PIH(Pregnancy-induced-hypertension)

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PIH(Pregnancy-induced-hypertension)

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• Common and form one of the deadly triad
  (hemorrhage,infection)
• most common medical risk factor (Ventura and
  colleagues,2000, National Center for Health
  Statistics)
• 18 of maternal deaths in USA(1987-1990) were
  from complication of PIH

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Terminology

• Any new-onset pregnancy-related hypertension
• include hypertension without proteinuria
• potential precursor to preeclampsia or eclampsia
• most hypertensive nulliparous women had only
  transient uncomplicated hypertension that
  subsided promptly after delivery

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Diagnosis

• Gestational hypertension ( PIH
  or transient hypertension )
• Preeclampsia
• Eclampsia
• Preeclampsia superimposed on chronic hypertension
• Chronic hypertension

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Gestational hypertension(PIH or transient
hypertension)

• BP gt/ 140/90 mmHg for first time during
  pregnancy
• No proteinuria
• BP return to normal lt 12 weeks postpartum
• Final diagnosis made only postpartum
• May have other signs of preeclampsia, for
  example, epigastric discomfort or
  thrombocytopenia

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Transient hypertension

• preeclampsia does not develop and BP has turned
  to normal by 12 weeks postpartum

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Preeclampsia

• Minimal criteria
• 1.BP gt/ 140/90 mmHg after 20 weeks gestation
• 2.Proteinuria gt/ 300 mg/24 hours or gt/ 1
  dipstick

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• Increased certainty of preeclampsia
• BP gt/ 160/110mmHg
• Proteinuria 2.0 g/24 hours or gt/ 2 dipstick
• Serum creatinine gt 1.2 mg/dL unless known to be
  previously elevated
• Platelets lt 100,000/mm3
• Microangiopathic hemolysis (increased LDH)
• Elevated ALT or AST
• Persistent headache or other cerebral or visual
  disturbance
• Persistent epigastric pain

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Severity of preeclampsia

• Severe
• gt/ 110 mmHg
• gt/ 2
• present
• present
• present
• present
• present(eclampsia)

• Mild
• DBP lt 100 mmHg
• proteinuria trace to 1
• headache absent
• visual disturbance absent
• upper abdominal pain absent
• oliguria absent
• convulsion absent

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Severity of preeclampsia(2)

• Severe
• elevated
• present
• marked
• obvious
• present

• Mild
• Serum creatinine normal
• thrombocytopenia absent
• liver enzyme elevation minimal
• fetal growth restriction absent
• pulmonary edema absent

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Eclampsia

• Preeclampsia that is complicated by generalized
  tonic-clonic convulsions
• fatal coma without convulsions
• All pregnant women with convulsions should be
  considered to have eclampsia
• Most common in the last trimester
• increasingly more frequent as term approaches

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Eclampsia (2)

• Seizures may appear before, during or after labor
• Seizures that develop more than 48 hours
  postpartum may be encountered up to 10 days
  postpartum
• the convulsive movements
  ---gt facial twitchings
  ---gt
  generalized muscular contraction
  ---gt jaws open and close violently
  ---gt all muscles alternately
  contract and relax ---gt lies motionless

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Complication of eclampsia

• respiratory arrest, coma, hypoxemia ---gt lactic
  acidosis
• fever from CNS hemorrhage
• fetal bradycardia (usually recovers 3 - 5 min, if
  gt 10 min ---gtplacental abruption must be
  considered

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Complication (2)

• pulmonary edema aspiration pneumonitis, cardiac
  failure
• blindness retinal detachment, occipital lobe
  ischemia, infarction, edema (prognosis is good
  and usually complete return to normal lt 1 wk)
• psychosis usually lasts for lt 2 wk

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Superimposed Preeclampsia ( on chronic
hypertension )

• New-onset proteinuria gt/ 300 mg/24 hours in
  hypertensive women but no proteinuria before 20
  weeks gestation
• A sudden increase in proteinuria or blood
  pressure or platelet count lt 100,000/mm3 in women
  with hypertension and proteinuria before 20
  weeks gestation

