Vidyya Medical News Service
*
Volume 6 Issue 341 Published - 14:00 UTC 08:00 EST 6-Dec-2004 Next Update - 14:00 UTC 08:00 EST 7-Dec-2004
little clear gif used for spacer
 
 

Information for patients: What is sickle cell anemia?



Sickle cell anemia is an inherited blood disease. That means you are born with it and it lasts a lifetime.

Sickle cell anemia affects the red blood cells. Normal red blood cells are smooth and round like doughnuts. They move easily through blood vessels to carry oxygen to all parts of the body. In sickle cell anemia, the red blood cells become hard, sticky, and shaped like sickles or crescents. When these hard and pointed red cells go through the small blood vessels, they tend to get stuck and block the flow of blood. This can cause pain, damage, and a low blood count or anemia.

Sickle-shaped red blood cells
The sickle-shaped red blood cells tend to get stuck in
narrow blood vessels, blocking the flow of blood.

Anemia is a shortage of red blood cells in your blood. In sickle cell anemia, this shortage of red blood cells occurs because sickle cells do not last very long. It is hard for your body to make new red blood cells fast enough to keep up. Normal red blood cells last about 120 days in the bloodstream. Sickle cells die after only about 10 to 20 days.

Sickle cell trait is different from sickle cell anemia. A person with sickle cell trait does not have the disease but carries the gene that causes the disease. Persons with sickle cell trait can pass the gene to their children. For more information on sickle cell trait, see the section on "What Causes Sickle Cell Anemia."

Sickle cell anemia is a serious disease and there is no universal cure. Bone marrow transplantation offers a cure, but very few patients have matched donors. Some patients also do not want bone marrow transplants because of the risks involved. Over the past 30 years, doctors have learned a great deal about the disease. They know what causes it, what it does to your body, and how to treat many of the complications. Today, with good health care, many people with the disease:
  • Are in reasonably good health much of the time
  • Live fairly normal lives
  • Live 40 to 50 years and longer.


Other Names for Sickle Cell Anemia

  • Hemoglobin SS Disease


What Causes Sickle Cell Anemia?

People with sickle cell anemia inherit two genes, one from each parent, that are variant (different from normal). The variant genes are call sickle cell genes.

The sickle cell genes tell the body to make the variant hemoglobin (hee-muh-glow-bin) that results in deformed red blood cells. Hemoglobin is the protein in red blood cells that carries oxygen to all parts of the body.

Children who inherit sickle cell genes from both parents will have sickle cell anemia. Children who inherit the sickle cell gene from only one parent will not have the disease. They will have sickle cell trait. Persons with sickle cell trait:
  • Generally have no symptoms
  • Live normal lives
  • Can pass the sickle cell gene on to their children.
When two people with sickle cell trait have a baby, there is a:
  • One in four chance (25 percent) the baby will inherit two sickle cell genes and have the disease.
  • One in four chance (25 percent) the baby will inherit two normal genes and not have the disease or trait.
  • Two in four chance (50 percent) the baby will inherit one normal gene and one sickle cell gene. The baby will not have the disease, but will have sickle cell trait like the parents.
Sickle cell genes

The presence of two sickle cell genes (SS) is needed for sickle cell anemia.
If each parent carries one sickle hemoglobin gene (S) and one normal gene
(A), with each pregnancy, there is a 25 percent chance of the child's inheriting
two SS genes and having sickle cell anemia; a 25 percent chance of inheriting
two AA genes and not having the disease; and a 50 percent chance of being
an unaffected carrier (AS) like the parents.


Who Gets Sickle Cell Anemia?

Sickle cell anemia affects millions of people throughout the world.

Sickle cell anemia is common in people whose families come from:
  • Parts of Africa (the region south of the Sahara Desert)
  • Spanish-speaking areas like South America, Cuba, and Central America
  • Saudi Arabia
  • India
  • Mediterranean countries, such as Turkey, Greece, and Italy.
In the United States, sickle cell anemia affects about 72,000 people. The families of most of the people affected come from Africa. The disease occurs in about:
  • One in every 600 African-American births
  • One in every 1,000-1,400 Hispanic-American births.
About 2 million Americans carry the sickle cell trait. About 1 in 12 African Americans have the trait.


What Are the Signs and Symptoms of Sickle Cell Anemia?

