PIH

高雄榮總婦產部李如悅

Preview

Obstetrics deadly triad: hemorrhage, infection, preeclampsia

Incidence: 3.7-5% 16% of 3201 pregnancy-related deaths

in the United States from 1991-1997

Gestational hypertensionBP 140/90mm Hg for ≧ first time during pregnancy

No proteinuria

BP returns to normal < 12 weeks’ postpartum

Final diagnosis made only postpartum

May have other signs or symptoms of preeclampsia, for example, epigastric discomfort or thrombocytopenia

TABLE 34-1 Diagnosis of Hypertensive Disorders Complicating

Pregnancy

Preeclampsia

Minimum criteria

– BP 140/90mm Hg after 20 weeks’ gestation, 2 ≧measurements a minimum of 6 hours apart

– Proteinuria 300 mg/24 hours≧ or 1+ dipstick of two urine ≧specimens collected at least 4 hours apart

Increased certainty of preeclampsia– BP ≧ 160/110 mg Hg – Proteinuria 2.0 g/24 hours or 2+ dipstick ≧– Serum creatinine > 1.2 mg/dL unless known to be previously

elevated – Platelets < 100,000/mm3

– Microangiopathic hemolysis (increased LDH or schistocytes or helmet cells on peripheral blood smear)

– Elevated ALT or AST– Persistent headache or other cerebral or visual disturbance– Persistent epigastric pain

Eclampsia

Seizures that cannot be attributed to other causes in a woman

with preeclampsia

Superimposed Preeclampsia (on chronic hypertension)

New-onset proteinuria 300mg/24 hours≧ in hypertensive

women but no proteinuria before 20 weeks’ gestation

A sudden increase in proteinuria or blood pressure or platelet

count < 100,000/mm3 in women with hypertension and

proteinuria before 20 weeks’ gestation

Chronic Hypertension

1. BP 140/90 mm Hg ≧ before pregnancy or

diagnosed before 20 weeks’ gestation not

attributable to gestational trophoblastic disease or

2. Hypertension first diagnosed after 20 weeks’

gestation and persistent after 12 weeks’ postpartum

Etioloty

Abnormal trophoblastic invasion

In normal implantation uterine spiral arteries undergo extensive

remodeling as they are invaded by endovascular trophoblasts

In preeclampsia Incomplete trophoblastic invasion Decidual vessels, not myometrial vessels,

become lined with endovascular trophoblasts

Immunological factors

Preeclampsia is immune mediated. The microscopic changes at the maternal-

placental interface are suggestive of acute graft rejection

Atherosis is demonstrated in blood vessels.

The vasculopathy and the inflammatory changes

Inflammatory changes are a continuation of the placental causes.

These then serve as mediators to provoke endothelial cell injury.

To cause a series of oxidative stress, TNF-α, interlukins, endothelins

PGI2 ↓; TXA2 ↑

Pathogenesis

Vasospasm Endothelial cell activation Increased pressor responses

X: gestational age Y: the dosage of angiotensin II for inducing hypertension

Blue line: preeclampsia group

Black line: normal pregnancy women

Prediction and prevention

Roll-Over test (hypertensive reponse

after laterally recumbent to supine position) Uric acid Fibronectin Coagulation activation Positive predictive value<40% Routine prenatal examination

Prevention

Dietary manipulation

salt restriction, Calcium supplementation, fish oil capsules (of no use)

Antioxidants: vit C or E,

significant reduction of preeclampsia

(17% vs 11%) Low-dose aspirin: ineffective

Management

1. Termination of pregnancy with the least possible trauma to mother and fetus

2. Birth of an infant who subsequently thrives

3. Complete restoration of health to the mother

The most important information that the obstetrician has for successful management is precise knowledge of the age of the fetus

在每一次產前檢查都會測量血壓以及檢查尿蛋白，以期早期發現 PIH or preeclampsia

對於輕微的 PIH 病人可以在家中臥床休息，以降血壓藥物控制血壓，並於門診追縱治療即可。一旦血壓持續上升或有 severe preeclampsia 的症狀出現時，則需要住院觀察及治療

對於 preeclampsia 的病人需要安排下列的檢查，以評估病人目前的狀況：

(1) CBC ＋ platelet (2) Blood chemistry screening (3) Urine analysis (4) 24 小時 urine protein (5) 眼底檢查

(6) Coagulation profile (PT ， PTT ， FDP ， Fibrinogen ， Bleeding time)

