Hypertensive disorders of pregnancy Flashcards
(25 cards)
What the the epidemiology of hypersensitive disorders in pregnancy
7-10% of pregnancies:
70% are maternal new onset/gestational
30% are chronic HTN
Eclampsia - 0.05%
Risks:
20% of maternal deaths
10% of preterm births
What are some risk factors for HTN in pregnancy?
Primigravidity Young female - 3x risk Black - 2x risk Multifoetal pregnancies Renal disease Collagen vascular disease
How is HTN classified?
Gestational - during pregnancy only
Preeclampsia-eclampsia
Chronic HTN
Preeclampsia superimposed on chronic HTN or renal disease
What is gestational HT?
New onset HTN after 20th week
Systolic >140
Diastolic >90
No or little proteinuria
25% of these develop preeclampsia
What is preeclampsia-eclampsia?
New onset HTN after 20th week
Increased BP (same as gestational - >140/>90) + proteinuria (1+ on dipstick, confirmed using protein:creatinine ratio >30 mg/mmol as a threshold for significant proteinuria)
Oedema not part of definition (though is an associated sign)
Eclampsia - preeclampsia + generalised tonic clonic seizures
Can occur up to 6wks after delivery
What is chronic HTN?
Before pregnancy
Before 20wks gestation
Extends from before pregnancy and is not resolved post partum
What is superimposition of HTN?
A. Gestational HTN increase + no proteinuria @ <20wks with new proteinuria after 20wks
B. Gestational HTN increase and proteinuria @ <20wks with sudden increase in proteinuria + elevated BP from previously well controlled + thrombocytopenia + AST/ALT derangement
How do you diagnose preeclampsia-eclampsia?
Gestational HTN
+
Proteinuria - 1+ on urine dip or >3mg/mmol on protein:creatinine
How do you measure BP?
Sitting zbak MORE
How is preeclampsia-eclampsia risk classified by severity?
High risk factors: HTN disease in previous pregnancy Chronic HTN Chronic kidney disease Autoimmune disease e.g. SLE or antiphospholipid syndrome T1/T2DM
Moderate risk factors: First pregnancy >40yrs old Pregnancy interval >10yrs BMI >35 FHx preeclampsia Multiple pregnancy
Early onset - <34 wks - MORE SEVERE usually
What are the clinical criteria for severe preeclampsia?
Presentation: (HHPPPV) Headache Hyperreflexia/clonus Papilloedema Pain - RUQ, epigastric Pulmonary oedema Visual disturbance - floaters, flashing lights
Investigations: HTN - usually >170/110mmHg Proteinuria +1 or more on dipstick Platelets - <100*10^6 Abnormal LTF’s or HELLP syndrome
What is the pathophysiology of preeclampsia-eclampsia? How does this manifest clinically?
Exact mechanism uncertain
Spiral arteries become fibrous and narrowed rather than dilating massively to become vascular sinuses/uteroplacental arteries that deliver large quantities of blood to foetus like they would in normal pregnancy, less blood gets to the placenta - hypoperfused placenta leads to production of inflammatory cytokines (intrauterine growth restriction, foetal death) - dysfunction of maternal endothelial cells in circulation - vasoconstriction = HTN
Deceased renal blood flow - reduced GFR = raised uric acid levels + proteinuria + hypocalciuria + impaired Na excretion and suppression of RAAS = compounds HTN
Maternal activation of coagulation system - thrombocytopenia, low antithrombin III, higher fibronectin
Maternal liver derangement - HELLP syndrome - Haemolysis, Elevated ALT and AST, Low Platelets
Other possible symptoms - epigastric pain, hepatic swelling/infalmmation, stretch of liver capsule, oedema, rapid weight gain
Maternal CNS involvement - migraine-like headache, visual disturbance, scotoma, cortical blindness, eclampsia/generalised TC seizures
What are the maternal complications of preeclampsia?
Eclampsia Emergency C-section Haemorrhage (stroke) HELLP syndrome - haemolysis, elevated liver enzymes, low platelets Pulmonary oedema Liver and renal failure DIC Placental abruption
What are the foetal complications of preeclampsia?
