Approach To A Bleeding Child

Initial Assessment And Stabilization

• Stabilize child before diagnostic workup.
• Assess disorder severity and magnitude of blood loss.
• Administer adequate replacement fluids and blood products.
• Initiate component therapy if hemodynamically unstable.

Clinical Evaluation

Detailed History

• Age of onset: Neonatal presentation suggests severe congenital defects; later onset suggests acquired or mild congenital defects.
• Site of bleeding: Differentiates primary (platelet/vascular) from secondary (coagulation) hemostasis defects.
• Provoked versus spontaneous: Spontaneous bleeding implies severe defect. Note bleeding after circumcision, heel stick, or immunizations.
• Antecedent events: Recent viral infections, rashes (IgA vasculitis, varicella), jaundice, or diarrhea (hemolytic uremic syndrome).
• Medication history: Anticonvulsants, penicillins, warfarin, aspirin, non-steroidal anti-inflammatory medications, heparin.
• Family history: Identify sex of affected members, specific bleeding manifestations, consanguinity.

Clinical Features Suggestive Of Pathologic Bleeding

• Umbilical stump bleeding (suggests factor XIII deficiency).
• Intracranial hemorrhage in neonates.
• Excessive bleeding post-circumcision or heel stick.
• Palpable bruises in non-mobile infants.
• Hematomas, hemarthroses, retroperitoneal bleeding.
• Menorrhagia: Bleeding >7 days, >80 mL loss, soaking pads within 1 hour.
• Traumatic bleeding out of proportion to injury (rule out nonaccidental trauma).

Physical Examination

• Degree of anemia: Assess pallor, tachycardia, hemodynamics.
• Skin manifestations: Fading versus new ecchymoses, petechiae, purpura.
• Vascular lesions: Hemangiomas, telangiectasias (Kasabach-Merritt syndrome, hereditary hemorrhagic telangiectasia).
• Organomegaly: Splenomegaly suggests infection, malignancy, hypersplenism, collagen vascular disorders.
• Joint mobility: Assess Beighton score (maximum 9 points; score >5 indicates hypermobility, suggests Ehlers-Danlos syndrome).
• Syndromic stigmata: Evaluate for congenital bone marrow failure syndromes (Fanconi anemia, thrombocytopenia with absent radii).

Diagnostic Algorithm

Interpretation Of Screening Tests

Laboratory Finding	Associated Etiologies
Isolated Prolonged PT	Factor VII deficiency, early vitamin K deficiency, early liver synthetic dysfunction.
Isolated Prolonged aPTT	Hemophilia A (FVIII), Hemophilia B (FIX), Hemophilia C (FXI), FXII deficiency, von Willebrand disease, acquired inhibitors, heparin effect, lupus anticoagulant.
Prolonged PT And aPTT	Common pathway factor deficiency (FII, FV, FX), afibrinogenemia, dysfibrinogenemia, disseminated intravascular coagulation (DIC), severe liver disease, marked vitamin K deficiency, dilutional coagulopathy.
Normal PT And aPTT	Platelet dysfunction, factor XIII deficiency, mild von Willebrand disease, vascular connective tissue defects (Ehlers-Danlos, scurvy).

Advanced Coagulation Laboratory Assessment

Mixing Studies

• Differentiates factor deficiency from acquired circulating inhibitors.
• Normal plasma added to patient plasma (1:1 ratio).
• Complete correction indicates clotting factor deficiency.
• Failure to correct or partial correction indicates coagulation inhibitor (e.g., specific factor antibody, lupus anticoagulant).

Thrombin Time And Reptilase Time

• Thrombin Time (TT): Measures final conversion of fibrinogen to fibrin. Prolonged by hypofibrinogenemia, dysfibrinogenemia, heparin, or elevated fibrin degradation products.
• Reptilase Time: Utilizes snake venom to clot fibrinogen. Unaffected by heparin. Differentiates heparin contamination (prolonged TT, normal reptilase) from true fibrinogen defects (prolonged TT and reptilase time).

