Acquired von Willebrand disease in twins with autoimmune hypothyroidism: response to desmopressin and L-thyroxine therapy

Prolonged Bleeding After Dental Extraction Due to Decreased Serum Level of Von Willebrand Factor Caused by Untreated Profound Hypothyroidism

BACKGROUND

Delayed diagnosis of hypothyroidism may result in atypical presentations. Here, we report a case with decreased serum level and activity of von Willebrand factor due to untreated profound hypothyroidism.

OBSERVATION

A 9-year-old girl, presented with prolonged gingival bleeding after dental extraction. Clinical findings of the case were consistent with hypothyroidism, and the laboratory workup results revealed decreased serum level and activity of von Willebrand factor associated with profound hypothyroidism. Restoration of euthyroidism normalized the coagulation parameters.

CONCLUSION

Delayed diagnosis of hypothyroidism may lead to atypical presentations such as bleeding diathesis. Profound hypothyroidism should be considered in the differential diagnosis of acquired von Willebrand disease to avoid undue treatment.

Acquired von Willebrand Syndrome in a Patient Undergoing Extracorporeal Membrane Oxygenation: A Case Report

Acquired von Willebrand syndrome (AvWS) is a rare bleeding disorder caused by dysfunction of the von Willebrand factor (vWF), leading to bleeding manifestations. It usually occurs due to an underlying disorder in patients with no family or personal history of bleeding diathesis. The exact mechanism causing this syndrome is not fully understood, but it involves a complex interplay of factors. Specifically, vWF deficiency or reduced activity can occur due to antibodies, adsorption of vWF onto tumor cells, shear stress, or increased proteolysis. We describe a patient with severe, right-sided heart failure secondary to idiopathic pulmonary hypertension. The patient was admitted to the intensive care unit to be placed on a venoarterial extracorporeal membrane oxygenation (VA ECMO) machine while awaiting bilateral lung transplantation. A few hours after initiation of VA ECMO, the patient experienced epistaxis and continuous bleeding from the cannula tips. The laboratory investigations were based on the measurements of vWF antigen (vWF:Ag), vWF ristocetin cofactor activity (vWF:RCo), and multimer analysis. The obtained results revealed a decreased VWF:RCo/VWF:Ag ratio (<0.7) and the loss of high-molecular-weight multimers of vWF, thus confirming the diagnosis of AvWS. This report reviews how to make the clinical diagnosis of AvWS, including a discussion of necessary laboratory results and their pitfalls, and highlights the importance of having a high index of suspicion of AvWS in the ECMO population so that laboratory values are obtained on time to allow for treatment and successful recovery.

Acquired von Willebrand Syndrome

Acquired von Willebrand syndrome can occur in the setting of myeloproliferative neoplasms; plasma cell dyscrasias and other lymphoproliferative disorders; autoimmune conditions; and causes of increased shear forces, such as aortic stenosis or other structural heart disease and mechanical circulatory support. The depletion of von Willebrand factor, especially high-molecular-weight multimers, can lead to mucocutaneous bleeding and the formation of arteriovenous malformations, particularly in the gastrointestinal tract. Management focuses on correction of the underlying cause when possible, but may include intravenous immunoglobulins, von Willebrand factor concentrate, rituximab, or antiangiogenic therapy depending on the clinical context.

Acquired von Willebrand syndrome: focused for hematologists

The acquired von Willebrand syndrome (AvWS) is a rare bleeding disorder with laboratory findings similar to those of inherited von Willebrand disease. However, unlike the inherited disease, AvWS occurs in persons with no personal and family history of bleeding and is often associated with a variety of underlying diseases, most frequently lymphoproliferative, myeloproliferative and cardiovascular disorders. After the presentation of a typical case, in this narrative review we discuss the more recent data on the pathophysiology, clinical, laboratory and therapeutic aspects of this acquired bleeding syndrome. We chose to focus particularly on those aspects of greater interest for the hematologist.

