Anaesthetic management of emergency caesarean section with isolated cortical vein thrombosis and subacute intracerebral haemorrhage

Summary

We report the case of an emergency caesarean section 5 days following the onset of a right‐sided hemiparesis due to an intracerebral haemorrhage. Computerised tomography imaging in the postoperative period revealed an isolated cortical vein thrombosis as the likely cause. The caesarean section was conducted under general anaesthesia following consideration of the risks and benefits and discussion of these with the patient. No peri‐operative complications occurred and neuro‐rehabilitation was commenced as an inpatient. This case highlights the importance of maintaining a targeted systolic blood pressure whilst avoiding increased intracranial pressure in the obstetric patient with an intracerebral haemorrhage, and that the mode and conduct of anaesthesia can have a profound impact on these measurements. To our knowledge, this is the first reported case of a patient having an emergency caesarean section after subacute intracerebral haemorrhage caused by an isolated cortical vein thrombosis and it demonstrates that general anaesthesia can be used safely in this context. In this complex obstetric case, the role of multidisciplinary team collaboration in the peri‐operative period was essential to optimising the patient’s outcome.

Introduction

The incidence of stroke in pregnancy is 30 per 100,000 gestations and the associated mortality rate it is relatively high at 10% [1, 2], conferring an increased risk in managing these patients. Intracerebral haemorrhage presenting in the antenatal period can have a wide range of aetiologies. Isolated cortical vein thrombosis is an extremely rare cause and is identified in the absence of associated thrombosis in the cerebral venous sinuses on radiological imaging [3]. The predominant goal of the anaesthetic management of patients with intracerebral haemorrhage is to preserve cerebral perfusion pressure by maintaining a targeted mean arterial pressure while avoiding an increase in intracranial pressure. This can be challenging as both general and regional anaesthesia cause a reduction in systemic vascular resistance. Conversely, a significant hypertensive response to direct laryngoscopy can occur with a risk of extension of intracerebral haemorrhage, unless modifications are made to the conduct of general anaesthesia. In the obstetric setting, there is an increased risk of postpartum haemorrhage due to uterine atony if volatile anaesthesia is provided. As such, it is currently advocated that the preferred anaesthetic technique for caesarean section in patients with subacute intracerebral haemorrhage is regional anaesthesia [4]. In this report, we describe a case of subacute intracerebral haemorrhage caused by an isolated cortical vein thrombosis and explain the rationale for the decision to manage this rare obstetric presentation with general anaesthesia.

Report

A 23‐year‐old primigravida at 31 weeks gestation with a background of obstetric cholestasis was admitted via the emergency department with a right‐sided hemiparesis. Magnetic resonance imaging (MRI) of the head revealed a hyperacute subcortical haematoma, centred on the paramedian left pre‐central gyrus (Fig. 1). On day three of the admission whilst on the hyper‐acute stroke unit, the patient experienced intermittent abdominal pain suggestive of threatened preterm labour. A multidisciplinary team discussion involving the patient with her neurologist and obstetrician concluded that any imminent delivery should be via caesarean section.

Figure 1.

An axial T2 view of the magnetic resonance image of the brain identifying the left‐sided subcortical haematoma.

The decision regarding time of delivery was expedited on day four of the admission when the patient experienced a spontaneous rupture of membranes with regular uterine contractions. A category two caesarean section was declared by the obstetric team and the patient was transferred to the delivery suite. A neurosurgical opinion was sought and it was confirmed that surgical intervention was not necessary for the subcortical haematoma as a subsequent procedure. The benefits and risks of regional vs. general anaesthesia were therefore discussed with the patient, and the consensus was to proceed with a general anaesthetic. As part of the anaesthetic pre‐operative assessment, it transpired that the patient was appropriately starved. A detailed neurological examination of the patient was conducted and documented before transfer to the operating theatre.

In the operating theatre an arterial line was inserted and a modified rapid sequence induction (RSI) was conducted using 2 mg midazolam, 2 mg alfentanil and 120 mg propofol. Intubation of the trachea was facilitated with the administration of 80 mg rocuronium. A phenylephrine infusion was titrated to maintain the systolic blood pressure between the 110 and 150 mmHg target set by the neurologist pre‐operatively. Anaesthesia was maintained using a sevoflurane, oxygen and air mixture. The age‐adjusted minimum alveolar concentration of sevoflurane was maintained at 0.9 throughout. Bilateral transversus abdominis plane blocks were performed, and 400 mg sugammadex was given for reversal of the neuromuscular blockade at the end of surgery. To prevent a hypertensive response on emergence from general anaesthesia, 5 mg boluses of labetalol were given up to a total of 50 mg, before removal of the tracheal tube with the patient obeying commands and opening her eyes spontaneously. The estimated surgical blood loss was 530 ml.

The patient was transferred to the intensive care unit (ICU) postoperatively for invasive monitoring with no further requirement for vasoactive medications. In the absence of a neuraxial block, morphine was administered using a patient‐controlled analgesia pump. A computed tomography (CT) angiogram of the head performed on day one post‐delivery revealed an isolated cortical vein thrombosis as the likely pathology underlying the intracerebral haemorrhage. The patient was transferred to the rehabilitation ward on day two following delivery with gradual improvement in her right‐sided weakness. The preterm neonate required admission to the neonatal ICU but later joined the patient whilst she continued her rehabilitation. A thrombophilia screen sent 7 weeks into the postpartum period revealed a protein S deficiency. The patient was discharged home 8 weeks after admission to hospital and without anticoagulation.