Interuterine growth restriction leading to small for gestational age
Haemorrhage
Preterm delivery (+ problems of prematurity), ICU admission
Cardiac failure
Stillbirth
How does preeclampsia present?
Mostly unremarkable - will simply pick up HTN and proteinuria
Symptomatic = becoming severe:
Signs:
Raised BP
Proteinuria
Brisk/hyperactive reflexes (though common in pregnancy)
Ankle clonus - neuromuscular irritability that raises concern
Retinal vasospasm or oedema
Right upper quadrant tenderness
What are the lab tests and findings in preeclampsia?
HELLP work up:
FBC - Hb low Serum uric acid - high (because impaired renal function) U+E - elevated creatinine, LFTs - elevated AST/ALT Platelets - low in severe
Can also do urine dip - 1+ proteins
IS THIS CARD CORRECT?
How is preeclampsia managed?
New onset: hospital for assessment; if mild gestational HTN, can manage at home with regular review
Prophylactic aspirin - started at booking visit at 12wks, 75mg OD and continuing to delivery if any one of the following:
HTN disorder in prev pregnancy
CKD
Autoimmune disease - SLE, antiphospholipid
SLIDES
Labetalol PO is first line in treating the HTN throughout pregnancy; nifedipine if asthmatic and contraindicated
If suspect preterm delivery is likely give dexamethasone (lung development) magnesium sulphate (CP risk reduction)
Monitor urine output - restrict to 80mls/hr
Mg SO4 - if indicated e.g. hyperreflexia - prevents eclampsia
Delivery is the only ‘cure’ - always beneficial for mother, but may not be beneficial for baby if means being born seriously premature - so manage maternal problems best as possible in this instance to allow foetal maturation and cervical ripening
What is a favourable Vs unfavorable cervix?
Soft, opening, approaching readiness for delivery
Can use prostaglandins to ‘ripen’ the cervix
Why would we give anticonvulsants in pregnancy?
To prevent recurrent seizures in women with eclampsia
Consider in: women with severe preeclampsia where birth is planned within 24hrs or with 1+ symptoms - ongoing severe headache, N+V, epigastric pain, progressively deteriorating bloods etc
Only drug: Magnesium sulphate IV 4g/5mins then 1g/hr/24hrs
SE: Caution in renal failure as Mg is renally excreted and thus can lead to hypermagnesia - paralysis including respiratory depression, slurred speech, diplopia; flushing
What are the indications for delivering in preeclampsia?
Maternal:
Gestational age >38wks
Platelets <100,000cells/mm3
Progressive deterioration in liver and renal function
Persistent severe headaches, vomiting, visual changes, nausea, epigastric pain or vomiting
Suspected premature separation of placenta from uterus (abruptio placentae)
Foetal:
Severe growth restriction
Oligohydramnios - deficiency of amniotic fluid
Vaginal delivery is best, labour induction (within 24hrs), may get hydralazine/labetalol go keep BP down during delivery
What follow up is necessary in preeclampsia?
Counselling for future pregnancies:
Risk of recurrence is high before 30wks, if there’s a new father and in black people
What are some risk factors for developing preeclampsia?
First pregnancy
Multiple foetuses
Mother >35yrs
Hx - HTN, renal disease, diabetes; F/Hx - preeclampsia
Smoking might weirdly be protective - fewer smokers get preeclampsia..
How do you treat acute severe HTN in pregnancy?
> 160 systolic and/or >105 diastolic
IV hydralazine (vasodilator; SE - hypotension, angina) and labetalol (alpha and beta blocker; SE - severe bradyc. - give atropine)
Avoid in: asthma, congestive heart failure
What is HELLP syndrome?
Pregnancy complication associated with:
Haemolysis, Elevated Liver enzymes, Low Platelets
Usually begins in 3rd trimester, associated with preeclampsia-eclampsia
Presents with:
Fatigue, oedema, headache, RUQ pain, nosebleed, seizure
Dx:
Anaemia, High AST and LDH, low platelets
