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PIH
高雄榮總婦產部李如悅
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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!