Week 4 - H - Hypertension in Pregnancy (Pre-eclampsia and Eclampsia) Flashcards
What is the commonest medical problem in pregnancy?
Hypertension is the commonest medical problem in pregnancy
How many pregnancies does hypertension affect?
Hypertension affects 10-15% of all pregnancies
Pre-eclampsia is the commonest cause of iatrogenic prematurity What is it known as when pre-eclampsia progresses causing seizures? This effects 1in3000 pregnancies
Eclampsia is what pre-eclampsia will progress to if untreated - it affects 1in3000 pregnancies
When does the biggest cardiovascular change occur in pregnnacy? How much does the cardiac ouput increase during pregnancy?
The biggest cardiovascular change occurs during the first 12 weeks of gestation The CO increases by 30-50% during gestation
If the SV, HR are increasing causing the CO to increase, why isnt there a big change in the blood pressure?
This is because the uteroplacental circulation expands and there is a decrease in peripheral vascular resistance - therefore in first 12 weeks of pregnancy - there is a drop in BP
Blood pressure (BP) proportional to systemic vascular resistance and cardiac output When does pregnancy reach its lowest blood prssure?
Pregnnacy reaches its lowest blood pressure by 22-24 weeks gestation
What is hypertension in pregnancy defined as? (ie what is the blood pressure required to be, if you can try remember the guidelines for change in BP use in america)
This would be a BP of 140/90mmHg on two different occasions or 160/110mmHg once In america (American College of Obstetricians and Gynecologists) say that an increase >30/15mmHg compared to first trimester BP is hyerptension
Hypertension in pregnancy: Pre-existing hypertension - chronic hypertension Pregnancy induced hypertension - gestational hypertension (without proteinuria) Pre-eclampsia - pregnancy induced hypertension with proteinuria What is the cut off for each of these diagnosis? *
Pre-existing hypertension - hypertension present at booking or developing before 20 weeks gestation Pregnancy induced hypertension - hypertension that develops after 20 weeks gestation without proteinuria Pre-eclampsia - hypertension that develops after 20 weeks with proteinuria
How much doespre-existing hypertension increase the risk of pre-eclampsia?
Pre-existing hypertension doubles the risk of pre-eclampsia Also increases the risk of IUGR and placental abruption
How long should it take for pregnancy induced hypertension to resolve? What percentage of these cases progress to pre-eclampsia?
PIH should resolve within 6 weeks of delivery 15% of cases progress to pre-eclampsia during the pregnancy
Pre-eclampsia is pregnancy induced hypertension with proteinuria +/- oedema What does the BP have to be when measured? What does the level of protein in the urine have to be?
BP Greater than 140/90 on two different occasions or Greater than 160/11 on one occasion Proteinuia >/= 0.3g/l or >/= 0.3g over 24 hours
Pre-eclampsia A pregnancy-specific multi-system disorder with unpredictable, variable and widespread manifestations May be asymptomatic at time of first presentation Diffuse vascular endothelial dysfunction widespread circulatory disturbance What systems tend to be affected by pre-eclampsia?
Renal Liver Kidney Eyes Placenta Haem CNS
When do early and late preeclampsia occur? When does pre-eclampsia resolve after pregnancy?
Early pre-eclapmsia is osnet before than 34 weeks Late pre-eclapmsia is onest after 34 week Pre-eclampsia usually resolves within 10 days post-delivery
Pre-eclampsia is said to occur in two stages Stage 1 - Placental dysfunction Stage 2 - Endothelial dysfunction What is the endothelium?
Endothelium refers to the cells that line the interior surface of blood vessels and lymphatic vessels, forming an interface between circulating blood and the lumen. It is a thin layer of squamous cells known as the endothelium.
What happens in stage 1 of pre-eclampsia?
In Stage 1, there is failure of the trophoblastic invasion of the maternal spiral arteries causing failure of the spiral arteries to become high capacitance and low resistance - this cause a poor maternal to foetal blood flow leading to placental ischaemia Increasing BP partially compensates for this
How does the ischaemic placenta cause stage 2 of pre-eclampsia, the endothelial dysfunction?
The ischaemic placenta releases different proteins causing an imbalance between angiogenic and antiangiogenic leading to endothelial dysfucntion in the mother- mutlisystem disorder
Any maternal system as well as the placenta can be effected by pre-eclampsia What happens to the renal system in pre-eclampsia?
Causes a decrease in the glomerular filtration rate causing a build up of chemicals ie creatinine, urea, potassium, uric acid
What happens to the urine production in pre-eclampsia?
Women will often become oliguric and women with severe pre-eclampsia may become anuric
What are the symptoms of liver disease when effected by pre-eclampsia?
Epigastric pain/RUQ pain - Pain in this area is very common in pregnancy- e.g. gastritis. But check bloods and liver enzymes. Abnormal liver enzymes Hepatic capsule rupture
What is hepatic capsule known as? What is the syndrome due to the liver and blood clotting being affected known as?
Hepatic capsule is known as Glisson’s capsule Syndrome - HELLP Haemolysis Elevated Liver enzymes Low Platelet count
Most severe pre-eclampsia can effect the coagulation pathway What is the condition known as where small blood clots develop throughout the bloodstream, blocking small blood vessels. The increased clotting depletes the platelets and clotting factors needed to control bleeding, causing excessive bleeding. this condition can be brought on by pre-eclampsia
This is disseminated intravascular coagulation - because the clotting factors and platelets are used up, excessive bleeding can occur - need to rapidly correct this
What effect can pre-eclampsia have on the foetus?
