Thalassemia Patient & Family Handbook

A Handbook for Families

Thalassemia

HEMATOLOGY SERIES

A Handbook for Families

Thalassemia

HEMATOLOGY SERIES

Thalassemia A HANDBOOK FOR FAMILIES

Authors Helene Greenberg, BSN RN Joana Duran, MSN CPNP CNS Beth Savage, MSN RN CNL CPON ® Lori Vertz, MSN RN CNL CPON ®

Content Reviewers 2020 Steering Council

This handbook is published by the Association of Pediatric Hematology/Oncology Nurses (APHON) for educa- tional purposes only. The material has been developed by sources believed to be reliable. The material is not intended to represent the only acceptable or safe treatment of thalassemia. Under certain circumstances or conditions, additional or different treatment may be required. As new research and clinical experience expand the sources of information available concerning the treatment of thalassemia, adjustments in treatment and drug therapy may be required. APHON makes no warranty, guarantee, or other representation, express or implied, concerning the validity or sufficiency of the treatments or related information contained in this handbook. APHON provides this handbook for educational use. Users may copy and distribute this material in unadapted form only, for noncommercial use, and with attribution given to APHON.

n WHAT IS THALASSEMIA? Thalassemia is a group of inherited blood disorders that affect the body’s ability to produce normal hemoglobin. Hemoglobin is a protein in the blood that carries oxygen to the cells in the body. To understand how thalassemia affects the body, it helps to know a little more about blood.

n WHAT IS BLOOD? Blood is a mixture of cells, proteins, and a watery substance called plasma. Blood cells are made in our bone marrow, the sponge-like center in the skull, spine, pelvis, and rib bones. Similar to water being pumped through a hose, the heart pumps blood through small tubes called blood vessels. There are two types of blood vessels: arteries and veins. The arteries carry blood away from the heart and bring oxygen to the body’s tissues. The veins then return the oxygen-poor blood from the tissues back to the heart. Blood carries nutrients to and from the tissues and organs. Blood also helps fight infection and heal wounds. Blood has four major components:

• Red blood cells—Red blood cells pick up the oxygen we breathe in while traveling through the small blood vessels of the lungs. They deliver the oxygen to all the cells in the body’s tissues and organs. The body’s cells use the oxygen and create carbon dioxide, which is a waste product. The red blood cells then pick up the carbon dioxide and deliver it to the lungs, where it is exhaled from the body. • White blood cells—White blood cells are part of the immune system and protect the body from infection. • Platelets—Platelets help stop bleeding by forming a plug after skin or tissue has been injured. • Plasma—Plasma is a yellowish liquid that is mostly water. It helps white blood cells, red blood cells, and platelets to flow freely through the blood vessels. Plasma also carries nutrients, hormones, proteins, and waste products around the body. n WHAT CAUSES THALASSEMIA? Genes are passed along from parents to their children. Genes determine all the traits and characteristics of the body. We have tens of thousands of genes, which are located on 46 chromosomes. These chromosomes work in pairs with half of the pair inherited from the father and half from the mother. These pairs are numbered 1 through 23. Hemoglobin is the protein in red blood cells that carries oxygen. In order for the body to produce hemoglobin normally, we need two types of genes: alpha ( α ) globin and beta ( β ) globin. Normally, a child inherits two alpha globin genes from each parent and one beta globin gene from each parent. The alpha globin genes are divided, two on each half of chromosome 16. There is one beta globin gene on each half of chromosome 11. Thalassemia occurs when one or more of these inherited genes are missing or abnormal. The missing or abnormal genes will decrease the amount of hemoglobin made by the body. When the amount of hemoglobin is low, it is called anemia . The severity of the anemia depends on how many genes are missing or abnormal. Mild anemia may go undetected, but severe anemia can cause a person to be very tired and make activity difficult.

n WHO GETS THALASSEMIA? Most people who have thalassemia are descendants from Africa, Southeast Asia, Southern China, India, Pakistan, the Middle East, Greece, and Italy. More than 2 million Americans carry the thalassemia trait. About 1,000 people are affected by beta thalassemia major, the most severe type of thalassemia.

n WHAT ARE THE TYPES OF THALASSEMIA? There are two main types of thalassemia: alpha thalassemia and beta thalassemia. People who did not inherit four normal alpha globin genes have alpha thalassemia . People who did not inherit two normal beta globin genes have beta thalassemia . Each of these types of thalassemia has different subtypes.

Alpha Thalassemia Subtypes

SILENT CARRIER One of the four alpha globin genes is missing or abnormal. This type of thal- assemia usually does not cause any health problems, and there is no anemia. Patients should be aware that they are carriers of alpha thalassemia because they risk passing it onto their children. Alpha thalassemia may show up on routine blood work or as part of newborn screening. ALPHA THALASSEMIA TRAIT/MILD ALPHA THALASSEMIA Two of the four alpha globin genes are missing or abnormal. This type of thalassemia causes smaller red blood cells and mild anemia.

There may be one abnormal gene on each side of chromosome 16, or both of the abnormal genes can be on the same half of chromosome 16. This is called a cis mutation and is more common in people of Asian descent.

HEMOGLOBIN H DISEASE Three of the four alpha globin genes are missing or abnormal. One of the strands of chromosome 16 will have two abnormal genes, or the cis mutation. The other half will have one normal gene and one abnormal gene. Hemoglobin H disease will cause moderate to severe anemia. There can be serious health problems, such as an enlarged spleen, bone deformities, and fatigue. Because the cis mutation is more common in people of Asian descent, Hemoglobin H also is more common in this group. HYDROPS FETALIS/ALPHA THALASSEMIA MAJOR All four alpha globin genes are missing or defective. Most babies with this type of thalassemia will die shortly before or after birth. If parents are known to carry a cis mutation, testing for hydrops fetalis/alpha thalassemia major may be done before birth. In this case, blood transfusions can be given to the fetus during pregnancy. After birth, the child will then require lifelong blood transfusions and ongoing medical care.