Acquired von Willebrand's syndrome caused by primary hypothyroidism in a 5-year-old girl

Background Acquired von Willebrand's syndrome (aVWS) associated with hypothyroidism is rare in children and more often diagnosed during the peripubertal period in the context of Hashimoto's thyroiditis. Case presentation A 5-year-old girl was referred to the paediatric haematology unit for rectal bleeding, anaemia and prolonged activated partial thromboplastin time (aPTT). Her developmental and learning skills were normal. The physical examination revealed severe short stature (height SDS: -3.6) with overweight (body mass index SDS: 1.8) and clinical sign of hypothyroidism. Laboratory investigation revealed aVWS type 1 associated with severe primary hypothyroidism. Anti-thyroid antibodies were negative and thyroid ultrasound found thyroid hypoplasia in favour of congenital hypothyroidism. Restoration of euthyroidism was associated with increased growth velocity and normalisation of coagulation parameters. Conclusion This report highlights the importance of excluding an underlying pathology (including hypothyroidism) in children with suspected VWS, even in young age.

Hemostatic changes in thyroid diseases

Several studies have reported hemostatic abnormalities, both in terms of bleeding or thrombosis, in patients with various thyroid dysfunctions. The aim of this review is to briefly discuss the relationship between thyroid disorders and hemostasis (i.e. primary hemostasis, coagulation factors and fibrinolytic system). From the analysis of the more recent literature data, it appears evident that most of the coagulation abnormalities associated with thyroid disorders are a consequence of a direct action of thyroid hormones on the synthesis of various hemostatic factors or a derangement of immune function. On the whole, these data suggest that a hypercoagulable state is present in hyperthyroid patients, while patients suffering from moderate hypothyroidism are at increased risk of thrombosis contrasting with the bleeding tendency of those presenting severe hypothyroidism.

Diagnosis and treatment of acquired von Willebrand syndrome

Acquired von Willebrand syndrome (AVWS) is a rare bleeding disorder that is characterized by structural or functional alterations in von Willebrand factor (VWF) caused by a range of lymphoproliferative, myeloproliferative, cardiovascular, autoimmune, and other disorders. The pathogenic mechanisms responsible for the VWF abnormalities depend on the underlying condition, but include clearance due to binding of paraproteins, inhibition of VWF, adsorption to the surface of platelets, increased fluid shear stress, and resultant proteolysis or, more rarely, decreased synthesis. The diagnosis and treatment of AVWS are complicated by the need for multiple laboratory tests and the management of bleeding risk in a typically elderly population with serious underlying conditions that predispose towards thrombosis. Recently developed diagnostic algorithms, based on standard laboratory assays, may assist clinicians with the diagnostic workup and help differentiate between AVWS and von Willebrand disease (VWD) types 1 and 2. AVWS should be considered in all patients with new-onset bleeding whenever laboratory findings suggest VWD, particularly in the presence of an AVWS-associated disorder. AVWS testing is also recommended prior to surgery or an intervention with a high risk of bleeding in any individual with an AVWS-associated disorder. Treatment of the underlying condition using immunosuppressants, surgery, or chemotherapy, can lead to remission of AVWS in some individuals and should always be considered. Strategies to prevent and/or treat bleeding episodes should also be in place, including the use of VWF-containing factor VIII concentrates, desmopressin and tranexamic acid. Treatment success will depend largely on the underlying pathogenesis of the disorder.

Congenital von Willebrand's disease and clinical hypothyroidism

Data from case reports and systematic reviews suggest an association of Hypothyroidism and Acquired von Willebrand's syndrome. It is not known if congenital von Willebrand's disease is associated with hypothyroidism in a similar way. The aim of this study was to identify the association of congenital von Willebrand's disease (VWD) with clinical hypothyroidism. A total of 350 cases of congenital VWD were initially screened from our institution database from 1985 to 2010. A careful review of patient records was carried out to see if patients truly had congenital VWD and coexisting clinical hypothyroidism. Patients with uncertain diagnoses or other bleeding disorders were excluded, leading to 197 patients remaining in the final sample. A random age- and sex-matched parallel control group was also obtained from the hospital database. Of 197 patients (mean age 43.8 ± 17.5 years, women 72%) of congenital VWD, 32/197 (16%) were diagnosed with clinical hypothyroidism, while only 11/197 (5.6%) of the matched controls were clinically hypothyroid. Univariate and multivariate analysis demonstrated that VWD was an independent predictor of developing clinical hypothyroidism (OR 3.45; 95% CI 1.65-7.22, P = 0.001). The proportion of patients diagnosed with clinical hypothyroidism was more in the VWD group (P < 0.0001). Our analysis shows a strong association of clinical hypothyroidism in patients with congenital VWD, but future studies will be required to delineate a pathological mechanism. In our opinion, clinicians should consider checking thyroid function in the newly diagnosed and established cases of congenital VWD.

