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Platelets play an important role regarding coagulation by contributing to thrombus formation by platelet adhesion, aggregation, and α-/δ-granule secretion. Inherited platelet disorders (IPDs) are a very heterogeneous group of disorders that are phenotypically and biochemically diverse. Platelet dysfunction (thrombocytopathy) can be accompanied by a reduction in the number of thrombocytes (thrombocytopenia). The extent of the bleeding tendency can vary greatly. Symptoms comprise mucocutaneous bleeding (petechiae, gastrointestinal bleeding and/or menorrhagia, epistaxis) and increased hematoma tendency. Life-threatening bleeding can occur after trauma or surgery. In the last years, next-generation sequencing had a great impact on unrevealing the underlying genetic cause of individual IPDs. Because IPDs are so diverse, a comprehensive analysis of platelet function and genetic testing is indispensable., Competing Interests: Research funding from CSL Behring and Takeda (to B.Z.)., (Thieme. All rights reserved.)

Competing Interests: The authors declare that they have no conflict of interest.

Although mild skin and mucosal bleeding symptoms are common in patients with inherited bleeding disorders, both can also be observed in healthy individuals. These bleeding symptoms may be caused by disorders of primary hemostasis (i.e., von Willebrand disease and platelet function disorders), mild deficiencies of clotting factors and some rare hyper fibrinolytic disorders are also included. To date, mild bleeding symptoms pose a frequent and substantial diagnostic challenge, and the definitive diagnosis of inherited bleeding disorders is not feasible in a vast majority of individuals despite an extensive laboratory workup. However, it must be diagnosed precisely to avoid severe complications and decrease bleeding risks before invasive procedures. Thus, a comprehensive diagnostic approach, from structured patient history to highly specialized laboratory diagnosis, is warranted to establish diagnosis of inherited bleeding disorders. Furthermore, the prophylaxis should be offered to prevent excessive bleeding in these patients with bleeding symptoms, even if they remain undiagnose of bleeding disorders.

Mild inherited bleeding disorders are relatively common in the general population. Despite recent advances in diagnostic approaches, mild inherited bleeding disorders still pose a significant diagnostic challenge. Hemorrhagic diathesis can be caused by disorders in primary hemostasis (von Willebrand disease, inherited platelet function disorders), secondary hemostasis (hemophilia A and B, other (rare) coagulant factor deficiencies) and fibrinolysis, and in connective tissue or vascular formation. This review summarizes the currently available diagnostic methods for mild bleeding disorders and their pitfalls, from structured patient history to highly specialized laboratory diagnosis. A comprehensive framework for a diagnostic approach to mild inherited bleeding disorders is proposed., (© 2016 International Society on Thrombosis and Haemostasis.)

Functional disorders of platelets can involve any aspect of platelet physiology, with many different effects or outcomes. These include platelet numbers (thrombocytosis or thrombocytopenia); changes in platelet production or destruction, or capture to the liver (Ashwell receptor); altered adhesion to vascular injury sites and/or influence on hemostasis and wound healing; and altered activation or receptor functions, shape change, spreading and release reactions, procoagulant and antifibrinolytic activity. Procoagulant membrane alterations, and generation of thrombin and fibrin, also affect platelet aggregation. The above parameters can all be studied, but standardization and quality control of assay methods have been limited despite several efforts. Only after a comprehensive clinical bleeding assessment, including family history, information on drug use affecting platelets, and exclusion of coagulation factor, and tissue deficits, should platelet function testing be undertaken to confirm an abnormality. Current diagnostic tools include blood cell counts, platelet characteristics according to the cell counter parameters, peripheral blood smear, exclusion of pseudothrombocytopenia, whole blood aggregometry (WBA) or light transmission aggregometry (LTA) in platelet-rich plasma, luminescence, platelet function analysis (PFA-100) for platelet adhesion and deposition to collagen cartridges under blood flow, and finally transmission electron microscopy to exclude rare structural defects leading to functional deficits. The most validated test panels are included in WBA, LTA, and PFA. Because platelets are isolated from their natural environment, many simplifications occur, as circulating blood and interaction with vascular wall are omitted in these assays. The target to reach a highly specific platelet disorder diagnosis in routine clinical management can be exhaustive, unless needed for genetic counseling. The elective overall assessment of platelet function disorder primarily aims at better management of hemostasis in case of emergency surgery or other interventions and acute bleeding events., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