Beta Thalassemia Subtypes

BETA THALASSEMIA MINOR/BETA THALASSEMIA TRAIT One of the two beta globin genes on chromosome 11 is abnormal. A person with beta thalassemia trait may have mild anemia. BETA THALASSEMIA MAJOR/COOLEY’S ANEMIA Both of the two beta globin genes passed from the parents are abnormal. When this happens, very little or no normal hemoglobin is made by the body, causing severe anemia. Blood transfusions are needed to maintain all functions of the body and remain healthy. BETA THALASSEMIA INTERMEDIA This type of thalassemia is inherited like beta thalassemia major. While both beta globin genes are abnormal, they still allow the body to produce some normal hemoglobin. There is moderate to severe anemia. Blood transfusions will likely be needed throughout the child’s lifetime, especially during growth spurts, illness, and pregnancy.

n WHAT ARE THE COMPLICATIONS OF THALASSEMIA?

ANEMIA The abnormal genes characterized by thalassemia cause anemia, or decreased hemoglobin, that ranges from very mild to severe. Mild anemia may cause a child to be pale. Severe anemia can cause a child to tire easily, grow slowly, and may affect the function of the heart. For children living with hemoglobin H disease, beta thalas- semia major, and, sometimes, beta thalassemia intermedia, red blood cell transfusions will be needed to keep them healthy. The frequency of red blood cell transfusions depends on the degree of anemia and how well your child is growing. BONE DEFORMITIES Blood is made in the bone marrow of the body’s large bones. In thalassemia, the bone marrow works very hard to fix the anemia, causing the bone marrow to expand inside the large bones. As a result, the bones widen and deformities can develop, especially in the face and skull. The bones can also weaken and easily fracture. The way to prevent these bone changes is to correct the anemia with red blood cell transfusions. SPLENOMEGALY (ENLARGED SPLEEN) The spleen is an organ in the abdomen under the left side of the ribs that is usually the size of a fist. The spleen acts as a filter by breaking down and removing old and abnormally shaped red blood cells, such as those caused by thalassemia. Although it does not usually make blood cells, the spleen will try to help out if anemia is severe enough. This can happen when a child with thalassemia is not receiving enough blood through transfusions. When the spleen starts to make blood it can become bigger. The spleen also begins breaking red blood cells down faster, even the ones from transfusions. This condition is known as hypersplenism. Increasing transfusions may correct hypersplenism. Sometimes it cannot be corrected. A splenectomy , which is the surgical removal of the spleen, may be needed to treat the hypersplenism. The spleen helps protect the body from infection by making lymphocytes , special infection-fighting white blood cells. As a filter, the spleen also catches bacteria that invade the blood so they can be destroyed. Without a spleen, bacteria will flow through the bloodstream and can cause a serious infection in a very short period of

time. Fever is the first sign of infection. Because of this, fever is a lifelong medical emergency for people who have had their spleen surgically removed (splenectomy). If your child develops a fever after having a splenec- tomy, contact your child’s healthcare provider immediately. TRANSFUSION REACTIONS The immune system’s function is to fight off what it thinks is foreign. Although uncommon, transfusion reactions can happen when the body’s immune system considers the transfused blood to be foreign. These reactions are often mild, causing a rise in body temperature or hives. The reaction can be very severe, causing trouble breath- ing, a drop in blood pressure, and bleeding. A rare but serious reaction that can occur is a delayed transfusion reaction. The symptoms of this include back pain, jaundice (yellowing of the skin and eyes), and dark urine. A delayed transfusion reaction may occur 2 days to 2 weeks after transfusion. IRON OVERLOAD Iron overload occurs when too much iron accumulates in the body. Blood transfusions contain iron. With each blood transfusion, extra iron is added to the body. The extra iron is stored in the body’s organs, where it can cause damage to the tissue. Many of the complications of thalassemia are a result of the organ damage resulting from iron overload. The impact of this damage will be discussed in upcoming sections.

ENDOCRINE SYSTEM PROBLEMS The endocrine system includes special organs called glands. Glands produce hormones that are needed for different func- tions of the body, including growth and puberty. The endocrine system is very sensitive to the effects of iron overload. Chronic anemia and iron overload may lead to slow growth rates, and children with thalassemia major rarely reach normal adult height. Puberty may also be delayed in children with thalas- semia.

Damage from iron deposits can affect the pancreas, an organ of the endocrine system that releases the hormone insulin. Insulin manages the glucose, or sugar, in the body. Diabetes can develop when the pancreas is damaged from iron over- load. Diabetes results in the body being unable to produce insulin and manage glucose. Hormones released by organs of the endocrine system help form and maintain healthy bones. Along with bone marrow expansion, damage to these organs can lead to weakened bones. HEART PROBLEMS Many patients with thalassemia have heart-related problems that result from both the anemia and iron overload. Anemia causes the blood to have less oxygen, and the heart then has to work harder, which can lead to an en- larged heart. Iron overload can cause iron deposits in the heart that result in arrhythmias (abnormal heartbeats) and congestive heart failure (a decreased ability of the heart to pump blood). Pulmonary hypertension is a rare condition in which there is a gradual narrowing of the blood vessels in the lungs and those carrying blood from the heart to the lungs. This condition may occur in people with thalassemia as a result of chronic anemia and abnormal red blood cells. Pulmonary hypertension is more concerning in children with very low hemoglobin, especially if a splenectomy was done.

