1. Take the Blood Disorders Quiz

Medical Author:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

View Full Profile

Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

View Full Profile

Sickle cell disease is a genetic alteration that causes some hemoglobin molecules to be defective (the defective hemoglobin is termed hemoglobin S). When red blood cells have hemoglobin S, and are subjected to low oxygen levels, they can become crescent or "sickle shaped" and do not easily move through capillary vessels with small diameters, thus depriving tissues from exchanging oxygen and carbon dioxide. In extreme situations, tissue can begin to die. Sickle cells may lead to anemic conditions because sickle cells have a life-span of about 10–20 days, while normal red blood cells live about 120 days; thus the bone marrow may fall behind in synthesizing new red blood cells. Moreover, dead or dying sickle cells may clog up the spleen as the spleen tries to remove the sickle cell debris from the blood. The common symptoms of sickle cell disease include the following in addition to the symptoms of anemia:

• Bone pain
• Shortness of breath
• Abdominal pain
• Delays in puberty and growth
• Ulcers
• Jaundice
• Painful and prolonged erections (about 10%–40 % of men)
• Blindness
• Strokes

In some individuals, the spleen becomes so damaged that it needs surgical removal. Surgical removal of the spleen makes an individual more susceptible to certain diseases, most notably, pneumococcal pneumonia. Sickle cell disease is fully expressed in individuals that inherit a defective hemoglobin gene from each parent. The individual that inherits only one defective gene has much milder symptoms or no symptoms, and is considered to have sickle cell trait, not sickle cell disease.

Must Read Articles Related to Hemoglobin Levels

Anemia Anemia can be caused by many conditions and diseases such as iron deficiency, poor diet and nutrition, cancers, bone marrow problems, and more. Symptoms of anem...learn more >>

Chemotherapy Chemotherapy or "chemo" is a treatment for cancer. Depending on the type of cancer an individual has, it can cure cancer, control cancer. or ease cancer symptom...learn more >>

Chronic Obstructive Pulmonary Disease (COPD) Chronic obstructive pulmonary disease, or COPD, is a long-lasting obstruction of the airways that occurs with chronic bronchitis, emphysema, or both. This obstr...learn more >>

See the Entire Hemoglobin Levels Topic Guide »