The Role Of von Willebrand Factor In Hemorrhagic And Thrombotic Disorders

von Willebrand factor (VWF) is a multimeric plasma protein that mediates platelet adhesion as well as platelet aggregation at sites of vascular injury and acts as a carrier of factor VIII. Although acquired or inherited VWF deficiency is associated with a bleeding tendency, there is increasing evidence that VWF has a pivotal role in thrombogenesis. In fact, while the presence in the plasma of unusually large VWF multimers, due to a congenital or acquired deficiency of a VWF-cleaving metalloprotease, has been implicated in the pathogenesis of thrombotic thrombocytopenic purpura, high plasma levels of VWF have been associated with an increased risk of both arterial and venous thrombosis. The role of VWF in normal and pathological hemostasis is discussed in this review, and important advances in the pathophysiology, diagnosis, and treatment of VWF-associated disorders are also described.

Acquired Factor VIII and von Willebrand Factor (aFVIII/VWF) Deficiency and Hypothyroidism in a Case With Hypopituitarism

This article reports a female who presented with bleeding, acquired factor VIII and von Willebrand factor (aFVIII-VWF) deficiency, and central deficiency in the thyroid and adrenal axis (Sheehan’s syndrome). After starting hormone replacement therapy, relief of bleeding manifestations was associated with correction of both FVIII and VWF to normal. This report draws attention to a rare association between the acquired form of von Willebrand disease and hypothyroidism of central origin.

Hypothyroidism and acquired von Willebrand's syndrome: a systematic review

Acquired von Willebrand's syndrome type I is the supposed main underlying cause of bleeding tendency in hypothyroid patients. The purpose of this systematic review was to summarize the published evidence on the association between hypothyroidism and acquired von Willebrand's syndrome. All published clinical epidemiological and interventional studies, case reports and in vitro studies that investigated the association between hypothyroidism and acquired von Willebrand's syndrome were identified by a computer-assisted search of the MEDLINE and EMBASE electronic databases. A quality assessment was performed for clinical epidemiological studies. A total of 41 papers were included. A total of 22 epidemiological in vivo studies, two in vitro studies and 47 case reports were finally analyzed. No high quality in vivo study was identified. Almost all bleeding episodes described in the case reports were mucocutaneous. von Willebrand factor (VWF) antigen value was available for 23 patients: median value 28 U/dL (range: 4-45); VWF activity was available for 24 patients: median value 28.5 U/dL (range: <3-55); factor VIII activity was available for 16 patients: median value 47 U/dL (range: 9-74). Acquired von Willebrand's syndrome may be the main factor responsible for bleeding diathesis in overt hypothyroid patients. Even if bleeding episodes are mainly mild and mucocutaneous, blood transfusion, drug administration or surgical procedure may be required.

Acquired von Willebrand syndrome: an update

Acquired von Willebrand syndrome (aVWS) is a rare bleeding disorder with laboratory findings similar to those for congenital von Willebrand disease (VWD). However, unlike congenital VWD, it arises in individuals with no personal or family history of bleeding. aVWS occurs in association with a variety of underlying disorders, most frequently in lymphoproliferative disorders, myeloproliferative disorders, and cardiovascular diseases. Through an analysis of the more recent literature data, the pathophysiology and the clinical, laboratory, and therapeutic aspects of this syndrome are concisely reported in this review.

Recent acquisitions in acquired and congenital von Willebrand disorders

von Willebrand factor is a multimeric plasma protein that mediates platelet adhesion as well as platelet aggregation at sites of vascular injury and, moreover, acts as a carrier of factor VIII. Its deficiency is associated with a bleeding tendency. The progresses in the pathophysiology, diagnosis and management of inherited von Willebrand disease and acquired von Willebrand syndrome will be discussed in this review.