LIVER PROBLEMS The liver is an organ in the abdomen that filters waste from the body. Iron overload in the liver can lead to scarring called fibrosis . If the liver becomes very scarred, cirrhosis can occur. Cirrhosis is a serious complication because the liver cannot remove wastes properly. Other serious problems include liver infections from viruses such as hepatitis A, B, or C (hepatitis B and C also can cause cirrhosis). In the past, the spread of viruses through blood transfusions was a serious concern. Now there are many steps in place to prevent this, such as regular testing of blood products for these viruses. It is rec- ommended that patients with thalassemia be vaccinated for hepatitis A and B. There is no vaccine for hepatitis C. Your child’s healthcare team will test for these viruses regularly. PREGNANCY It is common for thalassemia and its complications to become more severe during pregnancy. There are risks to the developing baby as well. Young women who are pregnant must be closely monitored by both a specialist in high-risk pregnancy and a hematologist. n WHAT TYPES OF TESTS AND PROCEDURES WILL MY CHILD NEED? BLOOD TESTS Regular blood tests are needed to monitor the effects and complications of thalassemia and your child’s re- sponse to treatment. Blood tests involve a needle being inserted into a vein so a blood sample can be collected. Common blood tests for children with thalassemia include the following: • Hemoglobin electrophoresis—diagnoses thalassemia. This test measures the different types of hemo- globin made in the body. • Gene analysis—determines which globin genes are missing or damaged. There is a test for both alpha and beta globin genes. • Complete blood count (CBC)—determines the number of white blood cells (infection-fighting cells) and platelets (clot-forming cells) and the level of hemoglobin (degree of anemia) in your child’s body. A reticulocyte count, which measures the rate at which the body is producing new red blood cells, is often done with a CBC. • Chemistry panel—checks that your child’s body has the correct amount of certain important substances, such as electrolytes, protein, and sugar. It also checks the liver and kidney function and nutritional status. • Ferritin level—measures the level of iron in your child’s body and is a screening test for iron overload.

• Blood type and antibody screen—helps identify the correct donor blood for your child. This is done each time your child needs a blood transfusion. • Hepatitis panel—tests for hepatitis A, B, and C viruses. • Blood tests to measure thyroid function, cortisol levels, glucose levels, insulin levels, and sex hormones such as testosterone and estrogen—monitor the health of your child’s endocrine system.

RADIOLOGY TESTS Radiology tests are used to detect changes that may indicate a future problem, diagnose a complication, or monitor a response to a treatment plan. The following are examples of radiology tests: • X ray—takes pictures of the inside of the body to diagnose problems and is the most commonly used radiology test. A wrist X ray is often done to monitor bone growth. • Magnetic resonance imaging (MRI)—uses a magnetic field and radio waves to produce exact images of what soft tissues, bones, and organs look like. For the test, your child will lie on a table that will then move into a tubelike machine, which surrounds your child with a magnetic field. The test is painless, but the machine makes a loud banging noise that may be scary for some children. Children must be able to lie completely still during the scan, and some may require sedation to help them lie still. • T2* MRI—a special type of noninvasive MRI that measures iron content in the heart. • FerriScan MRI—a special type of MRI that measures the iron content in the liver. • Bone density test—a test that uses X rays to determine how much calcium and other bone minerals are present in areas of the bone such as the hip, forearm, or wrist. The density of the bone is compared to the average values based on sex, age, and size and helps determine if your child has strong bones or osteoporosis, a condition that causes weak, fragile bones that are likely to break.

OTHER TESTS • Electrocardiogram (ECG)—measures and records the electrical activity of the heart and diagnoses a range of heart problems. • Echocardiography (ECHO)—uses sound waves or ultrasound to look at the structure of the heart and how the blood flows through it. • 24-hour Holter monitor—diagnoses arrhythmias (irregular heartbeats). It is a noninvasive test that is usually used for children older than age 12. • Liver biopsy—removes a small piece of the liver and examines it for iron overload, scarring, and other problems.

n HOW IS THALASSEMIA TREATED?

BLOOD TRANSFUSIONS Your healthcare team will determine when and how often your child will

need a red blood cell transfusion. The healthy red blood cells that are being transfused have the hemoglobin needed to carry oxygen that is essential to the body. The goals of transfusions are to minimize bone marrow expansion, avoid hypersplenism, and promote normal growth and development. Transfusions are given through a vein during a 2–4-hour period. Patients with thalassemia major will depend on blood transfusions, which are usually given every 2–4 weeks. Patients with thalassemia intermedia or hemoglobin H disease may need blood transfusions only during times of stress, such as growth spurts, illness, surgery, or pregnancy. IRON CHELATORS An iron chelator is a medication that attaches to extra iron in the body and removes it. Currently, there are three chelators widely available: Deferoxamine (Desferal ® ), which is given by needle under the skin or into a vein, and Deferasirox (Exjade ® and Jadenu ® ) and Deferiprone (Ferriprox ® ), which are given by mouth. Your child’s healthcare provider will decide which chelator is the best option.

PENICILLIN (FOR PATIENTS TREATED WITH SPLENECTOMY) Infection is a serious medical emergency for children who have had a splenectomy. Children who undergo a sple- nectomy are treated with penicillin to prevent infection. Your child’s healthcare provider will determine how long penicillin is needed following the splenectomy. Fever is a sign of infection and should be addressed immediately by calling your child’s healthcare provider and going to the nearest emergency room.

FOLIC ACID Folic acid is a vitamin needed by the body to make blood. Your child’s health- care provider may prescribe folic acid daily. IMMUNIZATIONS Your child should receive all routine childhood vaccinations, including the 23-valent pneumococcal vaccine (Pneumovax ® ) and the meningococcal vaccine (Menactra ® ), in the event of a splenectomy. It is recommended that all thalassemia patients receive the hepatitis A vaccine as well as an annual influenza (flu) vaccine.

