Tetralogy Of Fallot

Tetralogy of Fallot consists of:

• Ventricular septal defect
• Right ventricular outflow tract obstruction
• Overriding aorta
• Right ventricular hypertrophy

The degree of right ventricular outflow obstruction determines the severity of cyanosis.

• Central cyanosis
• Harsh systolic ejection murmur
• Clubbing in older untreated children
• Poor growth

Hypercyanotic spells involve sudden worsening cyanosis, tachypnoea, irritability and potentially syncope or seizures.

Older children may instinctively squat because increased systemic vascular resistance reduces right to left shunting.

Echocardiography establishes anatomy.

Chest radiography may demonstrate the classic boot shaped cardiac silhouette, although this is not required for diagnosis.

A hypercyanotic spell is an emergency.

• Place infant in knee chest position.

• Give oxygen.

• Calm the child and minimize distress.

• Give morphine approximately 0.1 mg/kg IV, IM or SC where appropriate and closely monitored.

• Give isotonic fluid if volume depleted.

• Beta blockade such as propranolol may be used for recurrent spells.

Severe refractory spells may require vasoconstrictor therapy, airway control and emergency cardiology intervention.

Definitive treatment is surgical repair.