(1)
Medical School, University of Porto, Porto, Portugal
5.1 Definition, Incidence and Main Risk Factors
Hypertensive diseases of pregnancy remain a leading cause of maternal and perinatal mortality in both low- and high-resource countries, and eclampsia represents their most serious manifestation. Eclampsia is characterised by the occurrence of generalised tonic-clonic seizures (grand mal) in a woman who usually displays the typical symptoms, signs and laboratory findings of pre-eclampsia. The pathophysiologic mechanism behind eclamptic seizures remains incompletely understood, but endothelial lesion, exaggerated microvascular permeability, cerebral oedema and pericapillary haemorrhage are common findings.
The episode usually starts with a slight tremor of the facial muscles, shortly followed by a generalised tonic seizure of 15–20 s and then develops into generalised tonic-clonic seizures which may last over 1 min. The total duration of the episode rarely exceeds 90 s. Occasionally, seizures may recur rapidly with uninterrupted generalised contracture. No respiratory movements occur during tonic-clonic seizures, and this can have serious consequences on maternal and fetal oxygenation. When the episode terminates, there is a deep and noisy inspiration followed by a comatose state that is usually superficial and of variable duration, with slow recovery of consciousness. Subsequent agitation may develop, and the woman usually refers amnesia to the event. Transient cortical blindness and focal motor deficits may follow. Cerebral haemorrhage complicates 1–2 % of cases.
Eclampsia may occur during pregnancy (40–50 %), in labour (13–20 %) or in the postpartum period (28–40 %). With the implementation of policies for screening and early diagnosis of pre-eclampsia, as well as the prevention of seizures and prompt termination of pregnancy in cases of severe pre-eclampsia, the incidence of eclampsia has decreased dramatically over the last decades. In high-resource countries, pre-eclampsia is currently reported to occur in 2–8 % of pregnancies and eclampsia to complicate 0.2–0.3 % of these cases, for an overall incidence of 0.004–0.02 % of births. In many low- and medium-resource countries, the reported incidences of pre-eclampsia and eclampsia are much higher.
The main risk factors for eclampsia are similar to those of pre-eclampsia and are listed in Table 5.1.
Table 5.1
Risk factors for pre-eclampsia and eclampsia
Primigravid |
Extremes of reproductive age |
Family history of pre-eclampsia |
Gestational or pre-existing diabetes |
Chronic hypertension or renal disease |
Multiple pregnancy |
Gestational trophoblastic disease |
Hereditary or acquired thrombophilia |
5.2 Complications
In high-resource countries, maternal mortality occurs in about 0.07 % of eclampsia cases, and the main causes are intracranial haemorrhage, acute pulmonary oedema and multi-organ failure. Maternal morbidity includes acute pulmonary oedema, disseminated intravascular coagulation, renal insufficiency and more rarely intracranial haemorrhage and rupture of subcapsular hepatic haematoma. Prolonged stay in intensive care units is frequently required in these cases.
Iatrogenic prematurity is frequent in severe pre-eclampsia and eclampsia and is responsible for the majority of perinatal deaths, which complicate about 26 % of eclampsia cases.
5.3 Diagnosis
Eclampsia is diagnosed when generalised tonic-clonic seizures are observed in a pregnant woman or a recent mother who usually displays the typical symptoms, signs and laboratory findings associated with pre-eclampsia.
The other major cause of generalised tonic-clonic seizures is epilepsy, and this can usually be identified by a history of previous episodes provided by a family member and/or a review of the patient’s medication. When no other obvious cause exists, the episode should be treated as eclampsia, and other diagnoses can be later investigated, if there is inadequate response to treatment.
5.4 Clinical Management
5.4.1 Anticipate and Prevent the Situation
In patients with pre-eclampsia, the prodromal symptoms of severe frontal headache, continuous epigastric pain and visual complaints (blind spots, flashes, double vision and blurred vision) should alert to impending eclampsia. In patients with severe pre–eclampsia (papilloedema, hyperreflexia, platelets under 100 × 109/l, liver enzymes above 75 IU/l, oliguria, pulmonary oedema, nausea and vomiting), those with severe hypertension in the context of pre–eclampsia (blood pressure exceeding 160/110 mmHg) and those with prodromal symptoms, intravenous magnesium sulphate (see below) should be started to prevent seizures. Frequent re-evaluation of prodromal symptoms, blood pressure, laboratory results, together with seizure prevention with magnesium sulphate and termination of pregnancy if the situation deteriorates; these are the key elements for preventing eclampsia.
5.4.2 Ask for Help
The person(s) witnessing an eclamptic seizure should trigger a communication chain that results in the urgent summoning of at least two midwives, a senior obstetrician, and an anaesthetist. The anaesthetist will usually focus on maternal monitoring and maintenance of the airway, while the obstetrician will concentrate on starting magnesium sulphate and fetal monitoring. When the two specialities are not present, the person in charge needs to take all of these aspects into account.
5.4.3 Avoid Lesions During the Eclamptic Seizure
Restraining tonic-clonic movements is dangerous and confers no benefit to patients, so the recommended attitude during the seizure is to remove all objects that may cause injury and wait until it ends, which usually takes less than 90 s.
5.4.4 Left Lateral Safety Position, Inspect Airway and Monitor
When the seizure ends, the patient should be placed in left lateral safety position (Fig. 5.1) and the airway quickly inspected for patency. In a second step, oropharyngeal secretions may be aspirated if they are abundant, a Mayo tube inserted if the patient remains unconscious and breathing is made difficult by the tongue and oxygen by mask should be started at 8 l/min.
