Vitamin K Deficiency in Children

Introduction to Vitamin K Deficiency in Children

Vitamin K deficiency is a potentially serious condition that can occur in children, particularly in newborns and infants. Vitamin K is crucial for blood clotting and bone metabolism. Its deficiency can lead to life-threatening bleeding disorders, especially in the early weeks of life.

There are two main forms of vitamin K deficiency bleeding (VKDB) in infants:

  • Early VKDB: occurs within 24 hours of birth
  • Classical VKDB: occurs between 24 hours and 7 days after birth
  • Late VKDB: occurs between 2-12 weeks after birth

Understanding and preventing vitamin K deficiency is crucial for pediatric healthcare providers to ensure the health and safety of newborns and infants.

Etiology of Vitamin K Deficiency in Children

Vitamin K deficiency in children can result from various factors:

  1. Newborns and Infants:
    • Low placental transfer of vitamin K
    • Low vitamin K content in breast milk
    • Immature gut flora (unable to produce vitamin K)
    • Lack of vitamin K prophylaxis at birth
  2. Older Children:
    • Malabsorption disorders (e.g., celiac disease, cystic fibrosis)
    • Prolonged antibiotic use (disrupting gut flora)
    • Severe liver disease
    • Extremely restricted diets
  3. Maternal Factors:
    • Use of certain medications during pregnancy (e.g., anticonvulsants, anticoagulants)
    • Maternal vitamin K deficiency

Risk factors for VKDB include exclusive breastfeeding without supplementation, certain ethnic groups with lower rates of vitamin K prophylaxis, and infants with undiagnosed liver disease.

Pathophysiology of Vitamin K Deficiency

Vitamin K plays a crucial role in the coagulation cascade and bone metabolism:

  1. Coagulation:
    • Vitamin K is essential for the synthesis of coagulation factors II, VII, IX, and X
    • It acts as a cofactor for gamma-glutamyl carboxylase, which activates these factors
    • Deficiency leads to the production of undercarboxylated, non-functional coagulation factors
  2. Bone Metabolism:
    • Vitamin K is required for the carboxylation of osteocalcin, a protein involved in bone mineralization
    • Deficiency may impair bone formation and increase fracture risk
  3. Other Functions:
    • Vitamin K has roles in cell growth regulation and signal transduction

In vitamin K deficiency, the lack of functional coagulation factors leads to prolonged prothrombin time (PT) and partial thromboplastin time (PTT), increasing the risk of spontaneous bleeding.

Clinical Manifestations of Vitamin K Deficiency in Children

The clinical presentation of vitamin K deficiency varies depending on the age of onset and severity:

  1. Early VKDB (0-24 hours):
    • Often associated with maternal medications
    • Cephalohematoma, intracranial hemorrhage
    • Umbilical stump bleeding
  2. Classical VKDB (1-7 days):
    • Gastrointestinal bleeding
    • Umbilical bleeding
    • Skin bruising
    • Circumcision site bleeding
  3. Late VKDB (2-12 weeks):
    • Intracranial hemorrhage (most common and severe manifestation)
    • Sudden onset of seizures or altered mental status
    • Skin bruising or bleeding
  4. Older Children:
    • Easy bruising or prolonged bleeding from minor injuries
    • Nosebleeds or gum bleeding
    • Blood in urine or stool
    • In severe cases, internal bleeding

It's important to note that many infants with vitamin K deficiency may be asymptomatic until a catastrophic bleeding event occurs, highlighting the importance of prevention.

Diagnosis of Vitamin K Deficiency in Children

Diagnosing vitamin K deficiency requires a combination of clinical suspicion, laboratory tests, and imaging studies:

  1. Clinical Assessment:
    • Detailed history, including birth history, feeding practices, and medication use
    • Physical examination for signs of bleeding
  2. Laboratory Tests:
    • Prothrombin Time (PT) and International Normalized Ratio (INR): Prolonged in vitamin K deficiency
    • Partial Thromboplastin Time (PTT): May be prolonged
    • Vitamin K-dependent coagulation factors (II, VII, IX, X): Decreased levels
    • Protein Induced by Vitamin K Absence (PIVKA-II): Elevated in vitamin K deficiency
    • Complete Blood Count (CBC): To assess for anemia due to blood loss
  3. Imaging Studies:
    • Cranial ultrasound or CT scan: To detect intracranial hemorrhage
    • Abdominal ultrasound: If internal bleeding is suspected
  4. Diagnostic Criteria:
    • Prolonged PT that corrects with vitamin K administration
    • Normal fibrinogen and platelet count
    • Absence of liver disease or DIC

The diagnosis is often confirmed by the rapid improvement in coagulation parameters following vitamin K administration.

