Echinocyte (from the Greek word ''echinos'', meaning 'hedgehog' or 'sea urchin'), in human biology and medicine, refers to a form of

red blood cell Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cel ...

that has an abnormal

cell membrane The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of a cell from the outside environment (the extr ...

characterized by many small, evenly spaced thorny projections.Mentzer WC. Spiculated cells (echinocytes and acanthocytes) and target cells. UpToDate (release: 20.12- C21.4

/ref> A more common term for these cells is burr cells.

Physiology

Echinocytes are frequently confused with

acanthocyte Acanthocyte (from the Greek word ἄκανθα ''acantha'', meaning 'thorn'), in biology and medicine, refers to an abnormal form of red blood cell that has a spiked cell membrane, due to thorny projections. A similar term is spur cells. Often ...

s, but the mechanism of cell membrane alteration is different. Echinocytosis is a reversible condition of red blood cells that is often merely an artifact produced by

EDTA Ethylenediaminetetraacetic acid (EDTA), also called EDTA acid, is an aminopolycarboxylic acid with the formula . This white, slightly water-soluble solid is widely used to bind to iron (Fe2+/Fe3+) and calcium ions (Ca2+), forming water-solubl ...

, which is used as an

anticoagulant An anticoagulant, commonly known as a blood thinner, is a chemical substance that prevents or reduces the coagulation of blood, prolonging the clotting time. Some occur naturally in blood-eating animals, such as leeches and mosquitoes, which ...

in sampled blood. Echinocytes can be distinguished from acanthocytes by the shape of the projections, which are smaller and more numerous than in acanthocytes and are evenly spaced. Echinocytes also exhibit central pallor, or lightening of color in the center of the cell under

Wright stain Wright's stain is a hematologic stain that facilitates the differentiation of blood cell types. It is classically a mixture of eosin (red) and methylene blue dyes. It is used primarily to stain peripheral blood smears, urine samples, and bone ma ...

ing.

Causes

In addition to appearing as an artifact of staining or drying, echinocytes are associated with: * Uremia and

chronic kidney disease Chronic kidney disease (CKD) is a type of long-term kidney disease, defined by the sustained presence of abnormal kidney function and/or abnormal kidney structure. To meet criteria for CKD, the abnormalities must be present for at least three mo ...

pyruvate kinase deficiency Pyruvate kinase deficiency is an inherited metabolic disorder of the enzyme pyruvate kinase which affects the survival of red blood cells. Both autosomal dominant and recessive inheritance have been observed with the disorder; classically, and mo ...

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 soft ...

hyperlipidemia Hyperlipidemia is abnormally high levels of any or all lipids (e.g. fats, triglycerides, cholesterol, phospholipids) or lipoproteins in the blood. citing: and The term ''hyperlipidemia'' refers to the laboratory finding itself and is also use ...

* Phosphoglycerate kinase deficiency * Disseminated malignancy * Myeloproliferative disorders *

Vitamin E deficiency Vitamin E deficiency is a rare condition caused by low levels of vitamin E that may result from malabsorption disorders (such as abetalipoproteinemia, cystic fibrosis, or Crohn's disease), or impaired lipid transport. As a potent antioxidant, vit ...

* Early posttransfusion of RBC Echinocytes, like acanthocytes, may be found in hyperlipidemia caused by liver dysfunction, but the lipids themselves do not integrate into the membrane. Instead, it is speculated that cell surface receptors on the red blood cells bind with HDL cholesterol, which induces the shape change. These cells were also shown to develop in vivo during

hemodialysis Hemodialysis, American and British English spelling differences#ae and oe, also spelled haemodialysis, or simply ''"'dialysis'"'', is a process of filtering the blood of a person whose kidneys are not working normally. This type of Kidney dialys ...

, and disappear at the end of the procedure. The level of echinocytosis appeared to be related to the increase in blood viscosity that occurs during hemodialysis. The formation of echinocytes can also be induced by electric field pulses. Alternating electric current produces modifications in the membranes of red blood cells, attributed to a higher permeability to water and a decreased tonicity, leading to the transformation into echinocytes.

References

{{Abnormal clinical and laboratory findings Abnormal clinical and laboratory findings for RBCs Histopathology

Physiology

Causes

See also

References