Living With Sickle Cell Disease

Sickle Cell Disease

 

Sickle cell disease:

Sickle cell disease (SCD) is a group of genetic blood disorders. A normal blood cell is disc shaped and can carry oxygen in blood through blood vessels.

A protein called Hemoglobin which is present in blood carries oxygen to all parts of the body. In sickle cell disease, a normal blood cell transforms into a crescent or a sickle shape that affects the transportation of blood and can result in a shortage of oxygen to all parts of body.

These sickle shape blood cells also clog the blood vessels which affect blood flow and can lead to a range of different health problems such as episodes of pain, infection, acute chest syndrome, anemia, and stroke.

The most common type of SCD is found in North America. This disease is also common among population of Greece, Turkey, India, Italy and South America.

Types of Sickle cell disease:

There are several types of Sickle cell disease, but the most common are as follows:

  • Sickle Cell Anemia (SS): Persons with this type inherit two sickle cell genes (S) from each parent. This type of disease is commonly called ‘Sickle cell anemia’ and is one of the most severe forms of the disease found worldwide.
  • Sickle Hemoglobin-C (SC): Persons who have this type inherit a sickle cell gene (S) from one parent and a sickle cell gene from abnormal hemoglobin (C) from the other parent. This type of disease is not as severe compared to sickle cell anemia.

 

  • Sickle Beta plus Thalassemia: A person inherits a sickle cell gene (S) from one parent and one ‘beta thalassemia’ gene (another type of anemia) from the other parent. This type of thalassemia presents a decreasing level in hemoglobin. This type of thalassemia is of 2 types, which depends on the severity of the condition.

 

1: Thalassemia major (Cooley’s anemia):

The signs and symptoms of this type appear in the first couple of years. In children, it is life threatening. In adults, it can cause enlargement of the organs such as the Spleen, Liver, and Heart. Thalassemia major is the most severe form of Beta Thalassemia.

 

2: Thalassemia intermedia:

The sign and symptoms of this thalassemia usually appear in the first 2 years of life or much later. This type of Sickle beta plus thalassemia is mild compared to the previous type mentioned. A person with this type of thalassemia can suffer with bone abnormalities or growth retardation.

 

  • Sickle Hemoglobin-D Disease: A person with this type inherits a sickle cell gene (S) from one parent and one gene from an abnormal type of hemoglobin (D). This type of disease causes moderate to severe anemia.
  • Sickle Hemoglobin-O Disease: A person with this type inherits a sickle cell gene (S) from one parent and one gene from an abnormal type of hemoglobin (O). This type is mostly found in the Arabian and North African population.

 

SICKLE CELL TRAIT (HbAS): When an individual inherits one sickle cell gene (S) from one parent and one normal gene (A) from the other parent, this is referred to as ‘having a Sickle Cell trait. Sickle Cell trait is not a disease.

 

This condition shows that the individual has inherited the sickle cell gene from either the mother or father. People with this condition do not show any symptoms and can live a normal life provided they do not engage in highly vigorous activities as they are susceptible to ‘blood sickling’ where a blockage in blood vessels becomes a serious possibility.

Sign and symptoms:

The signs and symptoms of sickle cell disease usually appear in the first year of life. The severity of symptoms depends upon the condition of the person. Signs and symptoms also vary from person to person.

The most common sign of sickle cell disease is anemia which occurs because of a decrease in oxygen supply to the body.

Other symptoms include:

  • Jaundice (yellowing of the skin and whites of the eyes).
  • Pain and swelling in the hands, feet and chest.
  • Frequent infections.
  • Delayed growth.
  • Vision problems.
  • Headache or dizziness.
  • Enlargement of organs such as liver, spleen etc.
  • Shortness of breath.

In infants: In severe cases, an infant may suffer from an 'aplastic crisis'. The bone marrow stops producing red blood cells which can then lead to severe anemia. Other symptoms include enlargement of the spleen, low appetite, and fatigue.

 

Complications

Acute chest syndrome: Acute chest syndrome is life threatening and can only be treated in hospital. Signs and symptoms of acute chest syndrome are like pneumonia.

Chest pain, difficulty in breathing, fever, coughing are also the signs and symptoms of acute chest syndrome. Acute chest syndrome can also damage lungs because of sickling in blood vessels of lungs.

Sickle cell crisis is an acute condition that appears in patients with SCD. Sickle cell crisis is the episode of pain that starts suddenly and can last for several hours to several days. In Sickle cell crisis, sickled red blood cells block blood vessels. The pain can be sharp, severe, throbbing or mild.

Hand-Foot syndrome: Hand-foot syndrome is another complication caused by sickle cell disease. In hand-foot syndrome, swelling of the hands and feet occurs along with fever. The sickled cells block the blood flow to the hands and feet which causes the swelling.

Delayed growth and puberty: Children suffering from sickle Cell Disease can also suffer from delayed growth and puberty because of anemia.

Eye problems: Sickle cell disease can also damage blood vessels in the eye, especially to the retina. The vessels in the retina can get blocked, ruptured, or can bleed. It can also lead to loss of eye vision.

Heart disease: Sickle cell disease can also lead to various heart diseases such as coronary heart disease and pulmonary hypertension. Frequent transfusions of blood may also cause heart damage to those undergoing heart surgery.

Splenic - sequestration crisis: The Spleen helps to filtrate blood cells. It also helps in the destruction of old blood cells. In sickle cell disease, red blood cells may get trapped in the spleen which can result in Spleen enlargement. Severe anemia can result due to a lack of red blood cells in circulation. Because of spleen enlargement a person can also experience pain in the left side of pelvis.