BONE MARROW TRANSPLANT At this time, bone marrow transplant is the only cure for thalassemia. Bone mar-

row transplant is, for the most part, only available to people who have a tissue-matched donor. Most often this donor is a sibling who does not have thalassemia. Before a bone marrow transplant, your child will be given chemotherapy and, possibly, radiation to destroy his or her own bone marrow. Then, he or she will receive an infusion of the donor’s bone marrow or stem cells. In the weeks to months following the transplant, the donor cells should take over and produce blood cells that are unaffected by thalassemia. Transplant has risks that may include serious infection, bleeding, and organ damage from the chemotherapy and radiation. Graft-versus-host disease, in which the donor’s new marrow begins to attack the patient’s body cells, may also develop. Finally, the bone marrow may not replace the patient’s marrow. This is called graft failure.

n HOW CAN I HELP MY CHILD STAY WELL?

COMPREHENSIVE CARE Newborn screenings are blood tests done on babies in the days after birth that look for a number of inherited diseases. Newborn screening enables children to be referred shortly after birth to centers where care is delivered by a team approach. This team includes experienced hematologists, nurse practitioners, physician assistants, nurses, nutritionists, and social workers who will address all aspects of care. It is important for your child to see his or her healthcare team on a regular basis, even if he or she is doing well. The healthcare team will provide the education you need to care for your child in the best way. Also, routine screening and testing done during these visits is needed for the prevention and early detection of long-term chronic complications. Organ damage from iron overload is of great concern to the healthcare team. It is important to ensure that your child takes his or her chelator exactly as prescribed by the healthcare provider.

HEALTH MAINTENANCE Your child will continue to be monitored by his or her primary care doctor for all routine care, including immuni- zations, checkups, and minor illnesses or injuries that are unrelated to thalassemia.

n HOW CAN I WORK WITH THE HEALTHCARE TEAM? The care of your child requires a team approach. You are a key player on your child’s healthcare team. You know your child better than anyone else, and your input is important. Other members of your child’s healthcare team include doctors, nurses, and social workers. Always speak openly with the other members of your child’s healthcare team. Ask questions whenever there are things you are not sure about. It may help to write down your questions as you think of them. This can help you remember all of your questions when meeting with the healthcare team.

Important questions you may want to ask include the following: • What type of thalassemia does my child have, and what does that mean? • What treatment choices are available? • What treatment do you recommend and why? • What are the risks or side effects during the treatment? • What are the risks and side effects following the treatment? • What is my child’s life expectancy?

n ARE MY FEELINGS NORMAL, AND WHAT CAN I DO ABOUT THEM?

Learning that your child has thalassemia is shocking and overwhelming. Many parents say, “I didn’t remember anything after the words ‘your child has thalassemia.’” Parents often feel numb and have a hard time believing the diagnosis. This is especially true when there is no family history of thalassemia. It is important to know that this is normal and expected. Thalassemia is complicated. Most families have difficulty processing all of the information the healthcare team is providing to them in the beginning. However, with time, the information will be absorbed. Many families feel they are responsible somehow for their child’s disease. Guilt is common with any genetic disease. Feelings of sadness, anger, and helplessness about your child’s diagnosis also are common. These feel- ings are normal. Each member of the family may express these emotions in different ways and at different times. Talking honestly with each other about these feelings, emotions, and reactions will help everyone in the family. Keep in mind there is no right or wrong way to feel. Family members need the chance to express their feelings in their own way when they are ready. Talking to friends, family, and healthcare team members can be difficult at times; however, expressing your feelings can help you cope. Your child will benefit from family and friends who show their care through communication and support.

n HOW CAN I HELP MY CHILD? Children often think that something they did caused their thalassemia. Reinforce that this is not the case. Make sure your child understands that your feelings of anger and sadness are directed at the thalassemia and not at him or her. This will help to keep your relationship honest and maintain closeness. Your child will need to share his or her feelings with someone that he or she trusts. Sometimes, children choose to share feelings with some- one other than a parent because they are afraid they might upset their parent. Don’t be afraid to ask your child about his or her feelings. It may be what your child wants. Also, don’t be afraid to share information about what is happening, and why, with your child. The things children imagine on their own are sometimes more frighten- ing than what is actually happening.

In spite of your child’s condition, keep in mind that he or she is still a child. All children need love, attention, and the opportunity to learn and try new skills. Keep in mind that he or she still has all the needs of a growing child. Do not avoid talking to your child about thalassemia and its treatment, but use words your child will understand. Children tolerate treatment better if they understand it and are allowed to help make decisions about their care when appropriate. As a parent, it is difficult to watch your child undergo medical pro- cedures and treatment. Your feelings about what your child is going through must be balanced with the knowledge that treatment allows your child to live a full and meaningful life.

n IS MY CHILD’S DIET IMPORTANT DURING THERAPY? Yes. Your child should eat a well-balanced diet that has the number of healthy calories advised for his or her age; this sometimes includes a daily folic acid supplement, if prescribed. At each visit with your hematology team, your child will be weighed and measured. Your child will need nutritional support if he or she is not growing or gaining weight. It is also important to maintain a healthy weight because obesity can add stress to the joints and heart and lead to conditions such as high blood pressure and diabetes. A dietician is also a part of your child’s healthcare team. He or she is trained in the caloric and nutritional needs of children. The dietician can provide you with education regarding your child’s dietary needs as well as ideas about how you can meet these needs during treatment. When there is a concern about nutritional problems, your child’s healthcare team will get involved. Because of the risk of iron overload, you may be advised to limit the amount of iron-rich foods your child eats. Multivitamins, herbs, and certain over-the-counter drugs should be avoided unless approved by your child’s healthcare team, because many include extra iron. Please ask your healthcare provider if you are considering any of these types of therapy.

n CAN MY CHILD ATTEND SCHOOL? School is an important part of every child’s life. In addition to learning about reading, writing, and math, children also learn how to get along with others. Living life in ways that are similar to their siblings and peers also gives

children an important feeling of being included in the “regular” world. This helps children feel safe. Children who feel included and safe in their community grow up comfortable asking for help and wanting to contribute to their community. You can help your child be a part of activities that help with self-esteem and self-reliance. Your child’s hematolo- gist may recommend limiting some types of activities. You can explore alternatives that will give your child opportunities to develop skills and talents outside of the classroom. At the start of the school year, meet with your child’s teacher, principal, and school nurse. Beginning with preschool and kindergarten, make sure that school personnel are educated about your child’s thalassemia. Consider giving them educational materials provided by your hematology team. Nurses and social workers from the team can call or visit your child’s school to help educate your child’s teachers.

