Download - Hypertensive disorders in Pregnancy
HYPERTENSION IN PREGNANCY
Associate Professor Dr Hanifullah Khan
Objectives
• Understand definitions• Pathophysiology • Presentations of the disease• Important signs and symptoms
INTRODUCTION
Introduction
• H/T in pregnancy – leading cause of maternal & fetal morbidity
• The most frequent cause of iatrogenic prematurity
• PE & eclampsia – delivery is the only effective tx
Definitions – H/T
• H/T – – a DBP of 90mmHg or more, taken on 2
occasions > 4 hrs apart OR– A single DBP of > 110mmHg
• Can occur either in –– Women who already have H/T (10 or 20)– Manifest in 2nd half of pregnancy
Pregnancy HT & Chronic HT
• May be difficult to differentiate• Both have high risk of complications• Chr HT –
– Diagnosed prepregnancy– high BP early in pregnancy
Definitions - PE
• A multisystem disorder characterized by HT + proteinuria– Proteinuria - > 300mg urine pr / 24 hrs
• Occurs > 20 wks gestation• Resolves postnatally• Complications of PE – eclampsia,
HELLP synd
Definition - Eclampsia
• The occurrence of tonic-clonic convulsions in a woman with PE– Pregnancy – Any gestation– No neurological disease
• Gestational hypertension.• Preeclampsia (mild, severe).• Eclampsia.• Superimposed preeclampsia upon
chronic hypertension.• Chronic hypertension with pregnancy.
Classification
Incidence
• PE – 2-8% of all pregnancies– Risk in 1st pregnancy – 4.1%– Risk in later pregnancies – 1.7%– Risk in woman with PE in 1st pregnancies –
14.7%– Risk in woman with PE in previous 2
pregnancies – 31.9%
Summary
• Gestational hypertension: – Hypertension for first time after 20 w, without
proteinuria. BP returns to normal before 12 weeks postpartum.
• Chronic hypertension with pregnancy: – Hypertension antedates pregnancy and detected
before 20 w, & lasts more than 12 weeks postpartum.
PATHOPHYSIOLOGY
Basic understanding
• Complex disease• Appears to be triggered by the placenta
– Can occur in molar pregnancies where fetus absent
Trophoblast
• In normal conditions – – Trophoblast invades myometrium– Spiral arteries converted to low pressure system
• This process is inhibited in PE• Immunological process also involved• Thus HT & PE is caused by abnormal
placentation
Other factors
• Abn placentation → placental insufficiency & IUGR– Development of PE requires further changes
• ↑ Inflammatory activity– Widespread vascular endothelial damage– Capillary leak, vasoconstriction, intravascular
haemolysis, platelet activation– ↑ Immune status - ↑ leucocytes
Pathology • Primarily a disorder of placental dysfunction
– leading to a syndrome of endothelial dysfunction with associated vasospasm
• Evidence of placental insufficiency with associated abnormalities– diffuse placental thrombosis, an inflammatory placental
decidual vasculopathy, and/or abnormal trophoblastic invasion of the endometrium
• This supports abnormal placental development or placental damage from diffuse microthrombosis as being central to the development of this disorder
Pathopyhsiology
1. Placental factorsImmune complex deposition in kidney & placenta
Impair/ inadequate trophoblast invasion to the spiral arteries
Spiral arteries retain their charecteristic (narrow, tortuous, high resistance)
Reduce blood supply to placenta
Result in placental hypoperfusion
As a compensationHigh BP in maternal
2. Altered vascular reactivity
PG12 angiotensin II
vasoconstrict
HPT and reduce placenta blood flow
3. Coagulation disturbance
Activated endothelial cells promote coagulation and increase vasopressor sensitivity
Widespread coagulation occur (DIC)
Fibrin deposition in kidney & placenta
HPT & placental insufficiency
Summary
The development of PE is mediated through the degree of
placental pathology & the maternal inflammatory response
PREECLAMPSIA & ECLAMPSIA
• Is the most common medical disorder complicating pregnancy
• Is the most common hypertensive disorder in pregnancy
• More common in primigravidas and elderly multipara
Occurrence
• Chronic hypertension.• Chronic nephritis.• Past history .• Family history.• Obesity.• Multiple pregnancy.
Epidemiology
Maternal personal risk factors for preeclampsia
First pregnancyMultigravida pregnant by a different partnerAge younger than 18 years or older than 35 yearsHistory of preeclampsiaMultiple pregnancyFamily history of preeclampsia in a first-degree
relativeObesity Preexisting diabetesChronic hypertensionRenal diseaseSmoking
Multisystem Features Of Preeclampsia
Hypertension Proteinuria
Eclampsia HELLP syndrome
Intra-uterine growth restriction
Multi-organ disease
Cerebral vessels
Fetus
Liver
Systemic blood vessels Kidneys
Diagnosis Of PE
Hypertension + Proteinuria =
Two facets of a complex pathophysiological process
Peripheral oedema
• Not a useful diagnostic criterion– Common in pregnancy– PE can occur without oedema
• Headache.• Blurring of vision.• Nausea and vomiting.• Epigastric pain (distension of the liver
capsule)• Oliguria or anuria
Symptoms – non-specific
–The frequency and intensity of the signs and symptoms.
