von Willebrand disease: recent advances in pathophysiology and treatment

von Willebrand Disease : A Clinico-haematological Spectrum

BACKGROUND

Bleeding disorders are commonly seen in clinical practice. von Willebrand Disease (vWD), is the commonest and yet a profoundly under diagnosed cause, having a wide spectrum of clinical presentation. Of its three types, type 1 vWD (70% of the total vWD cases) has the mildest and a highly variable clinical and laboratory presentation.

METHODS

A series of ten cases of vWD were comprehensively evaluated using recommended diagnostic parameters and therapeutic interventions.

RESULTS

All major types of vWD were represented. A female preponderance, with primary presentation in the form of muco-cutaneous bleeds was observed. A positive history of consanguineous parental marriage and family history of bleeding disorder was elicited in two and three patients respectively. Nine patients were found to be anemic and thrombocytopenia was present in only one. Bleeding time by modified template (SIMPLATE) method, along with activated partial thromboplastin time (APTT) was increased in all ten cases and of these, nine had low factor VIII: C levels. Ristocetin induced platelet aggregation studies were abnormal in all the five cases it was performed. vWF:RCo activity determined in one individual was shown to be low. vWF:Ag assay was done in four cases revealing a near complete absence of von Willebrand factor antigen in one and mildly decreased levels in the other three. vWF multimer assay was advised in three cases. DDAVP, plasma derived vWF, blood products and local antifibrinolytics were used as primary modalities of treatment.

CONCLUSION

Thus, strong clinical suspicion, thorough clinical evaluation and judicious use of investigations including repeated investigations at different times are needed for making a diagnosis of vWD.

Coagulation defects in trauma patients: etiology, recognition, and therapy

Trauma patients have many reasons to have defects in coagulation. These can be caused by the trauma or because of pre-existing disorders. Trauma patients who are at risk for coagulation defects should be screened with the basic tests (aPTT, INR/PT, platelet counts, hematocrit, and fibrinogen), with therapy based on the results. Attention also should be paid to any other correctable factors such as hypothermia. Finally, pre-existing disorders can influence the patient's hemostasis greatly and may require specific therapies.

[Hemoperitoneum and pregnancy in a patient with von Willebrand's disease type 3]

A 24-year-old woman with type 3 (characterised by a blood level of von Willebrand factor less than 1%) was admitted to the surgical intensive care unit with an haemorrhagic shock. She was pregnant (Beta HCG = 115 Ul.L-1), the echography of the abdomen, soon after admission, revealed a haemoperitoeum. She underwent abdominal surgery after substitution treatment. The surgeon found an ovarian haemorrhagic cyst. Later the course of pregnancy was normal and she was delivered by caesarean section. We describe the therapeutic strategy of that care.

Hemorrhagic problems in obstetrics, exclusive of disseminated intravascular coagulation

During pregnancy many physiologic changes occur that result in an increase in coagulation factors and a decrease in fibrinolytic activity. Because hemorrhage during pregnancy is a major cause of maternal morbidity, it is important to recognize and understand the pathophysiology of hereditary and acquired bleeding disorders. This article reviews von Willebrand's disease types 1, 2, and 3 and acquired hemophilia.

The role of blood group antigens in infectious diseases

The medical literature contains a large number of publications attempting to correlate blood groups with disease. Many of these reports are poorly documented and have limited scientific validity. Only a few agents, such as malaria parasites and parvovirus B19, infect red blood cells (RBCs) and precursors. Most other agents use RBCs as carriers to the target tissue. There is an excess of blood group A individuals among cancer patients compared with normal individuals; malignancy has also been associated with the Lewis antigen. Plasmodium vivax only enters RBCs when the Fy6 Duffy protein is present. Certain Escherichia coli organisms will only attach to epithelial cells carrying P or Dr blood group antigens. The P antigen Is also the receptor for parvovirus B19. Le(b) appears to be the receptor for Helicobacter pylori in gastric tissue. The high frequency blood group antigen AnWJ is the receptor for Haemophilus influenzae. Knowledge of the functions of RBC surface molecules Is expanding and the ability to generate experimental animals devoid of certain molecules will clarify their physiological role.