Although children with thalassemia may miss some school due to doctor visits and periods of not feeling well, it is to their benefit to attend school as much as possible. Each child is unique, and there may be other ways the educational plan can be designed to help your child. Your child may need tutoring to help catch up after missing school because of treat- ments. Ask the school and your healthcare team if there are tutoring programs at school or at the hospital. Aim for your child to be healthy, happy, and successful, and work with your child’s healthcare team to provide the kinds of support your child deserves.

PROGNOSIS STATEMENT Prognosis is a word that doctors use to describe what they believe the outcome will be for a patient, including the chances of recovery. Your child’s cancer prognosis is as unique as he or she is. There are many factors that affect survival outcomes. A child’s age at diagnosis, the extent of disease, genetic factors, infections, nutrition, delays in the timing of treatment, and how well your child’s body can tolerate chemotherapy and radiation all play an important role in the child’s long-term outcome. Because general statements about survival rates are just numbers, please talk to your medical team about your child’s individual prognosis and plan of care. SUGGESTED READING Butler C., et al. (2011). Cooley’s Anemia Foundation: About Thalassemia . https://www.thalassemia.org Mayo Clinic Staff. (2012). Thalassemia. http://www.mayoclinic.org/diseases-conditions/thalassemia/home/ovc- 20261825 National Institutes of Health, National Heart, Lung, and Blood Institute. (2010). Explore Thalassemias . Washing- ton, DC: U.S. Department of Health and Human Services. https://www.nhlbi.nih.gov/health/health-topics/topics/ thalassemia

IMPORTANT PHONE NUMBERS

NOTES

8735 W. Higgins Road, Suite 300 Chicago, IL 60631 847.375.4724 • Fax 847.375.6478

info@aphon.org www.aphon.org

Manual para la Familia

Talasemia

SERIE DE HEMATOLOGÍA

Manual para la Familia

Talasemia

SERIE DE HEMATOLOGÍA

Talasemia MANUAL PARA LA FAMILIA

Autores Helene Greenberg, BSN RN Joana Duran, MSN CPNP CNS Beth Savage, MSN RN CNL CPON ® Lori Vertz, MSN RN CNL CPON ®

Revisor del contenido Steering Council

Este manual ha sido publicado por Association of Pediatric Hematology/Oncology Nurses (APHON) con fines educativos únicamente. El contenido ha sido desarrollado por fuentes confiables y no pretende ser el único tratamiento aceptable o seguro para la talasemia. Es posible que a medida que nuevas investigaciones y expe- riencias clínicas amplíen las fuentes de información sobre el tratamiento de la talasemia, sea necesario hacer ajustes en el tratamiento y la terapia con fármacos. APHON no garantiza ni asegura ninguna representación, expresa o implícita, con respecto a la validez o suficien- cia de los tratamientos o a la información relacionada contenida en este manual. APHON le otorga al comprador de este manual, o a su institución, permiso absoluto para fotocopiarlo o imprimirlo con fines educativos. El comprador no podrá alterar el contenido ni lucrar con la distribución de las fotocopias de este producto.

n ¿QUÉ ES LA TALASEMIA? La talasemia es un grupo de trastornos sanguíneos hereditarios que afectan la capacidad del cuerpo para pro- ducir hemoglobina normal. La hemoglobina es una proteína de la sangre que transporta oxígeno a las células del cuerpo. Para entender cómo la talasemia afecta al cuerpo, es bueno saber un poco más sobre la sangre.

n ¿QUÉ ES LA SANGRE? La sangre es una mezcla de células, proteínas y una sustancia acuosa lla- mada plasma. Las células de la sangre se producen en nuestra médula ósea, que es un tejido parecido a una esponja que se encuentra en el cráneo, la columna vertebral, la pelvis y los huesos de las costillas. Al igual que el agua que se bombea a través de una manguera, el corazón bombea la sangre a través de pequeños tubos llamados vasos sanguíneos. Hay dos tipos de vasos sanguíneos: arterias y venas. Las arterias llevan la sangre del corazón a los tejidos del cuerpo, llevándoles oxígeno. Las venas devuelven la sangre pobre en oxígeno de los tejidos hacia el corazón. La sangre transporta nutri- entes hacia y desde los tejidos y órganos y ayuda a combatir las infecciones y a curar las heridas. La sangre tiene cuatro componentes principales:

