Tetralogy of Fallot | Symptoms and Causes

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What are the symptoms of tetralogy of Fallot?

Cyanosis, a blue color of the skin, is often the first sign of tetralogy of Fallot (ToF). This happens when the level of oxygen in the blood is lower than normal. In other cases, a heart murmur — the sound of blood flowing through the heart — is the first sign. (Although the overwhelming majority of murmurs in babies and older children are benign.)

Even after it is apparent that a baby has ToF, there may be no further symptoms for weeks or even months. Some babies will show signs of cardiac overwork — becoming tired with feeding, poor weight gain — if the amount of pulmonary obstruction is mild.

More commonly, the baby has a few symptoms at first. But over time, the cyanosis will increase and, eventually, will become so severe that it interferes with normal growth, development and activities.

Tet spells

Tet spells, also known as hypercyanotic episodes, are another a symptom of tetralogy of Fallot. During these episodes, which often occur after feeding, warm baths or stress, the baby has a sudden decrease in the amount of oxygen in the blood. He or she will turn deep blue, breathe faster than normal and may appear to be very irritable or crying. If the baby is having difficulty breathing, passing out or having seizures, seek immediate medical attention.

What causes tetralogy of Fallot?

While most cases of ToF occur by chance with no clear reason for their development, there have been some documented cases of a genetic link. Parents who already have a child with a congenital heart defect are more likely to have a second child with a heart defect.

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