Presentation on theme: "Pregnancy Induced Hypertension"— Presentation transcript:
1Pregnancy Induced Hypertension Hypertensive disorders are among the most common and yet serious conditions seen in obstetrics. These disorders cause substantial morbidity and mortality for both mother and fetus, despite improved prenatal care.Jun MaDept. of Obstetrics & GynecologyThe First Hospital of Xi’an Jiaotong Univ
2Introduction Incidence: China: 9.4%, worldwide: 7-12% The most common and yet serious conditions seen in obstetricscause substantial morbidity and mortality in the mother and fetusDeath due to cerebral hemorrhage, aspiration pneumonia, hypoxic encephalophathy, thromboembolism, hepatic rupture, renal failureHypertensive disorders are among the most common and yet serious conditions seen in obstetrics. These disorders cause substantial morbidity and mortality in both the mother and fetus, despite improved prenatal care.
3Hypertension in pregnancy DefinitionDiastolic BP ≥90 mmHgSystolic BP ≥140 mmHgOr as an increase in the diastolic BP of ≥ 15 mmHg or in the systolic blood pressure of 30 mmHg, as compared to previous pressureThe increased blood pressures be present on at least two separate occasions, > 6h apartAlthough this definition seems quite clear, its use in clinical practice is difficult because of various problems in obtaining a reliable assessment of blood pressure.PositionCorrrect size blood pressure cuffBP normally decreases during the second trimester, and the decrease may mask the presence of chronic hypertension .
4ClassificationVarious classifications of hypertensive disorders in pregnancy have been proposed. Here the commonly used classification of ACOG is proposed.
5Classification of Hypertensive Disorders in Pregnancy (ACOG) Pregnancy-induced hypertensionPreeclampsiaMildSevereEclampsiaChronic hypertension preceding pregnancyChronic hypertension with superimposed PIHSuperimposed preeclampsiaSuperimposed eclampsiaGestational hypertensionHypertensive disorders in pregnancy represent a spectrum of disease, classification systems should not be considered as rigid markers on which all management decisions are made.
6Classification (1) Pregnancy-induced hypertension: Hypertension associated with proteinuria and edema, occurring primarily in nulliparas after the 20th week or near term.Preeclampsia【mild 】BP ≥ 140/90mmHgOnset after 20 weeks’ gestationProteinuria (>300mg/24-hr urine collection) or +Epigastric discomfortThrombocytopenia
7Classification (2) 【severe】 BP ≥ 160/110 mmHg Marked proteinuria (>1-2 g/24-hr urine collection or 2+ or more), oliguriaCerabral or visual disturbances such as headache and scotomataPulmonary edema or cyanosisEpigastric or right upper quadrant pain (probably caused by subcapsular hepatic hemorrhage)Evidence of hepatic dysfunction, or thrombocytopenia
8Classification (3) Eclampsia Meets the criteria of preeclampsia Presence of convulsions, not attributable to other neurological disease,Occurrence: %, with 25% occurring in the 1st 72 hs postpartum
9Classification (4)Chronic hypertension proceeding pregnancy (essential or secondary to renal disease, endocrine disease, or other causes)BP ≥ 140/90 mmHgPresents before 20 wk gestationPersists beyond 12 wk postpartum
10Classification (5)Chronic hypertension with superimposed preeclampsia or eclamptiaCoexistence of preeclampsia or eclampsia with preexisting chronic hypertensionCause greatest riskWhen diagnosis is obscure, it is always wise to assume that the findings represent preeclampsia and treat accordingly.Superimposed preeclampisa: preeclampsia may occur in women with chronic hypertension, the progress is worse for the mother and the fetus than either condition alone. The criteria for it are worsening hypertension before 20 weeks together with either nondependent edema or proteinuria.
11Classification (6) Gestational hypertension: not mentioned in the ACOG Finding of hypertension in late pregnancy in the absence of other findings suggestive or preeclampsiaTransient hypertension of pregnancyMay develop into chronic hypertension if elevated BP persists beyond 12 weeks postpartumGestational hypertension: is further divided into transient hypertension of pregnancy if preeclampsia is present at the time of delivery and the blood pressure is normal by 12 weeks postpartum, and chronic hypertension if the elevation in blood pressure persists beyond 12 weeks postpartum. This condition is often predictive of the later development of essential hypertension.
12High risk factors Nulliparous <18ys or >40 ys, multiple pregnancyHas previous gestational hypertensive disordersChronic nephritisDiabeticMalnutritionLow social statusHydatidiform mole
13Etiology: UNCLEARImmune mechanism (rejection phenomenon, insufficient blocking Ab)Injury of vascular endothelium----disruption of the equilibrium between vasoconstriction and vasodilatation, imbalance between PGI and TXACompromised placenta profusionGenetic factorDietary factors: nutrition deficiencyInsulin resistanceIncrease CNS irritabilityPreeclampsia has been described as a disease of theories, because the cause is unknown.