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Chronic hypertension

• BP gt/ 140/90 mmHg before pregnancy or diagnosed
  before 20 weeks gestation or
• Hypertension first diagnosed after 20 weeks
  gestation and persistent after 12 weeks
  postpartum

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Underlying chronic hypertension

• Essential familial hypertension
• arterial abnormalities
• renovascular hypertension
• coarctation of aorta
• endocrine disorders
• diabetes
• cushing syndrome
• primary aldosteronism
• pheochromocytoma
• thyrotoxicosis

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• Glomerulonephritis (acute and chronic)
• renoprival hypertension
• chronic glomerulonephritis
• chronic renal insufficiency
• diabetic nephropathy
• polycystic kidney disease
• acute renal failure
• obesity
• connective-tissue diseases
• lupus erythematosus
• scleroderma
• periarteritis nodosa

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Risk factor

• Multiple pregnancy
• Familial history of PIH
• DM
• Antiphospholipid syndrome
• History of chronic hypertension
• Maternal age gt 35 year
• Obesity
• African-American ethnicity(Conde - Agudelao and
  Beligan,2000Sibai and colleagues,1997Walker,2000
  )

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• Smoking during pregnancy has been associated with
  a reduced risk of hypertension during pregnancy(
  Zhang and colleagues, 1999)
• Placenta previa has also been claimed to reduce
  risk of hypertensive disorders due to
  pregnancy(Ananth and colleagues, 1997 )

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Pathogenesis

• Risk factors

Vasospasm platelet aggregation microangiopathy
regional bl. flow
PGI2 TXA2, vasoconstrictor
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Pathology

• Cardiovascular changes
• Hypovolemia
• - from vasospasm and
  increased vascular permeability
• ---gt hemoconcentration
• ---gt edema
• Coagulation
• - thrombocytopenia
• - microthrombi ---gt DIC
• - decreased antithrombin III ---gt prolong PT
• -microangiopathy ---gt fragmentation hemolysis

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Pathology (2)

• Fluid and electrolyte changes
• HCO3 is lowered following an eclamptic
  convulsion
• Kidney
• Decreased GFR
• ---gt oliguria
• ---gt renal failure
• ---gt uric acid, creatinine is elevated
• Glomerulopathy
• ---gt proteinuria
• Increased tubular reabsorption
• ---gt increased serum calcium

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Pathology(3)

• Liver elevated liver enzyme in severe case
• subcapsular hematoma
• Brain infarction, hemorrhage, cerebral edema
  ---gt headache, visual disturbance, convulsion
• EEG ---gtnonspecific change
• Placenta decreased blood flow
• ---gt IUGR, fetal distress
• Lung pulmonary edema

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HELLP Syndrome

• Hemolysis
• Elevated liver enzymes
• Low Platelet

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Prediction

• Angiotensin sensitivity test angiotensin II
  infusion
• roll over test
• uric acid
• Ca metabolism
• fibronectin
• urinary kallikrein excretion
• coagulation activator
• marker of oxidative stress
• immunological factors
• placental peptides
• doppler velocimetry of the uterine arteries

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Prevention

• Early prenatal detection
• 1 -28 wk., ANC every 4 wk.
• 28 - 36 wk., ANC every 2 wk.
• gt 36 wk., ANC every 1 wk.
• Dietary manipulation
• salt restriction, high calcium, fish oil
• Low dose aspirin
• suppression of thromboxane synthesis
• Antioxidant control lipid peroxidation --/--gt
  endothelial cell dysfunction

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Management

• Objective
• termination of pregnancy with the least possible
  trauma to mother and fetus
• birth of an infant who subsequently thrives
• complete restoration of health to the mother

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Hospital management

• Detailed examination
• BW. OD
• Urine protein on admittance
  and at least every 2 days thereafter
• BP every 4 hours, except between midnight and
  morning
• Plasma creatinine, Hct., platelet count, liver
  enzymes
• Frequent evaluation of fetal size and amniotic
  fluid volume either clinlcally or with sonography
  

