What Is Hereditary Spherocytosis?

Physician Assessing for Anemia
Physician Assessing for Anemia. BSIP/UIG/Getty Images

Definition

Hereditary Spherocytosis is an inherited condition where the red blood cells cannot maintain their normal shape (sort of like a donut) and become spherocytes (round like a globe).  This is due to a defect in the red blood cell membrane resulting in hemolytic anemia.

Symptoms

Symptoms are related to hemolysis (red blood cell breakdown) and anemia

  • Pallor or pale skin
  • Fatigue
  • Yellowing of the skin (jaundice) or eyes (scleral icterus)
  • Splenomegaly - enlargement of the spleen
  • Abdominal pain secondary to gallstones or large spleen

Who is at risk?

About 2/3 of patients, have a family member with hereditary spherocytosis.  It is passed down from their mother or father.  Usually, multiple family members have hereditary spherocytosis.  However, In about 1/3 of patients, there are no other family members affected.  This patient can then pass hereditary spherocytosis on to their children.  

Diagnosis

The initial diagnostic tests are a complete blood count (CBC) and reticulocyte count.  The CBC reveals anemia (low hemoglobin).  The mean cellular hemoglobin concentration (MCHC) may be elevated.  The reticulocyte (immature red blood cells) count is elevated.  When the body destroys red blood cells (hemolysis), the body should respond by making more red blood cells.  

A peripheral blood smear (a test to examine the blood cells under the microscope) reveals spherocytes (small round red blood cells).

 Spherocytes can be seen in other forms of hemolytic anemia, like autoimmune hemolytic anemia, so this must be ruled out.  

If you have a strong family history and laboratory values consistent with spherocytosis, this may be enough for diagnosis.  Patients with no family history or when diagnosis is not clear, osmotic fragility testing may be sent.

  Osmotic fragility looks at how easily red blood cells breakdown when exposed to sodium, increased osmotic fragility is consistent with spherocytosis.  Genetic testing has become more readily available recently.  

Complications

The spherocytes are fragile and hemolyze (breakdown) more easily resulting in anemia.  The majority of the hemolysis occurs in the spleen.  Spherocytes have a difficult time moving through the spleen and may get trapped there causing splenomegaly, enlargement of the spleen.  

Red blood cells release bilirubin, a pigment, when they are broken down.  In hereditary spherocytosis, the amount of bilirubin in the body goes up, causing yellowing of the skin or eyes.  This excess bilirubin which is stored in the gallbladder may harden and result in gallstones.  Gallstones can form even in young children.   

People with hereditary spherocytosis are risk for severe anemia during parvovirus B19 infection called an aplastic crisis.  This virus also causes Fifth Disease and halts red blood cell production for 7 -10 days.

  In people who already have anemia, this inability to make red blood cells results in severe anemia that may require transfusion.  

Treatment

There is no specific treatment for hereditary spherocytosis.  Most treatment is supportive.  

  • Transfusions:  During some illnesses, particularly those with fever or due to parvovirus B19, the anemia may worsen and require a transfusion.  Rarely patients have severe anemia and require transfusions on a regular basis.  
  • Splenectomy:  The spleen is the major site of red blood cell destruction in hereditary spherocytosis.  By removing the spleen, the red blood cells last for a longer amount of time in the body resulting in less anemia.  Having the  spleen removed has risks and should be weighed against the potential benefits. 
  • Cholecystectomy:  If you develop gallstones and have recurrent abdominal pain, you may need to have your gallbladder removed. 

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