Although sickle cell disease is incompatible with an active military career, it can affect other military beneficiaries, and have an impact on a service member's readiness. Still, treatment attempts to keep patients as healthy as possible.

The Centers for Disease Control and Prevention estimates that sickle cell disease affects approximately 100,000 Americans, including roughly one in every 365 African-American births and one out of every 16,300 Hispanic-American births.

Sickle cell disease, or SCD, is a group of inherited red blood cell disorders. The condition causes red blood cells to become hard and sticky, and look like a sickle, the c-shaped farm tool used for cutting grass or harvesting crops.

"Sickle cell disease is one of dozens and dozens of hemoglobin mutations that occur in humans and cause disease," said Army Col. (Dr.) Andrew Cap, director of research at the U.S. Army Institute of Surgical Research at Joint Base San Antonio-Fort Sam Houston, Texas, and a practicing hematologist at Brooke Army Medical Center.

"Sickle cell basically does two things: It causes what we call an 'ineffective hematopoiesis,' in the sense that your bone marrow is busy making red cells, but they tend to get cleared more quickly from circulation because they get damaged," he said. "The structural change of the shape of the cells also causes problems. When they change to that sickle shape, they lose their flexibility. They have the potential to get clogged up in multiple organs."

Cap explained that 'sickle cell crises' result from clogging capillaries, starving tissues of oxygen. This can be caused by increased metabolic demand, including physical activity, other ailments including colds and flus, and temperature changes.

"Not every patient with sickle cell looks the same, in the sense that it's not necessarily predictable - this amount of activity, or that degree of cold, or this illness," Cap said. "There's a spectrum of disease severity that's highly variable."

Problems resulting from sickle cell disease range from anemia and acute chest crisis, where sickled blood cells get trapped in a person’s lungs and prevent the normal gas exchange needed for normal breathing, to blockages in other vital organs and capillaries throughout the body.

Within the Military Health System, patients with sickle cell disease are limited to dependents of service members due to the health complications surrounding it.

"Unfortunately, the physiologic effects of sickle cell are quite dramatic and incompatible with having a healthy life, period," explained Cap. "Most of our sickle population is actually in the pediatric realm because they're dependents."

Treatments include folic acid and vitamin B12, due to the vitamin deficiencies created by the body's compensation for the lack of healthy red blood cells; hydration and pain management; as well as avoiding situations that may result in an adverse reaction.

"We try to keep these patients as healthy as possible," said Cap.

Another treatment is hydroxyurea, which causes your body to produce "younger" red blood cells, or red blood cells that are similar to what your body produced as a fetus.

"This causes your body to make more 'fetal' hemoglobin and less sickled hemoglobin," said Cap.

Although it doesn't affect active-duty service members, another vital treatment for those with sickle cell disease is blood transfusion. Among the most common uses of red blood cells obtained through red blood cell donation, which can be done through the Armed Services Blood Program, are transfusions for people with sickle cell.

World Sickle Cell Awareness Day was June 19.