Table 78–1 shows a clinical classification of hemophilia A based on factor VIII levels.
Hemostasis is generally normal with levels in excess of 30%.
The factor VIII level remains constant throughout the patient’s life, and it is similar in other affected members of the kindred but varies between kindreds.
Hemarthrosis accounts for 75% of bleeding episodes in patients with severe hemophilia A.
The most frequent sites are the knees, followed by the elbows, ankles, shoulders, wrists, and hips.
The acute form of hemarthrosis is characterized by initial mild pain without physical findings, followed by more intense pain, swelling and warmth of the joint, and decreased range of motion.
The patient may have mild fever. Significant or sustained fever suggests infection in the joint.
When bleeding stops, the blood resorbs and symptoms subside over several days.
Repeated bleeding into the joint results in synovial hypertrophy and inflammation, with limitation of motion and a tendency for more frequent bleeding in that joint (target joint).
Eventually, repeated hemorrhage into the joints causes destruction of the articular cartilage, synovial hyperplasia, and joint deformity with muscle atrophy and soft tissue contractures (Figure 78–2).
Hematomas may develop after bleeding into muscles or subcutaneous tissues (Figure 78–3).
Intramuscular hematomas occur most often in thigh, buttocks, calf muscles, and forearm.
Hematomas may stabilize and slowly resorb without treatment, but in individuals with moderate or severe hemophilia, they often enlarge progressively and dissect in all directions. This can cause compression of adjacent organs, nerves, or blood vessels, sometimes leading to permanent sequelae. Hematomas may obstruct the airway.
Pseudotumors are large, organized, encapsulated hematomas that may slowly expand and compress surrounding structures.
Central nervous system hemorrhage, the most common cause of bleeding mortality, occurs spontaneously or after trauma. The onset of symptoms is usually prompt but may be delayed by several days.
Virtually all patients with severe hemophilia have episodes of hematuria, which may cause renal colic because of clots in the ureters, but is seldom life-threatening.
Postsurgical bleeding, often delayed by hours to several days, is associated with poor wound healing.
Extraction of permanent teeth in patients with hemophilia may be followed by prolonged bleeding. Life-threatening pharyngeal or sublingual hematomas may follow extractions or regional block anesthesia.
Inhibitory antibodies to factor VIII may develop in patients receiving replacement therapy (discussed below).