Treatment of Vitamin K Deficiency in Children

Treatment of vitamin K deficiency focuses on rapid correction of coagulopathy and addressing any active bleeding:

  1. Vitamin K Administration:
    • Intravenous (IV) route preferred for rapid correction
    • Dosage: 1-5 mg IV, depending on age and severity
    • Can be given intramuscularly (IM) or orally in less severe cases
  2. Management of Active Bleeding:
    • Fresh Frozen Plasma (FFP) for immediate correction of coagulopathy
    • Prothrombin Complex Concentrate (PCC) in severe cases
    • Supportive care, including fluid resuscitation and blood transfusion if needed
  3. Ongoing Management:
    • Daily oral vitamin K supplementation until underlying cause is resolved
    • Monitoring of PT/INR until normalized and stable
  4. Treatment of Underlying Causes:
    • Management of malabsorption disorders
    • Adjustment of diet in cases of nutritional deficiency
    • Review and modification of medications if necessary

In cases of intracranial hemorrhage, neurosurgical intervention may be necessary. Close monitoring and follow-up are essential to prevent recurrence and manage any neurological sequelae.

Prevention of Vitamin K Deficiency in Children

Prevention is key in managing vitamin K deficiency, especially in newborns:

  1. Newborn Prophylaxis:
    • Intramuscular (IM) vitamin K (1 mg) at birth is the gold standard
    • Oral regimens are available but less effective and require multiple doses
  2. Breastfed Infants:
    • Encourage vitamin K prophylaxis at birth
    • Consider additional oral supplementation for exclusively breastfed infants
  3. Maternal Considerations:
    • Adequate maternal vitamin K intake during pregnancy and lactation
    • Careful management of medications that interfere with vitamin K metabolism
  4. Older Children:
    • Ensure a balanced diet rich in vitamin K (green leafy vegetables, vegetable oils)
    • Supplementation in children with malabsorption disorders or on long-term antibiotics
  5. Education:
    • Inform parents about the importance of vitamin K prophylaxis
    • Educate healthcare providers on recognizing and preventing VKDB

Implementing these preventive measures can significantly reduce the incidence of vitamin K deficiency bleeding in children, particularly the devastating late-onset VKDB.



Vitamin K Deficiency in Children
  1. What is the primary function of Vitamin K in the human body?
    To assist in blood clotting by activating certain coagulation factors
  2. Which of the following is NOT a form of Vitamin K?
    Vitamin K4
  3. What is the recommended prophylactic dose of Vitamin K for newborns?
    1 mg intramuscularly
  4. Which of the following is a common cause of Vitamin K deficiency in infants?
    Exclusive breastfeeding without supplementation
  5. What is the most severe consequence of Vitamin K deficiency in newborns?
    Intracranial hemorrhage
  6. Which of the following conditions can increase the risk of Vitamin K deficiency?
    Cystic fibrosis
  7. What is the term used for Vitamin K deficiency bleeding occurring between 2 and 12 weeks of age?
    Late Vitamin K deficiency bleeding (VKDB)
  8. Which of the following is NOT a typical sign of Vitamin K deficiency in infants?
    Jaundice
  9. What is the primary source of Vitamin K in the adult diet?
    Green leafy vegetables
  10. Which of the following antibiotics can interfere with Vitamin K metabolism?
    Cephalosporins
  11. What is the recommended daily intake of Vitamin K for children aged 1-3 years?
    30-55 micrograms
  12. Which of the following laboratory tests is most useful in diagnosing Vitamin K deficiency?
    Prothrombin Time (PT) / International Normalized Ratio (INR)
  13. What is the typical onset time for early Vitamin K deficiency bleeding in newborns?
    Within the first 24 hours of life
  14. Which of the following is NOT a risk factor for Vitamin K deficiency in newborns?
    Maternal Vitamin K supplementation during pregnancy
  15. What is the primary treatment for symptomatic Vitamin K deficiency?
    Immediate administration of Vitamin K1 (phytonadione)
  16. Which of the following medications can potentially cause Vitamin K deficiency?
    Warfarin
  17. What is the role of gut bacteria in Vitamin K metabolism?
    They produce Vitamin K2 (menaquinones)
  18. Which of the following is NOT a common site of bleeding in Vitamin K deficiency?
    Joints
  19. What is the recommended route of administration for Vitamin K prophylaxis in newborns?
    Intramuscular injection
  20. Which of the following conditions does NOT typically require long-term Vitamin K supplementation?
    Iron deficiency anemia
  21. What is the half-life of orally administered Vitamin K?
    Approximately 1-3 hours
  22. Which of the following is a potential complication of excessive Vitamin K intake?
    Hemolytic anemia in G6PD-deficient individuals
  23. What is the primary storage site for Vitamin K in the body?
    The liver
  24. Which of the following is NOT a typical clinical presentation of late Vitamin K deficiency bleeding?
    Petechiae
  25. What is the recommended dose of Vitamin K for treating symptomatic deficiency in infants?
    1-5 mg intravenously or intramuscularly
  26. Which of the following fat-soluble vitamins can interfere with Vitamin K absorption?
    Vitamin E in large doses
  27. What is the term used for the Vitamin K-dependent proteins involved in bone metabolism?
    Osteocalcin and matrix Gla protein
  28. Which of the following is NOT a typical sign of Vitamin K toxicity?
    Prolonged prothrombin time
  29. What is the recommended frequency of Vitamin K administration for infants exclusively breastfed?
    Weekly oral doses until the introduction of vitamin K-containing foods
  30. Which of the following conditions can lead to secondary Vitamin K deficiency in children?
    Celiac disease


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