Hypertensive disorders in Pregnancy

Hypertension
raised blood pressure
2 occasions 6 hours apart

140/90 mmHg

PIH
consequence of pregnancy
regress postpartum
1. without proteinuria
2. with proteinuria - Preecamlapsia
3. Eclampsia

Blood pressure normally 10mmHg lower
lowerst at 14th to 20th week
due to decrease in vascular tone

Gestational Hypertension
blood pressure
first detected after mid Pregnancy
No proteinuria

Pre-Eclampsia
DBP > 90mmHg
in second half od pregnancy
significant proteinuria (>300 mg/24hr)

Mechanisms:

Immunological mechanism
- trophoblast escape into maternal blood
- antigen-antibody complexes deposition on renal glomeruli and placenta

Inadequate trophoblastic invasion
- inadequate invasion of trophoblast into spiral arteries
- high resistance in spiral arteries
- Placental bed ischemia
- + of macrophate system - release of TNF-alpha
- Endothelial damage and dysfunction

Altered vascular reactivity
- Reduced PGI2
- Hence less opposition to vasoconstricors AngII and TXA2

Coagulation disturbance
- placenta release thromboplastin
- fibrin deposition in kidney and placenta > hypertension + Plancental insufficiency.
- Reduction in NO and PGI2 by vascular endothelium

Predisposing factors:
- large placenta (Multiple pregnancy, Diabetes, hydrops)
- Diabetes or autoimmune diseases
- Sickle cell disease
High risks:
- Nullparity
- Teenage
- Elderly
- Family history
- Past history
- New paternity
- Obesity
- Multiple
- Hydatidiform mole
- Hydrops
- Trisomy 13, triploidy
- Essential hypertension
- Renal disease
- diabetes
- connective tissue disorder
- Insulin resistance

PreEclampsia

Effects on vital organs
1. cerebral oedema, small hemorrhages
2. Retinal hemorrhae, exudates and papilledema
3. glomeruloendotheliosis
4. subendothelial fibrin deposition, elevated liver enzymes.
HELLP syndrome
epigastric pain and livertenderness due to distention of capsule
5. Arrhythmia, Pulm edema, HF
6. ARDS, bronchopneumonia, airway obstruction

Systemic changes:
- Generalised vasospasm
low CO and high peripheral resistance
Reduced CVP and pulmonary wedge pressure
- Platelet activation and consumptive coagulopathy
Decreased plasma volume and increased viscosity
- Proteinuria, reduced GFR
- Periportal necrosis, subcapsular hematoma
- Cerebral edema, hemorrhage, Increased ICT

Diagnosis:
Symptoms - headache, visual disturbances, epigastric pain, progressive edema
Signs - Elevated BP, rapid weight gain, non-dependent Edema, brisk reflexes, ankle clonus
Investigations -
24hr Urine collections for proteins and creatinine clearance
FBC - Platelets and hematocrit
Bloog Chemistry - RFT, Total protein, LFT
Plasma urate concentration
Coagulation profile
For Fetus- USG (AFI, Placental maturity, fetal maturity, Doppler), NST, Biophysical profile, Ophthalmic examination

Mild: BP < 160/110 mmHg No significant proteinuria
Severe: DBP > 110 mmHg or SBP > 160 mmHg or proteinura > 5g/24ht or:
- Oliguria < 400 ml
- Cerebral of visual disturbances
- Epigastric pain
- Pulmonary edema or cyanosis
- Impaired Liver funciton
- Thrombocytopenia
- IUGR/ Oligohydramnios

Predictive tests:
MAP in 2nd Trimester > 90 mmHg
Gant's roll over test - rise of DBP > 20 mmHg
Angiotensis infusion test
Uterine Artery Doppler waveform study

Management:

Preventive -
low aspirin (60-80 mg daily) - inhibits COX, prevents TxA2 release
Fish Oil
Calcium
Magnesium
Dipyridamole
Vit C & E

MILD Pre-eclampsia

Indications of hospitalization
DBP > 100 mmHg
Uric acid > 450 mmol/L
Urine proteins ++ or > 0.3g/24hr
Platelets < 100 x 10 9/L
non-reactive CTG
IUGR/oligohydramnios

Measures:
Bed Rest
Diet - low sodiu diet not required
Sedatives - no role
Diuretics - contraindicated
Antihypertensives - Nimodipine

Maternal monitoring - BP, Weight, Urine proteins, Albumins, symptoms.
Fetal monitoring - Daily fetal movement count, USG 3/week

Indications of early delivery
- worsening hypertension
- vital organ involvement
- Gross IUGR or fetal distress

Intrapartum monitoring
BP, Pulse and urine output
Continuous fetal monitoring
MethylErgometrine is Contraindicated

SEVERE Pre-eclampsia

complications may arise
abruptio, thrombocytopenia, HELLP
eclampsia, acute renal failure, DIC

Antihypertensives: target DBP below 105
Alpha Methyldopa 0.5-2g/day
Nifedipine 10-120mg/day
Labetalol 30-180mg/day

Pitchard regime:
- 20 ml of 20% MgSO4 over 10 minutes (4g)
- Maintainance 10ml of 50% MgSO4 IM, alt buttocks every 4 hours
- While MgSO4, monitor Resp rate > 16, Urine output > 25ml/h, Knee jerks
- Calcium gluconate IV 1g over 10 mins + oxygen
- MgSO4 is discontinued 24 hours postpartum

When to Deliver?
24-26 week - if mx fails, terminate after counselling
26-34 week - antihypertensives started, steroids administered, terminated when unfavourable parameters
34 weeks+ - terminated when biophysical profiels worsening

Induction of Labour
PGE2 or ARM/Oxytocin if cervix favourable

Indications of CS -
Worsening maternal condition
Fetal distress
Failure to progress
Hepatic capsular distention

Intrapartum management:
Avoid diuretics
control BP
Prophylactic MgSO4
Blood kept ready

Eclampsia

occurence of convulsions or coma unrelated to other
cerebral conditions, with signs and symptoms of preeclampsia

Incidence: 1/1000 deliveries

Can occur antepartum, intrapartum or postpartum
Sezures: tonic-clonic type
Initial or prodromal phase, may have aura
convulsive movements that begin around mouth
Tonic Phase - 15 to 20 seconds
Clonic phase - 1 minute
Reovery - conculsive movements subsides slowly
respiration resumes and patient passes into a coma.

General measures:
two large bore IV canulas - Ringer alctate
Emergency investigations - FBC, Platelets, LFT, RFT, arterial blood gas,
serum electrolytes, coagulation profile.
Continuous monitoring oxygen saturation
Bladder catheterized
Pitchards regiment - magnesium sulphate delivered
Antihypertensives to control BP - Hydralazine 5mg IV
Assess Fetal heart

Indications for CS
- fits not controlled after 6-8 hrs of therapy
- BP is too high >180/120 mmHg
- Vaginal delivery is not possible
- Hepatic capsular distension
- Fetal distress

Usually once fits are controlled
induction of labour, usually by ARM and oxytocin infusion.

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