Hemophilia is a group of bleeding disorders caused by hereditary coagulation factor deficiencies. Among them, deficiency of factor VIII (AHG, AHF) is called hemophilia A, while deficiency of factor IX (PTE) is called hemophilia B. Both conditions are X-linked recessive genetic disorders. The incidence ratio between the two is approximately 5:1. Clinically, the extremely rare autosomal dominant deficiency of factor XI was previously referred to as hemophilia C but is now more commonly called factor XI deficiency or plasma thromboplastin antecedent (PTA) deficiency.

bubble_chart Clinical Manifestations

1. Characteristics of onset: Boys experience recurrent bleeding from early childhood (often around 1 year of age). Once the condition manifests, it persists for life. The earlier the onset, the more severe the symptoms.
2. Bleeding characteristics: Spontaneous bleeding may occur, but it is often triggered by trauma. Even minor injuries can lead to prolonged oozing from the wound, sometimes lasting for days. Simple skin bleeding points are rare; instead, ecchymoses, subcutaneous hematomas, or deep tissue hematomas are more common. Joint bleeding is frequent, particularly in the knees, but may also occur in the ankles, elbows, wrists, shoulders, etc. Repeated bleeding can result in joint deformities and functional impairment. Other manifestations include epistaxis, as well as bleeding in the urinary tract, digestive tract, and thoracic or abdominal cavities.
3. Family history: Male relatives on the maternal side (such as brothers, maternal cousins, uncles, etc.) have a similar history of bleeding.

bubble_chart Auxiliary Examination

1. Coagulation profile test: Prolonged clotting time (may be normal in mild cases), poor prothrombin consumption (seen in about 70% of patients), normal bleeding time and prothrombin time. Activated partial thromboplastin time (APTT) is prolonged, and thromboplastin generation test shows poor results. The latter two tests are more sensitive.
2. Coagulation factor assay: The activity of factor VIII:C and factor IX in the blood can be measured by immunological methods. <2%為重型，2～5%為中等型，5～25%為輕型，25～45%為亞臨床型。

bubble_chart Treatment Measures

1. Alternative therapies, which involve supplementing the deficient clotting factors and blood loss, may include:
   1. Blood transfusion or plasma: Whole blood transfusion is preferred for significant blood loss, while plasma transfusion is suitable for replenishing clotting factors alone. For hemophilia A, fresh blood or plasma collected within 6 hours should be used. For hemophilia B, stored blood or plasma within 3 weeks may also be administered. For mild cases, plasma transfusion of 10 ml/kg each time (which can increase factor VIII activity by 20%) is recommended. For hemophilia A, transfusions should be repeated every 12 hours, while for hemophilia B, transfusions can be given every 24 hours (due to the longer half-life of factor IX).
   2. Clotting factor concentrates: Severe cases require concentrated preparations to achieve effective levels of the deficient clotting factors in the blood. (1) For hemophilia A: Two options are available—cryoprecipitate and lyophilized factor VIII concentrate, with the latter more commonly used domestically. Each bag contains 100–200 U (1 U = the amount of factor VIII in 1 ml of normal plasma), dissolved in 50–100 ml of sterile water for injection and administered intravenously. The initial dose should be sufficient, followed by repeat infusions every 12 hours at half the initial dose. The required dose of factor VIII per kg of body weight is approximately: Grade I bleeding, 8–14 U; general surgery or severe bleeding, 10–25 U; major surgery or intracranial bleeding, 35–60 U. (2) For hemophilia B: Prothrombin complex concentrate can be used. One unit is equivalent to the amount of factor IX in 1 ml of normal plasma. Supplementing 1 U/kg can increase plasma factor IX by 0.5–1%. Since this preparation also contains activated clotting factors (prothrombin, factor VII, X, etc.), repeated infusions may carry a risk of thrombosis. Therefore, heparin (5–10 U/ml) should be added to the reconstituted preparation.
2. Drug Therapy
   1. Antifibrinolytic drugs such as 6-aminocaproic acid (EACA) and para-aminomethylbenzoic acid (PAMBA) are commonly used. These are contraindicated in cases of hematuria, as they may promote the formation of small blood clots in the urinary tract, leading to obstruction or renal damage.
   2. Adrenal corticosteroids are generally used during acute bleeding episodes to reduce hemorrhage. Prednisone at 1–2 mg/(kg·d) for 7–10 days is recommended, or dexamethasone intravenously in emergencies.
   3. 1-Deamino-8-D-arginine vasopressin (DDAVP): This drug promotes the release of factor VIII attached to blood vessel walls into the bloodstream to aid hemostasis. The dosage is 0.4 μg/kg per dose, diluted in 10 ml of saline and injected slowly intravenously (over 10–15 minutes). For the first 2–4 days, it can be administered every 8–12 hours. Intranasal administration is also an option, with 0.5 ml per dose (1 ml contains 1300 μg).
   4. Other drugs: Reports suggest that ranitidine can increase plasma factor VIII:C levels and improve bleeding symptoms. Oral norethisterone at 1 mg daily for 1–2 months may also alleviate symptoms.
3. Local Management
   1. Joint bleeding and soft tissue hematomas: Apply local bandaging and maintain functional positioning. If necessary, perform joint cavity aspiration to remove accumulated blood and inject hyaluronidase or protease. Cold compresses can be used initially, switching to warm compresses once bleeding stops and swelling subsides. Early functional exercises are recommended to prevent joint deformities.
   2. Lip, tongue, or oral mucosal bleeding: Suture the wound and apply fibrin sponge soaked in thrombin preparation or sprinkle fibrinogen powder for hemostasis.
4. General Care and Precautions
   1. Provide intensive care for affected children to prevent trauma and excessive activity. Maintain oral hygiene and avoid intramuscular injections.
   2. Avoid drugs that inhibit platelet function, such as aspirin, dipyridamole, and indomethacin.

bubble_chart Differentiation

1. Differential diagnosis with other bleeding disorders: It should be differentiated from von Willebrand disease, factor M deficiency (Table 7-2), and deficiencies of factors II, V, VII, X, etc.
2. Differential diagnosis between types of hemophilia: Mainly based on correction tests such as the prothrombin consumption test or thromboplastin generation test.