User:Jeremywarner/sandbox

Blue baby syndrome can refer to a number of conditions that affect oxygen transportation in the blood, resulting in blueness of the skin in babies. Historically, the term "blue baby syndrome" has referred to babies born with one of two conditions:


 * 1) Cyanotic heart disease, which is a category of congenital heart defect that results in low levels of oxygen in the blood. This can be caused by either reduced blood flow to the lungs or mixing of oxygenated and deoxygenated blood.
 * 2) Methemoglobinemia, which is a disease defined by increased levels of methemoglobin in the blood. Increased levels of methemoglobin cause oxygen molecules to tightly bind to hemoglobin molecules in red blood cells, preventing oxygen from being released into the tissues.

Both of these conditions cause cyanosis, or a bluish discoloration of skin or mucous membranes.

Cyanotic Heart Disease
A number of cardiovascular defects may lead to blue baby syndrome. The most common cyanotic heart defects include tetralogy of Fallot, persistent (or patent) truncus arteriosus, tricuspid atresia, transposition of the great vessels, and anomalous pulmonary venous connection.

Methemoglobinemia
Blue baby syndrome can also be caused by nitrates in drinking water leading to methemoglobinemia. Nitrates from polluted drinking water form compounds in the body that change haemoglobin to methemoglobin, decreasing the ability of blood to carry oxygen. In infants, the condition can be fatal. The sources of nitrate can include fertilizers used in agricultural lands, waste dumps or pit latrines. For example, cases of blue baby syndrome have been reported in villages in Romania and Bulgaria, and were thought to be caused by groundwater polluted by nitrate leaching from pit latrines. Nitrate levels are subject to monitoring to comply with drinking water quality standards in the United States and other countries. The link between blue baby syndrome and nitrates in drinking water is widely accepted, but some studies indicate that other contaminants, or dietary nitrate sources, may also play a role in the syndrome.

Other causes
Other insults in neonates, such as respiratory distress syndrome, can also produce a "blue baby syndrome". Like methemoglobinemia, these are not structural lesions and are not regarded by most doctors as true "cyanotic lesions."