17. Hemorrhagic disease of the newbom. Flashcards
what are the homeostatic phases ?
vessel phase = 2-5 second
vasoconstriction denudation in the basement membrane
synthesis of prostacyclin and antithrombin 3
activation of factor 12
thrombocyte phase 3-10sec formation of platelet thrombus: adhesion to exposed sub collagen secretion of TrA2 and AF serotonin ,ADP TF activation on thrombocyte phospholipid
plasma phase 30-120sec activation of coagulation cascade with formation of fibrin activation of 7 and 12 thrombin form fibrin form
recovery phase 6-48 hours
or 10-60 days
lysine of the thrombin and fibrin clot
hemorrhagic disease of the new-born is also otherwise known as what ?
vit k deficicny bleeding
- most babies have low stores of vit k
when there is a deficiency of vit k what is there an impaired production of ?
impaired production of coagulation factor 2 , 7, 9, 10 by the liver
anticoagulants C and S
prothrombin
how is VKDB categorised into ?
according to the timing of the first symptom
early onset
within 24hrs - very rare
there is low levels of prothrombin and other vit k dependant factors
classic onset - 2-7 days
= very rare
late onset 2 weeks to six months
immaturity of the liver affects the production of clotting factors
what are the acquired diseases of newborn haemorrhages ?
vit k deficiency
liver diseases
thrombocytopenia : immune ,DIC
what are the inherited causes of abnormal newborn hemorrhage disease
haemophilia A
haemophilia B
von willebrand disease
why is there a vit k deficiency in newborn ?
vit k passes the placenta very poorly
the gut flora which produces vit is not fully developed
what is the diagnostic criteria fr vit k deficiency ?
prolonged prothrombin time / elevated INR golden standard
prolonged activated partial thromboplastin time
fibrinogen levels and platelet count within normal range
diagnosis confirmed if INR normalises if vitamin k administration and the bleeding is stopped
determine TT and fibrinogen conc aswell
should exclude sepsis
what does prothrombin times and INR measure ?
extrinsic pathway of coagulation
INR based on the ratio of prothrombin times and normal mean prothrombin time
what does prothrombin time measure ?
factor 1 fibrinogen factor 2 - thrombin factor 4 factor 7 factor 10
prothrombin time can also be prolonged because of ?
warfarin therapy
malabsorption
poor factor 7 synthesis due to liver diseases
or increased consumption in DIC
what is the initial empirical therapy of significant bleeding ?
platelet and or factor supplementation while diagnostic studies are underway
what can increase the risk of VKBD ?
early onset
mother takin anti seizure drug - interfere with vit k metabolism = phenytoin , phenobarbitural
blood thinning medication = aspirin coumadin
mother taking antibiotics = cephalosporins
late onset = low level of vit k in breast milk binary atresia cystic fibrosis celiac disease chronic diarrhea hepatitis alpha 1 antitrypsin def
what are the most common sites of bleeding in VKBD?
umbilicus mucos membranes gastrointestinal tract venipuncture intracranial bleeding hematurea melena
what can be the prevention of VKBD ?
injection of vit k immediately after birth
vit k shots in mothers who take anti seizure med
good nutrition of mothers
