The evaluation of a person for possible VWD or other bleeding disorders may be initiated because of a variety of clinical indications. These indications and situations may include evaluation of: (1) an asymptomatic person who will undergo a surgical or interventional procedure; (2) persons who present with current symptoms of or a history of increased bleeding, abnormal laboratory studies, and/or a positive family history of a bleeding disorder; or (3) persons who present with a prior diagnosis of VWD but do not have supporting laboratory documentation. In all cases, the initial step in assessment should focus on key aspects of the person’s clinical history to determine whether the person may benefit from further diagnostic evaluation. This section is divided into two parts. The first part uses a summary of the medical literature to provide suggested questions for an initial assessment of persons presenting for concerns about bleeding issues or for evaluation prior to procedures that may increase their risk of bleeding. Using the answers to the initial assessment, the second part focuses on a strategy for optimal laboratory assessment of those persons who potentially have bleeding disorders and suggests guidelines for interpretation of laboratory results.
Evaluation of the Patient
History, Signs, and Symptoms
The initial clinical assessment of a person who is being evaluated for VWD should focus on a personal history of excessive bleeding throughout the person’s life and any family history of a bleeding disorder. The history of bleeding should identify the spontaneity and severity, sites of bleeding, duration of bleeding, type of insult or injury associated with bleeding, ease with which bleeding can be stopped, and concurrent medications—such as aspirin, other nonsteroidal antiinflammatory drugs (NSAIDs), clopidogrel (Plavix™), warfarin, or heparin—at the onset of bleeding. Particularly when an invasive procedure is anticipated, the person should be asked whether he or she is currently taking any of these medications and also whether he or she has any history of liver or kidney disease, blood or bone marrow disease, or high or low platelet counts. If a history of any of these illnesses is present, further appropriate evaluation or referral should be undertaken.
Clinical manifestations. The most common presenting symptoms in persons subsequently diagnosed with VWD are summarized in Table 7. Symptoms usually involve mucous membranes and skin sites, and bleeding is of mild to moderate severity (bleeding that does not require blood transfusions and usually does not require visits to the physician) for most persons who have VWD, reflecting the predominance of type 1 VWD. However, life—threatening bleeding (CNS, gastrointestinal) can occur in persons who have type 3 VWD, in some persons who have type 2 VWD, and rarely in persons who have type 1 VWD. Uncommon bleeding manifestations, such as hemarthrosis, are more common in persons who have a more severe deficiency, especially those who have type 3 VWD.85,136 Clinical symptoms may also be modified by coexisting illnesses or other medications. For example, use of aspirin or other NSAIDs can exacerbate the bleeding tendency, whereas use of oral contraceptives can decrease bleeding in women who have VWD.
The clinical evaluation of bleeding symptoms is a challenge, because mild bleeding symptoms are also very common in healthy populations (Table 7, shaded column). Responses to questionnaires used to survey healthy controls indicate that they identify themselves as having specific bleeding manifestations as frequently as persons who have VWD, particularly type 1 VWD (Table 7).137,138,140,143 In addition, a family history of bleeding was reported by 44 percent of healthy children undergoing tonsillectomy143 and by 35 percent138 or 60 percent144 of persons referred because of bleeding. Because bleeding symptoms are so prevalent, it may be impossible to establish a causal relationship between bleeding and low VWF.
Initial Evaluation For VWD or Other Bleeding Disorders
Initial evaluation strategy to determine which patients would most benefit from further diagnostic evaluation for von Willebrand disease (VWD) Left Upper Box: Individuals would be asked three questions about their personal or family bleeding history which, if any are positive, would lead to a second set of questions selected for their sensitivity and specificity for VWD. Those patients answering positively to one or more of the second set of questions would benefit from laboratory evaluation. Right Boxes: Patients presenting with specific information or a concern about bleeding would be asked the questions and the initial 3 questions if not already asked, and would also undergo laboratory evaluation.
Some of the most important clinical issues in VWD apply specifically to women, particularly menorrhagia. Studies of women who have VWD report a high prevalence of menorrhagia although the definition of menorrhagia is not clearly specified in most of these studies and the diagnostic criteria for VWD are not uniform. The sensitivity of menorrhagia as a predictor of VWD may be estimated as 32–100 percent. However, menorrhagia is a common symptom, occurring with a similar frequency in healthy controls and women who have VWD; therefore, it is not a specific marker for VWD. In a survey of 102 women who had VWD and were registered at hemophilia treatment centers in the United States, 95 percent reported a history of menorrhagia, but 61 percent of controls also reported a history of menorrhagia.145 Studies have reported a prevalence of VWD of between 5–20 percent among women who have menorrhagia.146–152 Therefore, the specificity of menorrhagia as a predictor of VWD can be estimated as 5–20 percent. Three findings that predict abnormal menstrual blood loss of >80 mL include:
Clots greater than approximately 1 inch in diameter
Low serum ferritin
Changing a pad or tampon more than hourly153
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