A personal history of excessive mucocutaneous bleeding is a key component in the diagnosis of a number of mild bleeding disorders, including von Willebrand disease (VWD), platelet function disorders (PFD), and coagulation factor deficiencies. However, the evaluation of hemorrhagic symptoms is a well-recognized challenge for both patients and physicians, because the reporting and interpretation of bleeding symptoms is subjective. As a result, bleeding assessment tools (BATs) have been developed and studied in a variety of clinical settings. This work has been pioneered by a group of Italian researchers, and the resultant 'Vicenza Bleeding Questionnaire' stands as the original BAT. In this review, we will discuss the modifications of the Vicenza Bleeding Questionnaire that have taken place over the years, as well as the validation studies that have been published. Other BATs that have been developed and published will be reviewed, as will the special situations of assessing pediatric bleeding as well as menorrhagia. Lastly, the clinical utility of BATs will be discussed including remaining challenges and future directions for the field., (© 2012 International Society on Thrombosis and Haemostasis.)

Objective: To evaluate the incidence of perioperative bleeding among children with mild bleeding disorders who underwent adenotonsillar surgery in our hospital and were treated with our perioperative bleeding prophylaxis protocol., Methods: Retrospective chart review was aimed at determining the perioperative bleeding rate in children with mild bleeding disorders subjected to our prophylactic protocol while undergoing adenotonsillar procedures. Low von Willebrand factor (LVWF), unspecific platelet function disorders (UPFD) and mild factor VII deficiency were considered as mild bleeding disorders. The protocol utilizes intravenous desmopressin, tranexamic acid, NSAID avoidance, and overnight observation., Results: Between 2004 and 2009, 44 children with mild bleeding disorders underwent adenotonsillar procedures in our hospital and were treated with the protocol. One patient (LVWF+UPFD) developed perioperative bleeding (2.3%)., Conclusions: It is possible to obtain low rates of perioperative bleeding in children with mild bleeding disorders undergoing adenotonsillar procedures, provided there is a well-timed diagnosis and an adequate prophylaxis protocol. We believe that further efforts must be directed at preoperative diagnosis of mild bleeding disorders to ensure safer surgeries., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Congenital mild bleeding disorders (MBDs) are very prevalent and are the source of frequent diagnostic problems. Most MBDs are categorized as disorders of primary hemostasis (ie, type 1 VWD and platelet function disorders), but mild or moderate deficiencies of clotting factors and some rare hyperfibrinolytic disorders are also included. These patients have abnormal bleeding from the skin and mucous membranes, menorrhagia, and disproportionate hemorrhages after trauma, invasive procedures, and surgery. This review addresses the main problems that physicians and hemostasis laboratories confront with the diagnosis of these patients, including: discerning normal/appropriate from pathological bleeding, the role and yield of screening tests, the lack of distinctive bleeding pattern among the different diseases, the inherent difficulties in the diagnosis of type 1 VWD and the most common platelet functional disorders, improvements in assays to measure platelet aggregation and secretion, and the evidence that most of the patients with MBDs end up without a definite diagnosis after exhaustive and repeated laboratory testing. Much research is needed to determine the pathogenesis of bleeding in MBD patients. Better standardization of current laboratory assays, progress in the knowledge of fibrinolytic mechanisms and their laboratory evaluation, and new understanding of the factors contributing to platelet-vessel wall interaction, along with the corresponding development of laboratory tools, should improve our capacity to diagnose a greater proportion of patients with MBDs.

Inherited thrombocytopathies are much less frequent in comparison to acquired platelet function disorders. However, congenital disorders can lead to severe bleeding tendency and are often not diagnosed. They are induced by different platelet defects based on disorders of platelet adhesion, receptors, secretion and signal transduction. In some cases they are associated with thrombocytopenia, giant platelets and various comorbidities. This article gives an overview regarding diverse defects, their diagnosis and treatment options.