14PathophysiologyHypertension in pregnancy affects the mother and newborn to varying degrees, depending on the severity of disease. The effect is multisystem. One common pathophysiologic finding in hypertension in pregnancy , especially when there is progression to preeclampsia, is vasospasm.
15Central nervous system Raised BP disrupt autoregulationIncreased permeability due to vasospasm---thrombosis of arterioles, microinfarcts, and petechial hemorrhageCerebral edema: increased intracranial pressureCT scan (1/3-1/2 positive): focal hypodensityCerebral angiography: diffuse arterial vasoconstrictionEEG: nonspecific abnormality (75% in eclamptic patient)
17Pulmonary system Pulmonary edema Cardiogenic or noncardiogenic Excessive fluid retention, decreased hepatic synthesis of albumin, decreased plasma colloid oncotic pressure,Often occurs postpartumAspiration of gastric contents: the most dreaded complications of eclamptic seizures
18Kidneys Characteristic lesion of preeclampsia: glomeruloendotheliosis Swelling of the glomerular capillary endotheliumDecreased GFRFibrin split products deposit on basement membraneProteinuriaIncrease of plasma uric acid, creatinine,
19Liver The spectrum of liver disease in preeclampsia is broad Subclinical involvementRupture of the liver or hepatic infarctionHELLP syndrome: hemolysis, elevated liver enzymes and low platelets
20Cardiovascular system Generalized vasoconstriction, low-output, high-resistance stateUntreated preeclamptic women are significantly volume-depletedCapillary leakCardiac ischemia, hemorrhage, infarction, heart failureIncreased sensitivity to vasoconstrictor effects of angiotensin
21Blood (1) Volume: reduced plasma volume Normal physiologic volume expansion does not occurGeneralized vasoconstriction and capillary leakHematocrit
22Blood (2): coagulation Isolated thrombocytopenia: <150,000/ml Microangiopathic hemolytic anemiaDIC (5%)HELLP syndrome: in severe preeclampsiaschistocytes on the peripheral blood smearlactic dehydrogenase > 600 u/Ltotal bilirubin > 1.2 mg/dlaspartate aminotransferase >70 U/Lplatelet count <100,000/mm3Misdiagnosis: hepatitis, gallbladder disease, ITPITP: idiopathic thrombocytopenic purpura
23Endocrine systemVascular sensitivity to catecholamines and other endogenous vasopressors such as antidiuretic hormone and angiotensin II is increased in preeclampsiaDisequilibrium of prostacyclin/ thromboxane A2
24Placenta perfusion 500 mm vs 200 mm Acute atherosis of spiral arteries: fibrinoid necrosis of the arterial wall, the presence of lipid and lipophages and a mononuclear cell infiltrate around the damaged vessel----vessel obliteration---- placental infarctionFetus is subjected to poor intervillous blood flowIUGR or stillbirth
25Clinical findings (1) Symptoms and signs Hypertension Diastolic pressure ≥ 90 mmHg orSystolic pressure ≥ 140 mmHg orIncrease of 30/15 mmHgProteinuria>300 mg/24-hr urine collection or+ or more on dipstick of a random urineHypertension is the most important criterion for the diagnosis of preeclampsia, and it may occur suddenly. The criteria are as described before. It usually falls during sleep in patients with mild preeclampsia and chronic hypertension, but in severe preeclampsia, BP may increase during sleep, eg, the most severe hypertension may occur at 2 am.Proteinuria is the last sign to develop. Eclampsia may occur without proteinuria. Most patients with proteinuria will have glomeruloendotheliosis on kidney biopsy. Proteinuria in preeclampsia is an indicator of fetal jeopardy. The incidence of SGA infants and perinatal mortality is mardedly increased in patients with proteinuric preeclampsia.
26Clinical findings (2) Edema Weight gain: 1-2 lb/wk or 5 lb/wk is considered worrisomeDegree of edemaPreeclampsia may occur in women with no edemaMost recent reports omit it from the definition
27Clinical findings (3)Differing clinical picture in preeclampsia-eclampsia crises: patient may present withEclamptic seizuresLiver dysfunction and IUGRPulmonary edemaAbruptio placentaRenal failureAscites and anasarcaPreeclampsia-eclampsia is a multisystem dissease with varying clinical presentations.
28Laboratory findings (1) Clinical findings (4)Laboratory findings (1)Blood test: elevated Hb or Hct, in severe cases, anemia secondary to hemolysis, thrombocytopenia, FDP increase, decreased coagulation factorsUrine analysis: proteinuria and hyaline cast, specific gravity > 1.020Liver function: ALT and AST increase, alkaline phosphatase increase, LDH increase, serum albuminRenal function: uric acid: 6 mg/dl, serum creatinine may be elevated
30Differential diagnosis Pregnancy complicated with chronic nephritisEclampsia should be distinguished from epilepsy, encephalitis, brain tumor, anomalies and rupture of cerebral vessel, hypoglycemia shock, diabetic hyperosmatic coma
31Complications Preterm delivery Fetal risks: acute and chronic uteroplacental insufficiencyIntrapartum fetal distress or stillbirthIUGROligohydramnios
32Predictive evaluation (1) Mean arterial pressure, MAP= (sys. Bp + 2 x Dia. Bp) /3MAP> 85 mmHg: suggestive of eclampsiaMAP > 140 mmHg: high likelihood of seizure and maternal mortality and morbidityMore than 100 clinical , biophysical and biochemical tests have been reported to predict preeclampsia, unfortunately, most suffer from poor sensitivity and none are suitable for routine use a as screening test in clinical practice.
