Spherocytosis pathophysiology: Difference between revisions
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==Overview== | ==Overview== | ||
==Pathophysiology== | |||
Spherocytosis is caused by a molecular defect in one or more of the [[proteins]] of the red blood cell [[cytoskeleton]] (usually ''[[ankyrin]]'', sometimes ''[[spectrin]]''). Because the cell skeleton has a defect, the blood cell contracts to its most surface-tension efficient and least flexible configuration, a sphere, rather than the more flexible donut-shape. The sphere-shaped red blood cells are known as '''spherocytes'''. | |||
Though the spherocytes have a smaller surface area through which [[oxygen]] and [[carbon dioxide]] can be exchanged, they in themselves perform adequately to maintain healthy oxygen supplies. However, they have a high [[osmosis|osmotic]] fragility--when placed into water, they are more likely to burst than normal red blood cells. These cells are more prone to physical degradation. They are most commonly found in immunologically-mediated [[hemolytic anemia]]s and in [[hereditary spherocytosis]], but the former would have a positive [[Coombs test#Direct Coombs test|direct Coombs test]] and the latter would not. The misshapen but otherwise healthy red blood cells are mistaken by the [[spleen]] 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]]). | |||
==References== | ==References== | ||
{{reflist|2}} | {{reflist|2}} | ||
Revision as of 16:33, 21 September 2012
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Spherocytosis Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Spherocytosis pathophysiology On the Web |
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American Roentgen Ray Society Images of Spherocytosis pathophysiology |
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Risk calculators and risk factors for Spherocytosis pathophysiology |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Pathophysiology
Spherocytosis is caused by a molecular defect in one or more of the proteins of the red blood cell cytoskeleton (usually ankyrin, sometimes spectrin). Because the cell skeleton has a defect, the blood cell contracts to its most surface-tension efficient and least flexible configuration, a sphere, rather than the more flexible donut-shape. The sphere-shaped red blood cells are known as spherocytes.
Though the spherocytes have a smaller surface area through which oxygen and carbon dioxide can be exchanged, they in themselves perform adequately to maintain healthy oxygen supplies. However, they have a high osmotic fragility--when placed into water, they are more likely to burst than normal red blood cells. These cells are more prone to physical degradation. They are most commonly found in immunologically-mediated hemolytic anemias and in hereditary spherocytosis, but the former would have a positive direct Coombs test and the latter would not. The misshapen but otherwise healthy red blood cells are mistaken by the spleen 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).