Hypertensive Disorders In Pregnancy Flashcards
What are they?
A group of conditions in pregnancy characterized by an elevated blood pressure as the cardinal sign and the occurrence of other manifestations in several organ systems (CNS, cardiopulmonary, liver, kidneys, coagulation)
What is Pregnancy induced hypertension
Gestational hypertension
Occurs after 20 weeks gestation without proteinuria in a previously normotensive woman
What is Pre-eclampsia?
It is hypertension after 20 weeks gestation with proteinuria and /or end organ damage in a previously normotensive, non-proteinuria woman
What is Eclampsia?
The occurrence of generalized seizures in a pre-eclamptic patient.
What is Chronic/ Pre-gestational hypertension?
Hypertension present before pregnancy, before 20 weeks gestation or which persists for more than 6 weeks postpartum.
Essential/Secondary to a renal disease, endocrine disease or other cause.
FIGO Classification for hypertension
Pre-gestational hypertension
Gestational hypertension
Pre-eclampsia
Others: Masked, Transient, White coat
Masked Hypertension
BP that is consistently normal in the clinic but elevated in the house
White coat hypertension
BP that is found to be elevated in the health facility but is normal outside the facility
Transient Hypertension
Elevated BP due to environmental factors or the pain of labour
BP Profile during pregnancy
Pre-pregnant BP falls in earl second trimester then gradually increases to term.
What are the figures for Hypertension in pregnancy? How are they measured?
Sustained
Systolic BP >/= 140mmHg and/or
Diastolic BP >/= 90mmHg
Two successive readings of BP at least 6 hours apart
Values for severe hypertension
Systolic BP >/= 160mmHg
Diastolic BP >/= 110 mmHg
What is significant proteinuria in pregnancy?
> /= 300mg in a 24 hour urine collection
Urinary protein : creatinine ratio of >/= 30mg/mmol on a single specimen
Proteinuria of 2+ or more on dipstick
What entails end organ damage in pre-eclampsia?
Severe headaches Visual symptoms Epigastric pain Dyspnea Chest pain Low platelets, low haematocrit and deranged liver enzymes (all deranged lab parameters) - Hellp
Pre-eclampsia in a woman with chronic hypertension (superimposed)
After 20 weeks, there is
- Resistant hypertension- requires 3 concurrent medications for control
- New or worsening proteinuria
- One or more features of end organ damage
How is Pre-eclampsia classified?
Mild and severe.
Mild: BP is >/= 140/90 and there is proteinuria and/or end organ damage. However, none of the criteria for severe is present
Severe features of pre-eclampsia
BP>/= 160/110 on 2 occasions 6 hours apart
Proteinuria > 2g per 24hr urine specimen or 2-4+ on dipstick
Oliguria (<500ml/24 hrs)
HELLP syndrome
Cerebral or visual disturbances
Epigastric pain
Persistent frontal headache
Blurred vision
Retinal changes - hemorrhages, exudates, papilledema
What is the etiology of pre-eclampsia?
Defective placentation from impaired trophoblastic invasion of maternal spiral arteries during pregnancy. Leads to vasoconstriction instead of dilation of the spiral arteries supplying placental bed. Results in high pressure low volume blood flow instead of vice versa to the placental bed. Systemic hypertension results.
Risk factors for Pre-Eclampsia
Nulliparity with a particular father SLE Afro-Caribbean ethnicity Extremes of maternal age: <20, >35 Low socioeconomic status Large placental mass (in multiple gestation) Renal disease Molar pregnancy Polyhydramnios Obesity Diabetes Mellitus type 1 Chronic hypertension Mother in law had pre-eclampsia
What is the Pathogenesis of Pre-eclampsia?
Endothelial cell injury
Fetal rejection phenomenon (following inadequate blocking antibodies)
Compromised placental perfusion
Dietary insufficiency of Calcium, Magnesium, Selenium
Genetic predisposition
Decreased renal glomerular filtration with salt and fluid retention
Decreased intravascular volume
Organ specific lesions of pre-eclampsia
Glomerulo-endotheliosis - Kidneys
Sub-endothelial fibrin deposition and elevation of AST, ALT - Liver
Vasospasm and Cerebral edema - Brain
Vasospasm, hemolysis & DIC - General vasculature
What are the clinical features of pre-eclampsia
(Always measure the BP and check proteinuria in every pregnant woman).
Gradual onset hypertension (or sudden/superimposed on chronic one)
Proteinuria - After hypertension(or can rarely be a late finding)
Edema (not important criterion)
IUGR, Placenta abruptio, renal failure, HELLP syndrome
What are the Laboratory findings in Pre-eclampsia?
