Geometry.Net - Health_Conditions: Platelet Disorders

MEDLINEplus Medical Encyclopedia: Congenital Platelet Function Defects
Prevention Return to top Laboratory studies can detect the defectivegene responsible for these platelet disorders. Genetic counseling
http://www.nlm.nih.gov/medlineplus/ency/article/000582.htm

Extractions: Skip navigation Other encyclopedia topics: A-Ag Ah-Ap Aq-Az B-Bk ... Z Contents of this page: Blood clot formation Blood clots Alternative names Return to top Storage pool disease; Glanzmann's thrombasthenia; Bernard-Soulier syndrome; Platelet function defects - congenital Definition Return to top Congenital platelet function defects are disorders of platelet function, the blood cells essential for the coagulation of the blood, that is present at birth. Causes, incidence, and risk factors Return to top Congenital platelet function defects are bleeding disorders characterized by abnormal platelet function in spite of normal platelet counts. There is usually a family history of a bleeding disorder consisting of prolonged bleeding or easy bruising Bernard-Soulier syndrome is a congenital disorder where the platelets lack receptors to adhere to the walls of the blood vessels. Bleeding may be severe with this disorder. Glanzmann's thrombasthenia is a condition caused by lack of a protein required for platelet aggregation (clumping) This disorder may cause mucosal and postoperative bleeding, and it may also be severe.
Platelet Function Testing
hemostasis are complex. Extensive reviews are available to detail themechanisms and pathology of platelet disorders. In brief, platelet
http://www.itxm.org/TMU2002/Issue5.htm

Extractions: ITxM Diagnostics Chief Science Officer INTRODUCTION Many clinicians are challenged by a patient at risk for bleeding due to the presence of an acquired or functional platelet disorder. These complex disorders are difficult to diagnose in part due to the ambiguities in the laboratory assessment of platelet function. This review will discuss platelet functional activity and the traditional and newer laboratory methods for platelet function analysis. PLATELET FUNCTION The mechanisms by which platelets participate in hemostasis are complex. Extensive reviews are available to detail the mechanisms and pathology of platelet disorders. In brief, platelet activity can be divided into the following functions: 1) Adhesion-Platelets adhere to damaged blood vessels in a process mediated in part by binding of von Willebrand factor to the glycoprotein Ib-IX-V complex on the platelet plasma membrane. 2) Aggregation-This platelet-to-platelet interaction is initiated by many different agonists, which bind to specific receptors on the platelet membrane.
July 2000 - Platelet Closure Times
Suspected von Willebrands disease, inherited platelet disorders and evaluationof acquired disorders of platelet function (hepatic disease, renal disease
http://www.itxm.org/TMU2000/tmu7-2000.htm

Extractions: Franklin A. Bontempo, M.D. BACKGROUND Platelet dysfunction may be acquired, inherited, or induced by platelet inhibiting agents. It is clinically important to assess platelet function as a potential cause of a bleeding diathesis, especially in critically ill patients who may develop life-threatening hemorrhages. The most common causes of platelet dysfunction are related to uremia, liver disease, von Willebrands disease (vWD) and exposure to agents such as acetyl salicylic acid (ASA, aspirin). Current methods to assess platelet function include bleeding time (BT), aggregation studies and whole blood in vitro test systems such as the closure time (CT). CLOSURE TIME TESTING Closure times are performed on a PFA-100, an instrument and test cartridge system in which the process of platelet adhesion and aggregation following a vascular injury is simulated in vitro This system allows for rapid evaluation of platelet function on samples of anticoagulated whole blood.
1Up Health > Acquired Platelet Function Defect > Causes, Incidence, And Risk Fac
Comprehesive information on Acquired platelet function defect (Acquired disordersof platelet function, Acquired qualitative platelet disorders).
http://www.1uphealth.com/health/acquired_platelet_function_defect_info.html

