Hemophilia

Hemophilia is an inherited bleeding disorder that is mainly X-linked recessive and therefore occurs almost exclusively in males. There are two main subtypes: hemophilia A (80%) and hemophilia B (20%). 

Epidemiology

The incidence of hemophilia A is around 1 in 5000 male births, and the incidence of hemophilia B is around 1 in 25,000-30,000 male births. 

Clinical presentation

Most patients present with a bleeding diathesis. In severe cases, patients present during the neonatal or infantile period or with clinically significant bleeding (e.g. cephalohematoma, or postoperative bleeding). In adolescents and adults, hemorrhage typically manifests as bleeding into joints (hemarthrosis) and muscles, whereas bleeding in other more clinically significant sites such as intracranially or gastrointestinal is relatively uncommon. The types of hemophilia are impossible to delineate clinically ⁶.

Complications

• haemophilic arthropathy

• haemophilic pseudotumor

• osteopaenia and osteoporosis

• transfusion-related diseases

  • HIV

  • hepatitis C

  • Creutzfeldt-Jacob disease: very rare

Pathology

The main forms of hemophilia are inheritable X-linked recessive diseases ⁶, with ~70% considered familial and ~30% considered sporadic ⁸. Generally, severity is graded depending on baseline factor activity:

• mild: factor activity 6-40% of normal

• moderate: factor activity 1-5% of normal

• severe: factor activity <1% of normal

Hemophilia A

• ~80% of cases

• F8 gene mutation, on the long arm of the X-chromosome

• inherited as an X-linked recessive condition

• coagulation factor VIII deficiency or absence

Hemophilia B

• a.k.a. Christmas disease

• ~20% of cases

• F9 gene mutation, on the long arm of the X-chromosome

• inherited as an X-linked recessive condition

• coagulation factor IX deficiency or absence

Hemophilia C

• a.k.a. Rosenthal syndrome

• <1% of cases

• most common in the Ashkenazi Jewish population

• F11 gene mutation, on the long arm of chromosome 4

• inherited as an autosomal recessive or dominant condition

• coagulation factor XI deficiency or absence

Radiographic features

The hallmark of the disease is hemorrhage, particularly into joints and/or soft tissue, with several radiological consequences:

• haemophilic arthropathy occurs in almost all individuals

• haemophilic pseudotumor occurs in ~2%

• soft tissue hematoma formation may lead to contractures ³

• serious life-threatening hemorrhage (intracranial, thoracic, abdominal)

Treatment and prognosis

Treatment depends on the type, general severity, and current clinical state, and can be delivered episodically or prophylactically. Options for treatment include factor products (plasma-derived or recombinant) or novel medications such as emicizumab ¹⁰.

Prognosis depends on the severity and on the presence or absence of transfusion-related disease. Complications from HIV and cirrhosis are the leading causes of death. Life expectancy in those without HIV is ~62 years ².

• ~15 times increased risk of death from intracranial hemorrhage (~1/3 of all deaths)

• ~50 times increased risk of death from non-intracranial hemorrhage

See also

• polyarticular disease