St A - Immunological/Haematological Changes in Pregnancy Flashcards
What occurs as trophoblasts invade decidua?
- Increase in natural killer and dendritic cells to allow for re-modelling of uterine wall rather than cytotoxic or antigen presenting function.
What are the physiological haematological changes in pregnancy
- Haemoglobin decreases despite increase in RBCs but this is due to an increase in plasma volume so Hb is diluted.
- Rise in WBCs (mainly neutrophils),
- m Fall in platelets (gestational thrombocytopenia),
- Rise in MCV by 4fl,
- Rise in fibrinogen and factors VIII, IX, X so hypercoagulable state
Why does anaemia occur in oregnancy
High level of borderline deficiency going into pregnancy and then increased demands of iron from foetus and potentially poor dietary intake due to N&V.
Treatment of anaemia in pregnancy?
- IV iron, ferinject, but side effects of constipation, abdo pain and nausea so poorly tollerated.
- 400mcg per day of folic acid pre-conception to reduced neural tube defects and then continued in pregnancy due to increased demands
What is immune thrombocytopenic purpura and how is it treated?
It is an autoimmune disease which may be triggered by pregnancy. It is autoantibodies against platelets. Treated by waiting and watching, steroids, immunoglobins, splenectomy or drugs to mimic thrombopoietin. May need treatment to achieve platelet levels 50+ for labour. (igG antibodies can cross placenta causing neonatal thrombocytopenia)
What is thombotic thrombocytopenic purpura (TTP)?
Rare but life-threatening disease causing thrombotic microangiopathy. Enzymes prevent Von Willebrands polymers so platelets aggregate
How does TTP present and how is it treated?
With fever, neurological and renal disease, low platelets and fragmented RBCs.. Treated by plasma exchange
What are some risk factors for women developing thomboemobolic disease?
Pregnancy and up to 6 weeks post partum due to hypercoaguable state, previous clot, age, smoking, twins, obesity and thrombophilia
How can thomboembolic disease present in late pregnancy
Pelvic veins are compressed which can result in unilateral swelling (left is more common than right), progressive pain and tenderness. Doppler exam of leg, then investigate Chest X-ray and if abnormal then CT pulmonary angiogram. D dimers are normally raised in pregnancy so unhelpful
What is the treatment of thomboembolic disease?
Low molecular weight heparin but due to increased rate of clearance and volume of distribution it requires twice daily dose and monitoring. Need for future prophylactic anticoagulation in future pregnancies.
How does pre-eclampsia present?
Hypertension, fluid retention, proteinuria, headaches and high urate. Some patients will go on to develop HELLP.
What is HELLP syndrome?
Haemolysis (anaemia, red cell fragments and raised LDH), elevated liver enzymes (ALT/AST), low platelet syndrome
What is the treatment for pre-eclampsia and HELLP syndrome
Prompt delivery of baby and supportive care
When does disseminated intravascular coagulation present in pregnancy and how does it present?
Usually following placental abruption, amniotic fluid embolism or dead foetus. Presents with haemorrhagic, very unwell, organ failures, depletion of coagulation factors, low platelets and red cell fragments
How is DIC treated?
Treating the cause, coagulation factors and platelets