Extractions: 1Up Health Acquired platelet function defect Alternative Medicine Clinical Trials ... Health Topics A-Z Search 1Up Health Acquired platelet function defect Information Acquired platelet function defect Causes, Incidence, and Risk Factors Alternative names : Acquired disorders of platelet function, Acquired qualitative platelet disorders Definition : Non-hereditary diseases or associated conditions that cause the platelets (the blood cells essential for coagulation) to not function properly. Platelets are blood cells that are essential for blood clotting. Platelet disorders can include inappropriate number of platelets (too many or too few), or normal number but inappropriate functioning of the platelets. Any platelet disorder affects blood clotting. Disorders of platelet function can be caused by congenital diseases or acquired conditions. Acquired platelet function disorders are disorders of inappropriate platelet function, and that develop as a result of another disease or condition (acquired). In many cases, the platelet count may be normal or even elevated, but evidence of a bleeding disorder will be present.
1Up Health > Health Links Directory > Conditions And Diseases: Blood Disorders:
Disorders Differentiation of platelet versus coagulation defects, presentation,bleeding caused by qualitative platelet disorders and many more topics.
http://www.1uphealth.com/links/blood-disorders-platelet.html
Meet Others
Message Area Adults with platelet disorders. Are you an adult and haveITP? Message Area - Parents of Children with platelet disorders.
http://www.itppeople.com/discuss.htm

Extractions: Contribute via the United Way, CFC, car donations, matching gifts... Meet Others Many of us would like company in our plight, therefore we have designed several ways to meet and keep in touch with others who have ITP. Message Area - Adults with Platelet Disorders Are you an adult and have ITP? Have a friend or loved one in that category? Post a message and hear from others in the same situation. Message Area - Parents of Children with Platelet Disorders Do you have a child with ITP? Did you have ITP as a child? This area is for you. Message Area - Teens with Platelet Disorders A special place for our young folks to chat. The Message Archives Where do all the messages go? Here are some prior discussion group messages for you to view. ITP Inspirations Does ITP spark your creativity? View the projects and poetry of ITP people.
Archive List
Do not reply to these messages. Parents of Children with platelet disorders Discussion Archive. Teens with platelet disorders - Discussion Archive.
http://www.itppeople.com/archive.htm

Extractions: Contribute via the United Way, CFC, car donations, matching gifts... Message Archives The Platelet Disorder Support Association supports some very active discussion groups. You can find them listed at www.pdsa.org We periodically delete the messages in these discussion groups. Sample discussion groups appear in this space. Note: This is a READ ONLY area. Do not reply to these messages. Parents of Children with Platelet Disorders - Discussion Archive The Adult discussion group is in a different format and is self-archived. Teens with Platelet Disorders - Discussion Archive Platelet Disorder Support Association
From The Grand Rounds Archive At Baylor
Bleeding time is prolonged in thrombocytopenia, qualitative platelet disorders, vonWillebrand's Disease, fibrinolytic states, afibrinogenemia, vasculitis, and
http://www.bcm.tmc.edu/oto/grand/11394.html

Extractions: The information contained within the Grand Rounds Archive is intended for use by doctors and other health care professionals. These documents were prepared by resident physicians for presentation and discussion at a conference held at The Baylor College of Medicine in Houston, Texas. No guarantees are made with respect to accuracy or timeliness of this material. This material should not be used as a basis for treatment decisions, and is not a substitute for professional consultation and/or peer-reviewed medical literature. BLEEDING DISORDERS IN PEDIATRIC OTOLARYNGOLOGY Warren E. Morgan, M.D. Bleeding disorders may complicate many routine otolaryngology procedures. This may result from technical errors, but bleeding associated with defects in the coagulation system may be difficult to control. All otolaryngologists should be aware of common bleeding disorders and their treatment. Normal coagulation may be divided into three phases: vascular response, platelet activation, and the coagulation cascade. The initial vascular response of vasoconstriction occurs immediately after the injury. Platelet adherence occurs in response to collagen exposure by endothelial damage. Further platelet adhesion is mediated through specific platelet receptors and mediators creating an unstable hemostatic plug. Coincident with the platelet activation, the coagulation cascade is initiated by the release of tissue thromboplastin and contact-activating factors. The coagulation cascade forms a fibrin matrix that reinforces the platelet plug.
NHF | Resources | Nurses
platelet disorders 1. Mammen, EF, Comp, PC, Gosselin, R. et al. International Registryon Recombinant Factor VIIa and Congenital platelet disorders Group.
http://www.hemophilia.org/resources/nurses/bibliography4.htm
Guide'EM
Clotting Factor Disorders Hemophilias. 7 .1 .3, Hematologic disorders Hemostatic Disorders platelet disorders. 7 .1 .3 .1, Hematologic
http://www.ed.bmc.org/EMGuidelines/guideEM.cfm?CCN1_ID=7
ThirdAge - Adam - Acquired Platelet Function Defect
Alternative Names Acquired qualitative platelet disorders; Acquired disordersof platelet function. Causes, incidence, and risk factors
http://www.thirdage.com/health/adam/ency/article/000546.htm

