{{Short description|Abnormal form of red blood cell}} [[File:Scanning electron microscopy (SEM) of echinocytes.png|thumb|Scanning electron microscopy (SEM) of echinocytes]] [[File:Poikilocytes - Red blood cell types.jpg|thumb|Echinocyte compared to other forms of poikilocytosis]] '''Echinocyte''' (from the Greek word ''echinos'', meaning 'hedgehog' or 'sea urchin'), in human biology and medicine, refers to a form of red blood cell that has an abnormal cell membrane characterized by many small, evenly spaced thorny projections.<ref name="UTD">Mentzer WC. Spiculated cells (echinocytes and acanthocytes) and target cells. UpToDate (release: 20.12- C21.4) [http://www.uptodate.com/contents/spiculated-cells-echinocytes-and-acanthocytes-and-target-cells]</ref><ref name="Hoffman_2012_6">{{Cite book | last=Hoffman | first=R |author2=Benz, EJ |author3=Silberstein, LE |author4=Heslop, H |author5=Weitz J |author6= Anastasi, J. |title=Hematology: Basic Principles and Practice | publisher=Elsevier | year=2012 |edition=6th |isbn= 978-1-4377-2928-3}}</ref> A more common term for these cells is '''burr cells'''.
==Physiology== Echinocytes are frequently confused with acanthocytes, 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, which is used as an anticoagulant in sampled blood.<ref name="medialab2013">{{cite web|author = MediaLab|title=Burr Cells (Echinocytes)|url=http://www.medialabinc.net/spg28876/burr_cells_echinocytes.aspx|date=July 12, 2013}}</ref> 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 staining.<ref name="de Alarcon_20111130">{{cite web|author = de Alarcon PA|title=Acanthocytosis|url=http://emedicine.medscape.com/article/954356-differential|date=Nov 30, 2011}}</ref>
==Causes== In addition to appearing as an artifact of staining or drying, echinocytes are associated with:<ref>{{cite book|editor-last1=Tkachuk|editor-first1=Douglas C.|editor-last2=Hirschmann|editor-first2=Jan V.|title=Wintrobe's atlas of clinical hematology|date=2007|publisher=Lippincott Williams & Wilkins|location=Philadelphia, PA [etc.]|isbn=978-0781770231}}</ref> * Uremia and chronic kidney disease * pyruvate kinase deficiency * hypophosphatemia * hyperlipidemia * Phosphoglycerate kinase deficiency * Disseminated malignancy * Myeloproliferative disorders * Vitamin E deficiency * 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.<ref name="owen1985">{{cite journal|title=Erythrocyte echinocytosis in liver disease. Role of abnormal plasma high density lipoproteins.|last=Owen|first=J S|author2=Brown, D |author3=Harry, D |author4=McIntyre, N |author5=Beaven, G |author6=Isenberg, H |author7= Gratzer, W |date=December 1985|journal=Journal of Clinical Investigation |pmc=424351 |pmid=4077979 |doi=10.1172/JCI112237 |volume=76 |issue=6 |pages=2275–85}}</ref>
These cells were also shown to develop in vivo during hemodialysis, 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.<ref name="hasler1998">{{cite journal|url=http://ndt.oxfordjournals.org/content/13/12/3132|archive-url=https://archive.today/20130713031034/http://ndt.oxfordjournals.org/content/13/12/3132|url-status=dead|archive-date=2013-07-13|title=Echinocytosis induced by haemodialysis.|last=Hasler|first=C R|author2=Owen, G |author3=Brunner, D |author4= Reinhart, W |year=1998|journal=Nephrology Dialysis Transplantation|volume=13 |issue=12 |pages=3132–3137 |publisher=Oxford Journals|doi=10.1093/ndt/13.12.3132 |pmid=9870478 |doi-access=free}}</ref>
The formation of echinocytes can also be induced by electric field pulses.<ref name="Henszen1997">{{cite journal|title=Electric field pulses induce reversible shape transformation of human erythrocytes.|last=Henszen |first= MM|author2=Weske, M |author3=Schwarz, S |author4=Haest, CW |author5=Deuticke, B |date=October–December 1997|journal=Mol Membr Biol |pmid=9491371 |volume=14 |issue=4 |pages=195–204 |doi=10.3109/09687689709048182}}</ref> 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.<ref name="Jeican2017">{{cite journal|title=Changes observed in erythrocyte cells exposed to an alternating current.|last=Jeican|first=II|author2=Matei, H |author3=Istrate, A |author4=Mironescu, E |author5=Bâlici, S |date=April 2017|journal=Clujul Med. |pmc=5433566 |pmid=28559698 |doi=10.15386/cjmed-696 |volume=90 | issue = 2 |pages=154–60}}</ref>
==See also== * Poikilocytosis
==References== {{reflist|2}}
{{Abnormal clinical and laboratory findings}}
Category:Abnormal clinical and laboratory findings for RBCs Category:Histopathology