Definition

Tetralogy of Fallot (ToF) is a congenital heart condition that can cause cyanosis (bluish discoloration) of the skin. This cyanosis occurs due to a lack of oxygen in the blood being pumped from the heart to the body, including the skin. Normally, oxygen-rich blood gives the skin a healthy pink color.

This condition is characterized by pulmonary stenosis (narrowing of the pulmonary artery), a ventricular septal defect (a hole in the wall between the heart’s ventricles), an overriding aorta (the aorta receives blood from both ventricles), and right ventricular hypertrophy (thickening of the heart muscle in the right ventricle).

ToF is a rare cyanotic heart disease but is one of the most common congenital heart defects seen in children who survive birth without treatment. It requires medical intervention within the first year of life. ToF accounts for 7-10% of congenital heart defects, affecting 3-5 out of every 10,000 live births, with no significant difference in occurrence between boys and girls.

Causes

Tetralogy of Fallot has multiple potential causes (multifactorial), including:

• Uncontrolled maternal diabetes during pregnancy
• Use of retinoic acid (a vitamin A derivative) during pregnancy
• Phenylketonuria (a genetic disorder where the body cannot break down the amino acid phenylalanine)
• Chromosomal abnormalities such as Down syndrome

In addition, there are also several other genetic mutations that are associated with the occurrence of tetralogy of Fallot.

Risk Factor

Identifying risk factors plays a crucial role in the prevention and management of Tetralogy of Fallot. Some of the associated risk factors include:

• Alcohol consumption during pregnancy
• Diabetes during pregnancy
• Maternal age over 40
• Poor or imbalanced nutrition during pregnancy
• Additionally, some patients with ToF may have other congenital disorders such as Down syndrome, Alagille syndrome, or DiGeorge syndrome (which can cause heart defects, low calcium levels, and poor immune function)

Symptoms

Symptoms of Tetralogy of Fallot may appear at birth or within a few days. They include:

• Bluish skin (cyanosis)
• Clubbing of the fingers (rounded, swollen fingertips)
• Feeding difficulties
• Failure to thrive
• Delayed development
• Episodes of fainting or loss of consciousness
• During cyanotic episodes, affected children may squat to improve oxygen flow

Diagnosis

The diagnosis of tetralogy of fallot is a diagnosis that can be established through a medical interview, physical examination, and additional examinations if available and necessary. 

The doctor will inquire about the patient's current symptoms during a medical interview. As your child's guardian, you need to give a detailed description of the symptoms, including the onset time, as they may indicate a particular disease. The doctor needs to know this information in order to make a specific medical diagnosis. Should the symptoms suggest tetralogy of fallot, the physician will proceed with a physical examination and additional tests.

During a physical examination, the doctor will perform an examination based on the patient's symptoms in order to identify several clinical signs, which are objective signs obtained by the doctor through a physical examination. In cases of tetralogy of Fallot, the doctor can hear an abnormal heart sound through a stethoscope in the form of an additional abnormal sound in the heart area during a physical examination, or the doctor can see a bluish discoloration on the child's skin.

If the clinical signs indicate tetralogy of Fallot, the doctor will proceed with supporting examinations if the equipment is available and required.

In order to establish or confirm the diagnosis of tetralogy of fallot, additional examinations are also important. A complete blood count, electrocardiogram, chest x-ray to check for abnormalities, echocardiogram to check for abnormalities in the heart's shape and heart rate, cardiac MRI to check for structural issues with the heart, or an oximetry test to check blood oxygen levels before cardiac catheterization, if required, are examples of additional examinations that the doctor may perform.

Management

Handling tetralogy of fallot requires surgery. Surgery to improve tetralogy of fallot performed when children are young, generally before the age of 6 months. Sometimes surgery needs to be done more than once for treatment tetralogy of fallot. When the surgery was more than once, the first surgery was carried out to help increase the flow of blood to the lungs. The answer to correct the problem can be done at the next time. However, surgery corrections are only done once in the first few months of life. The corrections are made to widen the pulmonal (pulmonary) channel which narrows and closes the defects of the dividing wall between the chambers (ventricnels) with a special patch.

Complications

Complications that may arise in tetralogy of Fallot are delayed growth and development, heart rhythm disturbances (arrhythmia), seizures during periods when there is not enough oxygen, and even death due to cardiac arrest even after surgery.

Most cases can be corrected with surgery, and over 90% of children with ToF survive into adulthood and can lead active, healthy, and productive lives. However, if left untreated, death may occur by age 20. Regular follow-up with a cardiologist is crucial for monitoring health after surgery.

Prevention

There is currently no specific method to prevent tetralogy of fallot cases. It is possible to prevent tetralogy of fallot in children by taking a number of steps. Among these measures are:

• Avoid alcohol during pregnancy
• Control blood sugar levels if the mother has diabetes
• Avoid pregnancy after age 40, if possible
• Maintain a balanced, nutritious diet before and during pregnancy
• Ensure complete vaccinations, especially for rubella, which can affect the baby’s heart development during pregnancy

When to See a Doctor?

If your child shows signs of blue-tinged skin or symptoms that resemble those of Tetralogy of Fallot, it's important to consult a pediatric cardiologist (Sp.JP) or pediatrician (Sp.A). The doctor will conduct a medical interview, physical exam, and necessary diagnostic tests to confirm the diagnosis and recommend appropriate treatment.

Looking for more information about other diseases? Click here!