Acquired von Willebrand syndrome: features and management

Acquired von Willebrand syndrome (AvWS) is not a well-known bleeding disorder among clinicians and is associated with various underlying diseases. The clinical manifestations are similar to congenital von Willebrand disease. Diagnosis is confirmed mainly by a decrease of ristocetin cofactor activity (vWF:RCo) and/or collagen binding activity (vWF:CBA) and by vWF multimeric analysis, usually with a selective loss of large multimers. Plasma von Willebrand factor propeptide (vWF:AgII) is a good marker of vWF synthesis. Various pathogenic mechanisms have been proposed, including development of autoantibodies to the von Willebrand factor (vWF), adsorption of vWF onto tumor cells or activated platelets, increase of vWF proteolysis, and mechanical destruction of vWF under high shear stress. Treatment of the underlying disorder may resolve AvWS. Desmopressin (DDAVP) is a first-line therapeutic option. Factor VIII/vWF concentrates and high-dose immunoglobulin infusions are reserved for patients unresponsive to DDAVP.

Hemostasis and thyroid diseases revisited

Several papers have reported various hemostatic abnormalities in patients with thyroid diseases. In this concise review, the traditional associations between hypercoagulable state and hyperthyroidism and between hypocoagulative state and hypothyroidism are critically revised on the basis of more recent literature data. In particular, we analyze the hemostatic balance (primary hemostasis, coagulation factors and fibrinolytic system) in different thyroid disorders. Although most of the studies published so far include limited numbers of patients and their results are sometimes contradictory, we can conclude that hyperthyroidism is generally accompanied by a hypercoagulable state, whereas the hemostatic profile in hypothyroidism and thyroid cancer depends on the severity of the disease.

Acquired von Willebrand Disease in a Patient with Monoclonal Gammopathy of Undetermined Significance

We describe a patient with acquired von Willebrand disease (vWD), who had typical presentation and clinical manifestations of acquired vWD, but correct diagnosis was delayed because of lack of awareness and early recognition. The patient was initially seen at a community hospital with persistent nasal mucosal bleeding and was transfused with an excessive amount of cryoprecipitates before appropriate hemostatic evaluation. Hemostasis work-up revealed that he had classic features of acquired vWD. Further extensive evaluation revealed the patient to have monoclonal gammopathy of undetermined significance (MGUS). He was refractory to a high dose of corticosteroids and had a very transient response to desmopressin acetate (less than 4 hours) but responded well to a high dose of intravenous immunoglobulin (IVIG), which lasted at least 3 weeks with each treatment. He remained very responsive to IVIG 2 years later. His underlying MGUS has not progressed during the past 4 years.

Hypopituitarism, deficiency of factors V and VIII and von Willebrand factor: an uncommon association

A 9 year-old boy with hypopituitarism and blood coagulation abnormalities is presented and discussed. The association between acquired von Willebrand disease and hypothyroidism has been reported but the combination of hypopituitarism and coagulopathy is unusual. Combined multiple clotting deficiencies are rare and, when present, factors V and VIII is the commonest association. Although it is known that hypothyroid patients may have a decrease in von Willebrand's factor (vWf) and factor VIII, there are no reports of hypopituitarism associated with combined deficiency of factors V, VIII, and vWf.

Acquired von Willebrand disease

Acquired von Willebrand disease (AvWD) is a relatively rare acquired bleeding disorder that usually occurs in elderly patients, in whom its recognition may be delayed. Patients usually present predominantly with mucocutaneous bleeding, with no previous history of bleeding abnormalities and no clinically meaningful family history. Various underlying diseases have been associated with AvWD, most commonly hematoproliferative disorders, including monoclonal gammopathies, lymphoproliferative disorders, and myeloproliferative disorders. The pathogenesis of AvWD remains incompletely understood but includes autoantibodies directed against the von Willebrand factor (vWF), leading to a more rapid clearance from the circulation or interference with its function, adsorption of vWF by tumor cells, and nonimmunologic mechanisms of destruction. Laboratory evaluation usually reveals a pattern of prolonged bleeding time and decreased levels of vWF antigen, ristocetin cofactor activity, and factor VIII coagulant activity consistent with a diagnosis of vWD. Acquired vWD is distinguished from the congenital form by age at presentation, absence of a personal and family history of bleeding disorders, and, often, presence of a hematoproliferative or autoimmune disorder. The severity of the bleeding varies considerably among patients. Therapeutic options include desmopressin and certain factor VIII concentrates that also contain vWF. Successful treatment of the associated illness can reverse the clinical and laboratory manifestations. Intravenous immunoglobulins have also shown some efficacy in the management of AvWD, especially cases associated with monoclonal gammopathies. Awareness of AvWD is essential for diagnosis and appropriate management.