33Predictive evaluation (2) Roll over test: ROTPreeclamptic patients are more sensitive to angiotensin IIDifference between Bp obtained at left recumbent position and supine position (at a 5 min interval)Positive: > 20 mmHgUrine calcium/ creatinine < 0.04Several authors have reported reduced urinary excretion of calcium during preeclampsia and for several weeks prior to the onset of clinically apparent disease. In addition, abnormal intracellular calcium metabolism in platelets and RBC has been demonstrated in women with preeclampsia as compared with normotensive pregnant women.
34PreventionCalcium supplementation: not effective in low risk women bur show effect in high risk groupAspirin (antithrombotic): uncertainGood prenatal care and regular visitsBaseline test for high-risk womenEclampsia cannot always be prevented, it may occur suddenly and without warning.As a result, most studies of prevention have used patients with various risk factors for preeclampsia.Aspirin: There is evidence to suggest that thromboxane A2 production is markedly increased, while prostacyclin production is reduced in women with welll established preeclampsia and prior to the onset of preeclampsia. In addition, placental infarcts and thrombosis of the spiral arteries have been demonstrated in pregnancies complicated by preeclampsia, particularly in those with severe fetal growth retardation or fetal demise. As a result of these findings, several authors have used various antithrombotic agents in a an attempt to prevent preeclampsia.The baseline tests include:Hct and Hb, platelet countSerum creatine and uric acid24-h urine collection for protein and creatinine clearanceEarly ultrasounds and follow-up scans.
35Treatment Mild preeclampsia: bed rest & delivery Hospitalization or home regimenBed rest (position and why) and daily weighingDaily urine dipstick measurements of proteinuriaBlood pressure monitoringFetal heart rate testingPeriodic 24-h urine collectionUltrasoundLiver function, renal function, coagulationThe patient is usually hospitalized upon diagnosis, since this diminishes the possibility of convulsions and enhances the chance of fetal survival. Hospitalization to prevent premature delivery in preeclmapsia is far less expensive than the cost of caring for a premature infant.The mainstay of patients with mild preeclampsia and an immature fetus is bed rest, preferably with as much of the time as possible spent in a lateral decutitus position. In this position cardia function and uterine blood flow are maximized and maternal BP in most cases are normalized. This improves uteroplacental function, allowing normal fetal growth and metabolism.
36A. Mild preeclampsia: bed rest & delivery Observe for danger signals: severe headache, epigastric pain, visual disturbancesSedatives: debatable
37B. Severe preeclampsia: Prevention of convulsion: magnesium sulfate or diazepam and phenytoinControl of maternal blood pressure: antihypertensive therapyInitiation of delivery: the definitive mode of therapy if severe preeclampsia develops at or > 36 wk or if there is evidence of fetal lung maturity or fetal jeopardy.
38Magnesium sulfateDecreases the amount of acetylcholine released at the neuromuscular junctionBlocks calcium entry into neuronsVasodilates the smaller-diameter intracranial vessels
39Magnesium sulfate Prevent convulsion Virtually ineffective on blood pressurei.v. or i.m.5g loading dose 5-10 min, i.v.1-2g/hr constant infusionTotal dose: g/d
40Toxicity:Diminished or loss of patellar reflexDiminished respirationMuscle paralysisBlurred speechCardiac arrest
41How to prevent toxicity? Frequent evaluation of patellar reflex and respirationsMaintenance of urine output at >25 ml/hr or 600 ml/dReversal of toxicity:Slow i.v . 10% calcium gloconateOxygen supplementationCardiorespiratory support
42Antihypertensive therapy: reduce the Dia. pressure to 90-110 mmHg IndicationBp> 160/110 mmHgDia. Bp > 110 mmHgMAP > 140 mmHgChronic hypertension with previous antihypertensive drugs usage
46Delivery Indication of termination of pregnancy Preeclampsia close to term<34 wk with decreased placental function2 hs after control of seizure
47Delivery Induction of labor First stage: close monitor, rest and sedationSecond stage: shorten as much as possibleThird stage: postpartum hemorrhageCesarean sectionInduction of labor unsuccessfulInduction of labor not possibleMaternal or fetal status is worseningPostpartum eclampsia can happen at days after delivery.
48Eclampsia No aura preceding seizure Multiple tonic-clonic seizures UnconsciousnessHyperventilation after seizureTongue biting, broken bones, head trauma and aspiration, pulmonary edema and retinal detachment
49Management Control of seizure Control of hypertension Delivery Proper nursing care