The signs and symptoms of sickle cell anemia are different in each person. Some people have mild symptoms. Others have very severe symptoms and are often hospitalized for treatment.

The most common symptoms or signs are related to:
  • Anemia
  • Pain when sickle-shaped red blood cells block the flow of blood to an organ
  • Other more specific symptoms.
The general symptoms or signs of anemia are:
  • Fatigue (feeling very tired)
  • Paleness
  • Yellowing of the skin and eyes (jaundice)
  • Shortness of breath.
Pain is the symptom of sickle cell anemia that most people are familiar with. It occurs in both children and adults. Pain results from blocked blood and oxygen. Painful events or crises may occur in any body organ or joint. Some patients have painful crises less than once a year. Others may have as many as 15 or even more crises in a year. The pain can be acute (sudden), chronic (long lasting), or a mixture of the two.
  • Acute pain is the most common type of pain. It is sudden pain that can range from a mild ache to very severe pain. The pain usually lasts from hours to a few days. With complications or poor treatment, the pain can last for weeks.
  • Chronic pain usually lasts 3 to 6 months or longer. Chronic pain can be hard to bear and mentally draining. This can severely limit daily activities.
  • Mixed pain is a combination both of acute and chronic pain.
Other more specific symptoms and complications include:
  • Hand-foot syndrome. When the small blood vessels in hands or feet are blocked, pain and swelling can occur, along with fever. One or both hands and/or feet may be affected at the same time. This may be the first symptom of sickle cell anemia in infants. Pain may be felt in the many bones of the hands and feet. Swelling usually occurs on the back of the hands and feet and moves into the fingers and toes.
  • Eye problems. The retina is a thin layer of tissue at the back of the eye that receives and processes visual images. When the retina does not get enough blood, it can weaken and cause problems. These problems can be serious enough to cause blindness.
  • Infections. Both children and adults with sickle cell anemia have a hard time fighting off infections. The spleen is an organ in your body that helps fight infection. In sickle cell anemia, the spleen can become damaged and unable to do its job. Infants and young children with a damaged spleen are more likely to get infections that can kill them within hours or days. Pneumonia is the most common cause of death in young children with sickle cell anemia. Meningitis, influenza, and hepatitis are also common infections in persons with sickle cell anemia.
  • Acute chest syndrome. This is a life-threatening problem of sickle cell anemia similar to pneumonia. It is caused by infection or by trapped sickle cells in the lung. Patients usually have chest pain, fever, and an abnormal chest x-ray.
  • Delayed growth and puberty in children. Children with sickle cell anemia often grow more slowly and reach puberty later than other children. Adults with sickle cell anemia often have a slight build. The slow rate of growth is caused by a shortage of red blood cells (anemia).
  • Sores (ulcers) on the legs. Sickle cell ulcers usually begin as small, raised, crusting sores on the lower third of the leg. Leg sores occur more often in males than in females and usually appear between ages 10 and 50. The cause of leg ulcers is unclear. There can be just one ulcer or many. Some heal rapidly but others persist for years or come back after healing.
  • Stroke. The sickle-shaped red blood cell may stick to the walls of the tiny blood vessels in the brain. This can cause a stroke. This type of stroke occurs mainly in children. The stroke can cause learning disabilities or more severe problems.
  • Gallstones. Gallstones form in the gallbladder when there is too much bilirubin in the body. Bilirubin is made when red blood cells break down. People with gallstones may have steady pain in the upper right side of the belly, under the right shoulder, or between the shoulder blades that lasts for 30 minutes or more. The pain may occur:
    • After eating fatty meals
    • With nausea, vomiting, fever, sweating, chills, clay-colored stool and yellowish color of the skin or whites of the eyes.
  • Priapism. Males with sickle cell anemia may have painful and unwanted erections called priapism. This happens because the sickle cells stop blood flow out of an erect penis.


How is Sickle Cell Anemia Diagnosed?

Screening tests are done on newborn infants in most States. These tests can show if the newborn infant has sickle cell anemia or carries the sickle cell trait.

Early diagnosis of sickle cell anemia is very important so that children who have sickle cell anemia can get proper treatment.