Acquired von Willebrand syndromes: clinical features, aetiology, pathophysiology, classification and management

Acquired von Willebrand syndrome (AVWS) associated with hypothyroidism is of type I, results from a decreased synthesis of factor VIII and von Willebrand factor (VWF), responds to desmopressin with normal half-life times for factor VIII and VWF parameters, and disappears after treatment with I-thyroxine. AVWS type I or III, which occurs in a minority of patients with Wilms' tumour in the complete absence of an inhibitor against VWF and no absorption of factor VIII or VWF onto nephroblastoma cells, responds to chemotherapy and/or tumour resection. Hyaluronic acid produced by nephroblastoma cells may be the causative factor in atypical AVWS in Wilms' tumour. AVWS associated with thrombocythaemia of various myeloproliferative disorders is characterized by normal factor VIII and von Willebrand factor antigen (VWF: Ag) levels and a selective deficiency of functional ristocetin co-factor activity (VWF: RCo) and collagen-binding activity (VWF: CBA). AVWS type II in thrombocythaemia is caused by a platelet-dependent proteolysis of large VWF multimers, given the inverse relationship between platelet count and large VWF multimers in plasma and specific increases in the number of proteolytic VWF fragments in plasma. The laboratory findings of AVWS associated with systemic lupus erythematosus or IgG benign monoclonal gammopathy are characterized by a prolonged bleeding time and activated partial thromboplastin time, decreased or absent ristocetin-induced platelet activity, low to very low levels of factor VIII coagulant activity (mean 15%), VWF: Ag (mean 10.7%) and VWF: RCo (mean 6.2%), and a type II multimeric pattern of VWF. Neutralizing and non-neutralizing anti-VWF autoantibodies, usually IgG, have been detected in patient plasma either free or tightly bound to the intermediate and high molecular weight VWF factor VIII particles. The bound auto antibody-antigen complex is rapidly cleared from the circulation, resulting in low levels of factor VIII, VWF parameters as documented by a poor response to desmopressin and VWF factor VIII concentrate. High-dose intravenous immunoglobulin transiently corrects the factor VIII coagulant and VWF levels, lasting for a few weeks in AVWS type II associated with systemic lupus erythematosus or IgG benign monoclonal gammopathy. Prednisolone is effective in AVWS associated with autoimmune disorder. Prednisolone and chemotherapy will not affect AVWS associated with IgG benign monoclonal gammopathy because the monoclonal IgG protein remains to act as an anti-VWF autoantibody. An absorption of VWF to malignant cells has been documented in a few patients with various lymphoproliferative disorders or adrenal carcinoma and suggested to result in a depletion of VWF. The clinical picture of AVWS associated with early-stage IgG multiple myeloma, chronic lymphocytic leukaemia or non-Hodgkin's lymphoma without a paraprotein or no detectable underlying disorder is similar to that of AVWS type II in IgG benign monoclonal gammopathy but poorly documented with regard to the underlying immune mechanism of AVWS. The mechanical destruction of large VWF multimers may be of relevance in conditions in which the shear rate of flowing blood is increased, as may occur in cases of aortic stenosis, other heart valve defects or stenosed vessels. Drug-induced AVWS has been described in association with the use of pesticides valproic acid, ciprofloxacin, griseofulvin, tetracycline, thrombolytic agents and hydroxyethyl starch.

