Hematologic Conditions



Definition and Epidemiology

Hemophilia A and B are X-linked recessive inherited bleeding disorders affecting 1:5000 males with no racial predilection.1–3 Hemophilia A is caused by deficiency of factor VIII and hemophilia B is caused by deficiency of factor IX. The normal plasma levels of factor VIII or factor IX range between 50% and 150%. The severity of hemophilia is predictive of risk for bleeding and is based on plasma levels of the factor VIII or IX (Table 16-1).1

Table 16-1. Severity of Hemophilia


Hemophilias are X-linked inherited bleeding disorders resulting from deficiency of clotting factors VIII or IX. Two examples of how hemophilia can be inherited are illustrated in Figures 16-1 and 16-2.2 Female carriers have adequate levels of clotting factors because of the one normal X chromosome and do not manifest the clinical disease. In a very rare circumstance, a girl may be born with hemophilia when her father has hemophilia and the mother is a carrier. Hemophilia can also occur in males who are not born to mothers who are not carriers of the abnormal gene because of mutation in the gene.

Figure 16-1

Mode of inheritance of hemophilia. The mother is a carrier of hemophilia. Each daughter has a 50% chance of inheriting the abnormal gene from her mother and being a carrier. Each son has a 50% chance of inheriting the abnormal gene from his mother and having hemophilia. (From:www.nhlbi.nih.gov.)

Figure 16-2

Mode of inheritance of hemophilia. The father has hemophilia. The mother is not a carrier of hemophilia. Each daughter will inherit the abnormal gene from her father and be a carrier. None of the sons will inherit the abnormal gene from their father, and, therefore, none will have hemophilia. (From:www.nhlbi.nih.gov.)

Clinical Presentation

Clinically hemophilia A and B are indistinguishable and the differentiation is based on factor assays. The clinical presentation depends upon the severity of the hemophilia. Patients with hemophilia may present with a history of easy bruising, spontaneous bleeding in the joints or muscles, and prolonged bleeding after trauma1–3 They are also at risk for intracranial bleeding and internal bleeding at various other sites such as gastrointestinal tract and kidneys. Hemophilia should be differentiated from the most common inherited bleeding disorder, von Willebrand disease resulting from von Willebrand factor abnormality. The characteristics and differences between hemophilias and von Willebrand disease are summarized in Table 16-2.1

Table 16-2. Characteristics and Differences between Hemophilias and von Willebrand’s Disease


Diagnosis is suspected based on positive family history and clinical presentation and confirmed by factor assays. An approach to laboratory diagnosis to a bleeding patient is presented in Figure 16-3.

Figure 16-3

Evaluation of bleeding patient. Screening tests assess the degree of hemorrhage and the adequacy of hemostasis in a bleeding patient. (Used with permission from Kulkarni R, Gera R, Scott-Emuakpor AB. Adolescent hematology. In: Greydanus DE, Patel DR, Pratt HD, eds. Essential Adolescent Medicine. New York: McGraw Hill; 2006:371-390.)


Patients should be managed in consultation with a hematologist at hemophilia treatment centers (Box 16-1). Treatment is directed at raising and maintaining the factor levels above which the risk of bleeding is minimized.1,2,4–6 For minor bleeding such as joint or muscles the factor level should be raised up to 30% and for major bleeding such as internal organ bleeding it should be raised up to 100%. The factor level is raised by intravenous administration (either bolus or continuous infusion) of specific factor (factor VIII or IX or von Willebrand) concentrate. One unit per kilogram of body weight will raise plasma factor VIII by 2%, factor IX by 1.5%, and von Willebrand facor (Ristocetin cofactor activity) by 1.5%.1,4 The typical dose for prophylactic regimen for factor VIII is 25 to 40 U/kg body weight every other day and for factor IX is 25 to 40 U/kg body weight two times per week.

Box 16-1 When to Refer

Desmopressin has been shown to effectively raise the plasma levels of factor VIII and von Willebrand factor by two- to sixfold and is used to treat mild hemophilia A and von Willebrand disease.1,4 Epsilon amino caproic acid or tranexamic acid are used as adjunct hemostatic therapy for mucosal bleeds.

Sports participation and regular exercise are encouraged for patients with hemophilias and von Willebrand disease.1,2,5,6 Sport participation and regular physical activity have been shown to have significant positive effect on joint health, overall health, and psychosocial well being. Category 1 sports such as swimming, golf, and running are considered safe to allow full participation; category 2 sports such as bowling, weight lifting, and biking in which the benefits outweigh the risks are also generally appropriate to allow participation; and category 3 sports such as football and skateboarding in which the risks outweigh the potential benefits are generally not considered safe to allow participation. Athletes should maintain their factor levels in the normal range and administration of factor concentrate before the anticipated physical activity is also recommended. Factors to be considered in planning athletic participation include preparticipation evaluation and clearance by hematologist, ready availability of appropriate factor concentrate, knowledge by the athlete and the staff involved of the location and contact information of nearest hemophilia center while traveling for away games, and specific emergency action plan in case of bleeding.5 Specific sport related issues are summarized in Table 16-3.

Table 16-3. Canadian Hemophilia Society Guidelines for Sport Participation
Jan 21, 2019 | Posted by in SPORT MEDICINE | Comments Off on Hematologic Conditions

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