Stroke or Silent Brain Injury: Sickle cell disease also cause silent brain injury or ‘’silent stroke’’ due to a decreased amount of oxygen reaching an important area within the brain coined ‘the white matter.’ This injury can lead to learning difficulties and problems in executing basic tasks.

Liver issues: A person suffering from sickle cell disease can also experience a liver problem which is termed as ‘’Sickle cell intrahepatic cholestasis”. Decreased oxygen supply to the liver may also cause failure. In adults, this condition can cause chronic health problems to manifest.

Kidney issues: Sickle cell disease also affects the function of kidney. This disease may cause the kidneys to have difficulty in removing waste products and absorbing water from blood, making urine less concentrated than normal which can lead to uncontrolled urination. This complication often starts in childhood.

Deep vein thrombosis and pulmonary embolism: In sickle cell disease, chances of blood coagulation increase, which enhances the risk of blood clotting in the deep or pulmonary vein. This may lead to serious illness, disability and sometimes can cause death. Anti-Coagulation medication is used to prevent and treat deep vein thrombosis and pulmonary embolism.

Diagnosis of Sickle cell disease:

Sickle cell disease can be diagnosed by a simple blood test that is used to examine defective genes in hemoglobin. Several screening programs are also available that helps in detection or diagnosis of sickle cell disease at an early age which includes prenatal and antenatal screening. Sickle cell disease is an inherited genetic condition, so a detailed questionnaire of a family’s medical history is required. Early diagnosis is necessary for prevention and treatment.

Prenatal and newborn screening: This diagnostic test is for expectant parents who have a history of sickle cell disease. This test is performed before birth by using a small sample of amniotic fluid. These tests detect a mutated HBB gene as opposed to an abnormal hemoglobin protein.

All babies born in developed countries such as the USA and UK are offered screening for sickle cell disease. The test used for diagnosis a newborn is known as a ‘Heel prick test’. If the test is found to be positive, a second test should be done to confirm the diagnosis.

Sickle cell disease can also be identified by the following tests:

  • Review of newborn screening test
  • Hemoglobin electrophoresis
  • Complete family history
  • Additional blood tests

Diagnosis in adults: Patients who test positive for abnormal hemoglobin go through further testing for a definitive diagnosis. Patients diagnosed with sickle cell disease require frequent laboratory tests including blood and urine tests to determine the type of abnormal hemoglobin. These tests are helpful to monitor any complications that can arise which were mentioned previously.

Another test, a transcranial Doppler ultrasound or TCD is also done to identify narrowed blood vessels in the brain which can lead to a stroke. This test is also helpful in determine one’s risk of having a stroke.

Pre-implantation genetic diagnosis: If both parents are carriers of the sickle cell disease gene and prefer not to have a child with sickle cell disease, they can go for pre-implantation genetic diagnosis (PIGD) for the fertilization process. This test is essentially the same as in-vitro fertilization. An egg is removed from the ovary of a mother and fertilized in a laboratory. The embryo can then be tested for sickle cell disease and implanted into women’s womb for further process.

Prevention:

Treatment for sickle cell disease is aimed at relieving symptoms and preventing complications from developing.

For the prevention of bacterial infection and sepsis in children: Penicillin should be administered to children until at least age 5. All routine childhood vaccinations should be followed along with sickle cell specific vaccination.

Preventing painful episodes: A person should drink plenty of fluid to avoid dehydration. Hydroxyurea medication can also be used for the prevention of painful pains. Non-steroidal anti-inflammatory drugs (NSAID) such as ibuprofen and opioids such as morphine are also helpful in treatment.

Treatment:

Hydroxyurea therapy: Hydroxyurea is an oral medication that helps in the production of fetal hemoglobin. It is normally present in fetus’ and in young children. Hydroxyurea therapy is helpful in reducing side effects and complications that occur in sickle cell disease.

Transfusion therapy: Blood transfusions are given to treat severe anemia, acute chest syndrome and other complications of sickle cell disease. In children, chronic blood transfusions are required to avoid complications such as stroke. A patient with chronic blood transfusion can become overloaded with iron.  The accumulation of this iron can cause damage to vital organs. For the removal of excessive iron, medications called chelators are used. Children may take chelators orally or it can be administered through injections. Hydroxyurea, a treatment mentioned before is used as an alternative to blood transfusions as complications have arisen when blood transfusions have been administered.

Stem cell transplant: Stem cell transplant which is also known as bone marrow transplant is another treatment for sickle cell disease. It is the transplantation of normal blood stem cells from a healthy donor to the patient. These healthy stem cells replace the sickle blood stem cells and assist in normal blood production. The procedure is known to be very risky.

Medication:

These drugs are used to treat complications and prevent sickle cell disease!

Hydroxyurea: This medication helps in the supply of oxygen to all parts of the body. It is not safe in pregnancy. The benefits of this drug are shown in children younger than 9 months of age.

L- Glutamine oral powder: This drug helps in the reduction of sickle blood cells in the body. It is suitable from the age of 5 years.

Voxelotor (Oxbryta): This drug boosts the level of healthy hemoglobin

Crizanlizumab-tmca: This drug helps to reduce pain by preventing cells from sticking to blood vessels.

Pain relieving medications and opioids: Milder pain is treated with nonsteroidal anti- inflammatory drugs such as ibuprofen, ketorolac tromethamine or analgesics like acetaminophen and tramadol. The opioids used to treat SCD are morphine, hydro morphine, fentanyl, and codeine related agents.

Conclusion: Effective research into bone marrow transplant procedures will help in the reduction of SCD. It is an effective solution for many developed and undeveloped countries which have a high disease burden. Pharmacological therapies are also helpful in reducing complications and are also easy to administer. It is a great success in the field of science.

 

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