In newborns, vitamin K deficiency can lead to acute bleeding episodes.
Vitamin K is essential for the hepatic synthesis of key coagulation factors (II, VII, IX, X), while neonates have naturally low stores of this vitamin.
Prevalence: Without prophylaxis, the condition occurs in up to 1.7% of newborns.
Clinical forms:
Early form (within the first 24 hours) – associated with maternal use of medications that interfere with vitamin K metabolism (e.g., anticonvulsants, warfarin, certain antibiotics).
Classic form (day 2–7 of life) – more common in exclusively breastfed infants.
Late form (from 2 weeks to 6 months) – rare; often associated with liver disease or exclusive breastfeeding without prophylactic vitamin K administration.
Clinical manifestations: cutaneous and mucosal bleeding, gastrointestinal or rectal hemorrhage, umbilical stump bleeding, and, in severe cases, intracranial hemorrhage.
Laboratory findings: prolonged prothrombin time (PT) and occasionally activated partial thromboplastin time (aPTT), with normal platelet count and fibrinogen level. Diagnosis is confirmed by rapid normalization of coagulation parameters following vitamin K administration.
Treatment:
Vitamin K₁ (phytomenadione) is administered intravenously or intramuscularly according to the infant’s body weight.
In cases of active bleeding, immediate vitamin K injection combined with fresh frozen plasma (FFP); in severe cases, prothrombin complex concentrate (PCC) may be required.
Prevention: all newborns should receive vitamin K₁ (phytomenadione) 1 mg intramuscularly shortly after birth, which effectively prevents both classic and late forms of the disease.