Hereditary spherocytosis

What is hereditary spherocytosis?

As the name implies, hereditary spherocytosis (or HS) is an inherited disorder where the red blood cells have an abnormal shape.

Normal red cells have a doughnut shape whereas people with HS have spherical red cells, which have a shortened life span due to destruction by the spleen – the part of your body responsible for removing old or damaged blood cells.

Whether a person with HS develops anaemia depends on the severity of haemolysis and the extent to which their bone marrow, where all blood cells are manufactured, compensates for it. People with fully compensated haemolysis are not anaemic and usually have a milder course, whereas those with uncompensated haemolysis tend to have more of the problems outlined below.

How is it inherited?

HS is usually inherited as a dominant condition that affects both sexes equally. This means that both male and female children of HS patients have a 50% risk of inheriting the condition. Around 30% of patients have recessively inherited condition, which means that the risk of inheritance is much lower.

How does it affect health?

Most patients with HS have no problems with their health and do not need treatment other than supplements of a vitamin called folic acid that is necessary to sustain the increased production of red cells by their bone marrow. A few may have the following problems.

Jaundice at birth

Mild jaundice (increase in a blood pigment called bilirubin) is common at birth due to immaturity of the liver. HS increases the risk of severe jaundice in the first few days after birth and this can result in damage to the brain if not detected and treated in time. When you and your partner become pregnant, alert the midwife and doctor in charge of your antenatal care to this risk as they may wish to make special arrangements to monitor your newborn.

Anaemia and the need for blood transfusions

Most people with HS are not anaemic and do not need blood transfusions. However, some people have a severe form of the condition that requires regular blood transfusions, and these people usually have their spleens removed (see below).

Whatever the severity of HS, all patients are at risk of ‘crises’ when their haemoglobin drops to dangerously low levels due to a viral infection that either stops the bone marrow from producing red cells (aplastic crisis), or makes the haemolysis worse (haemolytic crisis).

Aplastic crisis is the more dangerous and you should contact us immediately in the event of sudden tiredness with a pale appearance.

Most crises will require transfusion of blood to correct the severe anaemia.

Gall stones

Destruction of red blood cells releases a pigment called bilirubin, which is removed from the blood by the liver. Since patients with HS have increased destruction of red cells, more bilirubin passes through the liver and gall bladder and most people accumulate this pigment within the gall bladder. In some, this produces gallstones and inflammation of the gall bladder, which can cause problems for people in their late teens and beyond.

How can it be treated?

HS can be treated by removal of the spleen. Apart from the spherical shape, the red blood cells of someone with HS function normally.

Since the spleen is the part of the body that destroys these otherwise normal red cells, removing the spleen (‘splenectomy’) provides an effective cure for the condition for most people.

However, splenectomy is associated with short and long-term risks that have to be weighed against the potential benefit of the procedure for the each person. We will discuss these risks and benefits with you before proceeding to splenectomy and we will also provide further information about the operation and its risks at that time.