Chapter 2
Cerebrovascular and Carotid Artery Disease
Timothy J. England1, Nishath Altaf2 and Shane MacSweeney2
1Division of Medical Sciences & GEM, School of Medicine, University of Nottingham, UK
2Department of Vascular Surgery, Nottingham University Hospitals NHS Trust, UK
Introduction
Each year in the United Kingdom there are 150 000 new cases of stroke, more than one every 5 min. In 2010, it was the fourth largest cause of death (almost 50 000 cases), though mortality rates have halved in the past 20 years. TIA affects 35 per 100 000 population and has a high risk of subsequent stroke, particularly in the first month after the event. Therefore, both stroke and TIA should be referred immediately for specialist inpatient or outpatient assessment in order to institute measures that reduce the burden of subsequent disability and death. The cost to the UK economy, including direct healthcare, informal care costs and indirect costs is in the region of £9 billion.
Stroke is a clinical syndrome presenting with rapidly developing focal (or global) loss of cerebral function lasting for more than 24 h or leading to death, with no apparent cause other than that of vascular origin (World Health Organisation, 1978). A transient ischaemic attack (TIA) is traditionally defined as a sudden focal neurological deficit of the brain or eye, presumed to be of vascular origin and lasts less than 24 h. While this definition is valid and useful, it is based on the assumption that TIAs are associated with complete resolution of cerebral ischaemia with no permanent brain injury. Advances in acute stroke imaging have shown this to be false and a ‘tissue-based’ definition is often preferred. The typical duration of a TIA is less than 20 min.
Aetiology
TIAs and 85% of strokes are due to atherothrombotic occlusion of a cerebral artery or cardioembolism. Neurons are extremely oxygen dependent, and an irreversible process of cell death begins if perfusion is not quickly restored. Haemorrhage accounts for 15% of strokes, mainly from primary intracerebral haemorrhage due to small vessel lipohyalinosis. This causes tissue damage through compression and reactive vasospasm. However, one-third of patients may have an underlying tumour, aneurysm or arteriovenous malformation, so further investigations should be considered for those surviving without major disability. Stroke predominantly occurs in older people at an average age of 74, but 15% are under the age of 60 (Table 2.1). For younger patients, it is important to consider mechanisms other than atheroma for ischaemic stroke, such as carotid dissection, patent foramen ovale, thrombophilia and uncommon genetic disorders such as CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leucoencephalopathy) or Fabry’s disease. However, no definitive cause is identified in one-third of patients despite investigations (Table 2.1).
Table 2.1 Important risk factors for ischaemic stroke and TIA.
| Clinical note | Assessment | First-line management | |
| Atherothrombotic | |||
| Hypertension | 50% patients have systolic BP >160 mmHg at presentation | <130/80 is secondary prevention target | BP-lowering drugs and lifestyle advice |
| Diabetes mellitus | 40% patients have moderate hyperglycaemia at presentation | Diagnose with fasting glucose, glucose tolerance test or HbA1c | Diet and glucose-lowering drugs |
| Hypercholesterolaemia | Check within 24 h of event | Treat if total cholesterol >4.0 mmol/l or LDL > 2 mmol/l | Statin |
| Smoking | Doubles the risk of stroke recurrence | Document pack years | Refer to smoking cessation service |
| Carotid artery stenosis | Adhere to local protocol for carotid ultrasound | Considering treating symptomatic stenosis of 50–99% | Carotid endarterectomy |
| Carotid dissection | Neck pain and Horner’s syndrome | CT or MR angiography of neck vessels | Anticoagulation or antiplatelet drugs for 3–6 months |
| Thrombophilia | Reserve for younger patients without vascular risk factors | Thrombophilia screen | Consider anticoagulation |
| Cardioembolic | |||
| Atrial fibrillation | Consider 24-h ECG | ECG | Long-term anticoagulation |
| Recent myocardial infarct (MI) | Highest risk is anterior MI <4 weeks | ECG Transthoracic echocardiogram | Anticoagulation for 3–6 months |
| Left ventricular aneurysm | ECG with ST elevation | Transthoracic echocardiogram | Long-term anticoagulation |
| Patent foramen ovale | Younger patients without vascular risk factors | Transoesophageal echocardiogram | Consider closure or anticoagulation if aneurismal atrial septal defect and/or previous events |
Table 2.2 Typical clinical features of a stroke or TIA.
| Symptom | Descriptive term |
| Motor symptoms | |
| Weakness of one side of the body | Hemiparesis |
| Difficulty swallowing | Dysphagia |
| Imbalance | Ataxia |
| Inability to perform certain actions not due to weakness | Dyspraxia |
| Sensory symptoms | |
| Altered feeling on one side of the body | Hemisensory disturbance |
| Neglect of one side | Tactile or visual inattention |
| Loss of vision in one eye | Monocular blindness or amaurosis fugax |
| Loss of vision in a visual field | Hemianopia or quadrantanopia |
| Double vision | Diplopia |
| A spinning sensation | Vertigo |
| Speech or language disturbance | |
| Difficulty understanding or expressing spoken language | Receptive or expressive dysphasia |
| Difficulty writing | Dysgraphia |
| Difficulty calculating | Dyscalculia |
| Slurred speech | Dysarthria |
Clinical assessment
The diagnosis of a stroke is initially based on a detailed history (taken from the patient or witness) and medical examination and confirmed with diagnostic radiological imaging. A typical history is one of a sudden loss of neurological function determined by the site of the brain that has been damaged by ischaemia or haemorrhage. Symptoms and signs (Table 2.2) are usually maximal at onset but occasionally they worsen gradually or in a stepwise manner. Alternative diagnoses (such as intracerebral malignancy) should be considered if ictus is not sudden. Unless there has been complete recovery at the time of medical review and the immediate risk of stroke is low, the patient should be admitted for neurological monitoring and urgent assessment. Stroke syndromes based on clinical features, established by the Oxfordshire Community Stroke Project (OCSP), allow the clinician to estimate information on the anatomical and vascular location of the stroke, its aetiology and prognosis (Box 1). Many conditions can present in a similar way to stroke (Box 2). Particular care should be taken when there is a global disturbance of consciousness as this hinders identification of precise neurological deficits and increases the probability of an alternative mechanism for any focal signs.
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