• Glóbulos rojos—Los glóbulos rojos capturan el oxígeno que respiramos mientras viajan a través de los pequeños vasos sanguíneos de los pulmones. Llevan el oxígeno a todas las células de los tejidos y órganos del cuerpo. Las células del cuerpo utilizan el oxígeno y producen dióxido de carbono, que es un prducto de desecho. Los glóbulos rojos luego recogen el dióxido de carbono y lo llevan a los pulmones, desde donde es expulsado del cuerpo. • Glóbulos blancos—Los glóbulos blancos forman parte del sistema inmunológico y protegen al cuerpo de las infecciones. • Plaquetas—Las plaquetas ayudan a detener el sangrado formando un tapón cuando la piel o el tejido se ha lesionado. • Plasma—El plasma es un líquido amarillento constituido principalmente por agua. Ayuda a los glóbulos blancos, glóbulos rojos y plaquetas a fluir libremente a través de los vasos sanguíneos. El plasma tam- bién transporta nutrientes, hormonas, proteínas y productos de desecho alrededor del cuerpo. n ¿QUÉ CAUSA LA TALASEMIA? Los genes se trasmiten de padres a hijos y determinan todos los rasgos y características del cuerpo. Tenemos decenas de miles de genes que se encuentran en 46 cromosomas. Estos cromosomas trabajan en pares, la mitad se hereda del padre y la otra mitad de la madre. Estos pares están numerados del 1 al 23. La hemoglobina es la proteína de los glóbulos rojos que transporta oxígeno. Para que el cuerpo produzca hemoglobina normalmente necesitamos dos tipos de genes: globina alfa (α) y globina beta (β). Normalmente, un niño hereda dos genes de globina alfa de cada uno de los padres y un gen de globina beta de cada no de los padres. Los genes de globina alfa están divididos y repartidos, dos en cada una de las mitades del cromosoma 16. Hay un gen de globina beta en cada una de las mitades del cromosoma 11. La talasemia ocurre cuando uno o más de estos genes heredados falta o es anormal. Los genes faltantes o anormales disminuirán la cantidad de hemoglobina producida por el cuerpo.

Cuando la cantidad de hemoglobina es baja, se llama anemia . La gravedad de la anemia depende de cuántos genes faltan o son anormales. La anemia leve puede pasar inadvertida, pero la anemia grave puede hacer que una persona se sienta muy cansada y que tenga dificultad para realizar actividades.

n ¿QUIÉN PUEDE PADECER TALASEMIA? La mayoría de las personas que padecen talasemia son descendientes de personas provenientes de África, el sudeste de Asia, el sur de China, la India, Pakistán, Oriente Medio, Grecia e Italia. Más de 2 millones de estadounidenses tienen riesgo de padecer talasemia. Alrededor de 1000 personas se ven afectadas por la beta- talasemia mayor, que es el tipo más grave de talasemia.

n ¿QUÉ TIPOS DE TALASEMIA HAY? Hay dos tipos principales de talasemia: alfa-talasemia y beta-talasemia. Las personas que no heredaron cuatro genes normales de globina alfa tienen alfa-talasemia . Las personas que no heredaron dos genes normales de globina beta tienen beta-talasemia . Cada uno de estos tipos de talasemia tiene diferentes subtipos.

Subtipos de Alfa-Talasemia

PORTADOR SILENCIOSO Uno de los cuatro genes de globina alfa falta o es anormal. Generalmente este tipo de talasemia no causa ningún problema de salud, y no hay anemia. Los pacientes deben de saber que son portadores de alfa-talasemia porque tienen el riesgo de transmitirla a sus hijos. La alfa-talasemia puede detectarse durante un examen de sangre de rutina o durante los exámenes neonatales. CARACTERISTICAS DE LA ALFA-TALASEMIA/ALFA-TALASEMIA LEVE Dos de los cuatro genes de globina alfa faltan o son anormales. Este tipo de talasemia provoca que los glóbulos rojos sean más pequeños y causa anemia leve.

Puede haber un gen anormal en cada uno de los lados del cromosoma 16, o es posible que ambos genes anor- males estén en la misma mitad del cromosoma 16. A esto se le llama mutación cis y es más común en personas de ascendencia asiática. ENFERMEDAD DE LA HEMOGLOBINA H Tres de los cuatro genes de globina alfa faltan o son anormales. Una de las hebras del cromosoma 16 tendrá dos genes anormales o la mutación cis. La otra mitad tendrá un gen normal y un gen anormal. La enfermedad de la hemoglobina H causa una anemia de moderada a severa. Esta enfermedad puede provocar serios problemas de salud, como un bazo agrandado, deformaciones óseas y fatiga. Debido a que la mutación cis es más común en personas de ascendencia asiática, la hemoglobina H también es más común en este grupo de personas. HIDROPESÍA FETAL / ALFA-TALASEMIA MAYOR Los cuatro genes de globina alfa faltan o son anormales. La mayoría de los bebés con este tipo de talasemia mueren poco antes o después del nacimiento. Si se sabe que los padres son portadores de una mutación cis , se

pueden realizer pruebas para detectar la hidropesía fetal / alfa talasemia mayor antes del nacimiento. En ese caso, el feto podrá recibir transfusiones de sangre durante el embarazo. Después del nacimiento, la criatura necesitará transfusiones de sangre a lo largo de toda su vida y atención médica continua.

Subtipos de Beta-Talasemia

BETA-TALASEMIA MENOR / RASGO BETA-TALASÉMICO Uno de los dos genes de la globina beta en el cromosoma 11 es anormal. Una persona con rasgo beta-talasémico puede tener anemia leve. BETA-TALASEMIA MAYOR / ANEMIA DE COOLEY Ambos genes de la globina beta heredados de los padres son anormales. Cuando esto sucede, el cuerpo produce muy poca o nada de hemoglobina normal, lo que causa una anemia severa. Las transfusiones de sangre son nece- sarias para que la persona permanezca sana y su cuerpo mantenga todas sus funciones. BETA TALASEMIA INTERMEDIA Al igual que la beta-talasemia mayor, la beta-talasemia intermedia se hereda. En este caso, ambos genes de la globina beta son anormales pero todavía permiten que el cuerpo produzca algo de hemoglobina normal. La anemia va de moderada a grave y es probable que el niño necesite transfusiones de sangre durante toda su vida, especialmente durante el periodo de crecimiento, las enfermedades y los embarazos.

n ¿CUÁLES SON LAS COMPLICACIONES DE LA TALASEMIA?