Discussion

The aetiology of an intracerebral haemorrhage in pregnancy is extensive including arteriovenous malformation; hypertension associated with pre‐eclampsia; space‐occupying lesion; and cerebral venous sinus thrombosis. In this case, the patient's arterial blood pressure profile was unremarkable and with the exception of being pregnant, the patient had no risk factors for venous thromboembolism known on admission. However, the demographics of this patient are consistent with a limited case series indicating that isolated cortical vein thrombosis is more prevalent in young, adult women who have a hypercoagulable state [5]. Headache and seizures are the most common presenting clinical features of isolated cortical vein thrombosis, although this patient presented solely with a right‐sided hemiparesis. Isolated cortical vein thrombosis is also strongly associated with intraparenchymal changes noted on radiological imaging, including haemorrhagic venous infarction [5]. The likely mechanism for the haemorrhagic infarction seen in this patient is obstruction of the cortical vein resulting in venous congestion; raised venous pressure; and disruption of the blood‐brain barrier [4].

The CT angiogram of the head revealed a subtle filling defect in one cortical vein, highlighting the difficulty in making this diagnosis, and this was indeed a finding after the caesarean section. The uncertainty regarding the aetiology of the intracerebral haemorrhage pre‐operatively compounded the difficulty in decision‐making. However, it is recommended to consider caesarean section as the mode of delivery if the patient is considered as being high risk of having an intracerebral haemorrhage [6]. The decision to opt for caesarean section in this patient was based on the rationale that this would avoid raising venous pressure during the second stage of labour with the potential risk of extending the size of the intracerebral haemorrhage.

A challenge in this case was the decision‐making regarding mode of anaesthesia for emergency caesarean section in the context of a subacute intracerebral haemorrhage. It has been suggested that regional anaesthesia is preferable and safer for caesarean section after a recent stroke, with the main indications for general anaesthesia including concomitant therapeutic anticoagulation; evidence of raised intracranial pressure; or if neurosurgical intervention is required around the same time period [4]. The decision taken in our patient to proceed with general anaesthesia is in accordance with this suggested practice and based on concerns regarding potential coagulopathy and raised intracranial pressure not being ruled out before the caesarean section. Obstetric cholestasis can result in deranged clotting and an increased risk of spinal canal haematoma if neuraxial anaesthesia is performed. It is therefore recommended that patients with obstetric cholestasis should have a normal coagulation profile within 24 h of siting a neuraxial block [7]. The most recent coagulation profile was taken 48 h before the onset of labour in this patient, and normal coagulation could therefore not be verified within the decision‐delivery interval of a category two caesarean section. Furthermore, the patient had dense right leg weakness and concern was raised that potential complications of neuraxial block, including epidural haematoma, could be confounded by the presence of this. Although there were no deteriorating neurological signs on clinical examination it was also postulated that the intracerebral haemorrhage could have evolved in size in the days since admission and this would confer a contraindication to placing a neuraxial block in the presence of potentially raised intracranial pressure and mass effect. Further radiological imaging was not feasible due to the emergency nature of the caesarean section.

The detailed aspects of the approach to general anaesthesia in this case involved inserting an arterial line before induction of anaesthesia so that the systolic blood pressure target set by the neurologist could be accurately and continually monitored [8]. Neuromuscular blockade during the modified rapid sequence induction was achieved with rocuronium, preferred to succinylcholine after an acute stroke due to the potential risk of hyperkalaemia related to the proliferation of extrajunctional cholinergic receptors [9]. Sevoflurane is regarded as the preferred volatile agent for neuroanaesthesia as it results in less cerebral vasodilatation than other volatile agents. Though it was not used in this case, an intra‐operative remifentanil infusion may have been useful to limit surges in blood pressure, and potentially reduce the risk of uterine atony associated with volatile anaesthetic agents by reducing the volatile anaesthetic requirement. Nitrous oxide was not administered and the patient’s lungs were ventilated using a volume‐controlled mode to maintain end‐tidal carbon dioxide between 4.5 and 5.0 kPa in order to limit any rise in intracranial pressure.

General anaesthesia has the propensity to cause a temporary altered level of consciousness in the immediate postoperative period, which may make neurological assessment challenging. To mitigate this, the neuromuscular blockade was reversed with sugammadex [10], and the continued use of sedating analgesics was minimised by siting transversus abdominis plane blocks.

Due to the rarity of isolated cortical vein thrombosis, the risk of recurrence for this patient in a subsequent pregnancy is difficult to ascertain. The obstetric team has suggested that there is no reason a vaginal birth after caesarean could not be offered in the future. Due to the protein S deficiency, the patient would be offered prophylactic low molecular‐weight heparin during any subsequent pregnancy. This would require further discussion, ideally at pre‐conception counselling, to determine at which time in any future pregnancy pharmacological thromboprophylaxis would be initiated.

It is important to consider an isolated cortical vein thrombosis as a rare, albeit potential cause, of stroke in pregnancy if other diagnoses are excluded. If concerns are raised that would contraindicate regional anaesthesia, this case highlights that careful general anaesthesia can be used safely for an emergency caesarean section in the context of a subacute intracerebral haemorrhage.