Spherocytosis is the presence of spherocytes in the blood, i.e. erythrocytes (

red blood cell Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...

s) that are sphere-shaped rather than bi-concave disk shaped as normal. Spherocytes are found in all hemolytic anemias to some degree.

Hereditary spherocytosis Hereditary spherocytosis (HS) is a congenital hemolytic disorder, wherein a genetic mutation coding for a structural membrane protein phenotype leads to a spherical shaping of erythrocytic cellular morphology. As erythrocytes are sphere-shaped ( ...

and

autoimmune hemolytic anemia Autoimmune hemolytic anemia (AIHA) occurs when antibodies directed against the person's own red blood cells (RBCs) cause them to burst (lyse), leading to an insufficient number of oxygen-carrying red blood cells in the circulation. The lifetime o ...

are characterized by having ''only'' spherocytes.

Causes

Spherocytes are found in immunologically-mediated

hemolytic anemia Hemolytic anemia or haemolytic anaemia is a form of anemia due to hemolysis, the abnormal breakdown of red blood cells (RBCs), either in the blood vessels (intravascular hemolysis) or elsewhere in the human body (extravascular). This most commonly ...

s and in

hereditary spherocytosis Hereditary spherocytosis (HS) is a congenital hemolytic disorder, wherein a genetic mutation coding for a structural membrane protein phenotype leads to a spherical shaping of erythrocytic cellular morphology. As erythrocytes are sphere-shaped ( ...

, but the former would have a positive

direct Coombs test A Coombs test, also known as antiglobulin test (AGT), is either of two blood tests used in immunohematology. They are the direct and indirect Coombs tests. The direct Coombs test detects antibodies that are stuck to the surface of the red blood c ...

and the latter would not. The misshapen but otherwise healthy red blood cells are mistaken by the

spleen The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes .

for old or damaged red blood cells and it thus constantly breaks them down, causing a cycle whereby the body destroys its own blood supply (auto-

hemolysis Hemolysis or haemolysis (), also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo o ...

). A complete blood count (CBC) may show increased reticulocytes, a sign of increased red blood cell production, and decreased hemoglobin and hematocrit. The term "non-hereditary spherocytosis" is occasionally used, albeit rarely. Lists of causes: *

Warm autoimmune hemolytic anemia Warm antibody autoimmune hemolytic anemia (WAIHA) is the most common form of autoimmune haemolytic anemia. About half of the cases are of unknown cause, with the other half attributable to a predisposing condition or medications being taken. Contra ...

Cold autoimmune hemolytic anemia Cold autoimmune hemolytic anemia caused by cold-reacting antibodies. Autoantibodies that bind to the erythrocyte membrane leading to premature erythrocyte destruction (hemolysis) characterize autoimmune hemolytic anemia. Presentation A common ...

paroxysmal cold hemoglobinuria Paroxysmal cold hemoglobinuria (PCH) is an autoimmune hemolytic anemia featured by Complement system, complement-mediated intravascular hemolysis after cold exposure. It can present as an acute non-recurrent postinfectious event in children, or chr ...

* Acute and delayed

hemolytic Hemolysis or haemolysis (), also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo o ...

transfusion reactions * ABO hemolytic diseases of newborn/Rh hemolytic disease of newborn *

* Intravenous water infusion or drowning (fresh water) *

Hypophosphatemia Hypophosphatemia is an electrolyte disorder in which there is a low level of phosphate in the blood. Symptoms may include weakness, trouble breathing, and loss of appetite. Complications may include seizures, coma, rhabdomyolysis, or softening ...

Bartonellosis Bartonellosis is an infectious disease produced by bacteria of the genus ''Bartonella''. ''Bartonella'' species cause diseases such as Carrión's disease, trench fever, cat-scratch disease, bacillary angiomatosis, peliosis hepatis, chronic bacter ...

Snake bites A snakebite is an injury caused by the bite of a snake, especially a venomous snake. A common sign of a bite from a venomous snake is the presence of two puncture wounds from the animal's fangs. Sometimes venom injection from the bite may occu ...

Hyposplenism Asplenia refers to the absence of normal spleen function and is associated with some serious infection risks. Hyposplenism is used to describe reduced ('hypo-') splenic functioning, but not as severely affected as with asplenism. ''Functional'' a ...

