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RESEARCH ARTICLE
SA JOURNAL OF DIABETES & VASCULAR DISEASE
6
VOLUME 16 NUMBER 1 • JULY 2019
neonate will need to be cared for in the best available circumstances.
The second means of improving perinatal outcome revolve around
the use of corticosteroids, given to the mother. These accelerate the
maturation of the foetal lungs and lessen the likelihood of neonatal
intraventricular haemorrhage in the newborn.
36
In addition to
the necessity of effecting delivery by either induction of labour
or caesarean section, the obstetrician plays a role in preventing
complications.
The prevention of eclampsia is ensured by the use of magnesium
sulphate, given as a continuous infusion or as intermittent
intramuscular doses.
37,38
This has been shown to be effective in
reducing the risk of developing eclamptic seizures (and recurrent
seizures) without adversely sedating the foetus.
The mechanism of action is poorly understood and the use of
magnesium sulphate needs to be weighed against potential risks.
These include the development of toxicity, which is more common
in women with renal failure. Toxicity leads to respiratory arrest,
which can be reversed with intravenous calcium gluconate.
Women who are fitting should have their seizures aborted with
intravenous benzodiazepines. Women who continue to fit despite
treatment or those who are unable to protect their airway because
of a low Glasgow coma scale need intubation and mechanical
ventilation until the pregnancy is over and the mother’s condition
shows signs of improvement.
13,39
Proper management of severe hypertension is always a priority.
Drugs used to lower the blood pressure are a variety of agents,
including direct-acting vasodilators (hydrallazine, dihydrallazine),
calcium channel blockers (nifedipine), alphaand beta-blockers
(labetalol), and combined arterial and venous vasodilators
(nitroglycerine). Potent vasodilators such as sodium nitroprusside
or diazoxide should not be used because they are associated with a
risk of precipitous decline in blood pressure.
Specific organ failure is managed according to specific
protocols
• Eclampsia requires attention to seizure control as outlined above.
Recurrent seizures may only be controllable by continuous
infusion of propofol or diazepam; this usually requires
intubation and ventilation for up to 24 hours after delivery
has been effected. The co-morbidity associated with seizures
needs individual management (see below); specific screening
and treatment of aspiration pneumonia is important. Any focal
neurological signs merit neuro-radiological investigation to
exclude haemorrhage and infarction. The differential diagnosis
of seizure activity also merits consideration and may extend to
other possible diagnoses, including metabolic causes for seizure
activity, thrombotic thrombocytopaenic purpura, systemic
lupus erythematosis, cerebral venous thrombosis, malaria and
amniotic fluid embolus.
40
• Renal failure may be manifest on the basis of diminished
preload together with peripheral, including renal, vasospasm.
Acute renal injury may also cause oliguria and azotaemia.
This is the consequence of ischaemia (due to pre-eclampsia
or pre-eclampsia complicated by hypovolaemia caused by
abruptio placentae) and haemoglobinuria. The principles
of management are those of cautious intravascular volume
expansion (no more than 300 ml of colloidal solution given
as a bolus dose) and vasodilatation.
41
Renal failure that fails
to respond to these measures should result in a policy of fluid
restriction, management of actual or incipient hyperkalaemia
and expectant management in anticipation of gradual recovery
after delivery.
42
In the acute phase of the illness, dialysis may be
necessary.
• Liver injury is associated with the HELLP syndrome. This
condition needs to be distinguished from other causes of
micro-angiopathic haemolytic anaemia as well as other causes
of liver failure. The differential diagnosis therefore includes
thrombotic thrombocytopenic purpura, acute fatty liver of
pregnancy, auto-immune disease, malaria and sepsis. The
hallmark of the HELLP syndrome is that it reverses after delivery,
with the nadir of thrombocytopaenia occurring on the third day
postpartum.
43
The management is obstetric, meaning delivery.
Patients who do not exhibit the characteristic resolution of
the thrombocytopaenia merit investigation for other causes
of micro-angiopathic haemolytic anaemia. The only lethal
complication of the HELLP syndrome is the development of a
large subcapsular liver haematoma, which ruptures, causing
massive intraperitoneal haemorrhage.
44
The liver injury itself
and the elevated liver enzymes seen in HELLP syndrome are not
associated with failure of hepatic synthetic function and do not
usually lead to coagulopathy or hypoglycaemia. These features,
if present, indicate an alternative diagnosis.
• Pulmonary oedema is the most difficult complication of severe
pre-eclampsia in which to make a specific diagnosis.
30
The
mechanisms of pulmonary oedema are outlined above and
the differential diagnosis will include other causes of acute
dyspnoea, commonly infection and embolus. Pulmonary
oedema itself may be the consequence of pre-eclampsia, or
pre-eclampsia complicating underlying illness. These illnesses
may include valvular heart disease and ventricular dysfunction
due to cardiomyopathy. Regardless of the cause, emergency
management is usually the same, involving supportive
management of oxygenation and various combinations of
diuretic and vasodilator therapy with a view to reducing both
afterload and preload. This is commonly accomplished by using
direct-acting vasodilators, such as dihydrallazine, together
with intravenous furosemide. The development of pulmonary
oedema is a signal for investigation by means of radiology, ECG
and echocardiography to try to ascertain as closely as possible
what the underlying cause may be. In some circumstances, the
acute management of critically ill women may be facilitated
by the use of pulmonary artery catheters to directly measure
haemodynamic variables.
45
Pulmonary oedema complicating
pre-eclampsia is also an indication for immediate delivery,
to begin reversing the underlying pathophysiology of pre-
eclampsia.
Postpartum management
Delivery of the pre-eclamptic pregnant woman will trigger reversal
of the underlying disease. Generalised oedema begins to dissipate
as the capillary leak reverses and the pregnancy preload is excreted.
Commonly, 48 to 72 hours after delivery, the left ventricular preload
may start to increase as the oedema resolves.
46
This is an appropriate
time to facilitate a diuresis.
The hypertension itself may persist for up to six weeks after
delivery, requiring management for this duration with diuretics
and second-line agents. Whereas angiotensin converting enzyme
(ACE) inhibitors are commonly used in non-pregnant hypertensives,