Specific Factor Assays

• Quantify precise functional activity of individual clotting proteins.
• Indicated when mixing studies normalize specific pathway abnormalities.
• Essential for classifying severity of hemophilias (Severe <1%, Moderate 1-5%, Mild 5-40%).

Von Willebrand Disease Panel

• vWF Antigen (vWF:Ag): Quantifies total vWF protein concentration.
• Ristocetin Cofactor Activity (vWF:RCo): Assesses functional interaction between vWF and platelets.
• Factor VIII Activity: Often reduced due to absent vWF chaperone function.
• vWF Multimer Analysis: Visualizes molecular weight multimers. Identifies absence of high-molecular-weight multimers in Types 2A and 2B.

Global Hemostatic Tests

• Thromboelastography (TEG): Assesses viscoelastic properties of whole blood clot formation under low shear.
• Evaluates clot initiation (R time), kinetics (K time, alpha angle), strength (Maximum Amplitude), and fibrinolysis.
• Thrombin Generation Assay: Fluorogenic substrate continuously measures endogenous thrombin potential.

Differential Diagnosis By Etiology

Platelet Disorders

• Manifest with mucocutaneous bleeding: epistaxis, petechiae, superficial ecchymoses, mucosal oozing.
• Hemarthrosis extremely rare.

Quantitative Disorders (Thrombocytopenia)

• Immune Destruction: Immune thrombocytopenic purpura (ITP), drug-induced, Evans syndrome, neonatal alloimmune thrombocytopenia (NAIT).
• Consumption: Hemolytic uremic syndrome (HUS), thrombotic thrombocytopenic purpura (TTP), disseminated intravascular coagulation (DIC), Kasabach-Merritt syndrome.
• Decreased Production: Congenital amegakaryocytic thrombocytopenia (CAMT), thrombocytopenia-absent radius (TAR) syndrome, aplastic anemia, marrow infiltration.
• Sequestration: Hypersplenism from portal hypertension, Gaucher disease.

Qualitative Disorders (Platelet Dysfunction)

• Bernard-Soulier Syndrome: Autosomal recessive. Absence of glycoprotein Ib-IX-V complex (vWF receptor). Macrothrombocytopenia. Absent ristocetin-induced aggregation.
• Glanzmann Thrombasthenia: Autosomal recessive. Deficiency of glycoprotein IIb/IIIa complex (fibrinogen receptor). Normal platelet count/morphology. Absent aggregation to all agonists except ristocetin.
• Storage Pool Deficiencies: Gray platelet syndrome (alpha granule deficiency). Hermansky-Pudlak syndrome (dense granule deficiency, oculocutaneous albinism).
• Acquired Dysfunction: Uremia, advanced liver disease, cardiopulmonary bypass, medication effects (aspirin, NSAIDs).

Coagulation Factor Deficiencies

• Manifest with deep tissue bleeding: hemarthroses, large intramuscular hematomas, delayed surgical bleeding.

Hemophilia A And B

• Genetics: X-linked recessive. Hemophilia A (Factor VIII deficiency); Hemophilia B (Factor IX deficiency).
• Laboratory: Prolonged aPTT, normal PT, normal platelet count. Specific factor assays establish definitive diagnosis.
• Clinical: Severe disease (<1% factor) causes spontaneous joint and muscle bleeds. Target joints develop from recurrent hemarthroses.
• Treatment: Specific recombinant factor concentrates. Prophylaxis recommended for severe phenotypes to prevent arthropathy.

Von Willebrand Disease

• Genetics: Most common inherited bleeding disorder. Mostly autosomal dominant.
• Pathophysiology: Deficient or defective vWF impairs platelet adhesion and factor VIII protection.
• Classification:
  • Type 1: Partial quantitative deficiency.
  • Type 2: Qualitative functional defects (Subtypes 2A, 2B, 2M, 2N).
  • Type 3: Complete quantitative absence.
• Treatment: Desmopressin (DDAVP) for Type 1. vWF-containing factor concentrates for severe types or unresponsiveness. Antifibrinolytics for mucosal bleeding.

