Hemorrhagic disease of newborn HDN VKDB

Definition and features It is hemorrhagic features in the newborn due to vit.K deficiency occurs in 3 onsets; Early in first 24 hr of life Classic 2-7 days of life Late at 2-12 weeks of life Features includes bleeding from umbilicus, melena, bruises, hematuria, rarely intracranial bleeding. The bleeding is more severe in late onset bleeding and the intracranial bleeding is more frequent than the classic type.

FORMS OF VIT K Main source of vit K is from plants essentially the green leaves which contain vit k1 (phytomenandione )and that formed by gut flora is vit K2 .gut flora(bacteroids) can convert vit K1 to vit K2 but cannot form vit K1.In the body cells can convert vit k1 to k2. both of them form coagulation factors and compensate vit k in the body that blocked by warfarin.

causes Early H : due to deficient store of vit.K in the newborn because of mother deficiency of vit K as a result of the use of some drugs by mother like antiepileptic e.g. phenytoin, carbamazepine, phenobarbitone, and anti tuberculous e.g. isoniazid ,rifampicin ;so placental passage of vit K to the baby is poor leading to features of bleeding during first 24 hrs and the vit K1 injection prophylaxis to the newborn after birth does not have time to prevent this early bleeding. Prevention of early bleeding is by giving the mother vit.K1 at 2-4 weeks before delivery .

causes classic HDN occurs after 24hr ;2-7 days of life Vit k store is small in the newborn because of naturally poor passage of vit K from the mother by placenta Breast feeding; breast milk contains small amount of vit k. Gut flora poorly developed in breast fed NB; the flora which is responsible for vitk2 formation and its supply; is the(bacteroids);that is not like the flora of the breast milk gut ;(lactobacillus)= which do not produce vit k.

causes Late onset HDN; It occurs in neonate at 2-12weeks of life. 1. in the breast baby who used broad spectrum antibiotics, which will kill the flora, 2.in those with problems that block vitK absorption (vit K is fat soluble for absorption) as in; Cystic fibrosis, biliary atresia, malabsorption, alpha1-antitrypsin deficiency. It is more severe than early onset H. regarding the high incidence of intracranial bleeding.

prevention Every newborn should be given vit K1 prophylactic dose 1mg IM soon after birth. This vit called vit k1,while that formed by the gut flora is vit K2.

Investigations and treatment Vitk deficiency cause reduced vit K dependent coagulation factors; II,XI,X,VII leading to prolonged PT, APTT. Bleeding should be treated by giving vit k1 1mg IV or to give FFP (fresh frozen plasma). Be careful vit k IV may cause anaphylaxis.