Sickle Cell Disease is an inherited blood disorder, characterized primarily by chronic anemia and periodic episodes of pain. The underlying problem involves hemoglobin, a component of the red cells in the blood. The hemoglobin molecules in each red blood cell carry oxygen from the lungs to the body organs and tissues and bring carbon dioxide back to the lungs.
In Sickle Cell Disease the hemoglobin is defective. After the hemoglobin molecules give up their oxygen, some of them may cluster together and form long rod-like structures. These structures cause the red blood cells that are normally soft and donut shaped to become stiff, creating difficulty for the sickled red blood cells to pass freely through small blood vessels. This causes them to stack up and create blockages that deprive the organs and tissue of oxygen carrying blood. This process produces periodic episodes of pain and can ultimately damage the tissues and vital organs and lead to other serious medical problems.
What conditions promote the sickling of the red blood cells in sickle cell anemia?
Sickling of the red blood cells in patients with sickle cell anemia results in cells of abnormal shape and diminished flexibility. The sickling is promoted by conditions that are associated with low oxygen levels, increased acidity, or low volume (dehydration) of the blood. These conditions can occur as a result of injury to the body's tissues, dehydration, or anesthesia.
Certain organs are predisposed to lower oxygen levels or acidity, such as when blood moves slowly through the spleen, liver, or kidney. Also, organs with particularly high metabolism rates (such as the brain, muscles, and the placenta in a pregnant woman with sickle cell anemia) promote sickling by extracting more oxygen from the blood. These conditions make the organs susceptible to injury from sickle cell anemiale cell disease was the first disease for which a specific molecular defect in a gene was identified, and it is the most common genetic disease identified as part of the Newborn Screening Program in the United States.