(7) 每星期 1-2 次 NST (8) 每星期至少一次 sonographic

screening 以了解胎兒生長情況 (9) Blood flow study (Waveform study)

(10) Severe preeclampsia 病人需要記錄intake 及 output

(11) 使用 MgSO4 的病人要記錄尿量、注意呼吸速率、以及肌腱反射 , serum Mg2+ level (4-7mEq/dL; 4.8-8.4mg/dL)

(12) 有肺水腫或需要補充體液時，最好能有central line 或 Swan-Ganz cather 以監測CVP 或 PCWP

在治療方面首先要控制血壓及 Vital sign 。如果血壓很高，超過 160/100 mmHg 以上時，可以給 Apresoline 5-10mg IV push ， 15-20-

minute interval, 20 分鐘後再 recheck 血壓 ;

如果需要，可以再給一個 dose 。

在口服降血壓藥方面，目前認為 Apresoline (Hydralazine) 以及 Aldomet (Methyldopa) 可以安全地用在孕婦，有效地降低血壓。一般使用的劑量為Apresoline 10mg tid ，最高劑量為 300 mg/day; Aldomet 250 mg bid - tid ，最高劑量可以用到 2000mg/day 。

其它的降血壓藥，如 Adalat (Ca

blocker) 、 Tenormin (β-blocker) 等，有人主張仍可用孕婦，但也有人認為對胎兒會有不良影響，仍未有定論，但 ACE inhibitor 如 Capoten ， Renitec 絕不可使用 (renal

toxicity)

原則上，血壓控制的目標在 140/90mmHg ，但是血壓的下降不可太快，最好是 step by

step ，否則降低子宮的血流，反而影響胎盤的 perfusion 造成胎兒窘迫的現象。

在 severe preeclampsia 和 eclampsia 的病人可以使用 MgSO4 IV infusion 來預防或控制 convulsion 。

要特別強調的是 MgSO4 的作用在於 anticonvulsion 而非降低血壓。

一般會先給 4gm (2 Amp) 作為 loading dose ，再以 1-2gm/hr 的速率 IV infusion 作為 maintenance dose ( 可用 5 Amp 加 在 400cc 5% G/W keep 50-100cc/hr ，或 10 Amp 加在 300cc 5% G/W keep 25-50cc/hr) 。

生產後， MgSO4 仍要繼續使用 24 小時，以防止產褥期的 eclampsia 發生。鎂離子的 safty range 很窄， theraputic level 大約在 4-7mEq/l(4.8-8.4mg/dL)

Clinical presentation of MgSO4 overdose 9.6-12mg/dL:

loss of deep tendon reflexes 12-18mg/dL

respiratory paralysis 24-30mg/dL

cardiac arrest

Calcium gluconate 1gm IV 5-10 mins for life-threatening symptoms of magnesium toxicity

Eclampsia

Preeclampsia complicated by generalized tonic-clonic convulsions

Fatal coma without convulsions Major complicationplacenta abruption:10%, neurological

deficits:7%, aspiration pneumonia:7%, pulmonary edema:5%, cardiopulmonary arrest4%, acute renal failure:4%, maternal death 1%

Treatment

the same as severe preeclampsia

何時要中止懷孕﹖

這是一個需要多方考慮的問題。如果病人只是血壓稍高，或是可以用降血壓藥物控制在正常範圍，而且胎盤功能正常、胎兒生長情況良好，可以等到足月再生產

門診追蹤

如果胎盤功能降低、血流阻力明顯升高 (UA

S/D ratio>3) ，或胎兒生長停滯 (IUGR) ，對於 severe preeclampsia 的病人首先要降低血壓、控制 vital sign ，等情況穩定後儘快生產 ; 如果發生 eclampsia ，在 convulsion 控制下來以後就應該立刻中止懷孕

The way of delivery

The decision to expedite delivery does not mandate immediate cesarean birth

A prolonged induction is best avoided Scheduled C/S for women with severe

preeclampsia when GA<30 wks and low Bishop score

Long-term consequences

Women who have had preeclampsia are more prone to hypertensive complications in future pregnancies.

Multiparous women with eclampsia tend to have higher risk in cardiovascular diseases than nullipara

Recurrent pregnancy hypertension were at increased risk for chronic hypertension

Women experiencing normotensive births in subsquent pregnancy have a reduced risk for remote HTN

Repeated pregnancy serves as a screening test for future HTN

Preeclampsia does not cause chronic hypertension

The End

Thanks for your attention!