Intrauterine growth restriction Itruetine death Placental abruption Placental ischaemia and infarction can cause fetal growth restriction.
What are the presenting symptoms of pre-eclampsia? Remember it can be a multi-system disorder so try focus on the most common
Headache Visual disturbance Epigastric/RUQ pain Nausea/vomiting Rapidly progressing oedema
What are signs of pre-eclampsia?
Hypertension Proteinuria Oedema Small for gestational age
What investigations are carried out in pre-eclampsia?
Urea and electrolytes Serum urate LFTs Liver function tests Full blood count Coagulation screening CTG
The risk of preeclampsia is assessed at the booking appointment originally Screening test at 20 weeks- maternal uterine artery doppler test- What is looked for in this doppler test?
Looks at blood flow to uterus- see if theres change in the uterine artery/spiral arteries. You should see a reduction in resistance in normal pregnancies as they spiral arteries should have a high capacitance to supply the placenta
When is the maternal uterine artery doppler test (MUAD) carried out to screenin for any abnormality?
Carried out at 20-24 weeks gestation
What are risk factors for pre-eclampsia? Age, pregnancies, BMI, birth interval
Multiple pregnancy Maternal BMI greater than 30 maternal age > 40 Parity - nullpaorus Previous pre-eclampsia Birth interval greater than 10 years
Pre-existing renal disease Pre-existing hypertension Diabetes (pre-existing/gestational) Connective tissue disease Thrombophilias (congenital / acquired) ALL RISK FACTORS FOR PRE-ECLAMPSIA What is given as prophylaxis to pre-eclampsia? Who is the prophylaxis given to?
Low dose aspirin - 75mg/24h daily drom 12th wee of pregnancy until delivery - used for high risk women or women with multiple risk factors
A woman can be admitted to the antenatal day care unit for a number of reasons to do with preclapmsia, ie HBP, proteinuria, oedema, pre-eclampsia symptoms What should you definitely admit?
BP - 170/110 or 140/90 with ++proteinuria Significant symptoms - headaches, visual disturbances Abnormal bicohemisty Significant proteinruia - 0.3g/24h Need for anti-hypertensive therapy Signs of foetal compromise
What is carried out once the patient is admitted to the antenatal day care unti?
BP - 4 hourly Daily urinalysis FLuid charts Urine PCR if protein on urinalysis - enables you to measure protein produced in 24 hours
Treat the hypertension regardless of the aetiology When should the treatment usually be started in hypertension in pregnancy? What blood presure requires immediate treatment?
Usually start treatment once Bp is >150/90 Immediate anti-hypertensive therapy required if BP 170/110
What are the 1st line drugs in treating hypertension during pregnancy? What is their mechanism of action?
Labetalol - dual alpha and beta antagnosim Methyldopa - centrally acting alpha agonist - stimulates brain to decrease activity of sympathetic nervous system Nifedipine - Ca chanel antagnosit
When should methyldopa and labetaolol be avoided? What is the main 3nd line anti-hypertensive and how does it work?
Methyldopa - avoid in women with depression - it inhibits an enzyme which converts a substance to dopamine peripherally (DOPA-decarboxylase inhibitor) Labetaolol - avoid in asthma 3rd line Hydralazine Smooth muscle relaxant therefore causing vasodilation
Name the drugs to treat hypertension in pregnancy again How do they work
1st line - labetalol - alpha and beta antagnoism - avoid in asthma 2nd line * Nifedipine - calcium channel blocker * Methyldopa - central alpha agonsit (stimulating the brain to decrease the activity of the sympathetic nervous system.) - avoid in depression 3rd line Hydralazine - smooth muscle relaxant
Ask all women to monitor fetal movements. If the baby gets sick it conserves energy and stops moving. Any concerns about the baby do CTG. Important to survey the foetus What may be seen on CTG inidcating foetal hypoxia?
Late decelerations on CTG are worrying that pre-eclampsia may have cause the foetus to enter foetal hypoxia
The only cure for pre-eclampsia is birth Mother must be stablised before birth Consider expectant management if pre-term Steroids Most women delivered within 2 weeks of diagnosis What steroid is given and why is it given?
Give betamethasone IM to the mother as this can help with foetal surfactant production lowering the rates of respiratory distress syndrome
If you cant control the bp- you need to deliver the baby- irrespective of the gestation. Eclamptic seizure- need to deliver. What type of seizure occurs in eclampsia?
a tonic clonic seizure can occur
Eclampsia is more associated with teenagers What anti-hypertensives are recommended? What drug is given for the seizures?
IV labetalol and/or hydralazine IV magnesium sulphate is recommended
If persistent seizures occur what is given? Why should this drug usually be avoided? What should be had at the ready incase of magensum sulphate toxicity?
If peristent sezirues occur, give diazepam (benzodiazepine) once only Benzos should be avoided in 1st semester due to foetal malformation eg cleft palate, avoid in third trimester due to risk of floppy baby syndrome Clacium gluconate given if magneisum sulphate toxicity (respiratory depression)
