Definition of Cyanotic heart disease:

Cyanotic heart disease is a heart defect, present at birth (congenital), that results in low blood oxygen levels. There may be more than one defect.

Causes, incidence, and risk factors:

Normally, blood returns from the body and flows through the heart and lungs. It will then leave the heart with enough oxygen to supply the body's tissues.

Heart defects can change the way blood flows through the heart and lungs. This abnormal blood flow (called right-to-left shunt) can result in too little oxygen in the blood moving through the rest of the body.

Cyanotic heart disease causes the child's skin to look blue (cyanosis). This bluish color is most often seen on the lips, fingers, and toes, or during exercise. Some heart defects cause major problems immediately after birth. Others cause few, if any, problems until adulthood.

Congenital heart defects that may cause cyanosis include:

• Coarctation of the aorta
• Critical pulmonary valvular stenosis
• Ebstein's anomaly
• Hypoplastic left heart syndrome
• Interrupted aortic arch
• Pulmonary valve atresia
• Pulmonic stenosis with an atrial or ventricular septal defect
• Some forms of total anomalous pulmonary venous return
• Tetralogy of Fallot
• Total anomalous pulmonary venous return
• Transposition of the great vessels
• Tricuspid atresia (a deformity of the tricuspid heart valve)
• Truncus arteriosus

Cyanotic heart diseases may be caused by:

• Chemical exposure
• Genetic and chromosomal syndromes, such as Down syndrome, trisomy 13, Turner syndrome, Marfan syndrome, Noonan syndrome, and Ellis-van Creveld syndrome
• Infections (such as rubella) during pregnancy
• Poorly controlled blood sugar levels in women who have diabetes during pregnancy
• Some prescription and over-the-counter medications and street drugs used during pregnancy

Cyanosis may also be caused by conditions other than congenital heart disease. Such conditions may include lung disease, abnormal forms of hemoglobin (the protein that carries oxygen through the blood), dehydration, and hypoglycemia.