During the haemostatic response, the formation of a primary platelet plug limits bleeding and provides a surface for clotting factors to assemble and become activated. The initial platelet plug is stabilized by fibrin monomers, covalently cross-linked by FXIII, forming a platelets-fibrin thrombus. Defects in platelets as well as inherited deficiencies of coagulation factors including fibrinogen, FII, FV, FV + FVIII, FVII, FX, FXI and FXIII deficiencies, generally lead to lifelong bleeding disorders, whose severity of bleeding symptoms is heterogeneous in platelets abnormalities but generally inversely proportional to the degree of the factor deficiency in rare bleeding disorders (RBDs). The prevalence of platelet defects among the general population has not been established, whereas for RBDs it ranges from approximately 1 in 2 million to 1 in 500,000, being higher in countries where consanguineous marriages are diffused. As a consequence of the rarity of these deficiencies, the type and severity of bleeding symptoms, the underlying molecular defects, and the actual management of bleeding episodes are not well established. In this review the main features, diagnosis, available treatment options and treatment complications of the platelet disorders, caused by abnormalities in platelet receptors for adhesive proteins, platelet receptors for soluble agonists, platelet granules, signal transduction pathways, or procoagulant phospholipids will be discussed by Dr Cattaneo, whereas fibrinogen deficiency and FXIII deficiency will be described by Dr Inbal and Dr de Moerloose, respectively. Finally, the update of the Rare Bleeding Disorders Database will be presented by Dr Spreafico.

Background and Objectives: Mucocutaneous bleeding (MCB) is the main expression of inherited disorders of primary hemostasis. However, the relative prevalence of these disorders, their clinical differential diagnosis, and the proportion of patients with MCB of unknown cause (BUC) after an initial comprehensive laboratory testing are unknown., Design and Methods: We studied prospectively 280 consecutive patients with MCB and 299 matched controls, using strict inclusion and exclusion criteria. A single physician recorded the clinical data in a bleeding score and estimated the severity of bleeding in clinical categories. Laboratory criteria for the diagnosis of von Willebrand's disease (VWD) and platelet function defects were established from reference values derived from controls., Results: Fifty patients (17.9%) had VWD (type 1VWD=45, type 2=5). Platelet function defects and mild clotting factor deficiencies were found in 65 (23.2%) and 11 (3.9%) patients, respectively. Thirteen (11.5%) patients had combined defects. The remaining 167(59.6%) patients had BUC, with prolonged bleeding time in 18.6% as their only abnormality. All these disorders, including BUC, were clinically undistinguishable. Moreover, no relationship was found between the severity of bleeding and VWF/platelet function variables., Interpretation and Conclusions: The diagnostic efficacy of a first laboratory testing in patients with hereditary MCB is 40.4%. Most patients have a disease(s) of high prevalence but unknown pathogenesis. Concurrent bleeding disorders in the same patient are frequent. Our results support the proposal that low plasma VWF levels, but also platelet function defects, should be considered risk factors rather than unequivocal causes of hemorrhages.

Background: Skin and mucous membrane hemorrhages are distinctive manifestations of hereditary diseases of primary hemostasis and, among them, the different types of von Willebrand disease and of platelet function disorders are the most prevalent., Aim: To know the relative frequency of these disorders and to know the clinical features of patients with mucocutaneous hemorrhages., Patients and Methods: Five hundred eighty nine patients whose main symptom was the presence of mucocutaneous hemorrhages were studied. Bleeding time, platelet count, coagulant activity of factor VIII (FVIII:C), FvW: Ag and FvW: CoRis and ABO blood group were measured in all patients in a first stage. According to the results of these tests, further studies were decided., Results: In patients younger than 13 years old, male predominated and, in older patients, females consulted with higher frequency. There was a higher proportion of individuals with O blood type than in the normal population. Bleeding time was abnormal in 330 patients (56%). One hundred ten patients (19%) had won Willebrand disease and, among them, one third had a normal bleeding time. Isolated reduction of factor WII activity was found in 66 patients (11%, 51 males) and 32 of these had normal bleeding time. Eighty one patients (14%) were considered to have an hereditary platelet function defect. A precise diagnosis was not achieved in 332 patients (56%)., Conclusions: Among patients consulting for mucocutaneous hemorrhages, 19% had von Willebrand disease, 11 had an isolated reduction of factor VIII activity, 14% had platelet function defects and in 56%, a precise diagnosis was not reached.

