Solving the Sickle Cell Crisis
The sickle cell trait has its origins in a genetic adaptation common in individuals in which the mosquito-borne disease, malaria, has impacted human life for thousands of years. In sub-Saharan Africa, for example, as many as one-third of people carry the gene. It is also found, although less commonly, in populations ringing the Mediterranean, such as North Africa, Spain, Greece and Italy.
Today, the disease is found throughout the world because of migrations from these regions.
Ordinarily, red blood cells have a doughnut-like shape. Individuals with the sickle cell trait, however, also have red blood cells that assume a crescent shape. This sickle cell’s shape confers resistance to the malaria parasite, plasmodium falciparum, which infects red blood cells.
Although the genetic mutation that causes sickle-shaped red blood cells helps people survive in regions plagued by malaria-carrying mosquitoes, it comes at a high price…
In individuals that carry two copies of the gene, for example, anemia is common, since the mutation reduces the ability of red blood cells to transport oxygen from the lungs to other parts of the body. This condition is called sickle cell disease (SCD).
However, on a purely physical level, sickle-shaped red blood cells can cause other problems as well. Since they aren’t as round as normal red blood cells, they don’t flow as well through the 60,000 miles of small, serpentine blood vessels that carry life-sustaining oxygen and nutrients to the body.
Normally, the percentage of sickle-shaped cells is low enough that this isn’t a big problem.
When the percentage of affected red blood cells in the body is high enough, however, a vaso-occlusive crisis can occur. When there are too many sickle-shaped red blood cells in the body, they clog in narrow capillaries like logs in a river bend. This occlusion in the blood vessels restricts blood supply to tissues, and can lead to pain and the death of cells in the affected areas.
The early symptoms are an imminent, looming pain in the body, much like the early stages of a flu infection. The pain eventually builds, and patients commonly describe it as being repeatedly hit with a baseball bat in the same place.
Female sufferers describe the pain as worse than childbirth.
In the United States alone, some 90,000 people are affected by SCD. It is most commonly found in people of African or Hispanic ancestry. In the US, 150,000 hospitalizations and ER visits are attributed to an SCD-caused crisis each year.
Patients suffering a crisis are administered intravenous narcotics and kept hydrated. They are monitored until the condition clears and then they are sent home. Typical hospital stays range from four-six days, but they can last up to two weeks. Other than waiting for the clogged blood cells to break down while administering analgesics to deal with the extreme pain, there are no good options to deal with the effects of an acute SCD condition. Extreme cases can cause death.
Even if it doesn’t kill immediately, SCD-caused crisis eventually shortens the life span of otherwise healthy people. Frequent clogging of blood flow can lead to early organ failure and death. A 1994 study, for example, showed the median age of death for SCD sufferers in the US at 42 years for males, and 48 for females.
However, what if there were a way to help blood flow better in patients experiencing this condition? Not only could the duration of a crisis be reduced, but the amount of damage that one could cause would be reduced as well.