HYPERTENSIVE DISORDERS IN PREGANCY

OBJECTIVES At the end of this session you should be able to: Outline diagnostic features of pre-eclampsia Classify pre-eclampsia according to severity Outline risk factors for pre-eclampsia Outline maternal and fetal complications of pre-eclampsia. Describe the management of pre-eclampsia and eclampsia.

I. INTRODUCTION Synonyms: Toxemia of pregnancy, pre-eclampsia, EPH gestosis, pregnancy induced hypertension. Pre-eclampsia commonly manifests after the 20th week of pregnancy. Prevalence of pre-eclampsia: varies from one place to another Severe pre-eclampsia and eclampsia Are serious and potentially fatal Third commonest cause of maternal mortality Occurs prior to, during or after delivery

II. DIAGNOSIS OF PRE-ECLAMPSIA When SBP > 140 mm Hg, DBP > 90 mm Hg in a woman known to be normotensive prior to pregnancy. The diagnosis requires 2 such abnormal BP measurements recorded at least 6 hours apart.

III. RISK FACTORS Young maternal age Nulliparity: 85% of pre-eclampsia occur in primigravida. Increased placental tissue for gestational age: Hydatiform moles, twin pregnancies Family history of pre -eclampsia Diabetes mellitus Renal diseases, Chromosomal abnormality in the fetus (eg, trisomy).

Worrisome signs for pre-eclapmsia development RISK FACTORS cont Worrisome signs for pre-eclapmsia development Rapid increase of weight during the latter ½ of pregnancy An upward trend in diastolic BP even while still within normal range

IV. CLASSIFICATION OF PRE ECLAMPSIA: ACCORDING TO SEVERITY Mild pre-eclampsia Moderate pre-eclampsia Severe pre-eclampsia Mild to Moderate Pre eclampsia Diagnostic Features Systolic BP is 140 -160 mmHg Diastolic BP is 90 – 100 mmHg Proteinuria up to ++

2. Severe pre-eclampsia Also called – Imminent eclampsia Symptoms Severe & persistent occipital or frontal headaches Visual disturbance: blurred vision, photophobia Epigastric and/or right upper-quadrant pain Signs Diastolic BP > 11ommHg, systolic BP > 160mmHg Proteinuria +++ or more Altered mental status Hyper-reflexia Oliguria

Is a severe form of pre-eclampsia HELLP SYNDROME Is a severe form of pre-eclampsia Affects approx 10% of women with severe preeclampsia and 30-50% of women with eclampsia. Characterized by: Hemolysis, Elevated liver enzymes Low platelet count. Increased mortality rate and DIC

V. PATHOPHYSIOLOGY There are several theories and etiologic mechanisms. Vasospasm theory: Most favored theory Vasospasms → vasoconstriction → resistance → arterial BP Eclampsia: Cerebral arterial vasospasm → cerebral edema or infarction and/or cerebral hemorrhage

VI. COMPLICATIONS OF SEVERE PRE-ECLAMPSIA AND ECLAMPSIA Maternal complications CVS Haemoconcentration (cause: vasoconstriction and vascular permeability) Hamatological changes – HELLP → DIC Kidneys Decr RBF→ ↓GFR → RTN and RCN→ acute RF Proteinuria – due to ⇈permeability to large protein, Oliguria – both renal perfusion and GFR decrease.

COMPLICATIONS OF SEVERE PRE ECLAMPSIA AND ECLAMPSIA cont Brain Cerebral edema Infarction, cerebral hemorrhage Blindness: Due to -?retinal artery vasospasms and retinal detachment Fever 39ºC: a grave sign, may be a consequence of intracranial hemorrhage. Coma – may be a result of CVA

COMPLICATIONS OF SEVERE PRE ECLAMPSIA AND ECLAMPSIA cont RS : Pulmonary oedema and cyanosis Utero-placental perfusion Vasospasms → decr perfusion → distress and death Histological changes in the placental bed: acute artherosis – lipid rich cells of the uteroplacental arteries Fetal complications IUFD, IUGR

MAJOR CAUSES OF MATERNAL DEATH Cerebrovascular accident (CVA) Pulmonary oedema Cardiac failure, Renal failure

VII. WORK UP - INVESTIGATIONS Urine analysis Proteinuria A 24-hour urine collection Quantity of urine and protein Uric acid level: GFR and creatinine clearance decrease →in ↑uric acid levels. LFT – Transaminases USS – fetal wellbeing, if the GA is < 20/40 R/O moles.

