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| | __NOTOC__ |
| | '''For patient information click [[Paroxysmal nocturnal hemoglobinuria (patient information)|here]]''' |
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| {{Infobox_Disease | | | {{Infobox_Disease | |
| Name = {{PAGENAME}} | | | Name = {{PAGENAME}} | |
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| Caption = | | | Caption = | |
| DiseasesDB = 9688 | | | DiseasesDB = 9688 | |
| ICD10 = {{ICD10|D|59|5|d|55}} | | | ICD10 = | |
| ICD9 = {{ICD9|283.2}} | | | ICD9 = {{ICD9|283.2}} | |
| ICDO = | | | ICDO = | |
| OMIM = 311770 | | | OMIM = 311770 | |
| MedlinePlus = | | | MedlinePlus = | |
| eMedicineSubj = med |
| | MeshID = | |
| eMedicineTopic = 2696 |
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| MeshID = D006457 | | |
| }} | | }} |
| {{Search infobox}} | | {{Paroxysmal nocturnal hemoglobinuria}} |
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| {{Editor Help}} | | {{CMG}} {{AE}} {{AEL}} Robert Killeen, M.D. [mailto:aak324@gmail.com] |
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| '''Paroxysmal nocturnal hemoglobinuria''' ([[PNH]]) is a rare, acquired, potentially life-threatening disease of the blood characterised by [[hemolytic anemia]], [[thrombosis]] and red [[urine]] due to breakdown of [[red blood cell]]s. [[PNH]] is the only hemolytic anemia caused by an ''acquired'' intrinsic defect in the [[cell membrane]].
| | {{SK}} PNH; Marchiafava-Micheli disease; paroxysmal nocturnal haematuria |
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| ==History== | | ==[[Paroxysmal nocturnal hemoglobinuria overview|Overview]]== |
| The first description of paroxysmal hemoglobinuria was by the German physician Paul Strübing (1852).<ref>Strübing P. Paroxysmale Hämoglobinurie. ''Dtsch Med Wochenschr'' 1882;8:1-3 and 17-21.</ref><ref>[http://www.whonamedit.com/synd.cfm/2918.html Whonamedit entry]</ref> A more detailed description was made by Dr Ettore Marchiafava and Dr Alessio Nazari in 1911,<ref>Marchiafava E, Nazari A. Nuovo contributo allo studio degli itteri cronici emolitici. ''Policlinico [Med]'' 1911;18:241-254.</ref> with further elaborations by Marchiafava in 1928<ref>Marchiafava E. Anemia emolitica con emosiderinuria perpetua. ''Policlinico [Med]'' 1928;35:105-117.</ref> and Dr Ferdinando Micheli in 1931.<ref>Micheli F. Uno caso di anemia emolitica con emosiderinuria perpetua. ''G Accad Med Torino'' 1931;13:148.</ref>
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| ==Classification== | | ==[[Paroxysmal nocturnal hemoglobinuria historical perspective|Historical Perspective]]== |
| PNH is classified:
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| * ''Classic PNH''. Evidence of [[PNH]] in the absence of another bone marrow disorder.
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| * ''[[PNH]] in the setting of another specified bone marrow disorder''.
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| * ''Subclinical PNH''. [[PNH]] abnormalities on flow cytometry without signs of hemolysis.
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| ==Pathophysiology== | | ==[[Paroxysmal nocturnal hemoglobinuria classification|Classification]]== |
| All cells have proteins attached to their membranes and they are responsible for performing a vast array of functions. There are several ways for proteins to be attached to a cell membrane. [[PNH]] occurs as a result of a defect in one of these mechanisms.
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| A molecule called {{Gene|PIGA}} (phosphatidylinositol glycan A) is needed to make a cell membrane anchor for proteins called GPI ([[glycosylphosphatidylinositol]]).<ref>Hu R, Mukhina GL, Piantadosi S, Barber JP, Jones RJ, Brodsky RA. ''PIG-A mutations in normal hematopoiesis.'' Blood 2005;105:3848-54. PMID 15687243.</ref> The gene that codes for PIGA is inherited in an [[Sex linkage|X-linked]] fashion, which means that only one active copy of the gene for PIGA may exist. If a mutation occurs in this gene then PIGA may be defective, which leads to a defect in the [[GPI anchor]]. When this mutation occurs in a [[bone marrow]] [[stem cell]] (which are used to make red blood cells as well as white blood cells and platelets), all of the cells it produces will also have the defect. Several of the proteins that anchor to GPI on the cell membrane are used to protect the cell from destruction by the [[complement system]]. The complement system is part of the [[immune system]] and helps to destroy invading microorganisms. Without the proteins that protect them from complement, red blood cells are destroyed. The main proteins which carry out this function are [[CD16]], [[CD55]] and [[CD59]] (CD is an acronym for [[cluster of differentiation]]).