–The more the severity of PE, the more likely the need to terminate pregnancy
Severity of PE
• Eclamptic fit stages ( 4 stages):– Premonitory stage (1/2 minute):
● Eye rolled up● Twitches of the face and hands.
– Tonic stage (1/2 minute):● Generalized tonic spasm with opisthotonus.● Cyanosis.● Tongue may be bitten between the clenched teeth.
Diagnosis of Eclampsia
EVALUATION
Evaluation of Hypertension in PregnancyHistory
ID and Complaint HPI (S/S of
Preeclampsia) Past Medical Hx, Past
Family Hx Past Obstetrical Hx, Past
Gyne Hx Social Hx Medications, Allergies Prenatal serology, blood
work Assess for Hypertension
in Pregnancy risk factors
Physical BP (essential) Oedema Hyperreflexia Clonus Fondoscopy Urine dipstick test Cardiovascular Respiratory Abdominal =
Epigastric pain, RUQ pain
Cardiovascular
• Generalized vasospasm• Increased peripheral
resistance• Reduced central venous/
pulmonary pressure
Hematological
• Platelet activation and depletion
• Coagulopathy• Decreased plasma volume• Increased blood viscosity
• Proteinuria• Decreased glomerular
filtration rate• Decreased urate excretion
Renal
Hepatic
• Periportal necrosis• Subscapular
hematoma
• Cerebral oedema• Cerebral haemorrhages
Central Nervous System
Organ Specific Changes associated with Pre-eclampsia
Clinical presentationSymptoms Signs
•Headache (frontal/ occipital)• Visual disturbance•Nausea & vomiting• Epigastric and right upper abdominal pain•Oliguria / anuria• Maybe asymptomatic
• Rapid rise in BP• Papilloedema•Fluid retention (non-dependent edema)• Hyperreflexia•Clonus • Uterus and fetus may feel small for gestational age
Investigations
• Urine - 24 hour urine, Proteinuria.
• Kidney functions - serum creatinine, urea, creatinine clearance and uric acid.
• Liver functions - bilirubin, Enzymes (SGPT and SGOT).
• Blood - CBC, HCt , Hemolysis and Platelet count (Thrombocytopenia).
• Coagulation Profile - Bleeding and clotting time
Differential Diagnosis:
• A. Hypertension With Pregnancy. • B. Proteinuria With Pregnancy.
• C. Edema With Pregnancy:
Differential Diagnosis ConvulsionsConvulsions With Pregnancy:• Eclampsia.• Epilepsy.• Hysteria.• Meningitis and Encephalitis.• Tetanus.• Tetany.• Brain tumors.• Uremic convulsions
Differential DiagnosisHELLP Syndrome:
• Acute fatty liver in pregnancy.• Hepatitis.• Thrombocytopenia purpura.• Hemolytic Uremic syndrome.
Treatment• PREVENTION.• Antepartum
● Proper antenatal care● Expectant treatment.● Control hypertension.● Treatment of eclampsia .● Prevention and control of convulsions.● Termination of pregnancy .
• Intrapartum care.• Postpartum care.
Control of Convulsions:
• Magnesium Sulfate (MgSO4):● It is the drug of choice.● Mechanism:
–CNS depression.–Mild VD.–Mild diuresis.– Inhibits platelet aggregation.– Increase PGI2 synthesis.
Prognosis:
• BP usually normalize after placental delivery .• Hypertension may persist.• Postpartum eclampsia carries the worst prognosis.• Maternal mortality is about 2% in severe preeclampsia and
10% in eclampsia.• Perinatal mortality rate is about 5% in mild cases, 25% in
severe cases and 30% in eclampsia.
CONCLUSIONS
SummaryHypertension diagnosed prior to 20 weeks'
gestation, is generally due to preexisting chronic hypertension rather than pregnancy induce hypertension
Pre- eclampsia may be diagnose by a combination of fetal and maternal features, including IUGR, hematological or biochemical abnormalities as well as clinical symptom and signs
Maternal deaths
• Confidential Enquiry into Maternal and Child Health UK (2003-2005)– 18 deaths from PE & eclampsia– 10 deaths caused by IC haemorrhage
● Due to uncontrolled BP
References
• Obstetrics by Ten Teachers 18th Edition• Obstetrics illustrated 6th Edition• Lecture Notes Obstetrics and gynaecology
3rd Edition• http://emedicine.medscape.com/article/
261435-overview