Spherocytosis
226540
213863138
2008-05-21T02:51:57Z
Davidruben
101637
workup infobox sorting out redirect too
{{Infobox_Disease
| Name = {{PAGENAME}}
| Image =
| Caption =
| DiseasesDB = 12289
| ICD10 = {{ICD10|D|58|0|d|55}}
| ICD9 = {{ICD9|282.0}}
| ICDO =
| OMIM = 182900
| OMIM_mul = {{OMIM2|270970}}
| MedlinePlus = 000530
| eMedicineSubj = med
| eMedicineTopic = 2147
| MeshID =
}}
'''Spherocytosis''' is an auto-[[hemolysis|hemolytic]] [[anemia]] (a [[blood diseases|disease of the blood]]) characterized by the production of [[red blood cell]]s (RBCs), or ''erythrocytes'', that are sphere-shaped, rather than donut-shaped or, more specifically, bi-concave disk shaped. It is 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, 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]]).
==Symptoms==
The [[spleen]]'s [[hemolysis]] results directly in varying degrees of [[anemia]] and hyperbilirubinemia, which in turn result in symptoms of [[Fatigue (physical)|fatigue]], [[pallor]], and [[jaundice]].
Acute cases can threaten [[Hypoxia (medical)|hypoxemia]] through [[anemia]] and acute [[kernicterus]] through hyperbilirubinemia, particularly in newborns.
Chronic symptoms include [[anemia]] and [[splenomegaly]], a potentially life-threatening enlargement of the [[spleen]] due to its increased activity. Furthermore, the detritus of the broken-down blood cells--[[bilirubin]]--accumulates in the [[gallbladder]], and can cause [[pigmented gallstones]] or "sludge" to develop. In chronic patients, an [[infection]] or other illness can cause an increase in the destruction of red blood cells, resulting in the appearance of acute symptoms, a ''hemolytic crisis''.
==Diagnosis==
In [[peripheral blood smear]]s, many of the [[red blood cell]]s will appear abnormally small and will lack the central pallor--the lighter area in the middle of an RBC as seen under a [[microscope]].
The CBC (cell blood count) laboratory values will show elevated [[MCHC]].
The [[spleen|splenic cords]] are congested with red blood cells to be destroyed and [[macrophage]]s of the spleen will show signs of actively destroying erythrocytes (erythrophagocytosis). This will result in an elevated [[bilirubin]] level.
The [[bone marrow]] in its role of manufacturing red blood cells will display [[hyperplasia]], the increased activity of replacing RBCs. As a result, immature red blood cell--or [[reticulocyte]]--counts will appear elevated.
==Treatment==
===Treatment of acute symptoms===
Acute symptoms of [[anemia]] and hyperbilirubinemia can indicate treatment with '''[[blood transfusion]]s or exchanges'''. Transfusions treat [[anemia]] by adding healthy donor blood to the patient's own, providing needed [[red blood cells]]. As the transfused blood does not contain spherocytes, it will not be hemolysed per se, but the overactive spleen may still break down a significant proportion of the transfused blood. Exchanges treat hyperbilirubinemia by replacing some portion of the patient's blood with healthy donor blood, thus removing some portion of the toxic [[bilirubin]].
===Treatment of chronic symptoms===
Chronic symptoms of [[anemia]] and [[splenomegaly]] typically indicate '''dietary supplementation of folic acid and eventual treatment by '''[[splenectomy]]''', the surgical removal of the [[spleen]].
In longstanding cases in which patients have taken supplemental [[iron]] or received numerous [[blood transfusion]]s, [[iron overload]] may be a significant problem, being a potential cause of [[cardiomyopathy]] and [[liver disease]]. If there is [[iron overload]], [[chelation therapy]] with agents such as [[desferrioxamine]] may be necessary.
While [[splenectomy]] does not affect the shape of the blood cells, it does remove the more obvious physical [[symptoms]] of the disorder, as the blood cells are no longer constantly broken down. Though it offers near-immediate relief from symptoms, splenectomy is often not performed until the patient is in late childhood, so as not to hinder the patient's ability to fight off childhood [[infection]]s. The [[surgery]] is often performed [[Laparoscopic surgery|laparoscopically]]. Given that surgery is preplanned, it is highly recommended that patients receive prior Pneumovax-II [[pneumococcus]], conjugated-C [[meningococcus]] & [[Haemophilus influenzae type b]] [[vaccinations]] to combat the patient's new lower tolerance against [[overwhelming post-splenectomy infection]]. The Pneumovax needs repeating every six years and the patient should have a yearly [[influenza vaccine]]. [[Prophylactic]] [[antibiotics]] are also given. (See [[asplenia]] for further details on these measures).
===Treatment of the disorder===
Both measures described above treat the symptoms, not the cause of the disorder. Non-hereditary spherocytosis has several causes, each treated differently. Experimental [[gene therapy]] exists to treat [[hereditary spherocytosis]] in lab mice; however, this treatment has not yet been tried on humans and because of the risks involved in human gene therapy, it may never be. See also [[Hereditary spherocytosis]].
==See also==
* [[Hereditary spherocytosis]]
* [[Anemia]]
* [[Blood]]
* [[Blood diseases]]
* [[Red blood cells]]
* [[Hereditary diseases]]
==External links==
* [http://www.healthsystem.virginia.edu/internet/hematology/HessEDD/Redbloodcelldisorders/spherocyte.cfm Spherocytes]: Presented by the University of Virginia
* {{OMIM|182900}}
*[http://my.webmd.com/hw/anemia/nord81.asp A short article from WebMD]
*[http://www.nlm.nih.gov/medlineplus/ency/imagepages/1220.htm A picture of spherocytes from Medline]
*[http://www.emedicine.com/med/topic2147.htm A detailed and technical (but good) article from eMedicine]
==References==
* Kumar, Vinay, Abul Abbas, and Nelson Fausto. "Robbins and Cotran Pathologic Basis of Disease, 7th edition (2004)."
* Schneider, Arthur S. and Philip A. Stanzo. "Board Review Series: Pathology, 2nd edition (2002)."
{{hematology}}
[[Category:Blood disorders]]
[[de:Kugelzellenanämie]]
[[fr:Maladie de Minkowski-Chauffard]]
[[it:Sferocitosi]]
[[nl:Congenitale sferocytose]]