Hypertension in pregnancy Flashcards
What forms can hypertension in pregnancy take?
Gestational hypertension (can develop into pre-eclampsia)
Chronic hypertension
Pre-eclampsia
Eclampsia
Pre-eclampsia superimposed on chronic hypertension or renal disease
What are the risk factors for hypertension in pregnancy?
young mother black people 1st baby, then more than 5 babies (primigravida and grand multipara) multifetal pregnancy pre-existing hypertension diabetes renal disease collages vascular disease - lupus, scleroderma, RA
What are the features that point towards chronic hypertension?
- before pregnancy
- Before the 20th week of gestation
- During pregnancy and not resolved postpartum
How do you diagnose gestational hypertension?
New HT after 20 wks gestation
Systolic >140; Diastolic>90
No or little proteinuria
How do you diagnose pre-eclampsia?
New HT after 20th week
Increased BP with proteinuria
(sometimes get oedema, but not part of definition)
Define pre-eclampsia
New HT after 20th week with proteinuria
Define eclampsia
New HT after 20th week with proteinuria AND generalised tonic clonic seizures
(pre-eclampsia plus seizures)
What clinical parameters would you use to diagnose pre-eclampsia and what are their abnormal ranges?
Gestational hypertension
Systolic >140; Diastolic>90
Proteinuria
≥ 0.3g protein /24hr
≥ +2 on urine dip specimen
How do you accurately measure BP in pregnancy?
Sitting position (NOT supine as get IVC compression) Sit quietly for 10-15 minutes
What are the classifications of pre-eclampsia-eclampsia?
Mild pre-eclampsia
Severe pre-eclampsia
Eclampsia
What are the clinical criteria for severe pre-eclampsia?
ONE OR MORE OF:
BP: >160 systolic, >110 diastolic
Proteinuria: >5gm in 24 hrs, over 3+ urine dip
Oliguria: < 400ml in 24 hrs
CNS: Visual changes, headache, scotomata, mental status change (confusion/drowsiness)
Fundoscopy: retinal oedema and vasospasm
Pulmonary Edema
Epigastric or RUQ Pain (due to liver enlargement and swelling)
Weight gain due to peripheral oedema
Effect on baby:
Intrauterine Growth Restriction on USS
Oligohydramnios on USS
What are the lab criteria for severe pre-eclampsia?
Impaired LFTs - high AST and ALT
Thrombocytopenia: <100,000 (normal 150,000 to 350,000) - this is the first step of DIC
Raised uric acid
How do you identify Preeclampsia Superimposed Upon Chronic Hypertension
Basically chronic hypertension pts will have hypertension <20 weeks. Pre-eclampsia can be identified in these individuals by:
New-onset proteinuria after 20 weeks
OR if they had HT and proteinuria anyway <20 weeks, they will now get:
Sudden increase in proteinuria Sudden increase in BP when HT was well controlled Thrombocytopenia (<100,000) Abnormal ALT/AST
What are the spiral arteries and what two structures do they join together?
They are arteries that grow from the placenta and join the mothers arteries (arcuate arteries) in the myometrium
They allow oxygenated blood to flow from mother to baby
Describe the pathophysiology of pre-eclampsia
- Normally the spiral arteries lose their torsuosity and dilate significantly
- In pre-eclampsia, the spiral arteries do not lose their toruosity as much and are not as dilated, so there is reduced blood flow from the mother to the fetus
- leads to placental ischaemia
- placenta produces thromboplastins which catalyse the conversion of prothrombin to thrombin
- renin is produced which causes vasoconstriction (think of it as there is placental ischaemia so the body is trying to increase blood flow by increasing BP)
- vasconstriction results in
- poor renal perfusion
- hypertension
- proteinuria
- oedema
Overall
- poor placentation
- ischaemia
- activation of the coagulation system
- deranged control of blood volume and pressure
- oxidative stress and inflammation
How does pre-eclampsia affect the kidney?
Reduced GFR Increased uric acid Proteinuria Hypocalciuria - hormone dysregulation Impaired Na+ excretion due to renin - so will retain water
How does pre-eclampsia affect the coagulation system?
Thrombocytopenia - due to consumption of platelets
low antithrombin III - low levels promote clotting
higher fibronectin (causes blood clots to form)
How does pre-eclampsia affect the liver system?
HELLP syndrome
Haemolysis
Elevated Liver enzymes - ALT and AST
Low platelets
How does pre-eclampsia affect the CNS system?
If severe: Headache Visual symptoms Scotoma Cortical blindness - blindness in a normal appearing eye as the pathology is in the occipital cortex
What examination findings are there with pre-eclampsia?
Hypertension >140/90
Fundoscopy - retinal vasospasm and oedema
Peripheral oedema
Auscultation of lungs - late sign is basal crackles
Increased reflexes
Ankle clonus
What investigations would you do for pre-eclampsia?
FBC - platelets, low Hb due to haemolysis, haemoconcentration with high haematocrit
LFTs - high AST and ALT
U+Es - high uric acid, late low GFR
Urine dip - proteinuria
Urine PCR - Protein creatinine ratio
Measure urine input and output (input-output chart)- oliguria <400ml/24 hrs
DO USS for foetal growth
What are the complications of pre-eclampsia?
Maternal
- eclampsia
- HELLP syndrome
- DIC and haematuria
- stroke
- reduced GFR and then renal failure
Foetal
- IUGR
- IUD
- premature delivery and complications related to this - ARDS
- abruptio placentae
How would you manage pre-eclampsia?
Ambulatory management at home or day-care unit for mild pre-eclampsia
Hospitalisation for severe pre-elampsia
Restrict activity
Deliver under certain criteria
What are the maternal indications for delivery in pre-eclampsia?
Gestational age 38 wks
Platelet count < 100,000 cells/mm3
Progressive deterioration in liver and renal function
Suspected abruptio placentae (ie bleeding and pain)
Persistent severe headaches, visual changes, nausea, epigastric pain, or vomiting
What are the fetal indications for delivery in pre-eclampsia?
- Severe fetal growth restriction - definition is growth <10th centile (USS)
- Nonreassuring fetal testing results (umbilical artery doppler - absent EDF or reversed flow, and suspicious or pathological CTG)
- Oligohydramnios (amniotic fluid index < 5cm on USS)
When would you deliver in mild pre-eclampsia?
If mother >37 weeks Favourable cervix Fetal jeopardy Visual disturbance Persistant headaches Ie pt is symptomatic
Does everyone with pre-eclampsia have to have a C section?
No - vaginal delivery is preferable
How would you treat severe pre-eclampsia?
- Induction of labour within 24 hours
- Antihypertensives - Labetalol or Hydralazine
- Anticonvulsant therapy - IV magnesium sulphate
What are the CIs for labetalol and what would you use instead?
Asthma
CHF
Hydralazine
And if Hydralazine is ineffective then use nifedipine
How is pre-eclampsia prevented for future pregnancies?
Aspirin 75 mg daily from the beginning of the next pregnancy
Reduces risk of HTN and it’s severity if it does happen again
