CONGENITAL HEART DISEASE WITH CYANOSIS

The congenital cardiac abnormalities that are associated with cyanosis involve shunting of blood from the right side of the heart to the left side. These include the following cardiac abnormalities:

  • Tetralogy of Fallot
  • Pulmonary atresia with ventricular septal defect (VSD)
  • Transposition of the great vessels
  • Truncus arteriosus (associated VSD is always present)
  • Eisenmenger syndrome
  • Hypoplastic left heart syndrome

Those abnormalities manifesting in the neonatal period have a poor prognosis.

TETRALOGY OF FALLOT

This is the commonest of the cyanotic group because of a slightly better prognosis in infancy, allowing more of them to survive longer.

Classically, Tetralogy of Fallot consists of;

  • Pulmonary stenosis
  • Ventricular septal defect
  • Dextroposition of the aorta
  • Right ventricular hypertrophy.

sSpecific Clinical Features

  • Cyanosis is a major feature. It may not be present at birth, but develops later during first year.
  • Other features include dyspnoea on exertion, to which the affected child responds by assuming a squatting position for a few minutes after such an exercise.
  • Affected children also tend to have paroxysmal hypercyanotic attacks often referred to as blue spells.
  • The pulse may be normal but a systolic thrill is felt along the left sternal border in 50% of cases.
  • Clubbing of fingers and toes occurs after a long time.

The following complications are associated with Tetralogy of Fallot:

  • Cerebral thrombosis due to polycythaemia,
  • Brain abscess (usually after 2 years of age) presenting with headache, fever, nausea and vomiting with or without seizures,
  • Bacterial endocarditis
  • Congestive heart failure.

Investigations

  • Full blood count or haematocrit
  • CXR – Boot shaped heart oligaemic lung fields
  • Electrocardiogram
  • Echocardiogram
  • Blood culture if suspect endocarditis
  • CT scan if cerebral thrombosis or abscess is/are suspected

Management

  • For children with blue spells, administer oxygen; child should be in kneechest position.
  • Prevent/correct dehydration in these children at all times.
  • Provide supportive therapy:
    • Venesection: Maintain haematocrit at 55–65% but avoid iron deficiency.
    • Intravenous or oral propranolol.
  • Refer all children to a specialist unit for definitive treatment by interventional closed repair or open heart surgery.