Disseminated Intravascular Coagulation (DIC)

• Acquired clinicopathologic syndrome.
• Triggers include sepsis, trauma, malignancy, massive tissue injury.
• Pathogenesis involves unregulated thrombin generation, widespread microvascular fibrin deposition, and consumption of platelets/coagulation factors.
• Secondary hyperfibrinolysis generates fibrin degradation products.
• Laboratory: Prolonged PT/aPTT, hypofibrinogenemia, thrombocytopenia, elevated D-dimers/FDPs, microangiopathic hemolytic anemia (schistocytes).
• Management: Treat underlying trigger. Replace depleted components (fresh frozen plasma, cryoprecipitate, platelets) only for active hemorrhage or invasive procedures.

Vitamin K Deficiency

• Required for gamma-carboxylation of factors II, VII, IX, X, Protein C, Protein S.
• Prolongs PT early (factor VII has shortest half-life), followed by aPTT.
• Responsive to parenteral vitamin K administration.

Liver Disease Coagulopathy

• Liver synthesizes most procoagulant and natural anticoagulant proteins.
• Promotes complex hemostatic imbalance.
• Laboratory: Prolonged PT/aPTT, thrombocytopenia (hypersplenism/decreased thrombopoietin), dysfibrinogenemia.
• Factor VIII remains normal or elevated (synthesized in endothelial cells), distinguishing liver failure from DIC.
• Decreased natural anticoagulants (Protein C, S, Antithrombin) and hyperfibrinolysis.

Vascular And Connective Tissue Disorders

• Bleeding caused by fragility of skin, subcutaneous tissues, and vessel walls.
• Coagulation studies usually normal.
• Ehlers-Danlos Syndrome: Vascular type (Type IV) involves defect in type III collagen. Prone to arterial rupture, sudden death, easy bruising.
• Hereditary Hemorrhagic Telangiectasia: Autosomal dominant. Arteriovenous malformations in mucocutaneous and visceral surfaces. Recurrent epistaxis.

Management Principles

General Hemostatic Interventions

• Apply direct pressure, pack wounds, immobilize joints.
• Antifibrinolytic agents (aminocaproic acid, tranexamic acid) stabilize mucosal clots (contraindicated with prothrombin complex concentrates).
• Desmopressin (DDAVP) induces endothelial release of vWF and FVIII. Useful for mild Hemophilia A, Type 1 vWD, and mild platelet dysfunctions.

Component Replacement Therapy

Component	Constituents	Clinical Indications	Recommended Dosing
Fresh Frozen Plasma (FFP)	All coagulation factors (1 U/mL), fibrinogen	Factor II, V, VII, X, XI deficiency; Liver disease coagulopathy; DIC	10-15 mL/kg.
Cryoprecipitate	Fibrinogen, vWF, FVIII, FXIII	Hypofibrinogenemia, specific factor XIII or fibrinogen deficiencies	1 bag per 5-10 kg (raises fibrinogen by 60-100 mg/dL).
Platelet Concentrates	Platelets	Severe thrombocytopenia with bleeding, severe platelet dysfunction	10-20 mL/kg (or 1 unit/10 kg).
Specific Factor Concentrates	Highly purified recombinant or plasma-derived factors	Hemophilia A/B, von Willebrand disease, rare factor deficiencies	Calculate based on target percentage, body weight, and volume of distribution.
Bypassing Agents (aPCC, rFVIIa)	Activated factors driving alternative thrombin generation	Hemophilia with inhibitors, severe refractory platelet dysfunction (Glanzmann)	rFVIIa: 90 mcg/kg. aPCC: 75-100 U/kg.