Acquired von Willebrand syndrome type 1 in hypothyroidism: reversal after treatment with thyroxine

In 16 cases, acquired von Willebrand syndrome (AvWS) and hypothyroidism have been described that occur with each other: 15 women and one man, at a mean age of 32 years, range, 13 to 82 years of age. Activated partial thromboplastin time (APTT) was normal in six patients, and five patients had factor VIII concentration (factor VIIIc) levels in excess of 60%. The bleeding time was prolonged in nine of 13 evaluable patients. Activated partial thromboplastin time was prolonged in seven patients, and five of these had factor VIIIc levels between 18 and 45%, with two patients having levels in excess of 60%. A deficiency of other coagulation factors, including factor VII, V, IX, and X, caused by a generalized diminution in protein synthesis in hypothyroidism, may have contributed to the prolongation of the APTT. The AvWS was very likely type 1 in all cases because of a normal von Willebrand factor antigen/ristocetin cofactor (vWF Ag/RCF) ratio. Acquired von Willebrand syndrome was documented via cross immunoelectrophoresis in three patients and via multimeric analysis of vWF in six patients. A definite diagnosis of AvWS type I has to be confirmed by a normal response to 1-desamino-8-D-arginine vasopressin (DDAVP). Treatment of hypothyroidism with thyroxine was associated with the disappearance of the AvWS and the bleeding diathesis. Decreased factor VIIIc, vWF Ag and vWF RCF levels (50%, 33%, and 36% respectively) before thyroxine treatment increased to normal values (97%, 93%, and 107% respectively) after treatment. The absence of bleeding, or mild bleeding, symptoms, in relation to those more commonly recognized with hypothyroidism, has led to the complication of acquired vWF deficiency being underdiagnosed. Acquired von Willebrand syndrome type I should be considered whenever hypothyroidism is diagnosed and thyroid biopsy or surgery is contemplated. The complete relief of AvWS via treatment of hypothyroidism with thyroxine is the final proof of this association and causal relationship.

Successful treatment with recombinant factor VIIa of therapy-resistant severe bleeding in a patient with acquired von Willebrand disease

We describe an elderly man who presented with life-threatening hematuria and gastrointestinal bleeding caused by acquired von Willebrand disease associated with monoclonal gammopathy of undetermined significance (MGUS). Standard therapy with desmopressin, von Willebrand factor-containing factor VIII concentrate, tranexamic acid, and immunoglobulin failed to achieve adequate hemostasis. However, treatment with recombinant activated factor VII (rFVIIa) arrested the bleeding completely. Since acquired von Willebrand disease can lead to life-threatening hemorrhage, clinicians should consider rFVIIa as an effective treatment option if standard therapy fails.

Acquired von Willebrand syndrome--report of 10 cases and review of the literature

Acquired von Willebrand syndrome (AvWS) is a rare bleeding disorder with clinical and laboratory features closely resembling hereditary von Willebrand disease (vWD), arising in previously haemostatically normal individuals. We present a retrospective review of 10 cases with AvWS diagnosed over 17 years. The severity of the bleeding tendency varied from mild to severe forms. Multimers electrophoresis showed that 8/10 patients had a normal pattern similar to type 1 vWD, 1/10 had a type 2A vWD pattern (with absence of high and intermediate molecular weight multimers) and 1/10 had a type 3 vWD pattern. An inhibitor screen was performed in 6/10 patients and autoantibodies against von Willebrand factor were found in only two cases. The underlying cause/associated conditions were identified in 8/10 patients. Treatment of the bleeding diathesis was successfully achieved with desmopressin or clotting factor concentrates. Resolution of underlying hypothyroidism (in two cases) and multiple myeloma (in one case) led to normalization of the coagulation parameters. The report on this cohort of 10 patients with AvWS illustrates the complexity of AvWS and its multifactorial aetiology. A brief review of the recent literature on AvWS is also presented, with emphasis on the current opinions in pathogenesis and treatment. Acquired von Willebrand syndrome (AvWS) is an acquired bleeding disorder, characterized by a phenotype similar to the inherited von Willebrand disease (vWD), with a prolonged bleeding time and low plasma levels of factor VIII - von Willebrand factor (vWF) measurements. It occurs in patients with no family history of vWD, who present with recent onset of bleeding symptoms. AvWS appears to be associated mainly with lymphoproliferative disorders, immunological conditions and neoplasia. AvWS is a rare condition and it is difficult to conduct prospective studies, therefore it is important to document the experience with such cases. The aim of this paper is first, to report 10 cases of AvWS identified at our Haemophilia Centre during the past 17 years. Second, to present a brief review of the recent literature on AvWS - outlining the salient features, associated disorders, mechanisms of acquisition and the available options of treatment.