ANEMIA Los genes anormales característicos de la talasemia causan anemia, o disminución de la hemoglobina, que va de muy leve a grave. La anemia leve puede hacer que el niño se vea pálido. La anemia severa puede hacer que se canse fácilmente, crezca lentamente y también puede afectar el funcionamiento del corazón. Los niños que viven con hemoglobina H, con beta-talasemia mayor y, a veces, con beta-talasemia intermedia, necesitarán reci- bir transfusiones de glóbulos rojos para mantenerse sanos. La frecuencia de las transfusiones de glóbulos rojos depende del grado de la anemia y de lo bien que esté creciendo tu hijo(a). DEFORMACIONES ÓSEAS La sangre se produce en la médula ósea de los huesos largos del cuerpo. En la talasemia, la médula ósea trabaja muy duro para corregir la anemia, haciendo que la médula ósea se expanda dentro de los huesos largos. Como resultado, los huesos se ensanchan y se pueden desarrollar deformaciones, especialmente en la cara y el cráneo. Los huesos también pueden debilitarse y fracturarse fácilmente. Para prevenir estos cambios óseos es necesario corregir la anemia mediante transfusiones de glóbulos rojos. ESPLENOMEGALIA (BAZO AGRANDADO) El bazo es un órgano que se encuentra en el lado izquierdo del abdomen, debajo de las costillas y generalmente es del tamaño de un puño. El bazo actúa como un filtro destruyendo y eliminando los glóbulos rojos viejos y con formas anormales, como los causados por la talasemia. Aunque generalmente no produce células sanguíneas, si la anemia es lo suficientemente grave el bazo tratará de ayudar al cuerpo; esto puede ocurrir cuando un niño con talasemia no está recibiendo suficiente sangre a través de transfusiones. Cuando el bazo comienza a producir

sangre puede crecer mucho y empezar a destruir los glóbulos rojos más rapidamente, incluso los de las trans- fusiones. Esta condición se conoce como hiperesplenismo y se puede corregir aumentando las transfusiones; si esto no fuera posible, será necesario realizar una esplenectomía , que es la extirpación quirúrgica del bazo. El bazo ayuda a proteger el cuerpo de las infecciones produciendo linfocitos , que son los glóbulos blancos especializados en luchar en contra de las infecciones. También captura las bacterias que invaden la sangre para que puedan ser destruidas, actuando como un filtro. Sin el bazo, las bacterias circulan por el torrente sanguíneo causando una infección grave en un período muy corto de tiempo. La fiebre es el primer signo de infección, por lo que es una señal de emergencia de por vida para las personas a las que se les ha extirpado el bazo quirúrgica- mente (esplenectomía). Si tu hijo(a) tiene fiebre después de una esplenectomía, comunícate de inmediato con su médico. REACCIONES A LA TRANSFUSIÓN La función del sistema inmunológico es luchar contra lo que piensa que es extraño al cuerpo. Aunque las reac- ciones ante una transfusión son poco comunes, pueden ocurrir cuando el sistema inmunológico del cuerpo considera que la sangre transfundida es extraña. A menudo estas reacciones son leves, causando un aumento de la temperatura corporal o urticaria. Si la reacción es muy severa, puede provocar dificultades para respirar, la caída de la presión arterial y sangrado. Una reacción rara pero grave que puede ocurrir es una reacción retardada a la transfusión. Los síntomas de ésta incluyen dolor de espalda, ictericia (color amarillento de la piel y los ojos) y orina oscura. Una reacción retardada a la transfusión puede ocurrir de 2 días a 2 semanas después de la trans- fusión. SOBRECARGA DE HIERRO La sobrecarga de hierro ocurre cuando se acumula demasiado hierro en el organismo. Las transfusiones de san- gre contienen hierro por lo que con cada transfusión de sangre, se añade hierro extra al cuerpo. El hierro extra se almacena en los órganos del cuerpo, donde puede causar daños al tejido. Muchas de las complicaciones de la talasemia son el resultado del daño que sufren los órganos debido a la sobrecarga de hierro. En las siguientes secciones se hablará sobre el impacto de este daño.

PROBLEMAS DEL SISTEMA ENDOCRINO El sistema endocrino está formado por órganos especiales llamados glándulas. Las glándulas producen hormonas que son necesarias para diferentes funciones del cuerpo, incluyendo el crecimiento y la pubertad. El sistema endocrino es muy sen- sible a los efectos de la sobrecarga de hierro. La anemia crónica y la sobrecarga de hierro pueden provocar tasas de crecimiento lentas, por lo que los niños con talasemia mayor rara vez alcanzan la estatura normal de un adulto. La pubertad también puede retrasarse en niños con talasemia.

El daño provocado por los depósitos de hierro puede afectar al páncreas, que es el órgano del sistema endocrino que libera la hormona insulina. La insulina controla la glucosa, o azúcar, en el cuerpo. La diabetes puede desar- rollarse cuando el páncreas se daña por sobrecarga de hierro haciendo que el organismo no produzca insulina y no controle la glucosa. Las hormonas liberadas por los órganos del sistema endocrino ayudan a formar y a mantener los huesos sanos. Además de la expansión de la médula ósea, el daño a estos órganos puede hacer que los huesos de debiliten.