Forty-four (44) States, the District of Columbia, Puerto Rico, and the Virgin Islands currently screen all newborns for sickle cell anemia. Screening is available by request in the other six (6) States. This screening includes a simple blood test for sickle cell anemia on all newborn infants. This test uses blood from the same blood samples as other routine newborn screening tests.

If the first test shows that the sickle hemoglobin is present, a second blood test is done to confirm the diagnosis. These tests also tell whether the child carries the sickle cell trait.

It is also possible to identify sickle cell anemia before birth. This is done by getting a sample of amniotic fluid or tissue taken from the placenta. This test can be done as early as the first few months of pregnancy.


How is Sickle Cell Anemia Treated?

Although there is no cure (other than bone marrow transplantation) for sickle cell anemia, doctors know a great deal about how to treat it.

People with sickle cell anemia need regular medical care. There are doctors and clinics that specialize in treating people with the disease.

The goal of treatment is to relieve pain, prevent infections, and control complications if they occur. The treatments include:
  • Medications
  • Blood transfusions
  • Specific treatment for complications.
Treatment for Pain

Painful crises are the leading cause of emergency room visits and hospitalizations. The usual treatment for acute pain crises is giving pain-killing medications and increasing fluids. The pain-killing medicines most often used are: The treatment of patients with mild-to-moderate pain usually begins with a NSAIDs or acetaminophen. If pain continues, an opioid may be added. Moderate-to-severe pain is treated with opioids. The opioid may be used alone or together with a NSAIDs or acetaminophen.

In adult patients with severe disease, doctors may give hydroxyurea to reduce the frequency of painful crises. This drug is used only for prevention and not to treat acute pain. Given daily, it reduces the frequency of painful crises and of acute chest syndrome in sickle cell anemia patients. Patients taking the drug may also need fewer blood transfusions. Hydroxyurea must be monitored carefully because it can cause a lowering of the white blood count if the dose is too high. Many questions about its use and effects remain unanswered. Hydroxurea is not the final solution in drug therapy, but it is a promising start. It is not yet approved for use in children.

Preventing Infections

Infection is a major complication of sickle cell anemia. In fact, pneumonia is the leading cause of death in children with the disease. Other infections common in persons with the disease include meningitis, influenza, and hepatitis.

To prevent infections in babies and young children, treatment methods include:
  • Daily doses of penicillin. Treatment may begin as early as 2 months of age and continue until the child is at least 5 years old.
  • Vaccinations for pneumonia, meningitis, influenza, and hepatitis.
Children with sickle cell anemia should have a flu shot each year.

If a child with sickle cell anemia shows early signs of an infection, such as fever, it is very important to get treatment right away.

Adults with sickle cell anemia should also have a flu shot every year. They should also be vaccinated for pneumonia.

Preventing Eye Damage

Since children may develop damage to the blood vessels in the back of their eyes, you should ask your doctor about regular checkups with an eye doctor who specializes in diseases of the retina. The retina is a thin layer of tissue inside the back of the eye.

Blood Transfusions

Blood transfusions are used to treat worsening anemia and sickle cell complications. A sudden fall in the patient's blood count resulting from infection or spleen enlargement is a common reason for a transfusion. Some, but not all, patients need transfusions to prevent life-threatening events such as stroke or pneumonia.

Treating Complications

Most complications of sickle cell anemia are treated as soon as they happen.

Acute chest syndrome is a frequent cause of death in children and adults with sickle cell anemia. Treatment usually requires hospitalization and may include the use of oxygen therapy, transfusions, antibiotics, and pain medication.

Hand-foot syndrome is an early complication seen in sickle cell anemia. It starts at less than 1 year of age. Treatment includes the use of pain medication and fluids.

Leg ulcers may be treated with cleansing solutions and zinc oxide. Skin grafts may be needed if the condition continues. Ulcers on the ankle are painful, and patients may be given strong pain medication. Bed rest and keeping the leg raised to reduce swelling are useful, though not always possible.

Regular Health Care for Children

Children with sickle cell anemia should get regular health care just as children without the disease. They need to have their growth checked and to get the usual shots that all children receive.

Up to age 2, children with sickle cell anemia should see the doctor every 2 or 3 months. After age 2, children should see the doctor at least every 6 months. These visits are good chances for parents to talk with their child's health care provider and ask questions about the child's care.

Penicillin is generally given to all children with sickle cell anemia until age 5.