Extractions: document.write(''); document.write(''); document.write(''); document.write(''); document.write(''); document.write(''); document.write(''); document.write(''); Activities Computers Family Tree Health ... Prevention Definition: Non-hereditary diseases or associated conditions that cause the platelets (the blood cells essential for coagulation) to not function properly. Causes, incidence, and risk factors: Platelets are blood cells that are essential for blood clotting. Platelet disorders can include inappropriate number of platelets (too many or too few), or normal number but inappropriate functioning of the platelets. Any platelet disorder affects blood clotting. Disorders of platelet function can be caused by congenital diseases or acquired conditions. Acquired platelet function disorders are disorders of inappropriate platelet function, and that develop as a result of another disease or condition (acquired). In many cases, the platelet count may be normal or even elevated, but evidence of a bleeding disorder will be present.
Platelet Function Disorders
Platelet function disorders. Definition. Periodicals Liesner, RJ, and SJ Machin. platelet disorders. British Medical Journal 314, no. 7083 (1997) 809.
http://www.healthatoz.com/healthatoz/Atoz/ency/platelet_function_disorders.html

Extractions: Definition Platelets are elements within the bloodstream that recognize and cling to damaged areas inside blood vessels. When they do this, the platelets trigger a series of chemical changes that result in the formation of a blood clot. There are certain hereditary disorders that affect platelet function and impair their ability to start the process of blood clot formation. One result is the possibility of excessive bleeding from minor injuries or menstrual flow. Description Platelets are formed in the bone marrowa spongy tissue located inside the long bones of the bodyas fragments of a large precursor cell (a megakaryocyte). These fragments circulate in the bloodstream and form the first line of defense against blood escaping from injured blood vessels. Damaged blood vessels release a chemical signal that increases the stickiness of platelets in the area of the injury. The sticky platelets adhere to the damaged area and gradually form a platelet plug. At the same time, the platelets release a series of chemical signals that prompt other factors in the blood to reinforce the platelet plug. Between the platelet and its reinforcements, a sturdy clot is created that acts as a patch while the damaged area heals. There are several hereditary disorders characterized by some impairment of the platelet's action. Examples include von Willebrand's disease, Glanzmann's thrombasthenia, and
Bernard-Soulier.html
Inherited giant platelet disorders. Giant platelet disorders in AfricanAmericanchildren misdiagnosed as idiopathic thrombocytopenic purpura.
http://tbase.jax.org/docs/Bernard-Soulier.html

Extractions: April 2000 features mouse knockouts harbouring a targeted replacement of the glycoprotein 1a, alpha polypeptide ) gene with the a phosphoglycerate kinase-neo r cassette. Ware et al. report that -null mice (TBASE:5858) are viable and fertile, yet they recapitulate the salient characteristics of the human Bernard-Soulier Syndrome (BSS) . BSS is an autosomal recessive bleeding disorder that presents with mild thrombocytopenia and circulating "giant" platelets. The defect responsible for the lack of ristocetin-mediated platelet function is an absent platelet membrane receptor, the glycoprotein (GP) Ib-IX-V complex, and an inability of platelets to agglutinate through an interaction with plasma von Willebrand factor -deficient mice(TBASE:5858) display increased bleeding times (>10 min) and platelet sizes, and reduced platelet counts (30% of normal level). Moreover, the disordered and vacuolated demarcation membrane system of mutant megakaryocytes resembles the aberrant ultrastructure noted in human megakaryocytes prepared from
Other Disorders Of Coagulation
Back to top. platelet disorders. The main clinical features of platelet disordersare they are usually acquired; inherited disorders are rare.
http://www.novoseven.com/content/haemostasis/disease_areas/other_disorders_of_co