PROBLEMAS CARDIACOS Muchos pacientes con talasemia tienen problemas cardíacos provocados tanto por la anemia como por la so- brecarga de hierro. La anemia hace que la sangre tenga menos oxígeno, por lo que el corazón tiene que trabajar más, ocasionando un corazón agrandado. La sobrecarga de hierro puede producir depósitos de hierro en el corazón lo que provoca arritmias (latidos cardíacos anormales) e insuficiencia cardíaca congestiva (disminución de la capacidad del corazón para bombear sangre). La hipertensión pulmonar es una condición poco común en la que tanto los vasos sanguíneos de los pulmones como aquellos que llevan sangre desde el corazón a los pulmones se estrechan gradualmente. Esta condición puede ocurrir en las personas con talasemia a consecuencia de una anemia crónica y glóbulos rojos anormales. La hipertensión pulmonar es más preocupante en los niños que tienen hemoglobina muy baja, especialmente si han sido sometidos a una esplenectomía. PROBLEMAS HEPÁTICOS El hígado se encuentra en el abdomen y es un órgano que filtra los residuos del cuerpo. La sobrecarga de hierro en el hígado puede causar cicatrices llamadas fibrosis. Si el hígado tiene muchas cicatrices fibrosas puede desarrollar una cirrosis. La cirrosis es una complicación grave que impide que el hígado elimine los desechos de manera correcta. Otros problemas graves incluyen infecciones hepáticas por virus, como la hepatitis A, B o C (las hepatitis B y C también pueden causar cirrosis). En el pasado, la propagación de virus a través de transfusiones de sangre era una preocupación seria, pero ahora hay muchas maneras de evitar esto, como el uso de pruebas regulares de productos sanguíneos para estos virus. Se recomienda que los pacientes con talasemia se vacunen contra la hepatitis A y B; para la hepatitis C no existe vacuna. El equipo de atención médica de tu hijo(a) realizará pruebas regularmente para monitorear la presencia de estos virus. EMBARAZO Es común que durante el embarazo tanto la talasemia como sus complicaciones se vuelvan más severas. Tam- bién el bebé en desarrollo corre riesgos. Las mujeres jóvenes que están embarazadas deben ser monitoreadas muy de cerca por un especialista en embarazos de alto riesgo y un hematólogo. n ¿QUÉ TIPO DE PRUEBAS Y PROCEDIMIENTOS NECESITARÁ MI HIJO(A)? ANÁLISIS DE SANGRE Los análisis de sangre regulares son necesarios para monitorear los efectos y las complicaciones de la talasemia así como la respuesta de tu hijo(a) al tratamiento. Las pruebas de sangre implican que una aguja sea insertada en una vena para que se pueda recoger una muestra de sangre. Los análisis de sangre habituales para los niños con talasemia incluyen los siguientes: • Electroforesis de la hemoglobina—diagnostica la talasemia. Esta prueba mide los diferentes tipos de hemoglobina producida en el cuerpo. • Análisis genético—determina qué genes de globina están ausentes o dañados. Existe una prueba para los genes de globina alfa y beta. • Conteo sanguíneo completo (CBC)—determina el número de glóbulos blancos (células que combaten

las infecciones), de plaquetas (células que forman coágulos) y el nivel de hemoglobina (grado de anemia) que existe en el cuerpo de tu hijo(a). El conteo de reticulocitos, que mide la velocidad a la que el cuerpo está produciendo nuevos glóbu- los rojos, a menudo se hace con un CBC.

• Panel de química—comprueba que el cuerpo de tu hijo(a) tenga la cantidad correcta de ciertas sustancias importantes, como electrolitos, proteínas y azúcar. También comprueba la función hepática y renal y el estado nutricional. • Nivel de ferritina—mide el nivel de hierro en el cuerpo de tu hijo(a) y detecta la sobrecarga de hierro. • Tipo de sangre y evaluación de anticuerpos—ayuda a identificar la sangre correcta para tu hijo(a). Esto se hace cada vez que tu hijo(a) necesita una transfusión de sangre. • Pruebas de hepatitis para los virus de la hepatitis A, B y C. • Análisis de sangre que miden la función tiroidea, los niveles de cortisol, los niveles de glucosa, los nive- les de insulina y las hormonas sexuales, así como la testosterona y el estrógeno, monitorean la salud del sistema endocrino de tu hijo(a). PRUEBAS DE RADIOLOGÍA Las pruebas de radiología se utilizan para detectar cambios que pueden indicar un problema futuro, diagnosticar una complicación o supervisar una respuesta a un plan de tratamiento. Los siguientes son ejemplos de pruebas de radiología:

• Rayos X—toman imágenes del interior del cuerpo para diagnosticar problemas y es la prueba radiológica más comúnmente utilizada. A menudo se realiza una radiografía de las muñecas para controlar el crecimiento óseo. • Resonancia magnética (MRI)—utiliza un campo magnético y ondas de radio para producir imágenes exactas de los tejidos blandos, los huesos y los órganos. Para la prueba, acostarán a tu hijo(a) sobre una mesa que se moverá al interior de una máquina similar a un tubo, ro- deándolo así con un campo magnético. La prueba es indolora, pero la máquina hace un ruido muy fuerte que puede asustar a algunos niños, quienes deben estar completamente inmóviles durante el escaneo. Algunos niños pueden requerir sedación para ayudarlos a permanecer inmóviles. • T2* MRI—un tipo especial de MIR no invasiva que mide el contenido de hierro en el corazón. • FerriScan MRI—un tipo especial de MIR que mide el contenido de hierro en el hígado.

• Prueba de densidad ósea—utiliza rayos X para determinar qué cantidad de calcio y de otros minerales óseos hay en áreas del esqueleto como la cadera, el antebrazo o la muñeca. La densidad del hueso se compara con los valores medios basados en el sexo, la edad y la talla del niño, además ayuda a determi- nar si tu hijo(a) tiene huesos fuertes u osteoporosis, una condición que hace que los huesos sean débiles y frágiles y con muchas posibilidades de romperse. OTRAS PRUEBAS • Electrocardiograma (ECG)—mide y registra la actividad eléctrica del corazón y diagnostica una serie de problemas cardíacos. • Ecocardiografía (ECHO)—utiliza ondas sonoras o ultrasonido para observar la estructura del corazón y

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