von Willebrand disease: recent advances in pathophysiology and treatment

This review focuses on new developments in the pathophysiology and treatment of von Willebrand disease (vWd). New aspects of the cell biology, gene control, and structure-function correlates of von Willebrand factor (vWf) are reviewed. vWd is more prevalent than previously recognized, affecting up to 1% of the population; this is particularly evident in women's health. Blood group is an important determinant of von Willebrand factor levels; individuals of blood group O tend to have lower plasma levels of vWf than those in other blood groups. Currently available blood tests of vWf quantity and function are discussed, in addition to newer tests undergoing validation. Treatment of classical vWd with desmopressin acetate and plasma derivatives is discussed, as is the potential for intravenous immunoglobulin and corticosteroids in acquired vWd. Special situations, such as the management of vWd in pregnancy, are also discussed.

Acquired von Willebrand disease: concise review of occurrence, diagnosis, pathogenesis, and treatment

Acquired von Willebrand disease (AvWD) is a rare complication of an autoimmune or neoplastic disease. It is associated mostly with a lymphoid or plasma cell proliferative disorder. The clinical manifestations are similar to congenital von Willebrand disease. Diagnosis is confirmed by the demonstration of decreased levels of factor VIII coagulant activity (VIII:C), ristocetin cofactor activity (vWF:RCo), and von Willebrand factor (vWF) antigen (vWF:Ag). vWF multimer analysis usually reveals a type II defect with decreased abundance of higher molecular weight vWF multimers. Various pathogenetic mechanisms have been described, including the development of anti-vWF antibodies and adsorption of vWF by tumor cells. Successful management approaches have included treatment of the underlying disorder, infusion of high-dose gamma globulin, replacement therapy with factor VIII/vWF concentrates, intravenous infusion of desmopressin, and administration of corticosteroids.

Acquired von Willebrand's disease: a concise review

Acquired von Willebrand's disease (AvWD), an adult-onset bleeding diathesis, has most commonly been found in patients with an underlying lymphoproliferative disease or monoclonal gammopathy. Other malignancies, autoimmune diseases, hypothyroidism, and drugs have also been associated with AvWD. We have included an illustrative case history of a patient with a bleeding diathesis consistent with AvWD and a monoclonal gammopathy who required emergent cardiac surgery. Our review of the literature determined that most cases of AvWD are due to a circulating antibody that combines with the high molecular weight multimers (HMWM) of von Willebrand factor (vWF). These vWF multimer-antibody complexes are subsequently cleared from the circulation either by the reticuloendothelial system or by adsorption onto tumor cells. Clearance of the HMWM of vWF thus results in extremely low functional levels and variable antigenic levels. Mixing studies which are traditionally used to diagnose factor inhibitors are useful only if removal of vWF-antibody complexes can be accomplished in vitro. Treatment with intravenous immunoglobulin has recently been shown to be the most effective therapy for patients with an underlying lymphoproliferative disorder or monoclonal gammopathy. This therapeutic strategy is based on the observed immune complex clearance phenomenon that appears to be operative in most cases. Other AvWD-associated diseases require treatment specifically directed at the underlying disorder.

von Willebrand disease in children and adolescents

The term von Willebrand disease includes many bleeding disorders caused by abnormalities of vWF. Frequent or severe bleeding may be indicative of vWD or other bleeding conditions. Primary care practitioners need to be familiar with vWD and evaluate possibly affected individuals with appropriate laboratory studies. Patients with vWD should be educated about their disorder and preventive measures to limit its effect. Medications are available that can treat or prevent bleeding complications for most patients with vWD. Intervention with blood products is occasionally necessary.

Acquired von Willebrand's syndrome causing a hemorrhagic diathesis in a patient with hypothyroidism

The occurrence of bleeding diathesis with menorrhagia and easy bruising may occur in patients with moderate to severe hypothyroidism sometimes linked to acquired von Willebrand's disease (VWD). We describe a patient with profound hypothyroidism in whom the diagnosis of hypothyroidism was established while evaluating uncontrolled gingival bleeding after a dental procedure. Thyroid hormone replacement led to a rise in von Willebrand factor, factor VIIIC, and a significant fall in the elevated bleeding time from 15 to 8 min. Acquired von Willebrand's disease is an unusual manifestation of hypothyroidism and is reversible.