* Rh-null phenotype

Pathophysiology

Spherocytosis most often refers to

. This is caused by a molecular defect in one or more of the

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...

s of the red blood cell

cytoskeleton The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is comp ...

, including

spectrin Spectrin is a cytoskeletal protein that lines the intracellular side of the plasma membrane in eukaryotic cells. Spectrin forms pentagonal or hexagonal arrangements, forming a scaffold and playing an important role in maintenance of plasma memb ...

ankyrin Ankyrins are a family of proteins that mediate the attachment of integral membrane proteins to the spectrin-actin based membrane cytoskeleton. Ankyrins have binding sites for the beta subunit of spectrin and at least 12 families of integral mem ...

Band 3 Band 3 anion transport protein, also known as anion exchanger 1 (AE1) or band 3 or solute carrier family 4 member 1 (SLC4A1), is a protein that is encoded by the gene in humans. Band 3 anion transport protein is a phylogenetically-preserved ...

, or

Protein 4.2 Erythrocyte membrane protein band 4.2 is a protein that in humans is encoded by the ''EPB42'' gene. It is part of the red blood cell cytoskeleton. Erythrocyte membrane protein band 4.2 is an ATP-binding protein which may regulate the association o ...

. Because the cell skeleton has a defect, the blood cell contracts to a sphere, which is its most surface tension efficient and least flexible configuration. Though the spherocytes have a smaller surface area through which

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as we ...

and

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is t ...

can be exchanged, they in themselves perform adequately to maintain healthy oxygen supplies. However, they have a high

osmotic Osmosis (, ) is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region of high water potential (region of lower solute concentration) to a region of low water potential (region of ...

fragility—when placed into water, they are more likely to burst than normal red blood cells. These cells are more prone to physical degradation. In short, spherocytosis has an attribute of decreased cell deformability.

Diagnosis

Spherocytosis can be diagnosed in Peripheral blood film by seeing spherical red blood cells rather than biconcave. Because spherical red blood cells are more prone to lysis in water (because they lack some proteins in their cytoskeleton) there will be increased osmotic fragility on acidified glycerol lysis test.

Treatment

Treatment may vary depending on the cause of the condition. In the case of hereditary spherocytosis, although research is ongoing, at this point there is no cure for the genetic defect that causes hereditary spherocytosis. Current management focuses on interventions that limit the severity of the disease. Treatment options for this type of spherocytosis include: * Splenectomy: As in non-hereditary spherocytosis, acute symptoms of

anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, ...

and hyperbilirubinemia indicate treatment with

blood transfusion Blood transfusion is the process of transferring blood products into a person's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but m ...

s or exchanges and chronic symptoms of anemia and an enlarged spleen indicate dietary supplementation of folic acid and

splenectomy A splenectomy is the surgical procedure that partially or completely removes the spleen. The spleen is an important organ in regard to immunological function due to its ability to efficiently destroy encapsulated bacteria. Therefore, removal o ...

, the surgical removal of the spleen. Splenectomy is indicated for moderate to severe cases, but not mild cases. To decrease the risk of

sepsis Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is foll ...

, post-splenectomy spherocytosis patients require immunization against the

influenza Influenza, commonly known as "the flu", is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptom ...

virus, encapsulated bacteria such as

Streptococcus pneumoniae ''Streptococcus pneumoniae'', or pneumococcus, is a Gram-positive, spherical bacteria, alpha-hemolytic (under aerobic conditions) or beta-hemolytic (under anaerobic conditions), aerotolerant anaerobic member of the genus Streptococcus. They a ...

and

meningococcus ''Neisseria meningitidis'', often referred to as meningococcus, is a Gram-negative bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life-threatening sepsis. The bacterium is referred to as a ...

, and prophylactic antibiotic treatment. However, the use of prophylactic antibiotics, such as penicillin, remains controversial. * Partial splenectomy: Since the spleen is important for protecting against encapsulated organisms, sepsis caused by encapsulated organisms is a possible complication of splenectomy. The option of partial splenectomy may be considered in the interest of preserving immune function. Research on outcomes is currently limited, but favorable. * Surgical removal of the gallbladder may be necessary.

References

External links