Hypertension and Pre-eclampsia Flashcards
Definition
New high blood pressure (hypertension) in pregnancy with end-organ dysfunction, notably with proteinuria
= Occurs after 20 weeks gestation, when the spiral arteries of the placenta form abnormally, leading to a high vascular resistance in these vessels.
Pre-eclampsia triad
- Hypertension
- Proteinuria
- Oedema
Chronic HTN definition
High blood pressure that exists before 20 weeks gestation and is longstanding.
- This is not caused by dysfunction in the placenta and is not classed as pre-eclampsia.
Pregnancy-induced hypertension/ gestational hypertension
Hypertension occurring after 20 weeks gestation, without proteinuria.
Eclampsia
When seizures occur as a result of pre-eclampsia.
High Risk factors
- Pre-existing hypertension
- Previous hypertension in pregnancy
- Existing autoimmune conditions (e.g. systemic lupus erythematosus)
- Diabetes
- Chronic kidney disease
Moderate Risk Factors
- Older than 40
- BMI > 35
- More than 10 years since previous pregnancy
- Multiple pregnancy
- First pregnancy
- Family history of pre-eclampsia
Pathophysiology
- Poorly understood
- When blastocyst implants on the outermost layer of endometrium (syncytiotrophoblast), and grows into it forming finger-like projections called chorionic villi containing fetal blood vessels.
- Trophoblast invasion of the endometrium sends signals to the spiral arteries in the area of the endometrium, reducing their vascular resistance + making them more fragile = blood flow to these arteries increases = eventually breakdown leaving pools of blood (lacunae). Maternal blood flows from the uterine arteries into lacunae and back out through the uterine veins. lacunae form at around 20 weeks gestation.
When the process of forming lacunae is inadequate, the women can develop pre-eclampsia.
Effects on placenta due to pre-eclampsia
Poor perfusion of the placenta. This causes oxidative stress in the placenta, and the release of inflammatory chemicals into the systemic circulation, leading to systemic inflammation and impaired endothelial function in the blood vessels.
Symptoms
- Headache
- Visual disturbance or blurriness
- Nausea and vomiting
- Upper abdominal or epigastric pain (this is due to liver swelling)
- Oedema
- Reduced urine output
- Brisk reflexes
Diagnosis
- Systolic blood pressure above 140 mmHg
- Diastolic blood pressure above 90 mmHg
+ any of:
= Proteinuria (1+ or more on urine dipstick)
= Organ dysfunction (e.g. raised creatinine, elevated liver enzymes, seizures, thrombocytopenia or haemolytic anaemia)
= Placental dysfunction (e.g. fetal growth restriction or abnormal Doppler studies) - Proteinuria can be quantified using:
= Urine protein:creatinine ratio (above 30mg/mmol is significant)
= Urine albumin:creatinine ratio (above 8mg/mmol is significant)
Placental growth factor (PGIF) completed between 20 -35 weeks gestation = low
Prophylactic Treatment
Aspirin - given 12 weeks of gestation until birth to women with:
- A single high-risk factor
- Two or more moderate-risk factors
Routine check up to check for pre-eclampsia
Blood pressure
Symptoms
Urine dipstick for proteinuria
Gestational hypertension (without proteinuria) management
- Treating to aim for a blood pressure below 135/85 mmHg
- Admission when BP < 160/110 mmHg
- Urine dipstick testing at least weekly
- Blood tests weekly (FBC, LFT and renal profile)
- Monitoring fetal growth by serial growth scans
- PlGF testing on one occasion
Pre-eclampsia treatment
Similar to GH +
- Scoring systems used to determine whether to admit woemn (fullPIERS or PREP-S)
- Blood pressure is monitored closely (at least 48 hours)
- Urine dipstick weekly not necessary (Dx already made)
- USS. amniotic fluid and dopplers = two weekly to monitor fetus
