
1. neonatal period
  1. heart failure
  2. shock
    1. circulatory collapse
2. diagnosed on antenatal US
3. Mx
  1. resus 1st (ABC)
  2. start prostaglandin @ earliest opportunity
  3. early referral to cardiac centre
    1. surgical intervention

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outflow obstruction in sick infant

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	Created by v.djabatey over 10 years ago