Summary about Disease
Transposition of the great vessels (TGA) is a serious, but rare, heart defect present at birth (congenital). In TGA, the two main arteries leaving the heart—the aorta and the pulmonary artery—are switched (transposed). The aorta normally carries oxygen-rich blood from the left ventricle to the body, and the pulmonary artery normally carries oxygen-poor blood from the right ventricle to the lungs. In TGA, the aorta carries oxygen-poor blood to the body, and the pulmonary artery carries oxygen-rich blood to the lungs. This creates two separate and parallel circulations, preventing oxygenated blood from reaching the body. Without surgical intervention, TGA is fatal.
Symptoms
Symptoms of TGA usually appear within hours or days of birth. They can include:
Cyanosis (bluish tint to the skin, lips, and nails)
Shortness of breath (rapid breathing)
Poor feeding
Lethargy (extreme sleepiness)
Poor weight gain
Clubbing of fingers and toes (in more severe cases that are not treated immediately)
Causes
The exact cause of TGA is often unknown. It is considered a multifactorial condition, meaning that a combination of genetic and environmental factors may play a role. Some potential risk factors include:
Maternal diabetes
Maternal age over 40
Maternal exposure to certain medications or illnesses during pregnancy (though specific causes remain elusive in most cases)
Genetic syndromes (rarely)
Medicine Used
Medications are primarily used to stabilize the infant before surgery. These may include:
Prostaglandin E1 (PGE1): This medication keeps the ductus arteriosus open. The ductus arteriosus is a blood vessel that connects the aorta and pulmonary artery in the fetus. Keeping it open allows some mixing of oxygenated and deoxygenated blood, improving oxygen levels.
Diuretics: May be used to manage fluid overload, if present.
Inotropic drugs: May be needed to improve heart function in some cases.
Antibiotics: May be used to prevent or treat infections. Definitive treatment requires surgery.
Is Communicable
No, TGA is not communicable. It is a congenital heart defect, meaning it is present at birth and not caused by an infectious agent.
Precautions
TGA is not preventable, however, the following precautions should be taken during pregnancy.
If you are planning a pregnancy or are pregnant, manage existing conditions, such as diabetes, well.
Consult your doctor before taking any medications during pregnancy.
Ensure you receive appropriate prenatal care.
How long does an outbreak last?
TGA is not caused by an outbreak, it is a birth defect and not infectious.
How is it diagnosed?
TGA is often diagnosed before or shortly after birth. Diagnostic methods include:
Prenatal Ultrasound: May detect heart defects, including TGA, during pregnancy.
Echocardiogram (Echo): Uses sound waves to create a picture of the heart, allowing doctors to visualize the abnormal connections of the great arteries.
Electrocardiogram (ECG or EKG): Measures the electrical activity of the heart, but is not specific for TGA.
Chest X-ray: Can show the size and shape of the heart and lungs.
Pulse oximetry: Measures the oxygen saturation in the blood.
Cardiac Catheterization: In some cases, this invasive procedure may be needed to further assess the heart's structure and function.
Timeline of Symptoms
Within Hours of Birth: Cyanosis, rapid breathing, and poor feeding are typically the first symptoms to appear.
Within Days of Birth: Lethargy and poor weight gain may become more apparent if the condition is not promptly diagnosed and treated.
Without Treatment: The condition will deteriorate rapidly, leading to severe respiratory distress, heart failure, and death.
Important Considerations
Early Diagnosis is Crucial: Prompt diagnosis and treatment are essential for survival.
Surgical Intervention is Necessary: The arterial switch operation is the primary surgical procedure to correct TGA. This surgery involves reconnecting the aorta and pulmonary artery to the correct ventricles.
Long-Term Follow-Up: Children who have undergone surgery for TGA require lifelong monitoring by a cardiologist to check for complications such as arrhythmias, valve problems, or narrowing of the arteries.
Genetic Counseling: While TGA is not usually inherited, genetic counseling may be recommended to families with a history of congenital heart defects.
Emotional Support: Parents of children with TGA need emotional support and resources to cope with the stress of diagnosis, treatment, and long-term care.