Haematology Flashcards
What is physiological anaemia of pregnancy
Plasma volume increases by more than haemoglobin mass
Most common cause of true anaemia in pregnancy
Iron deficiency
Complications of IDA
Maternal - fatigue, infection
Fetus - intrauterine growth restriction, premature, death
Treatment for IDA
Oral ferrous sulphate
Iron infusion if poor compliance
How is risk of NTDs reduced
400 micrograms folate OD 3 months pre-conceptually and first trimester
Who needs a higher folic acid dose and what is the dose
5mg OD if:
Previous child with NTD
Increased cell turnover
Anticonvulsants
Types of B12 deficiency in pregnancy
Physiological (dilutional in third trimester)
True
Why is true B12 deficiency rare
Causes infertility
Reasons for increased VTE risk in pregnancy
Decreased blood flow in legs due to gravis uterus
Increased clotting factors
Decreased protein S
Inhibition of fibrinolysis
Difficulties of diagnosis for PE in pregnancy
D dimers raised in pregnancy
V/Q and CTPA high radiation risk to fetus
Use wells score and Perfusion scan
Why are left VTE more common than right
Left iliac vein compressed by right iliac and ovarian arteries
Treatment of VTE in pregnancy
LMWH
Causes of maternal haemorrhage
Uterine atony e.g muscle fatigue in prolonged labour Placenta Previa Placenta abruption Genital tract injury Ectopic pregnancy Uterus rupture DIC Dilutional coagulation deficit
Describe haemolytic disease of the newborn
If mother is rhesus neg, fetus likely to be rhesus pos
Fetal cells released into maternal circulation in first pregnancy
Mother produces igM (can’t cross placenta) to rhesus D
On reexposure to rhesus D, mother produces IgG antibodies which cross placenta causing haemolysis in fetus
Prevention of haemolytic disease of the newborn
RhesusD neg women have anti-D at week 28 and 34
Extra IM anti-D within 72 hours of a sensitising event
Examples of sensitising events in terms of rhesus incompatibility
Delivery
Amniocentesis
Abdo trauma
Antepartum haemorrhage
Monitoring for haemolytic disease of the newborn
Middle cerebral artery USS - high flow = higher risk of anaemia
Antibody levels
Classification of alpha thalassaemia
1/2 genes missing: carrier
3 genes missing: HbH disease
4 genes missing: hydrops fetalis
Clinical features of HbH disease
Microcytic anaemia
Splenomegaly
beta tetramers
When does anaemia occur in beta thalassaemia major and why
3-6 months because of conversion of gamma to beta chains
Clinical features of beta thalassaemia
Microcytic anaemia
Hepatosplenomegaly
Bone marrow hyperplasia - hair on end appearance of skull
Iron overload (transfusion)
Diagnosis of beta thalassaemia carrier
Raised HbA2
Describe ABO incompatibility
Mother O
Baby A/B/AB
Maternal antibodies cross placenta and cause allogenic haemolysis of the newborn
Describe the kleihauer test
Detect fetal blood cells in maternal circulation after delivery to determine the amount of antiD to give the mother