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Hospital management(2)

• Reduce physical activity is beneficial (absolute
  bed rest is not necessary, sedatives and
  transquilizers are not prescribed)
• protein and calories should be included in the
  diet
• sodium and fluid intake should not be limited or
  forced
• further management depends upon
• 1. Severity of preeclampsia
• 2. Duration of gestation
• 3. Condition of the cervix

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Specific treatment

• Prevent convulsion
• control BP
• termination of pregnancy

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Prevent convulsion

• MgSO4 therapy is superior to phenytoin in
  preventing eclamptic seizures
• Hallak and associates (1999) ---gt maternal
  seizures were associated with fetal brain injury
  due to maternal hypoxia during the convulsion

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MgSO4 dosage schedule

• Continuous intravenous infusion
• 1. MgSO4 4 - 6 g. 100 mL of IV fluid IV drip in
  15 - 20 min.
• 2. Begin 2 g/h in 100 mL of IV maintenance
  infusion
• 3. Serum Mg level at 4 - 6 h, keep levels between
  4 -7 mEq/L
• 4. MgSO4 is discontinued 24 h after delivery

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• Intermittent intramuscular injections
• 1. 20MgSO4 4 g IV push (rate lt 1 g/min)
• 2. 50 MgSO4 10 g IM at buttock
• (??????5 g1.0 mL of 2lidocaine )
• If convulsions persist after 15 min,
• --- 20 MgSO4 2-4 g IV push (rate lt 1 g/min)
• 3. 50 MgSO4 5 g IM alternate buttock q 4 hr.
• but only after assuring that
• a. the patellar reflex is present
• b. respirations are not depressed
• c. urine output gt/ 100 ml /4 hr.
• 4. MgSO4 is discontinued 24 h after delivery

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Antihypertensive drug therapy

• Sibai and associates (1987) ---gtgrowth-restricted
  infants were twice as frequent in patient given
  labetalol compared with those treated by
  hospitalization alone
• Von Dadelszen and associates (2000) ---gttreatment
  - induced decreases in maternal BP may adversely
  affect fetal growth

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Antihypertensive drug therapy (2)

• Easterling and colleagues (1999) ---gt women at
  risk for preeclampsia ( high cardiac output
  measured by doppler technique at 24 wk) were
  randomized to prophylactic atenolol or placebo,
  the incidence of preeclampsia in control group
  atenolol group 18 4
• the use of ACEI during second and third
  trimesters should be avoided
• diuretics should not be used

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Hydralazine

• SBP gt/ 160 mmHg and/or DBP gt 105 mmHg (National
  High Blood Pressure Education Program, 2000 )
• 5 mg IV as the initial dose
• 5 - 10 mg IV q 15 - 20 min. until a
  satisfactory response is achieved
• Satisfactory response DBP 90 - 100 mmHg

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Labetalol

• Lower BP more rapidly, and associates tachycardia
  was minimal, but hydralazine lowered MAP to save
  levels more effectively
• The Working Group(2000) recommends 20 mg IV
  bolus.
• If not effective within 10 min, this is followed
  by 40 mg, then 80 mg every 10 min but not to
  exceed a 220 mg total dose

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Termination of pregnancy

• Severe preeclampsia
• Near term

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Post-partum

• Physiologic diuresis 12 -72 h postpartum
• proteinuria and edema disappear lt 1 wk
• BP returns to normal within a few days to 2 weeks
• Gestational hypertension must resolve within 12
  weeks

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Counseling for future pregnancies

• Women who had preeclampsia are more prone to
  hypertensive complications in future pregnancies
• The earlier diagnosis, the greater recurrence
• Multiparous are at increased risk compared with
  nulliparas

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Counseling (2)

• Women with early-onset severe PIH may be at risk
  for underlying thrombophilias (factor V Leiden,
  protein S and C deficiency, antiphospholipid
  antibodies)
• Preeclampsia does not cause chronic hypertension

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