Spherocytic Anemia

What, Laboratory Findings, Possible Causes

What is a spherocyte?

• A small spherical red blood cell.• Caused by a molecular defect in one or more of

the proteins of the red blood cell cytoskeleton, including, spectrin, ankyrin, Band 3, or Protein 4.2.

• Because the cell skeleton has a defect, the blood cell contracts to its most surface-tension efficient and least flexible configuration, a sphere. The sphere-shaped red blood cells are known as spherocytes.

Electron Microscope Image

Normal Red Blood Cells

Spherocytes on Smear

Spherocytic RBC’s

Various RBC Shapes

Laboratory Indications

CBCMild anemia MCV is usually normal (77-87fL)MCH normal MCHC is >36% (This is the only condition in which an MCHC can be truly increased.)

RBC morphologySpherocyteVarying degrees of polychromasia, anisocytosis and poikilocytosis

Urinalysis: Hemoglobinuria Increased urobilinogen

Lab Features

Reasons for Spherocytosis

• Hereditary Spherocytosis – Inherited genetic defect in Band 3 protein causing

spherocytes.• (Acquired) Autoimmune Hemolytic Anemia (AIHA)– AIHA may be:– Idiopathic, that is, without any known cause[3] – Secondary to another disease, such as systemic lupus

erythematosus or rheumatoid arthritis[4] or a malignancy, such as chronic lymphocytic leukemia (CLL)[3]

– Associated with receiving a drug[3]

Hereditary spherocytosis (HS)Defect in ankyrin & spectrinResults in the formation of fragile spherocytic red cells.Spherocyte becomes less flexible and more permeable

to Na+

Tends to affect Northern Europeans

Inherited

Acquired Autoimmune Hemolytic Anemia (AIHI)

• Immune mediated hemolytic anemia (direct Coombs test is positive)

Differential DiagnosesAlgorithm for Hemolytic Anemias CBC and Retic Counts

• MSCV = Average of (MRV + MCV)

• When MSCV was lower than MCV, a flow cytometric test for HS was performed (EMA).

• Delta (MCV–MSCV) values >9.6 fl were obtained for all HS patients.

Treatment of HS

• Splenectomy– Corrects for the anemia, but the membrane

defect remains

Treatment for AIHI• More than 200 types of hemolytic anemia exist, and each

type requires specific treatment. – Transfusion therapy– Discontinuing medications– Administer folic acid, because active hemolysis may consume

folate and cause megaloblastosis. – Corticosteroids are indicated in autoimmune hemolytic anemia.– Intravenous immunoglobulin G (IVIG) has been used for patients

with AIHA, but only a few patients have had treatment responses, and the response has been transient.

– Iron therapy

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