Full Blood count - Low platelets (HELLP, DIC, Thrombocytopenia), (Normocytic anemia & schistocytes - Hemolytic anemia/HELLP)
BUN/Cr disturbances
Proteinuria
Haemoconcentration
Thrombocytopenia
Fibrin degradation products
Elevated renal function tests (Uric acid >5.5mg/dl)
Elevated AST/ALT - HELLP syndrome
Prothrombin Time/PTT - If elevated, points to DIC
Decreased Fibrinogen- DIC
Maternal complications of Pre-eclampsia
Maternal Eclampsia IUGR Cerebral hemorrhage DIC and Thrombocytopenia Hepatic Failure Renal failure Edema Pulmonary edema
Fetal complications of Pre-eclampsia
Prematurity Dysmaturity Uteroplacental insufficiency / Placental infarction Placenta abruptio Intrapartum fetal distress IUGR /SGA from chronic uteroplacental insufficiency Oligohydramnios Still Birth Perinatal morbidity and mortality
Plausible Pathogenesis
Prevention of Pre-eclampsia
Detection of high vascular resistance in uterine artery using USG
Use of prophylactic medication with calcium and aspirin supplements ( issa no)
Treatment Principles
Specific and Curative - Deliver fetus and placenta.
But first, examine the viability of the fetus , severity of the disease and maternal risks.
4 main principles- Stabilize the patient, Control blood pressure with anti hypertensives, Prevent fits by giving MgSo4, Deliver the baby (24-48 hours) - whenever is practical.
Treatment of Mild Pre-eclampsia
Bed rest and expectant management
Maternal monitoring: 4 hourly BP, daily. Weight measurement, urine testing and monitoring for protein; weekly LFTs, RFTs
Anti hypertensive medication are given when the diastolic BP > 100Hg
Fetal monitoring: daily kick count, FH; twice weekly non-stress test.
Deliver the woman when the gestation reaches 37 weeks even if monitored parameters are good.
Mild pre-eclampsia treatment continued
Woman must be delivered earlier than 37 weeks when monitoring parameters reveal signs of worsening disease:
Worsening BP and proteinuria
Deranged lab parameters - uric acid, LFT, RFT
Development of HELLP syndrome
Persistent headache, Epigastric pain, visual disturbances
Fetal compromise
Pre-eclampsia with severe features
Eclampsia
Pre-eclampsia with severe features
Obstetric emergency - treated as eclampsia
- Prevent convulsions by giving MgSO4
- Control BP with anti-hypertensives (Nifedipine, a Methyl Dopa, Hydrallazine)
- End pregnancy by delivery of fetus. Assess the woman for induction and vaginal delivery if no contraindication is present and an easy vaginal delivery can be expected- otherwise C/S
When does Eclampsia occur
Follows uncontrolled pre-eclampsia and usually occurs after 20 weeks gestation (rarely before).
75% occurs before delivery.
Postpartum eclampsia rarely seen after 72 hours
How can Eclampsia be prevented?
Adequate treatment of pre-eclampsia and prompt intervention
What causes and eclampsia’s seizure?
Cerebral cortical hypoxia due to platelet microthrombi and foci of hemorrhages in the brain
Describe the seizure of Eclampsia
Preceded by no aura.
Post-seizure duration of unconsciousness lasts for variable amount of time.
Seizure induced complications- Tongue biting, fractures, head injury, aspiration of secretions.
Principles of Treatment of Eclampsia
- Provision of life support during and after fits - ABC
- Control of the seizure and prevention of further seizures using MgSO4
- Control of hypertension (anti hypertensives)
- Resuscitation and assessment of the woman for delivery
- Special care for the peri-delivery period
KATH MgSO4 protocol - Loading dose
Given to all patients with severe pre-eclampsia and those who’ve had eclampsia.
Loading dose: 14g
4g (8ml of 50% in 12 ml N/S to make 20 ml 20% MgSO4) slowly Iv over 5 - 10 minutes AND 5g (10ml 50%) into each buttock (total 10g) by deep IM injection.
If convulsions occur within 20 minutes of the loading dose, don’t repeat injection. If it occurs after 20 min, another 2g IV MgSO4 can be given.
KATH MgSO4 protocol - Maintenance dose
Maintenance dose
Give 2.5g (5ml 50%. MgSO4) into each buttock [ie total of 5g (10ml)] every 4hours for 24 hours.
The schedule total dose of 5g may be given into alternate buttocks.
KATH MgSO4 Clinical Observations
Clinical parameters to monitor each time before the next dose of MgSO4 is given:
Patellar reflex (must be present) Respiratory rate (must be >16/min) Hourly urine output (must be >25ml)
Do not give next dose of MgSO4 if patellar reflex absent; give 1g Calcium Gluconate slowly IV
If urine output <100ml in 4hrs, give half dose of MgSO4.
Things to note about MgSO4 protocol
The use of MgSO4 in pre-eclampsia with severe features/eclampsia must be followed with the decision to deliver the woman within 24-48 hours.
Treatment with MgSO4 should not exceed 24hrs or 24 hrs after the last convulsion, whichever comes first
High yield
Patient counseling before start treatment
About condition, treatment, prognosis, and Rick of recurrence in future pregnancies. After delivery, psychological counseling is important especially if she had the pregnancy terminated
