FCPS Paediatrics TOACS · Interactive Station

✅ Candidate's answer:
• VKDB definition: Bleeding disorder in newborns caused by deficiency of vitamin K-dependent coagulation factors (II, VII, IX, X, protein C, protein S).
• Types of VKDB:
  1️⃣ Early VKDB (0-24 hours): Due to maternal medications that interfere with vitamin K (e.g., warfarin, phenytoin, phenobarbital, rifampin, isoniazid). Often presents with severe intracranial hemorrhage.
  2️⃣ Classic VKDB (2-7 days): Occurs in exclusively breastfed infants who did not receive vitamin K prophylaxis. Presents with GI bleeding (melena), circumcision bleeding, or oozing from umbilical stump.
  3️⃣ Late VKDB (1-6 months): Occurs in infants with malabsorption (cholestasis, biliary atresia, cystic fibrosis) or in those with inadequate oral prophylaxis. Presents with intracranial hemorrhage (50-60%) or severe GI bleeding.
• Risk factors: No vitamin K at birth, exclusive breastfeeding, maternal anti-epileptic drugs, malabsorption syndromes, cystic fibrosis, biliary atresia.

✅ Candidate's answer:
• Interpretation: This is classic VKDB. Prolonged PT and PTT with normal platelets and normal fibrinogen is characteristic of vitamin K deficiency. D-dimer is negative (unlike DIC).
• Why PT and PTT are prolonged: Vitamin K-dependent factors (II, VII, IX, X) are reduced. Factor VII has the shortest half-life (4-6 hours), so PT (extrinsic pathway) becomes prolonged first. As deficiency worsens, PTT (intrinsic pathway) also becomes prolonged.
• Isolated PT prolongation: Early VKDB or factor VII deficiency (congenital).
• Combined PT/PTT prolongation: VKDB (advanced), DIC (with low fibrinogen and platelets), liver disease (factor deficiency, low albumin), or hemophilia (PTT only prolonged).
• Normal platelets and fibrinogen: Excludes DIC.
• PIVKA (proteins induced by vitamin K absence) is elevated – diagnostic for VKDB.

✅ Candidate's answer:
• 1. Vitamin K deficiency bleeding (VKDB) – most common; normal platelets and fibrinogen.
• 2. Liver disease (hepatic failure) – low factors (all), low albumin, elevated transaminases, direct hyperbilirubinemia.
• 3. Hemophilia A (FVIII deficiency) or B (FIX deficiency) – PTT prolonged, PT normal. Family history may be absent (new mutation).
• 4. Congenital factor VII deficiency – PT prolonged, PTT normal.
• 5. DIC (Disseminated intravascular coagulation) – prolonged PT/PTT, low platelets, low fibrinogen, elevated D-dimer.
• 6. Factor XIII deficiency – PT/PTT normal; clot solubility test abnormal.
• 7. Von Willebrand disease – PTT prolonged, von Willebrand factor low.
• 8. Acquired inhibitors (lupus anticoagulant) – rare, transient in newborns.

✅ Candidate's answer:

Feature	VKDB	DIC
Platelets	Normal	Low (thrombocytopenia)
Fibrinogen	Normal	Low (consumption)
D-dimer	Normal	Elevated
PT/PTT	Prolonged (both)	Prolonged
Factors II, VII, IX, X	Low	Low (consumption)
Factor VIII	Normal	Low (consumed)
PIVKA	Elevated	Normal
Underlying cause	No vitamin K / malabsorption	Sepsis, asphyxia, NEC, shock

✅ Candidate's answer:
• Immediate treatment (for active bleeding):
  1️⃣ IV Vitamin K (phytomenadione): 1-5 mg (neonate) IV over 15-30 minutes. Do not give IM in a bleeding infant (risk of hematoma).
  2️⃣ Fresh frozen plasma (FFP): 10-15 mL/kg IV over 2-4 hours – provides immediate replacement of vitamin K-dependent factors. May need to repeat if bleeding is severe.
  3️⃣ Packed red blood cells (PRBC): 10-15 mL/kg if hemoglobin <8-10 g/dL (hemorrhagic anemia).
  4️⃣ Vitamin K administration: Continue for 3 days (IV or IM after bleeding stops).
  5️⃣ If intracranial hemorrhage: Neurosurgical consultation, correction of coagulopathy before any procedure.
• Response to vitamin K: PT improves within 6-12 hours, PTT within 24-48 hours.

✅ Candidate's answer:
• FFP is indicated for active, severe bleeding (life-threatening hemorrhage, intracranial hemorrhage, or hemodynamic instability) because vitamin K takes 6-12 hours to correct the coagulopathy.
• FFP dose: 10-15 mL/kg IV over 2-4 hours. Each mL of FFP contains approximately 1 unit of activity of each coagulation factor.
• FFP replaces factors II, VII, IX, X, and proteins C and S. It also contains factor VIII and fibrinogen.
• FFP is also used in DIC (with cryoprecipitate for fibrinogen) and in liver disease.
• Monitor for TRALI (transfusion-related acute lung injury) and volume overload in preterm infants.

✅ Candidate's answer:
• Recommended prophylaxis: All newborns should receive intramuscular (IM) vitamin K (phytomenadione) at birth.
• Dose:
  - Term infants: 1 mg IM (single dose).
  - Very low birth weight (VLBW) infants: 0.5 mg IM or 1 mg IM (depending on unit protocol).
• Why IM over oral?
  - Efficacy: IM provides >95% protection against classic VKDB and near 100% against late VKDB.
  - Oral vitamin K: Less effective, especially for late VKDB (requires multiple doses, compliance issues).
  - AAP recommends IM vitamin K as standard of care.
• Oral vitamin K: May be used in some countries (e.g., Netherlands) but requires 3 doses (at birth, day 7, day 28) and still has a higher failure rate (late VKDB).
• IM vitamin K is safe – no increased risk of childhood cancer (retrospective studies have disproven the association).

