Pregnancy-specific conditions presenting with neurological symptoms
(Pre-)Eclampsia
Pre-eclampsia is a multisystem disorder characterized by de novo hypertension (systolic blood pressure >140 mmHg or diastolic blood pressure >90 mmHg) present after 20 weeks of gestation combined with one or more of the following: proteinuria greater than 300 mg/ day, other maternal organ involvement (renal/hepatic/neurological/ haematological complications), or uteroplacental dysfunction (130).
The progression to eclampsia is defined by new-onset generalized tonic-clonic seizures or coma.Pre-eclampsia complicates approximately 3-5% of pregnancies. Genetic disposition seems to exist at least in a subset of patients. Further risk factors include pre-eclampsia/hypertension in previous pregnancies, a positive family history for eclampsia, nulliparity, chronic kidney disease, hypertension, diabetes, maternal obesity, and autoimmune disorders (131).
Neurological signs and symptoms of (pre-)eclampsia include headache, visual disturbances due to cortical blindness or retinal detachment, hyperreflexia, seizures, cerebral ischaemia, confusion, and altered levels of consciousness secondary to cerebral oedema. It is a predisposing factor for PRES.
Women with suspected or diagnosed (pre-)eclampsia should be subject to regular monitoring of blood pressure, urine protein, haematological, renal, and hepatic parameters, and fetal assessment. The occurrence of neurological complications may warrant cerebral imaging by MRI or electroencephalographic studies (90).
The definitive treatment for (pre-)eclampsia is delivery, which should be indicated based upon gestational age, the severity of the disease, and maternal and fetal condition. Severe hypertension requires pharmacological intervention. The benefit of treating mild hypertension is less clear (131, 132). Magnesium sulphate is effective for seizure prophylaxis in women at risk for eclampsia (133).
Women who have suffered from pre-e clampsia during their first pregnancy carry a risk of about 15% for recurrence (134). Furthermore, they are at increased risk of developing cardiovascular disease later in life (131). Low-dose aspirin (50-150 mg/day) has some benefit for preventing pre-eclampsia, particularly if initiated at 16 weeks or less of gestation (135). For a discussion of the safety of aspirin in the first trimester, see ‘Ischaemic stroke’. The World Health Organization recommends calcium supplementation for women with a low dietary calcium intake (131).
Amniotic fluid embolism
Amniotic fluid embolism is caused by the entry of amniotic fluid into the maternal circulation, causing vaso-occlusion by mechanical and possibly humoral and immunological mechanisms. Although amniotic fluid embolism is rare (2-8:100,000 deliveries), it is one of the leading causes of maternal death resulting directly from childbirth due to its high mortality (136).
Amniotic fluid embolism occurs during delivery and up to 48 hours postpartum (136). Risk factors include maternal age of 35 years or above, multiparity, induction of labour using any method, placenta praevia, instrumental vaginal delivery, and caesarean section (137). Diagnosis is based on clinical criteria (one or more of the following: acute fetal compromise, cardiac arrest, cardiac arrhythmia, coagulopathy, hypotension, maternal haemorrhage, premonitory symptoms such as anxiety, seizures, dyspnoea) (138) and exclusion of any other cause of acute cardiovascular decompensation such as pulmonary embolism and myocardial infarction.
Therapy is interdisciplinary and focuses on stabilizing haemodynamic and cardiorespiratory function and correcting coagulopathies. This will usually require an intensive care setting. Emergency caesarean section ought to be considered (136).
Maternal/fetal mortality in amniotic fluid embolism ranges from 13% to 44% and 7% to 38% respectively (136). Reported rates of neurological morbidity vary widely with 6-61% of survivors suffering from permanent neurological sequelae secondary to hypoxia or cerebrovascular accidents.
Although there is little data, amniotic fluid embolism does not seem prone to recurrence (139).Sheehan syndrome
Sheehan syndrome denotes postpartum hypopituitarism due to pituitary necrosis caused by hypovolaemic shock after severe peripartum haemorrhage. A secondary autoimmune process may also play a role in delayed pituitary dysfunction (140, 141).
The suggested diagnostic criteria for Sheehan syndrome include an obstetric history of significant postpartum vaginal bleeding resulting in severe hypotension/shock, failure of postpartum lactation, failure to resume regular menses after delivery, partial or panhypopituitarism, and empty sella on CT scanning or MRI (142).
Symptoms predominantly result from failure of the anterior pituitary endocrine axis (e.g. hypotension, fatigue, and hypopigmentation). With severe insufficiency, coma and death resulting from Addisonian crisis may ensue. Clinically overt involvement of the posterior pituitary is rare (140). Sheehan syndrome may manifest itself with considerable postpartum latency (143).
Diagnosis of Sheehan syndrome is made based on the patient's history, basal hormone levels, and pituitary functioning tests. Cerebral imaging may demonstrate an empty sella. Sheehan syndrome should be differentiated from pituitary adenoma infarction, which may require decompressive surgery (140). Treatment is by substitution of deficient hormones, particularly hydrocortisone and levothyroxine.
Chorea gravidarum
Chorea is characterized by brief, involuntary, irregular movements involving multiple parts of the body. Chorea beginning during pregnancy has been termed chorea gravidarum. Important causes include antiphospholipid antibody syndrome, systemic lupus erythematosus, and rheumatic fever. Patients should also be screened for Wilson's and Huntington's diseases, hyperthyroidism, basal ganglia infarction, drug-∕toxin-induced chorea, and hyperglycaemia (144). In about half of the cases, chorea gravidarum is idiopathic (145).
Symptoms usually start during the second to fifth month of pregnancy and tend to remit spontaneously within weeks or months or shortly after delivery (146).
If pharmacological treatment is required in severe cases, low-dose haloperidol may be utilized if the potential benefit justifies the potential risk to the fetus (144).