Cyanotic Heart Disease, Symptoms, Diagnosis, Treatment, Complications

Cyanotic heart disease is a group of congenital heart defects (present at birth) that lower the level of oxygen in the blood. Cyanosis means a bluish color of the skin, lips and mucous membranes caused by poorly oxygenated blood.

Cyanotic defects are less common than non-cyanotic defects such as a simple hole in the heart, but they are often more serious and usually need surgery in infancy.

Causes of Cyanotic heart disease

According to MedlinePlus, defects that can cause cyanotic heart disease include:

• Tetralogy of Fallot
• Transposition of great arteries
• Ebstein anomaly
• Tricuspid atresia and other valve defects
• Total anomalous pulmonary venous return
• Truncus arteriosus
• Hypoplastic left heart syndrome

Tetralogy Of Fallot (Tof)

Tetralogy of Fallot is the most common cyanotic heart defect. The CDC estimates that about 1 in every 2,041 babies born in the US each year has it.

The cause is unknown for most babies. Some have gene or chromosome changes, and a mix of genetic and other factors, such as the mother's health, diet or medicines, may play a role. Tetralogy of Fallot is made up of four defects:

1. Ventricular septal defect (VSD), a hole between the two lower chambers
2. Pulmonary stenosis, a narrowing of the pulmonary valve and main pulmonary artery
3. Right ventricular hypertrophy (RVH), a thickened right ventricle wall
4. Overriding aorta, where the aorta sits over the hole and receives blood from both ventricles

Because of the narrowed pulmonary outflow, oxygen-poor blood from the right ventricle crosses through the VSD into the aorta (a right-to-left shunt). That mixing lowers the oxygen level in the blood going to the body. The right ventricle works harder against the narrowing, so its wall thickens.

Heart Disease causes, symptoms, risk factors & Treatment

Signs & Symptoms of Tof

Symptoms often appear soon after birth or in the first weeks of life and vary with the severity of the narrowing.

• The baby may or may not look blue at birth.
• Sudden episodes of deep blue skin, fast breathing and irritability, called "tet spells," often during crying or feeding.
• Labored or fast breathing.
• Difficulty feeding, tiring or sweating during feeds.
• Poor weight gain and delayed growth and development.
• Polycythemia (a high red blood cell count) in long-standing cyanosis.
• Low oxygen levels in the blood.
• Clubbing of fingers and toes in older children with untreated disease.
• A heart murmur.
• Older children may squat after exertion. Squatting raises resistance in the body's arteries, which reduces the right-to-left shunt and sends more blood to the lungs.
• The second heart sound is often single.

If a baby has blue lips or skin, trouble breathing or a tet spell, get emergency medical care right away.

INVESTIGATIONS FOR TETRALOGY OF FALLOT

Following investigations and tests are done to make the diagnosis.

Pulse oximetry

A painless sensor measures blood oxygen. Newborn screening with pulse oximetry helps find critical congenital heart defects such as tetralogy of Fallot.

Complete blood count

This blood test may show raised hemoglobin, red blood cell count and hematocrit, depending on how low the oxygen saturation is.

ECG

It shows right ventricular hypertrophy and right axis deviation.

Chest X-ray

Heart size is usually normal. The classic finding is a "boot-shaped" heart, with an upturned apex and reduced blood vessel markings in the lungs. In about 25 percent of cases, the aortic arch is on the right side.

Echocardiogram

An echocardiogram is the main test. It shows the ventricular septal defect, pulmonary stenosis, right ventricular hypertrophy and overriding aorta.

Cardiac catheterization or angiography

These may be done to clarify the anatomy of the coronary and pulmonary arteries before surgery. Heart MRI or CT may also be used.

WHO IS AT RISK?

Babies have a higher risk of cyanotic heart defects if the mother had rubella infection during pregnancy, poorly controlled diabetes, or exposure to certain medicines, chemicals, alcohol or street drugs. Genetic syndromes, such as Down syndrome, also raise the risk.

WHAT ARE THE COMPLICATIONS OF TETRALOGY OF FALLOT?

Without treatment, or sometimes after repair, this cyanotic heart disease can lead to

• Brain abscess
• Stroke
• Bacterial endocarditis (heart infection)
• Anemia
• Polycythemia
• Delayed growth and development
• Pulmonary valve leakage (pulmonary regurgitation) after repair
• Irregular heart rhythms
• Fainting or seizures

Management Of Tetralogy of Fallot

The aims are to prevent episodes of low oxygen and to improve blood flow to the lungs. Surgery is the main treatment, and medical care supports the baby before and after it.

1- Medical Therapy

Before surgery, doctors keep the baby well hydrated and watch blood glucose and temperature. Iron may be given if the baby has iron deficiency, which can make symptoms worse.

Good nutrition and extra calories help growth. During a tet spell, doctors may place the baby in a knee-to-chest position and give oxygen and medicines.

Good dental care matters. Some children with cyanotic heart disease need antibiotics before certain dental or medical procedures to prevent endocarditis, as advised by their cardiologist. Complications such as a brain abscess need urgent hospital treatment.

2- SURGICAL THERAPY

Open-heart surgery is the main treatment. Complete repair is usually done in infancy, typically in the first year of life: surgeons close the VSD with a patch and widen or replace the narrowed pulmonary valve and artery.

Some babies first need a temporary shunt between a body artery and the pulmonary artery to improve blood flow to the lungs. Most children live active lives after repair but need lifelong checkups with a heart specialist, and some need more surgery as adults.

HP Thoughts: The fourth most common heart ailment in our series: Pulmonary Heart Disease.

Sources

• About Tetralogy of Fallot, CDC
• Cyanotic heart disease, MedlinePlus