-in the clinical setting, this is sometimes hard to do due to various problems on obtaining reliable assessment of blood pressure. -position; high when pt. is standing, low when pt. is laying down in lateral position and intermediate when pt. Is sitting -inappropriate cuff size can over and under estimate BP -no previous info on baseline BP
Potential mechanisms that have been postulated
Hypertension in Pregnancy
Hypertension in Pregnancy Dapinderjit Gill Ross University MS3 S
Hypertension S Gestational HTN S Transient HTN ofDisorders in pregnancy Pregnancy S Preeclampsia S Mild S Severe Classification of the American College of S Eclampsia Obstetricians and Gynecologists S Chronic HTN preceding pregnancy S Chronic HTN with superimposed pregnancy- induced hypertension S Superimposed preeclampsia S Superimposed eclampsia
Gestational HTNS sustained systolic blood pressure at or above 140mmHg, or a diastolic blood pressure of 90mmHg or greaterS increase in BP must be present on at least two separate occasions, 6 hours or more apartS HTN in late pregnancy (>20 weeks gestation) in the absence of other findings suggestive of preeclampsiaS if BP returns to baseline by 12 weeks postpartum = dx. of Transient hypertension of pregnancy
Gestational HTNS 5-10% of pregnancies that proceed beyond 1st trimester develop gestational HTNS increased incidence of up to 30% in multiple gestationS 15-25% of women initially diagnosed with gestational HTN develop preeclampsiaS Earlier onset of gestational HTN are more likely to progress to preeclampsia
Pathophysiology Changes seen in patientsS Cardiovascular effects S Elevated BP S Increased cardiac outputS Hematologic effects S Third spacing of fluid due to increased blood pressure and decreased plasma oncotic pressureS Renal effects S Atheroscleroticlike changes in renal vessels (glomerular endotheliosis) decreased glomerular filtration rate and proteinuria S Uric acid filtration is decreased
Pathophysiology Changes seen in patientsS Neurologic effects S Hyperreflexia/hypersensitivity (does not correlate with severity of disease) S In severe cases, grand mal seizuresS Pulmonary effects S Pulmonary edema may occur due to decreased colloid oncotic pressureS Fetal effects (severe gestational HTN) S Vasospasm Decreased intermittent placental perfusion IUGR, oligohydramnios, low birth weight
Pathophysiology MechanismsS Uterine vascular changes S Trophoblastic-mediated vascular changes decreased musculature in spiral arterioles development of low resistance, low pressure, high-flow system S Inadequate maternal vascular response S Endothelial damage is also noted within the vesselsS Hemostatic changes S Increased PLT activation with increased endothelial fibronectin and decreased antithrombin III and alpha-2-antiplasmin further endothelial damage is thought to promote further vasospasm
Pathophysiology MechanismsS Changes in prostanoids S During pregnancy, both PGI2 (vasodilation and decreased PLT aggregation) and TXA2 (vasoconstriction and PLT aggregation) are increased with balance favored to PGI2 S In preeclampsia, TXA2 is favoredS Changes in endothelium-derived factors S Decrease in Nitric oxide promoting vasoconstriction
Gestational HTNS Mild: outpatient with weekly visits, bed restS Antihypertensive therapy: S Indicated if diastolic pressure is repeatedly above 110mmHg S Hydralazine (Apresoline) 5mg increments IV until acceptable BP is obtained (diastolic pressure to 90-100mmHg range) S Other medications that can be used in pregnancy (oral): S methyldopa 250mg BID/TID max 3g/day S Labetalol 100mg max 2400mg/day S Nifedipine 30-60mg max 120mg/dayS Magnesium sulfate in severe gestational HTN for seizure prophylaxis
Chronic HTNS HTN present before 20th week of gestation or beyond 6 weeks postpartum (>12 weeks postpartum from uptodate.com)S 15% of gestational HTN cases go on to develop chronic HTNS 25% risk of developing superimposed preeclampsia or eclampsia S Close monitoring of maternal BP and follow appropriate fetal growth and well-being S Pt. should be encouraged to increase the amount of time she rests
PreeclampsiaS Development of HTN with proteinuria induced by pregnancy generally in the second half of gestationS More frequent at the extremes of reproductive yearsS More common in women who have not carried a previous pregnancy beyond 20 weeks old women or young lady?
PreeclampsiaS Mild: S BP: systolic > 140mmHg and/or diastolic > 90mmHg S Proteinuria: >300mg on 24h collection of +1 on single sampleS Severe: S BP: systolic > 160-180mmHg and/or diastolic > 110mmHg S Proteinuria: >5g on 24h collection or +2 on single sample S Multisystem alterations: cerebral or visual disturbances, oliguria, pulmonary edema, cyanosis, epigastric or right upper quadrant pain, thrombocytopenia
PreeclampsiaS Mild preeclampsia S If immature fetus bed rest mainly in lateral decubitus position S HTN therapy if neededS Severe preeclampsia S Magnesium sulfate 4g loading dose with 1-3g/hr infusion rate S Antihypertensive therapy S Induction or cesarean delivery S fetal pulmonary maturity depending on gestational age should be considered (>=34weeks)
EclampsiaS addition of convulsions in a woman with preeclampsiaS occurs in 0.5-4% of deliveriesS most cases occur within 24h of delivery with about 3% of cases diagnosed between 2-10 days postpartumS 25% have eclamptic seizures before labour, 50% during labour, and 25% after delivery
EclampsiaS Anticonvulsant therapy S Diazepam or similar drugsS Magnesium sulfate to prevent further seizuresS Maintain adequate airway, oxygenation, restraining gently as needed and inserting a padded tongue blade
HELLP SyndromeS HTN patients with hemolysis (H), elevated liver enzymes (EL), low platelet count (LP)S 4-12% of pt. with severe preeclampsia and eclampsia develop HELLP syndromeS first sx. often missed: nausea, emesis, and non-specific viral-like syndrome
HELLP SyndromeTreatment:S cardiovascular stabilization, correction of coagulation abnormalities, and deliveryS PLT transfusion before or after delivery if PLT count is <20,000/mm3 (advised at <50,000/mm3 before cesarean) S <32 weeks gestation; steroid therapy may help stabilize maternal PLT count
ReferencesBeckmann, Charles R.B., Ling, Frank W., Smith, RogerP., Barzansky, Barbara M., Herbert, William N.P., Laube, DouglasW. “Obstetrics and Gynecology”. 5th edition Lippincott Williams &Wilkins. pp. 188-196Magloire, Lissa etc. “Gestational Hypertension”. May2011.<uptodate.com>August, Phyllis et. al. “Management of hypertension in pregnancyand postpartum women”. May 2011 <uptodate.com>
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