Extractions: Search novoseven.com ... Haemostasis Award 2003 Other disorders of coagulation Print Factor deficiencies Platelet disorders Quantitative disorders (thrombocytopenia and thrombocytosis) ... Coagulation disorders associated with inhibitors The complexity of the mechanism of coagulation and the large number of proteins involved in its initiation and regulation sets the potential for a myriad of possible inherited disorders. Such disorders are, however, relatively rare. Acquired disorders of specific coagulation factors (inhibitors) are often the result of replacement therapy in factor-deficient patients, but may also be spontaneous or associated with other systemic disorders. Both inherited and acquired disorders of coagulation frequently result in bleeding diatheses and often present a challenge to treating clinicians. Von Willebrand's disease - With an incidence of ~1%, this is the most common inherited disorder of haemostasis. 70% of patients are classified as Type 1 (quantitative deficiency of von Willebrand Factor (VWF) - antigenically and functionally normal protein) and 20-30% as Type 2 (qualitative deficiency of VWF). Both Type 1 and 2 can be further classified into subtypes and their inheritance patterns vary. Type 3 deficiency refers to the almost complete absence of VWF and bleeding problems may be severe. In most cases of von Willebrand's disease, bleeding time is prolonged; 60% have frequent or severe nose bleeds, 40% report easy bruising, 35% have gingival bleeding, 10% have GI bleeds, and 35% of women have menorrhagia. Major bleeds outside of trauma and surgery are rare.
Health Ency.: Disease: Acquired Platelet Function Defect
Alternative names Acquired qualitative platelet disorders; Acquireddisorders of platelet function. Definition Nonhereditary diseases
http://www.accessatlanta.com/shared/health/adam/ency/article/000546.html

Extractions: Important notice Ency. home Disease A Acquired platelet function defect Overview Symptoms Treatment Prevention Alternative names: Acquired qualitative platelet disorders; Acquired disorders of platelet function Definition: Non-hereditary diseases or associated conditions that cause the platelets (the blood cells essential for coagulation) to not function properly. Causes and Risks Platelets are blood cells that are essential for blood clotting. Platelet disorders can include inappropriate number of platelets (too many or too few), or normal number but inappropriate functioning of the platelets. Any platelet disorder affects blood clotting. Disorders of platelet function can be caused by congenital diseases or acquired conditions. Acquired platelet function disorders are disorders of inappropriate platelet function, and that develop as a result of another disease or condition (acquired). In many cases, the platelet count may be normal or even elevated, but evidence of a bleeding disorder will be present. Myeloproliferative disorders such as primary thrombocytopenia polycythemia vera chronic myelogenous leukemia , and myelofibrosis can produce abnormalities in platelet function. Other causes include
Small Animal 84
platelet disorders. Linda L. Werner, DVM, Ph.D., ACVIM, ACVP. IDEXXVeterinary Services, Inc. 2825 KOVR Drive. West Sacramento, CA 95691.
http://www.wildwestspeakers.com/small_animal_84.htm

Extractions: Platelet Disorders Linda L. Werner, DVM, Ph.D., ACVIM, ACVP IDEXX Veterinary Services, Inc. 2825 KOVR Drive West Sacramento, CA 95691 Bleeding due to platelet deficiency or dysfunction generally appears clinically as one or more of the following: Petechiae, ecchymoses, purpuras (spontaneous small vessel-type bleeding) Trauma-induced bleeding of many types, including venipuncture, surgical, pressure or abrasion Mucosal bleeding (GI, gingival, epistaxis, urogenital) The most common causes of clinical bleeding from simple platelet disorders are severely thrombocytopenic states where platelet counts fall well below the 20-40 thousand/ul range. Most common are the following: Immune Mediated Thrombocytopenia - IMT Primary* (idiopathic) Secondary* infectious, drug or vaccine-induced (many drugs, FeLV*, FIV, EIAV*, rickettsial*, Babesiosis) Defects in Hematopoiesis (reduced megakaryocyte production) Neoplasia* - myelo- or lymphoproliferative Infectious* - FeLV, E. Canis, EIAV, sepsis Drugs estrogens, chloramphenicol, sulfas, cytotoxic drugs, many can cause idiosyncratic myelosuppression Immune Mediated* Platelet-type bleeding can also occur with defects of platelet function, both congenital and acquired. The most common is von Willebrand's Disease, which clinically can be described as an extrinsic failure of platelet function due to lack of VWF, an important protein functioning in the adhesion step of platelet activation. Platelet function defects include the following types:
Featured Topic: Rare Bleeding Disorders: A Detailed Guide To Bleeding Disorders
platelet disorders. Platelets are small proteincontaining cellular fregmentsthat circulate in the blood. They platelet disorders. von
http://www.hemophiliagalaxy.com/1_PATIENTS/topics/rare/rare03.html

