preeclampsia
Table of Contents
pre-eclampsia and eclampsia
see also Obstetrics
hypertension in pregnancy
risk factors for pregnancy-induced HT:
- nulliparity (3x) (but HELLP syndrome has a pre-dilection for multigravids)
- age > 40yrs (3x)
- African American race (1.5x)
- FH pregnancy-induced HT (5x)
- chronic HT (10x)
- chronic renal disease (20x)
- antiphospholipid syndrome (10x)
- diabetes (2x)
- twin gestation (4x)
- angiotensinogen gene T235 (HZ 20x, heterozygous 4x)
Classification of hypertension during pregnancy:
chronic HT:
- HT (BP >= 140/90mmHg) present & observed before pregnancy or is Dx < 20th wk or 1st Dx during pregnancy & persists > 42nd day post-partum
pre-eclampsia/eclampsia:
- increased BP in pregnancy assoc. with proteinuria &/or generalised oedema
- NB. it is rare <20wks unless either:
- multiple pregnancy
- hydatidiform mole
- foetal triploidy
- antiphospholipid syndrome
- severe renal disease
pre-eclampsia superimosed on chronic HT:
- as for chronic HT, with BP increase of > 30mmHg systolic, 15mmHg diastolic or 20mmHg MAP with roteinuria &/or generalised oedema
transient HT:
- elevated BP developing during pregnancy or in 1st 24h post-partum without signs of pre-eclampsia or chronic HT
pre-eclampsia
diagnostic criteria for pre-eclampsia:
- elevated BP:
- sustained systolic BP >= 140mmHg or diastolic BP >= 90mmHg measured on 2 occasions >=6h apart
- AND EITHER:
- significant proteinuria:
- > 300mg/24h or >= 1g/ml measured on 2 separate occasions 6h apart (approx. 1+ on dipstick)
- oedema:
- generalised oedema or weight gain of at least 5lb in 1wk
diagnostic criteria for severe pre-eclampsia:
- in addition to above criteria, any 1 of:
- BP > 160-180mmHg systolic or > 110mmHg diastolic
- proteinuria > 5g/24h
- oliguria < 500ml/24h
- cerebral or visual disturbances (eg. scotomata)
- pulmonary oedema
- IUGR or oligohydramnios
- elevated serum creatinine
- grand mal seizures (ie. eclampsia)
- if occur > 20th wk gestation to 7 days post-partum (but reported up to 26th day puerperium)
- assume all seizures in this period to be eclamptic until proven otherwise
- up to 30% will not have HT, proteinuria or oedema
- risk of eclampsia in pre-eclampsia is ~ 1 in 300
- may be preceded by headache, blurred vision or decreased visual acuity
- may be focal or generalised
- usually are a single seizure lasting < 1min responding to IV MgSO4
- any one feature of HELLP syndrome:
- Haemolysis as manifest by microscopic features consistent with microangiopathic haemolytic anaemia on blood film (eg. presence of schistocytes)
- NB. due to depleted intravascular volume, haematocrit may actually rise!!
- Elevated Liver enzymes (hepatic transaminases) in absence of other causes
- Low Platelets <100,000/mm3
- epigastric or RUQ pain
Differential diagnosis of HELPP syndrome:
- autoimmune thrombocytopenic purpura
- chronic renal disease
- pyelonephritis
- cholecystitis
- gastroenteritis
- hepatitis
- pancreatitis
- thrombotic thrombocytopenic purpura
- HUS
- acute fatty liver of pregnancy
Assessment & management of pre-eclampsia:
general supportive care:
- monitoring of maternal vital signs, initally every 15-30min
- place in left lateral recumbent position so that gravid uterus does not produce aortocaval compression
- ABC's:
- oxygen if severe PET to maintain SaO2 > 90% (or > 95% if undelivered)
- if resp. depression intubate & ventilate as indicated
- IV line & bloods for:
- FBE, LFT, U&E, Group & hold with Ab screen
- IV fluid volume loading with 500ml:
- prior to giving anti-hypertensives
- prior to epidural Rx
- if immediate delivery
- as part of Mx of oliguria
- NB. routine volume expansion in Rx of severe PET is NOT recommended except under certain circumstances
- pros:
- volume depletion has been demonstrated in these pts
- correction of this may improve maternal and uteroplacental circulation
- volume expansion reduces the risk of hypotension during vasodilator Rx
- cons:
- risk of pulmonary oedema
- effects are transient
- may cause resistance to anti-hypertensives
- not all pts are volume deplete
- strict fluid balance record
- consider CVC line if severe PET
- clean catch urine for semi-quantitative protein concentration
