February 24, 2020
Treatment for sickle cell disease has come a long way since the 1970s when the life expectancy of people living with it was less than 20 years.
People with sickle cell disease are not only living longer – life expectancy is now 42 to 47 years of age – but are enjoying a better quality of life, too.
"In the Philadelphia area, there has been great pediatric care for sickle cells disease and because of that people who have it are living very well," said Dr. Farzana Sayani, a hematologist at Penn Medicine.
Sayani is the director of a comprehensive sickle cell program focusing on adults living with the disease. Penn also has an active transition program for youth transitioning from a pediatric institution to adult care.
Sickle cell disease is an inherited red blood cell disorder that affects about 100,000 Americans. It is most often found in people of African or Hispanic descent. About 1 in 365 African-American babies are born with sickle cell disease, according to Sayani.
People who have the disease inherit an abnormal type of hemoglobin in their red blood cells, called Hemoglobin S, from both their mother and father. When only one parent has the hemoglobin S gene, a child will have the sickle cell trait, but usually does not develop the disease. But they may pass it on to their children.
Hemoglobin is the protein in the blood responsible for carrying oxygen to the rest of the body. Hemoglobin S causes red blood cells to become stiff and sickle-shaped. Instead of being round in shape, they look like crescent moons.
Sickle cells are sticky and can bind together, blocking the flow of blood and preventing oxygen from getting where it needs to go in the body. This causes sudden attacks of pain referred to as a pain crisis.
There are several different types of sickle cell disease. Hemoglobin SS, also known as sickle cell anemia, is the most common and most severe type of sickle cell disease.
Anemia occurs when red blood cells die at a rate faster than the body can replace them. Normal red blood cells generally live for 90 to 120 days. Sickled cells only live for 10 to 20 days. This shorter life-to-death cycle is harder for the body to sustain.
Another form, Hemoglobin SC, is not as severe as sickle cell anemia, but it can still cause significant complications, Sayani said. Other forms include Hemoglobin Sβ0 thalassemia, Hemoglobin Sβ+ thalassemia, Hemoglobin SD and Hemoglobin SE.
Sickle cell disease screening is a mandatory part of newborn screenings in Pennsylvania.
If the screening is positive, the family is informed and plugged into the health care system in order to receive the proper care.
If the disease is not diagnosed at birth, a blood test can confirm it at any age in which symptoms start to surface.
The severity of sickle cell disease can vary.
Each individual is affected differently, making it difficult to predict who will get what complications, Sayani said. That is why a comprehensive sickle cell program is so important.
Early signs include a yellowish tint to the skin or jaundice, fatigue and a painful swelling of the hands and feet.
"Young children with sickle cell disease may be tired, not eat very well and have delayed growth," Sayani said. "They may also develop anemia, be at greater risk of infection and start to experience pain crises."
Acute pain crises, also known as vaso-occlusive crises, can lead to long stays in the hospital to manage the crippling pain. Children with sickle cell disease also tend to experience delayed growth and puberty.
As a person with sickle cell disease grows older, the sickled red blood cells start to affect various organs, bones and joints.
This can lead to acute chest syndrome, which occurs when damaged lung tissues makes it difficult to breathe. Brain complications, including stroke, are possible. People with sickle cell disease are also prone to heart damage, eye problems, and infections like chlamydia, salmonella and staphylococcus. Chronic and acute pain is common.
There are different types of medicine that can help manage sickle cell disease.
Last year, an oral medicine was approved that makes sickle cells less likely to sickle. So was an intravenous medicine that has been shown to reduce pain crises and hospitalizations by 50%. Some people living with sickle cell disease also may need regular blood transfusions.
Hydroxyurea has also been used successfully for many years to reduce pain crises and the need for blood transfusions and hospitalizations.
Currently, blood and bone marrow transplant is the only way to cure the disease. But it is not an option for everyone because of the difficulty of finding a well-matched stem cell donor.
A related donor is best but only about a third of sickle cell patients have a donor that is related and fully-matched, Sayani said.
While these transplants have a 85% or more success rate, they also are associated with significant risks, including organ dysfunction, infection and graft vs. host disease – which can be quite debilitating.
Transplants completed in children have the best results, Sayani said. But because of the risks involved, doctors only suggest it for patients with severe forms of the disease.
Early clinical trials with gene therapy are also showing promise, she added.