✅ Candidate's answer:
• This is late VKDB (1-6 months) due to cholestasis → fat malabsorption → vitamin K deficiency.
• Risk factors for late VKDB: Biliary atresia, cholestatic liver disease, cystic fibrosis, alpha-1 antitrypsin deficiency, short bowel syndrome, chronic diarrhea.
• Management:
  - IV vitamin K (1-5 mg) + FFP if bleeding.
  - Long-term vitamin K supplementation: Oral water-soluble vitamin K (e.g., K1) 2-5 mg weekly or daily (depending on severity of cholestasis). Some infants require parenteral vitamin K.
  - Treat underlying disease (biliary atresia: Kasai procedure).
  - Monitor PT/INR and vitamin K levels.

✅ Candidate's answer:
• Differential diagnosis of isolated PTT prolongation:
  - Hemophilia A (FVIII deficiency) – X-linked, most common.
  - Hemophilia B (FIX deficiency) – X-linked.
  - Von Willebrand disease (vWD) – PTT may be prolonged.
  - Factor XI deficiency – rare.
  - Lupus anticoagulant (transient in newborns).
• Differentiating Hemophilia A vs B:
  - Factor VIII assay – low in Hemophilia A.
  - Factor IX assay – low in Hemophilia B.
  - Family history – both X-linked, but new mutations are common (30% of cases).
  - Treatment: Factor VIII concentrate (Hemophilia A) vs Factor IX concentrate (Hemophilia B).
• Hemophilia A is 7x more common than Hemophilia B.

✅ Candidate's answer:
• Treatment of Hemophilia A in newborns:
  - Recombinant factor VIII (preferred) or plasma-derived factor VIII.
  - Dose calculation: Each IU/kg of FVIII raises the factor level by approximately 2%.
  - Dose for mild bleeding (e.g., cephalohematoma): 25-50 IU/kg (target 30-50%).
  - Dose for severe bleeding (intracranial, GI): 50-75 IU/kg (target 80-100%).
  - Prophylactic dosing: 25-40 IU/kg 2-3 times weekly (for severe disease).
• Desmopressin (DDAVP): Not effective in neonates (ADH response immature).
• Avoid: IM injections, circumcision without factor coverage.
• Hemophilia B (FIX deficiency): Recombinant factor IX, dose 50-80 IU/kg.

✅ Candidate's answer:
• Likely diagnosis: Factor XIII deficiency (or platelet function disorder).
• Factor XIII (fibrin-stabilizing factor): Cross-links fibrin clots. Deficiency causes bleeding despite normal PT/PTT.
• Clinical features: Umbilical stump bleeding (common), intracranial hemorrhage, delayed wound healing, spontaneous hematomas.
• Diagnosis:
  - Clot solubility test (5M urea or monochloroacetic acid) – clot dissolves in 5M urea (normal clot does not).
  - Confirm with factor XIII quantitative assay.
• Treatment: FFP (10-15 mL/kg) or factor XIII concentrate (if available).
• Prophylaxis: Long-term factor XIII replacement for severe deficiency.

✅ Candidate's answer:
• Diagnosis: Disseminated Intravascular Coagulation (DIC) secondary to NEC (sepsis, asphyxia, shock).
• Lab findings in DIC: Thrombocytopenia, prolonged PT/PTT, low fibrinogen, elevated D-dimer.
• Management:
  - Treat the underlying condition – NEC: stop feeds, IV antibiotics, surgical consultation.
  - FFP: 10-15 mL/kg (replaces factors).
  - Cryoprecipitate: 5-10 mL/kg (fibrinogen replacement, target >100 mg/dL).
  - Platelet transfusion: 10-15 mL/kg if platelets <30,000 (or <50,000 with active bleeding).
  - Avoid factor concentrates (unless directed).
  - Heparin is NOT recommended in neonatal DIC.

✅ Candidate's answer:
• VKDB (Vitamin K deficiency):
  - Recurrence risk: Essentially zero if vitamin K prophylaxis is given at birth in subsequent pregnancies.
  - Prevention: Ensure future newborns receive IM vitamin K at birth.
  - If mother is on anti-epileptic drugs: She should receive oral vitamin K (20 mg/day) in the last month of pregnancy.
• Hemophilia A (X-linked recessive):
  - If mother is a carrier: 50% chance of affected male, 50% chance of carrier female.
  - If new mutation (30% of cases): Mother is not a carrier; recurrence risk is low.
  - Prenatal diagnosis: Chorionic villus sampling (CVS) or amniocentesis for gender and factor assays.
  - Management of future pregnancies: Genetic counseling, consider C-section to avoid instrumental delivery, and ensure factor concentrate availability at delivery.

✅ Candidate's structured answer:
• “Your baby has a condition called Vitamin K Deficiency Bleeding – it happened because your baby did not receive the vitamin K injection at birth and is exclusively breastfed. Breast milk is low in vitamin K, and babies have low stores at birth.”
• “The bleeding is caused by a temporary lack of certain clotting proteins in the blood. We have given your baby vitamin K through the IV line, and we have given fresh frozen plasma (FFP) to replace the missing proteins. Your baby is already doing much better, and the bleeding has stopped.”
• “The good news is that this is completely preventable in future pregnancies – all future babies will receive the vitamin K injection at birth. There is no underlying genetic disorder in your baby.”
• “We will monitor your baby's blood tests to make sure the clotting function has returned to normal. He will need vitamin K for the next 2-3 days, and then he will be fine.”
• “Please do not worry – this is a temporary problem. Your baby will go home once he is stable. We will teach you the importance of vitamin K for your next baby.”