Misshaped and fragile red blood cells
Hereditary spherocytosis (HS) is an inherited blood disease that results in anemia. If your child has HS, either parent may also have the disease; however, in about 25% of cases, neither parent of an affected child has the disease. In the United States, HS affects about 1 in 2,000 people of Northern European ancestry.
Red blood cells (RBCs) are an important part of your blood. It is the job of the red blood cells to circulate oxygen to all parts of the body. Hemoglobin is the part of the RBC that carries oxygen. Normal red blood cells look donut-shaped, they are flexible, sleek, and circulate easily through all of the body’s organs.
HS is a blood disorder in which the RBCs are misshaped and fragile. The RBC’s in patients with HS can have a sphere-like shape. These types of cells are called spherocytes (sphere-shaped RBC’s) and are more plump, round, and are not very flexible. They are unable to change shape to pass through some of the organs and small blood vessels in the body as easily as normal red blood cells.
Because spherocytes can’t change their shape easily, they have a particularly difficult time passing through the spleen. The spleen is a filtering organ in the body. Often the spherocytes become damaged in the process of passing through the spleen and break apart in a process called hemolysis. This results in a reduced number of RBCs in the body and can also cause the spleen to become enlarged. The loss of RBCs causes the hemoglobin level in a patient to become low, possibly resulting in anemia.
Signs and Symptoms
The symptoms of HS vary depending on the severity of the disease. As the body naturally produces more red blood cells in the bone marrow to compensate for a low hemoglobin level, many people with HS have mild anemia or no anemia at all. As there is an increased demand on the bone marrow to make more cells, the new cells tend to be immature. These young, immature red blood cells (reticulocytes) are only seen in high numbers when there is a reason for the body must produce extra red blood cells. This process can be measured by the reticulocyte count.
Certain conditions like infection, fever, and physical stress can lead to more red blood cell destruction than usual. If this occurs, the body will try to produce more red blood cells to keep up with the level of destruction that occurs. The body’s ability to keep up with its losses can be measured by the reticulocyte count. If the body is able to produce enough red blood cells to keep up with the amount of red cell destruction occurring in the spleen, the hemoglobin level will stay the same (or drop only slightly), while the reticulocyte count will increase. If the reticulocyte count is low, the body is not able to keep up with the increased red blood cell production demands. The result of this is worsening anemia, and in these cases the spleen often becomes larger.
One of the results of red blood cells breaking apart is an increased level of bilirubin in the body. This can lead to jaundice, or a yellow tint to the skin and eyes. It may turn the urine dark (tea or coke colored). Over a long period of time, increased bilirubin can lead to the development of gallstones.
Possible signs of anemia include headache, shortness of breath, extreme fatigue, paleness, jaundice, fainting, irritability, sensations of dizziness or heart palpitations. In infants, restlessness and difficulty feeding, as well as sleeping too much or too long can be signs of anemia.
Blood cells (including red blood cells) are produced inside the bone marrow. There are certain infections (specifically, parvovirus, also called Fifth disease) which can cause the bone marrow to temporarily stop production of blood cells. This is called an aplastic crisis. The hemoglobin level will fall, and the body will not be able to produce many reticulocytes. It may take several days before the bone marrow is able to resume production of blood cells. This condition can result in severe anemia and may require red blood cell transfusions.
Blood tests to look at the amount of hemoglobin, the number of reticulocytes, and possibly the bilirubin level will be performed. Additionally, the hematologist will examine the red blood cells under a microscope to determine their shape, size, and characteristics.
One blood test used to diagnose HS is called osmotic fragility. The patient’s red blood cells are placed in different concentrations of salt water (saline) for 24 hours. The cells absorb water while soaking in the saline solution and eventually burst. Fragile Spherocytes do not tolerate the saline solution well and will burst their membranes sooner than normal cells. Sometimes other special tests are used to diagnose HS.
The symptoms of HS are treatable, but the inherited red blood cell defect is not curable. The treatment for young children and those with mild HS may include oral folic acid which is needed to make RBC’s. Red blood cell transfusions may be necessary if severe anemia occurs.
For children who have moderate or severe HS, surgical removal of the spleen (splenectomy) may be the treatment of choice. A splenectomy does not cure this disease, but it can cure the anemia and prevent the development of gallstones. Since the spleen is a filter of bacteria for the body, its removal can result in an increased risk of certain infections. To decrease this risk, additional vaccinations (pneumococcal and meningococcal) are given prior to the removal of the spleen. After removal of the spleen, antibiotics are taken by mouth daily to further lower the risk of infection.
When to call the doctor
You are in a partnership with the medical team caring for your child with hereditary spherocytosis. Your input and observations are important. You should consult your medical team for any of the following reasons:
- You notice that your child’s skin is more pale or yellow than usual, or that the whites of the eyes are more yellow than usual
- Your child is more tired than usual, having headaches or not acting right
- Your child has a fever of 101F or higher (>38.5C)
- Your child has difficulty with, or refuses the medications prescribed
- Your child is breathing unusually fast or their heart is beating unusually fast
- Your child is complaining of severe abdominal pain or does not want to eat
How the IHTC can help you
The IHTC is committed to providing expert care for infants, children, teens, and adults with spherocytosis. As a center of excellence in the treatment of bleeding and clotting disorders, the IHTC offers a high level of coordinated care for patients with this disorder. We also provide prompt communication with your local healthcare provider related to our treatment plan and your progress. The IHTC team collaborates with national experts and patient participation in research studies may be available.
At the IHTC we have clinicians who are experts in treating and providing support to patients with spherocytosis. It is very important that you are seen by a clinician who is familiar with the signs and treatment of this disorder. Although there is currently no cure for spherocytosis, we can help you or your child with diagnosis and testing; can provide treatments for the symptoms of the disease; and offer our expert guidance on other medical options. We can also provide genetic and general counselling depending on your specific needs.
For more information, please contact the IHTC.