| | ==[[Paroxysmal nocturnal hemoglobinuria pathophysiology|Pathophysiology]]== |
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| The increased destruction of red blood cells results in [[anemia]]. The increased rate of thrombosis is due to dysfunction of [[platelet]]s. They are also made by the bone marrow stem cells and will have the same GPI anchor defect as the red blood cells. The proteins which use this anchor are needed for platelets to clot properly, and their absence leads to a hypercoagulable state.
| | ==[[Paroxysmal nocturnal hemoglobinuria causes|Causes]]== |
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| ==Signs and symptoms== | | ==[[Paroxysmal nocturnal hemoglobinuria differential diagnosis|Differentiating Paroxysmal nocturnal hemoglobinuria from other Diseases]]== |
| Quite paradoxically, the destruction of red blood cells ([[hemolysis]]) is neither paroxysmal nor nocturnal the majority of the time (this constellation of symptoms is seen in only 25% of patients). On-going [[hemolysis]] is a more common characteristic.
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| A common finding in [[PNH]] is the presence of breakdown products of [[RBC]]s ([[hemoglobin]] and [[hemosiderin]]) in the urine.
| | ==[[Paroxysmal nocturnal hemoglobinuria epidemiology and demographics|Epidemiology and Demographics]]== |
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| An inconsistent, but potentially life-threatening, complication of PNH is the development of clot in the veins (venous [[thrombosis]]). These clots (thrombi) are often found in the [[hepatic vein|hepatic]] (causing [[Budd-Chiari syndrome]]), [[Portal vein|portal]] (causing [[portal vein thrombosis]]), and cerebral veins (causing [[cerebral venous thrombosis]]).
| | ==[[Paroxysmal nocturnal hemoglobinuria risk factors|Risk Factors]]== |
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| Many patients with bone marrow failure ([[aplastic anemia]]) develop [[PNH]] (10-33%). Aplastic anemia can be caused by an attack by the immune system against the bone marrow. For this reason, drugs that suppress the immune system are being researched as a therapy for PNH.<ref>Sacher, Ronald A. and Richard A. McPherson. "Wildman's Clinical Interpretation of Laboratory Tests, 11th edition."</ref> <ref>Kumar, Vinay, Abu Abbas, and Nelson Fausto. "Robbins and Cotran Pathologic Basis of Disease, 7th edition."</ref>
| | ==[[Paroxysmal nocturnal hemoglobinuria screening|Screening]]== |
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| | ==[[Paroxysmal nocturnal hemoglobinuria natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
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| ==Diagnosis== | | ==Diagnosis== |
| A sugar or sucrose lysis test, in which a patient's red blood cells are placed in low ionic strength solution and observed for hemolysis, is used for screening. A more specific test for PNH, called ''Ham's acid hemolysis'' test, is performed if the sugar test is positive for hemolysis.<ref>Ham TH. Chronic haemolytic anaemia with paroxysmal nocturnal haemoglobinuria: study of the mechanism of haemolysis in relation to acid-base equilibtium. ''[[N Engl J Med]]'' 1937;217:915-918.</ref>
| | [[Paroxysmal nocturnal hemoglobinuria history and symptoms| History and Symptoms]] | [[Paroxysmal nocturnal hemoglobinuria physical examination | Physical Examination]] |[[Paroxysmal nocturnal hemoglobinuria laboratory findings|Laboratory Findings]] | [[Paroxysmal nocturnal hemoglobinuria x ray|X Ray]] | [[Paroxysmal nocturnal hemoglobinuria CT|CT]] | [[Paroxysmal nocturnal hemoglobinuria MRI|MRI]] | [[Paroxysmal nocturnal hemoglobinuria echocardiography or ultrasound|Echocardiography or Ultrasound]] | [[Paroxysmal nocturnal hemoglobinuria other imaging findings|Other Imaging Findings]] | [[Paroxysmal nocturnal hemoglobinuria other diagnostic studies|Other Diagnostic Studies]] |
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| Modern methods include [[flow cytometry]] for [[CD55]], [[CD16]] and [[CD59]] on [[white blood cells|white]] and [[red blood cells]]. <ref>Parker C, Omine M, Richards S, Nishimura J, Bessler M, Ware R, Hillmen P, Luzzatto L, Young N, Kinoshita T, Rosse W, Socie G, International PNH Interest Group. Diagnosis and management of paroxysmal nocturnal hemoglobinuria. ''[[Blood (journal)|Blood]] 2005;106:3699-709. PMID 16051736.</ref>Dependent on the presence of these molecules on the cell surface, they are classified as type I, II or III PNH cells.
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| ===MRI===
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| *Renal cortical signal intensity loss (hemosiderin accumulates in the renal cortex when intravascular hemolysis results in the direct release of hemoglobin into the plasma).