- if delivery not imminent, commence 24hr urine collection for protein & creatinine clearance & fluid balance charting
early obstetric consultation
assess fetus:
- if fetus is pre-viable (< 24wks) then intermittent fetal heart rate recording
- if fetus viable (> 24wks) then evaluate fetal well being & biophysical assessment:
- ultrasound:
- fetal number & biophysical profile (tone, movement, breathing pattens, anatomy, size, gestation, amniotic fluid volume), placental location
- CTG monitoring:
- continuous if severe PET ASAP
- +/- oxytocin challenge test
treat hypertension:
mild HT:
- strict bed rest, quiet room
severe HT (>160 systolic or > 110 diastolic):
- expand maternal intravascular volume with crystalloid 500-1000ml, then,
- urgent IV hydralazine
- 10mg slow IV boluses every 20min prn (max. 60mg)
- NB. need to wait 10-20min for response
- if BP still high, add IV labetalol (not available in Australia as IV) 20mg stat then either:
- 10-20mg slow IV doubling every 10-2min prn to max. 300mg, or,
- infusion at 1-2mg/min titrated to response (decrease to 0.5mg/min or less once BP controlled)
- NB. nitroprusside can be used for short periods but risks cyanide toxicity
- NB. GTN can be used but requires arterial line to monitor & risks metHb
- NB. ACEI's are C/I as may cause fetal anuria or renal failure
seizure prophylaxis:
IV magnesium sulphate therapy:
- indications:
- eclampsia
- severe PET with either:
- decision to deliver baby has been made
- hyper-reflexia with clonus
- fundal vasospasm
- visual disturbances
- persistent headache
- ??? all pts with severe PET:
- see MJA 16 Feb 1998 Vol.(4) Mg in Rx of pre-eclampsia & eclampsia
- IV 50% magnesium sulphate:
- from MAGPIE and Collaborative Eclampsia trials:
- 4g load over 5min, then 1g/hr (if further seizure, give a further 2-4g IV over 5min)
- monitor for toxicity looking for:
- check BP, HR RR every 5min during load dose
- loss of deep tendon reflexes (usually at 8-10mEq/L)
- slurred speech, muscle weakness, hypotension
- decreased resp. rate & cardiac depression (resp. then cardiac arrest usually at 13mEq/L)
- decreased urine output
- monitor serum levels (normal range in pregnancy 1.5-2mEq/L, Rx range 4-7mEq/L
- if mild Mg toxicity, with-hold infusion
- if severe Mg toxicity:
- resp. support, O2, monitor ECG, SaO2
- IV 10% calcium gluconate 10ml at rate`< 5ml/minute
- consider giving loop diuretic to enhance excretion
Rx of eclamptic seizure:
- IV MgSO4 as above as well as Mx as for severe PET & deliver baby ASAP
- if ongoing seizures despite Rx levels of Mg, consider:
- ensure U&E's, glucose checked
- CT scan to exclude intracranial pathology
- seizure Rx as for non-pregnant adults:
- see seizures
- diazepam (risks fetal resp. depression)
- phenytoin 20mg/kg IV over 60min
deliver baby:
- severe PET, deliver ASAP at any gestation
- mild PET:
- ASAP if > 37wks (although some may wait if Cx unripe)
- consider delivery if < 23-34wks (ie. pre-viable)
- if 34-37wks consider amniocentesis to determine lung maturity
disposition:
if mild PET:
- if < 37wks, then:
- admit for bed rest, or,
- after D/W obstetric team, discharge home for bed rest with close F/U within 7 days & advised to contact hospital if:
- headaches, scintillating scotomata or other visual changes, abdominal pain, bleeding PV, or decreased fetal movements
- if > 37wks, then admit for inducement of labor or C.S.
if severe PET then:
- admit for inducement of labor or C.S. & close monitoring & support as above, or,
- if stable & delivery not imminent, and pre-term fetus, consider transfer to tertiary obstetric centre with neonatal intensive care prior to delivery
- NB. C/I to immediate transport (ie. transfer neonate after delivery):
- severe uncontrolled HT
- uncontrolled eclamptic seizures
- severe haemorrhage
- impending delivery
- significant fetal compromise
References:
- Magpie Trial. Lancet 2002; 359:1877-90;
- Consensus Statement of the Aust. Soc. for the Study of HT in Pregnancy. Aust.NZ J. Obstet.Gynecol. 2000; 40:139-55;
- Pearlman, Tintinalli: Emergency Care of the Woman 1st Ed. 1998
- MJA 16 Feb 1998 Vol.(4) Mg in Rx of pre-eclampsia & eclampsia
preeclampsia.txt · Last modified: 2012/10/02 07:59 by 127.0.0.1