Hypertensive disorders

Question 1

uterine ischemia/underperfusion

Answer 1

insufficient blood flow to the uterus

Question 2

inflammation

Answer 2

excessive maternal inflammatory response to pregnancy

Question 3

angiogenesis

Answer 3

factors regulating the formation of new blood vessels in the placenta are overproduced –> affect the blood vessel health in the mother leading to hypertension

Question 4

prostacyclin/thrombaxane imbalance (ASA)

Answer 4

disruption of the balance of hormones that maintain the diameter of the blood vessels

Question 5

endothelial activation and dysfunction

Answer 5

damage to lining of blood vessels that keep fluid and protein inside

Question 6

calcium deficiency

Answer 6

helps maintain blood vessels and normal blood pressure

Question 7

hemodynamic vascular injury

Answer 7

injury to vessels due to excessive blood flow or pressure

Question 8

immunological activation

Answer 8

Immune system mistakenly responds as if damage has occurred to the blood vessel and in trying to fix the ‘injury’ makes issue worse

Question 9

preeclampsia

Answer 9

multi-system disorder characterised by hypertension and involvement of one or more organ systems

Question 10

trigger of preeclampsia

Answer 10

poor placental perfusion due to abnormal placental trophoblastic infiltration of the uterine spiral arteries

Question 11

secondary pathology (preeclampsia)

Answer 11

reduced blood flow to major organs which causes endothelial damage

Question 12

pathophysiology (preeclampsia)

Answer 12

decreased blood flow to placenta causes inadequate placental perfusion
RESPONSE = vasoactive substances are released by the hypoperfused placenta, which in turn leads to further widespread endothelial damage and profound vasospasm with a consequent reduction in plasma volume
- Endothelial damage then activates the coagulation cascade and platelets adhere to the sites of endothelial damage
- As a result serious effects present in the mother and fetus

Question 13

effects preeclampsia

Answer 13

• Abnormal placentation
• CVS and haematological changes
• Coagulation system effects
• Renal involvement
• Liver involvement
• CNS involvement
• Fetoplacental changes

Question 14

blood pressure

Answer 14

force exerted by the blood on the vessel walls

Question 15

systolic

Answer 15

pressure exerted on the blood vessel walls following ventricular systole, when the arteries contain the most blood and is the time of maximal pressure

Question 16

diastolic

Answer 16

pressure exerted on the blood vessel wall during ventricular diastole, when the arteries contain the least amount of blood, resulting in the least pressure being exerted on the blood vessel walls

Question 17

hormonal and anatomical changes results in…

Answer 17

increase blood volume, increased cardiac output, HR

Question 18

Bp … first trimester

Answer 18

decreases

Question 19

rises … from the middle of pregnancy then returns to … levels by term

Answer 19

gradually
pre-pregnant

Question 20

hypertension in pregnancy

Answer 20

systolic 140mmHg, diastolic 90mmHg

Question 21

severe hypertension

Answer 21

170
110

Question 22

risks factors for developing pre-eclampsia

Answer 22

primips
40+
new partner
past history/fam history
multiples
medical conditions
obesity
autoimmune diseases
ART

Question 23

eclampsia

Answer 23

occurence of seizures in patient with pre-eclampsia
- 1:2000 pregnancies
50 000 women worldwide die

Question 24

management for eclampsia

Answer 24

pre-conception counselling
risk factors and referral
screening
surveillance
treatment options
own institutional protocols
department of health policies

Question 25

hospital management

Answer 25

FMAU
admission
low dose aspirin (100mg) cease 36 weeks

Question 26

fetal management eclampsia

Answer 26

early transfer to tertiary
USS
umbilical artery doppler velocimetry,
amniotic fluid volume estimation
cardiotocography (CTG)
IMI steroids if <34 weeks

Question 27

medication acute

Answer 27

severe hypertension e.g 170/110mmHg due to risk of intracerebral haemorrhage and eclampsia

Question 28

acute medications EXAMPLES

Answer 28

if conscious, commence oral antihypertensive therapy: e.g. Oral Nifedipine 10-20mg, onset of action 30-45 minutes.
I.V bolus of Hydralazine: 5mg loading dose and repeat at 20 minute intervals, maximum of 3 doses. Onset 10-20 mins.
MgSO4 infusion: loading dose of 4g over 15-30 mins with maintenance infusion of 1g/hr for at least 24 hours

Question 29

medications chronic

Answer 29

In cases of mild hypertension for B.P maintenance i.e. if B.P reaches 140-160/90-100mmHg on more than one occasion.
For ongoing treatment, initial drugs of choice: labetalol, oxprenolol, methyldopa, hydralazine, nifedipine, clonidine, prazosin.
Treatment aims at maintaining the diastolic ≤90mmHg

Question 30

haematological disturbances

Answer 30

• The term HELLP (haemolysis, elevated liver enzymes and low platelets) is a manifestation of severe pre-eclampsia and occurs in 0.6% of all pregnancies
• HELLP is involved in over half of the maternal mortality cases of eclampsia.
• HELLP is often accompanied by S/S of heartburn, vomiting, headache and epigastric pain.

Question 31

Disseminated intravascular coagulation

Answer 31

• platelet consumption and clotting, that occurs in the placental bed and more widely throughout the circulation, coupled with the anticoagulant effect of fibrin degradation products. This creates a bleeding tendency and organ failure.
• Treat the underlying cause, and practice caution with I.V fluid replacement as overload and pulmonary oedema common. Platelet transfusions, FFP and/or cryoprecipitate may all be used in treatment.

Question 32

Investigation of new onset hypertension in pregnancy

Answer 32

• Urine dipstick testing for proteinuria, with quantitation by laboratory methods if >’1+’ (30mg/dL)
• Full blood count
• Urea, creatinine, electrolytes
• Liver function tests
• Ultrasound assessment of fetal growth, amniotic fluid volume and umbilical artery Doppler flow

Question 33

methyldopa (dose, action, contraindication, practice points)

Answer 33

dose - 250-750mg TDS
central action
depression contraindication
Slow onset of action over 24 hr. Dry mouth, sedation, blurred vision
Withdrawal effect with clonidine

Question 34

labetalol (dose, action, contraindication, practice points)

Answer 34

100-400mg tds
B blocker with mild alpha vasodilator effect
B blocker with ISA
Asthma, chronic airways limitation
Heart block
Bradycardia, bronchospasm, headache, nausea, scalp tingling which usually resolves within 24-48 hours (labetalol only)

Question 35

nifedipine (dose, action, contraindication, practice points)

Answer 35

20mg bd - 60mg SR bd
Ca channel antagonist
Aortic stensosis
Severe headache associated with flushing, tachycardia Peripheral edema, consipation

Question 36

prazosin (dose, action, contraindication, practice points)

Answer 36

0.5-5mg TDS
A blocker
flushing, headache, nausea, lupus-like syndrome

Question 37

hydralazine (dose, action, contraindication, practice points)

Answer 37

25-50mg TDS IV
vasodilator increase cardiac output
Flushing, headache, nausea, lupus-like syndrome

Question 38

magnesium sulphate

Answer 38

decreases CNS irritability and blocks neuromuscular conduction by blocking the release of acetylcholine at neuromuscular junctions
→ therapeutic administration initial loading dose of 4-6g by IV in 100mL of fluid over 15-20 minutes