Abnormalities that have been reported for platelet indices and function, coagulation factors and tests, and the fibrinolytic system in hypothyroidism are reviewed. These abnormalities, although usually of limited importance clinically, may occasionally lead to major bleeding episodes and to diagnostic confusion.

In a retrospective study the results of laboratory investigations were correlated with actual or previous bleeding symptoms of 40 patients. In 22 patients, a defect of hemostasis was documented in the laboratory, whereas the bleeding disorder, suggested by severe hemorrhage, could not be classified in 3 additional patients. In the remaining 15 individuals, no abnormality could be detected by the available laboratory methods. In the group with a documented bleeding disorder, 13 of 22 patients had prolonged bleeding following dental extraction or other surgery of the oral cavity. Other bleeding symptoms were equally distributed among patients with and without a documented defect. 3 patients had a positive family history, i.e. relatives with a hemorrhagic tendency. In 6 patients, a correlation between bleeding and the ingestion of acetylsalicylic acid could be established, while in 4 it was probable. Hemorrhagic complications following oral surgery, particularly in combination with drugs known to interfere with platelet function and a positive family history, strongly suggest an abnormality of hemostasis. Among the 22 patients with a documented defect of hemostasis, only 6 were found who did not present at least one of these leading symptoms.

The author has commented on the more frequently encountered acquired haemostatic defects and briefly outlined the relevant routine laboratory investigations that should be performed and their clinical significance. It is important that any replacement therapy with plasma, coagulation factor preparations and concentrates, and platelet infusions should be given promptly and their effectiveness assessed at regular intervals (Urbaniak and Cash, 1977). One's approach to the bleeding patient should be a combination of clinical assessment and interpretation of laboratory data, thus allowing an effective flexible policy to be followed.

A bleeding disorder, probably familial, with absent adrenaline-induced platelet aggregation and lack of secondary aggregation response to ADP and platelet activating factor (PAF), is described. The laboratory findings do not fit any hitherto recognized hemorrhagic disease. The disorder was not caused by alpha-adrenergic receptor deficiency, but the ultimate defect has not yet been unraveled. This patient illustrates that a normal response to more than one aggregating stimulus is necessary for normal hemostasis, and indicates a physiopathological role for adrenaline not hitherto recognized. Whether this also applies to PAF remains to be proven.

Based upon a survey of the pathophysiology of haemostasis, the causes of epistaxis in the dog are discussed, and guidelines for a diagnostic and therapeutic approach are given.

In two siblings, brother and sister, with a history of bleeding Bernard-Soulier syndrome was diagnosed: The stronger affected sister showed a high percentage of giant blood platelets, an abnormal platelet spreading test and a defect in ristocetin and bovine fibrinogen-induced platelet aggregation. In addition, the content of platelet ATP, ADP and AMP was increased. As leucocyte counts were consistently decreased in the more seriously affected anaemic sister, repeated cytochemical examinations of the haemopoietic cells were carried out, revealing maturational defects in the whole haemopoietic system. Therapy with tranexamic acid reduced bleeding in the sister and she has not been anaemic since.

We have studied a woman with a history of mild bruising and bleeding, with a normal platelet count and normal clotting factors, who had platelets that appeared grey when stained and viewed under the microscope. Unlike the grey platelet syndrome, the abnormality was only evident when blood had been collected into EDTA and not when citrate or heparin was used as anticoagulant. This 'pseudo grey platelet syndrome' was associated with platelet dense body and alpha granule secretion with no aggregation and occurred on removal of extracellular Ca2+. We discovered that a plasma factor was responsible which could be an immunoglobulin but which is clearly different from the EDTA-sensitive antibodies which cause platelet aggregation and agglutination. We were not able to demonstrate a relationship between the mild bleeding tendency and the in vitro abnormality.