Key Learning Points

1. 1. Delineation of the lobes on CT is more difficult than on MRI, and instead they are often referred to as ‘regions’ on CT.

2. 2. Appreciation of the cerebrospinal fluid (CSF) spaces is useful to assess brain volume, mass effect, hydrocephalus and haemorrhage.

3. 3. Subarachnoid haemorrhage (SAH) is commonly seen as abnormal high attenuation within the cerebral sulci, ventricles and/or the basal cisterns.

4. 4. Subdural haematomas (SDH) appear on CT as a concave extra-axial collection (outside the brain parenchyma).

5. 5. Extradural haematomas (EDH) appear as a convex/lens shape and usually underlie a fracture. If the haematoma extends past a suture, it is not extradural.

Aneurysmal SAH is a severe disease, and the post-haemorrhage period fraught with potential complications that must be recognized and treated early for favourable outcome. While diagnosis of SAH is often straightforward from clinical history and initial CT, some patients will require cerebrospinal fluid evaluation. The aneurysm must be secured urgently to reduce rerupture and clinical worsening. Endovascular coiling is preferable when feasible, but surgical clipping is sometimes needed based on patient or aneurysmal characteristics, or presence of intraparenchymal haemorrhage requiring evacuation. Treatment of symptomatic hydrocephalus with CSF diversion is also crucial. Patients with aneurysmal SAH should be managed by a team of nurses and physicians with neurocritical care, neuroendovascular, and neurosurgical expertise, preferably in a dedicated neurosciences intensive care unit. Early complications include aneurysmal rebleeding, hydrocephalus, and neurogenic cardiopulmonary injury. In the subacute phase, delayed cerebral ischaemia and hyponatremia are more commonly seen. With optimal multidisciplinary management, many patients can return to their previous level of function only weeks after the aneurysm rupture. Still, most treatments in SAH are based on insufficient evidence, and more collaborative research from the bench to the bedside is necessary to continue improving patient outcomes.

Intracerebral haemorrhage and subarachnoid haemorrhage are associated with considerable morbidity and mortality. Too often the focus is on acute treatment after a haemorrhage has occurred, instead of primary and secondary prevention. Medical therapies to control hypertension, achieve tobacco abstinence, and avoid excessive alcohol consumption can confer broad reductions in haemorrhage risk across pathophysiological subtypes. Judicious restriction of antiplatelet and anticoagulant therapies to only those individuals and those intensities for which they are indicated also can substantially reduce haemorrhagic stroke frequency. Specific endovascular and surgical therapies, judiciously employed, will further reduce risk of first or recurrent haemorrhage from structural vascular anomalies, including arteriovenous malformation, cavernous malformations, and saccular aneurysms. For unruptured intracranial aneurysms, features that favour consideration of preventive occlusion include include younger patient age, prior subarachnoid haemorrhage from a different aneurysm, familial intracranial aneurysms, large aneurysm size, irregular shape, basilar or vertebral artery location, and aneurysm growth on serial imaging. Among individuals who are technical candidates for either coiling or clipping, endovascular coiling is associated with a reduction in procedural morbidity and mortality but has a higher risk of recurrence.

Prehospital stroke care is the first link in the stroke chain of survival and includes symptom recognition, engagement of the Emergency Medical Services (EMS) system, timely and effective dispatcher response, and emergency medical response. Prehospital stroke screening tools are an important component in guiding the EMS response to stroke and proper triage of patients. Additionally, there is a growing body of research focused on applications for telemedicine, mobile stroke units, and diagnostic testing in the prehospital arena. Prehospital stroke care is integral to the organization of regionalized stroke systems. Implementation of stroke systems of care can lead to improved access to specialty services and improved patient health outcomes. In addition to increasing access to acute stroke care, telestroke shows great potential for integrating stroke systems of care and facilitating interactions between centres.

Pre-clinical studies provide clear and consistent evidence that a variety of centrally acting drugs affecting specific neurotransmitters can either facilitate or interfere with functional recovery after brain injury. Although at least some clinical trials suggest similar effects in humans, results have been inconsistent. The impact of important factors such as drug dose, duration, and intensity of physiotherapy, and timing between injury and treatment are difficult to translate from preclinical studies. Issues related to variability in stroke severity, location of injury, and comorbid conditions further complicate trial design and could obscure a true treatment effect. Because of these and other issues, the design of efficacy trials assessing putative neuro-restorative interventions is not trivial. Although a proven pharmacological approach resulting in a clinically meaningful improvement in post-stroke recovery remains elusive, it is reasonable to avoid medications that may have harmful effects in patients who have had a stroke. It is also important to control for these possible harmful effects in future clinical trials assessing the outcomes of stroke patients after the acute period.

In the year 2010, an estimated 16.9 million strokes occurred worldwide at an incidence rate of 258 per 100,000 persons per year. Approximately 70% of these strokes occurred in low- and middle-income countries. The 16.9 million incident strokes were added to a pool of 33 million prevalent stroke survivors. There were 5.9 million deaths and 102 million disability-adjusted life-years (DALYs) lost due to stroke in 2010, making stroke the second leading cause of death and the third leading cause of DALYs worldwide. In the preceding two decades, between 1990 and 2010, the incidence rate of stroke remained stable but the absolute number of incident strokes increased by 68%, the prevalence rate increased modestly yet the absolute number of stroke survivors nearly doubled, the rate of DALYs lost due to stroke decreased but the absolute number of DALYs lost increased by 12%, and the mortality rate fell but the absolute number of stroke-related deaths increased by 26%. Most of the burden of stroke is in low-income and middle-income countries, which bear 63% of incident ischaemic strokes and 80% of haemorrhagic strokes. The average age of incident ischaemic and haemorrhagic strokes was 6 years younger in low- and middle– than high–income countries.

While the neurosurgical patient is not normally one junior prescribers should be caring for in a nonspecialist area, they may encounter them in the acute setting while a referral is being made. Readers are provided with key information on the management of subarachnoid haemorrhage, including how to manage blood pressure, prevent vasospasm and rebleeding. Adjuncts to reduce the chances of secondary brain injury, including steroids, mannitol and anticonvulsants, are also discussed, while the importance of good quality analgesia is also emphasised.

Acute aneurysmal subarachnoid haemorrhage (aSAH) is associated with significant morbidity and mortality. The worldwide incidence is approximately 9 per 100,000 per year; however, there are regional differences. Accurate, timely diagnosis and treatment is imperative to avoid aneurysmal re-rupture, which has a mortality in the region of 80%. For patients that survive the initial aSAH, the re-rupture rate is approximately 5% in the first 24 hours and thereafter, approximately 1% per day. Patient outcome may be further compromised by complications such as seizures, cerebral vasospasm, cerebral infarction, electrolytes disturbances and hydrocephalus. Definitive treatment of patients admitted with acute aSAH is based on early exclusion of the aneurysm from the circulation in order to prevent rebleeding and for many years, the treatment of choice was an open craniotomy and surgical clipping of the aneurysm. However, over recent years the development of interventional neuroradiological techniques has provided alternative less invasive management options that raise a number of ethical issues that must be considered when faced with a patients with an acute aSAH.