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| *Venous thrombosis.
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| *Liver and spleen are usually of normal signal intensity in paroxysmal nocturnal hemoglobinuria, unless repeated transfusions have resulted in hepatic and splenic signal intensity loss owing to transfusional siderosis.
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| (Images shown below are courtesy of RadsWiki)
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| <gallery>
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| Image:Paroxysmal nocturnal hemoglobinuria 001.jpg
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| Image:Paroxysmal nocturnal hemoglobinuria 002.jpg
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| Image:Paroxysmal nocturnal hemoglobinuria 003.jpg
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| Image:Paroxysmal nocturnal hemoglobinuria 004.jpg
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| Image:Paroxysmal nocturnal hemoglobinuria 005.jpg
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| Image:Paroxysmal nocturnal hemoglobinuria 006.jpg
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| Image:Paroxysmal nocturnal hemoglobinuria 007.jpg
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| Image:Paroxysmal nocturnal hemoglobinuria 008.jpg
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| </gallery>
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| ==Treatment== | | ==Treatment== |
| ===Long-term===
| | [[Paroxysmal nocturnal hemoglobinuria medical therapy|Medical Therapy]] | [[Paroxysmal nocturnal hemoglobinuria surgery|Surgery]] | [[Paroxysmal nocturnal hemoglobinuria primary prevention|Primary Prevention]] | [[Paroxysmal nocturnal hemoglobinuria secondary prevention|Secondary Prevention]] | [[Paroxysmal nocturnal hemoglobinuria cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Paroxysmal nocturnal hemoglobinuria future or investigational therapies|Future or Investigational Therapies]] |
| PNH is a chronic condition. In patients who have only a small clone and few problems, monitoring of the flow cytometry every six months gives information on the severity and risk of potential complications. Given the high risk of thrombosis in PNH, preventative treatment with [[warfarin]] decreases the risk of thrombosis in those with a large clone (50% of white blood cells type III).<ref name=parker2005/><ref>{{cite journal |author=Hall C, Richards S, Hillmen P |title=Primary prophylaxis with warfarin prevents thrombosis in paroxysmal nocturnal hemoglobinuria (PNH) |journal=Blood |volume=102 |issue=10 |pages=3587–91 |year=2003 |month=November |pmid=12893760 |doi=10.1182/blood-2003-01-0009 |url=http://bloodjournal.hematologylibrary.org/cgi/content/full/102/10/3587}}</ref>
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| Episodes of thrombosis are treated as they would in other patients, but given that PNH is a persisting underlying cause it is likely that treatment with [[warfarin]] or similar drugs needs to be continued long-term after an episode of thrombosis.<ref name=parker2005/>
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| ===Acute attacks===
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| There is disagreement as to whether steroids (such as [[prednisolone]]) can decrease the severity of hemolytic crises. Transfusion therapy may be needed; in addition to correcting significant [[anemia]] this suppresses the production of PNH cells by the bone marrow, and indirectly the severity of the hemolysis. Iron deficiency develops with time, due to losses in urine, and may have to be treated if present. Iron therapy can result in more hemolysis as more PNH cells are produced.<ref name=parker2005/>
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| A new [[monoclonal antibody]], ''[[eculizumab]]'', protects blood cells against immune destruction by inhibiting the [[complement system]]. It has been shown to reduce the need for blood transfusion in patients with significant hemolysis.<ref>{{cite journal |author=Hillmen P, Hall C, Marsh JC, ''et al'' |title=Effect of eculizumab on hemolysis and transfusion requirements in patients with paroxysmal nocturnal hemoglobinuria |journal=N. Engl. J. Med. |volume=350 |issue=6 |pages=552–9 |year=2004 |pmid=14762182 |doi=10.1056/NEJMoa031688}}</ref>
| | ==Case Studies== |
| | | [[Paroxysmal nocturnal hemoglobinuria case study one|Case #1]] |
| ==References==
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| {{reflist|2}}
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| ==Additional Resources==
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| * Ross L. Titton, and Fergus V. Coakley. [http://radiology.rsnajnls.org/cgi/content/short/225/1/67 Case 51: Paroxysmal Nocturnal Hemoglobinuria with Thrombotic Budd-Chiari Syndrome and Renal Cortical Hemosiderin.] Radiology 2002 225: 67-70.
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| ==External links== | |
| *[http://www.aamds.org Aplastic Anemia & MDS International Foundation]
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| *[http://www.pnhdisease.org PNH Support Group]
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| *[http://www.pnhfoundation.org PNH Research and Support Foundation]
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| *[http://goldminer.arrs.org/search.php?query=Paroxysmal%20nocturnal%20hemoglobinuria Goldminer: Paroxysmal nocturnal hemoglobinuria]
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| {{Hematology}} | | {{Hematology}} |
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