Haematology in the Neonate Flashcards
Why is vitamin K a problem in the neonate?
This occurs as there are no enteric bacteria in the gut to make vitamin K. The baby will usually be well in itself but have bruising and increased PT and PTT as well as deranged platelets.
How do we prevent vitamin k deficient bleeding in the neonate?
To prevent give Vit K IM or mixed colloidal phytomenadione. Repeat in 7 days, if breast fed repeat again at one month if bottle fed then no need as it is already fortified.
For active bleeding give plasma and vit K
What usually causes DIC in the neonate?
Secondary to sepsis or necrotising enterocolitis
How does DIC present in the neonate?
Clinical features – septic, petechiae, oozing wounds and GI bleeding
How should DIC be investigated in the neonate?
Investigations – reduced platelets, schistocytes, increased INR, decreased fibrinogen, increased PT and PTT and increased D dimer.
How is DIC managed in the neonate?
Management – treat cause, give vit k and platelets, fresh plasma and cryoprecipitate, heparin and protein C. If bleeding continues consider exchange transfusion.
What is autoimmune thrombocytopenia?
Can occur randomly but 10% of babies born to a mother with ITP will also develop it. There is also something called alloimmune thrombocytopenia where the mothers antibodies attach the foetal platelets leading to a deranged platelet count in the baby.
How is ITP managed in utero?
If this occurs in utero it can cause CNS problems. Treat with compatible platelets or irradiated maternal platelets. Steroids may also help. Platelet transfusion via cordocentesis from 24 weeks may be needed in later pregnancies.
How is a diagnosis of ITP made in utero?
Diagnosis made by detecting maternal platelet allo-antibodies against father’s platelets.
What is rhesus haemolytic disease?
A conditions that occurs after the mother develops an immune response to rhesus positive babies.
This becomes progressively worse with each Rh+ baby that is born to a sensitised mother.
Note ABO incompatibility can occur as well but treatment is the same.
How does a baby with Rhesus disease of the newborn present?
Clinical presentation of the baby varies with severely ill babies termed foetal hydrops due to oedematous stiff lungs occurring due to anaemia induced congestive cardiac failure as well as hypoalbuminaemia as the liver becomes preoccupied with producing RBCs.
Jaundice Yellow vernix CCF – Oedema and ascites Hepatosplenomegaly Progressive anaemia Bleeding CNS signs Kernicterus
When does a Rhesus -ve mother receive her doses of Anti D?
All mothers are tested for D antibodies when booked and at 28 and 34 weeks. Doses of Anti-D less than 4u/ml are unlikely to cause any disease
How are foetuses monitored for Rhesus disease?
Foetuses can be monitored by US (and amniocentesis if >4u/ml) to detect oedema, cardiomegaly, pericardial effusion, hepatosplenomegaly and ascites).
Monitoring should occur 10weeks prior to event in the previous pregnancy.
How is Rhesus disease managed?
Prevention – Anti-D immunoglobulin to all Rh- mothers at 28 and 34 weeks
Exchange transfusion – indicated with foetal Hb <7
Phototherapy may be all that is needed if jaundice is the only symptom
What is hydrop fetalis?
Serious foetal conditions defined as abnormal accumulation of fluid in two or more foetal compartments including ascites, pleural effusion, pericardial effusion and skin oedema. This occurs as the liver fails to produce enough albumin or as a result of other fluid management issues secondary to an underlying condition. It is rare for this to occur as a result of Rhesus or ABO incompatibility but can happen, this is termed immune hydrops. Nonimmune hydrops is more common and occurs as a result of anaemia, infection, heart, liver or lung defects and chromosomal abnormalities.