VIII. MANAGEMENT OF PRE ECLAMPSIA MILD - MOD PRE ECLAMPSIA A: Dispensary & Health centre Antihypertensives Aldomet 250 mg 8 hourly for 7 days, Bed rest at home REFER within one week to Hospital for further management

MANAGEMENT OF PRE ECLAMPSIA 1. MILD - MOD PRE ECLAMPSIA cont B. Hospital Antihypertensives: Aldomet, Bed rest at home, Sequential work ups, Fetal movements monitoring, Schedule antenatal clinic every 2 weeks up to 32 wks and weekly thereafter

MANAGEMENT OF PRE ECLAMPSIA 1. MILD - MOD PRE ECLAMPSIA cont B. Hospital Strongly advice the woman to deliver in a hospital Plan delivery at 38/40 Advice the mother to come to the health facility in case of severe headache, blurred vision, nausea or upper abdominal pain. Manage as severe pre-eclampsia: If not responding to treatment i.e. if the systolic BP is > 160 mmHg, or the diastolic BP is > 100mmHg or there is proteinuria +++

MANAGEMENT OF SEVERE PRE ECLAMPSIA AND ECLAMPSIA Note: Severe pre-eclampsia is managed like eclampsia Management protocol for eclampsia Keep airway clear Control convulsions Control BP Control fluid balance Antibiotics Investigations Deliver the mother

MANAGEMENT CONT BP CONTROL Keep SBP between 140 -160 mm Hg and DBP between 90 -110 mm Hg ?Why these levels: Avoid potential reduction in either uteroplacental blood flow or cerebral perfusion pressure. Drugs: Anti HPTs: Hydralazine, nifedipine, or labetalol Diuretics are not used except in the presence of pulmonary edema

MANAGEMENT: CONTROL CONVULSIONS I. An overview on MgSO4. Mechanism: Cerebral vasodilator → reducing cerebral vasospasm → ↓ischemia (brain). Superior to other anti-convulsants used to control and prevent fits; Important part of mgt of eclampsia Recurrence rate after MgSO4 = 10 -15% Improves maternal and fetal outcome

CONTROL CONVULSIONS - REGIMEN 1. INTRAMUSCULAR REGIMEN i. Loading dose Give MgSO4 4 g (i.e. 20mls of 20% solution) + 200mls NS or sterile water I.V over 5 minutes Follow promptly with 10g (i.e. 20ml of 50% solution), 5g in each buttock as deep I.M with 1ml of 2% lignocaine in the same syringe

CONTROL CONVULSIONS - REGIMEN MANAGEMENT CONT CONTROL CONVULSIONS - REGIMEN 1. INTRAMUSCULAR REGIMEN cont ii. Maintenance dose MgSO4 5 g (i.e. 10ml of 50% solution) + 1 ml lignocaine 2% 4 hourly in alternate buttocks. NOTE: IM inj. are painful and are complicated by local abscess formation in 0.5% of cases. The intravenous (IV) route is therefore preferred

MgSO4 4 g (i.e. 20mls of 20% solution) + 200mls NS I.V over 5 minutes MANAGEMENT CONT CONTROL CONVULSIONS - REGIMEN 2. INTRAVENOUS REGIMEN i. Loading dose MgSO4 4 g (i.e. 20mls of 20% solution) + 200mls NS I.V over 5 minutes ii. Maintenance dose MgSO4 4 g (i.e. 20ml of 20% solution) IN 500ml NS 4 hourly for 24 hrs after the last fits

Recurrent fits (any regimen): MANAGEMENT CONT CONTROL CONVULSIONS - REGIMEN Recurrent fits (any regimen): Therapeutic dose may not have been reached Give 2g (i.e. 10ml of 20% solution) i.v. over 5 minutes Treatment duration: Continue for 24 hours after delivery or last convulsion, whichever occurs first

Causes loss of deep tendon reflexes, followed by MANAGEMENT CONT Magnesium toxicity Causes loss of deep tendon reflexes, followed by respiratory depression and ultimately respiratory arrest. Thus, before repeating MgSO4, ensure that; RR ≥ 16/min Patellar reflexes are present Urinary output is at least 30ml per hour over 4 hours Otherwise withhold or delay MgSO4 Keep antidote ready In case of respiratory arrest: Assist ventilation and administer calcium gluconate

Delivery should be within 6-8 hours of onset of fits MANAGEMENT CONT DELIVER THE MOTHER Delivery should be within 6-8 hours of onset of fits Vaginal delivery is the safest mode of delivery Assessment R/O contraindications to SVD Bishop score If the cervix is favourable - induce labour Otherwise prepare for C/S

MANAGEMENT CONT Management of labour 1st stage Relieve pain: pethidine 25 mg iv every 2-4 hours Augmentation of labour Monitor FHR, 2nd stage: Assist with vacuum extraction 3rd stage: Active management Oxytocin 10 IU i.m after delivery of anterior shoulder Cord traction Squeezing clots after delivery of the placenta

MANAGEMENT CONT Management of labour If there is delay perform C/S Post delivery: Continue observation for at least 48 hrs post delivery Record and monitor BP and urine output for at least 48 hours after delivery, Keep the pt in hospital until BP stabilizes, Continue with aldomet PO until BP back to normal