New Treatments

Today, research studies on sickle cell anemia are looking at new medications, bone marrow transplants, and gene therapy. The hope is that these studies can provide new treatments and find a possible cure for sickle cell anemia. Researchers are also looking at finding a way to predict the severity of the disease.


Living with Sickle Cell Anemia

If you have sickle cell anemia, it is important to take good care of yourself and see your doctor regularly.

Things you need to do to take care of your health include:
  • Maintain a healthy diet. Your doctor may also give you a vitamin (folic acid) every day to help your body make new red blood cells.
  • Drink adequate water every day.
  • Get enough sleep and rest.
  • See your doctor regularly for checkups and treatment.
  • Get a flu shot and other vaccinations to prevent infections.
  • See your dentist regularly to prevent loss of teeth and infections.
  • Educate yourself about your disease and learn what signs of problems to watch out for.
  • Avoid over-exertion, stress, and extremes of heat or cold.
Caring for a child with sickle cell anemia

If your child has sickle cell anemia, you should learn as much about the disease as possible. This will help you recognize early signs of problems, such as fever or chest pain, and seek early treatment. Sickle cell centers and clinics can provide information and counseling to help you handle the stresses of coping with this serious chronic disorder.

Make sure that your child gets daily penicillin up to age 5 to prevent serious infections. Children should also have a flu shot every year and a vaccination against pneumonia. Keep a thermometer on hand and know how to use it. Call a doctor if you child has a temperature above 101 degrees Fahrenheit (38.5 degrees Celsius). Talk to your child's doctor about your child's treatment and the best ways to help keep your child as healthy as possible.

School-aged children should participate in physical education. Teachers should allow children with sickle cell anemia to rest if they tire and to drink fluids after exercise. Children and teenagers may also play competitive sports. Coaches must watch for signs of fatigue and allow the athlete to rest.

Education and job training

If you have sickle cell anemia, it is important that you complete your education. You should not seek jobs that require strenuous work, long work hours, and exposure to extreme temperatures. Getting a good education and advanced job training "opens the door" to the kinds of jobs that are ideal for those who cannot do strenuous work.

Genetic counseling

People who are planning to have children should find out if they have sickle cell trait (carry the sickle cell gene). If both have sickle cell trait, they should get genetic counseling. The counselor can tell what the chances are that their child will have the sickle cell trait or sickle cell anemia. Accurate diagnostic tests and information are available from health departments, neighborhood health centers, medical centers, and clinics that care for people with sickle cell anemia.

With good health care, many people with sickle cell anemia are in reasonably good health much of the time and can live productive lives. People with sickle cell anemia are living longer today than in the past. Many patients with sickle cell anemia now live into their forties and fifties and beyond.


Summary

  • Sickle cell anemia is an inherited blood disease. That means you are born with it and it lasts a lifetime.

  • People with sickle cell anemia inherit two variant or sickle cell genes, one from each parent.

  • In the United States, sickle cell anemia affects about 72,000 people. The families of most of the people affected come from Africa.

  • About 2 million Americans carry the sickle cell trait. About 1 in 12 African Americans have the trait.

  • The signs and symptoms of sickle cell anemia are different in each person. Some people have mild symptoms. Others have very severe symptoms and are often hospitalized for treatment.

  • Painful crises are the leading cause of emergency room visits and hospitalizations.

  • Infection is a major complication of sickle cell anemia. In fact, pneumonia is the leading cause of death in children with the disease.

  • Screening tests are done on newborn infants in most States. These tests can show if the newborn infant has sickle cell anemia or carries the sickle cell trait.

  • Although there is no cure for sickle cell anemia, doctors know a great deal about how to treat it.

  • The goal of treatment is to relieve pain, prevent infections, and control complications if they occur. The treatments include:
    • Medications
    • Blood transfusions
    • Specific treatment for complications.

  • If you have sickle cell anemia, it is important to take good care of yourself and see your doctor regularly.

  • If your child has sickle cell anemia, you should learn as much about the disease as possible. This will help you recognize early signs of problems, such as fever or chest pain, and seek early treatment.


Links
  • Sickle Cell Anemia (MedlinePlus)
  • The Sickle Cell Information Center

Clinical Trials
Additional Vidyya Resources:

© Vidyya.
 
 

  More Today in Vidyya