Extractions: In this section: Introduction The Magees: Making It Against All Odds Detailed Guide to Bleeding Disorders Quick Comparison of Bleeding Disorders Internet Resources Acknowledgements Below is a detailed look at some of the many bleeding disorders affecting people worldwide. You'll learn about the most common inherited bleeding disorder (hint: it's not hemophilia), and discover the difference between factor deficiencies and platelet disorders. For a brief overview, see A Quick Comparison of Selected Bleeding Disorders In general, bleeding disorders can be divided into two major categories: Factor deficiencies. Clotting factors are specialized proteins circulating in the blood. These factors work together in a chain reaction to form clots. If even one of these factors is missing or deficient, clotting is impaired. Hemophilia is perhaps the best-known factor deficiency. Specifically, a deficiency of factor VIII results in hemophilia A, while a deficiency of factor IX leads to hemophilia B. There are many other factor deficiencies, however, as you can see from the summaries below. Platelet disorders.
Mary K. Boudreaux
research interests include evaluating the role of platelets in disease pathogenesisand identification and characterization of congenital platelet disorders.
http://www.vetmed.auburn.edu/~boudrmk/

Extractions: email: boudrmk@vetmed.auburn.edu Dr. Mary K. Boudreaux, Associate Professor of Clinical Pathology in the Department of Pathobiology , earned the DVM degree in 1979 at Louisiana State University . She practiced veterinary medicine in California before beginning a clinical pathology residency program under Dr. Julia Blue at Cornell in 1981. She developed an interest in hemostasis and platelet pathophysiology and in 1986 earned a PhD degree in a program jointly sponsored by Cornell University and the Wadsworth Center for Laboratories and Research in Albany. Her co-directors for the research which evaluated regulatory control of cAMP phosphodiesterase in canine platelets were Dr. David O. Slauson, Dr. James Catalfamo, and Dr. W. J. Dodds. She joined the faculty at Auburn in 1986 and has developed research interests involving platelets. My research interests include evaluating the role of platelets in disease pathogenesis and identification and characterization of congenital platelet disorders. Our platelet laboratory can isolate mammalian platelets from a variety of species for evaluation of platelet reactivity, including platelet aggregation and 14C-serotonin release. We have developed a monoclonal antibody that detects a receptor-induced binding site (RIBS) on canine fibrinogen. The antibody has been useful in detection of in vivo platelet activation in dogs using flow cytometry. The antibody has also been useful in the characterization of congenital platelet disorders. As an extension of our interest in congenital platelet disorders we recently began to evaluate the genes encoding for the platelet glycoprotein complex IIb-IIIa. Our laboratory was the first to determine the normal sequences for these genes in dogs and we were also the first to determine the genetic basis for Glanzmann's thrombasthenia in Great Pyrenees dogs and Otterhounds.
OBGYN.net - Fact Sheet: Menorrhagia And Mematologic Disorders
simple tests to assess platelet dysfunction in women, since 1998, the US has hada simple, highlysensitive test to detect platelet disorders, including von
http://www.obgyn.net/displayarticle.asp?page=/news/menorrhagia_faqs
Platelet Physiology 2002 Minutes
disorders. Dr. Catherine Hayward presented information on developingevidencebased approaches to the diagnosis of platelet disorders.
http://www.med.unc.edu/isth/02sscminutes/02plateletphysio.html

Extractions: There were two main themes addressed in this meeting of the Platelet Physiology Subcommittee. The first one was platelet-leukocyte interactions, an area where tremendous new information has become available over the last few years. The second theme was platelet function disorders with a focus on a specific methodology (Platelet Function Analyzer, PFA-100). Several speakers reviewed recent information on different aspects of platelet-leukocyte interactions. Dr. Bruce Furie reviewed interactions between P-selectin and PSGL-1. Dr. Jose Lopez reviewed the interactions between GPIb and MAC-1. Dr. Chiara Cerletti focused on the signaling interactions between platelets and leucocytes with a focus on Srk kinases. Dr. Michael Berndt reviewed the regulation of P-selectin binding to PSGL-1 by elastase and cathepsin G. Lastly, Dr. Alan Michelson reviewed recent information on circulating monocyte-platelet aggregates as a sensitive marker of in vivo platelet activation in patients. The second half of the session focused on presentations by the Working Group on Platelet Function Disorders. Despite major advances in our understanding of platelet physiology and available newer methods, our understanding of the mechanisms in patients with platelet function disorders remains low. In the vast majority of patients with inherited abnormalities in platelet responses, the underlying mechanisms leading to the platelet dysfunction are unknown. The focus of this session was on the role of PFA-100 in the diagnosis of platelet function disorders, excluding von Willebrand disease. PFA-100 has become widely available and is being used in the evaluation and management of patients with vWD and platelet function disorders.

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