Acute ischemic stroke: emergent evaluation and management

Cerebrovascular disease in dogs and cats

Cerebrovascular disease is defined as any abnormality of the brain resulting from a pathologic process affecting its blood supply. Stroke or cerebrovascular accident (CVA) is the most common clinical manifestation of cerebrovascular disease, and can be broadly divided into ischemic stroke and hemorrhagic stroke. Ischemic stroke results from occlusion of a cerebral blood vessel by a thrombus or embolism, depriving the brain of oxygen and glucose, whereas hemorrhagic stroke results from rupture of a blood vessel wall within the brain parenchyma or subarachnoid space. Previously considered uncommon, CVA is being recognized with greater frequency in veterinary medicine since magnetic resonance imaging has become more readily available. Once the diagnosis of ischemic or hemorrhagic stroke is confirmed, potential underlying causes should be sought after and treated accordingly.

The reciprocal risks of stroke and cognitive impairment in an elderly population

BACKGROUND

Stroke, dementia, and cognitive impairment no dementia (CIND) pose major threats to the elderly but have rarely been studied together in the same population. We aimed to compare the relative frequencies of stroke, CIND, and dementia in an elderly population and to examine whether cognitive impairment poses a risk for stroke.

METHODS

Prevalences of stroke, CIND, and dementia were estimated among participants in the first clinical examination of the Canadian Study of Health and Aging (CSHA-1, n = 2,914). Incidence rates were determined at the 5-year follow-up (CSHA-2) among those cognitively normal and stroke free at CSHA-1 (n = 828). The associations between cognitive impairment and stroke were assessed by Cox regression analyses.

RESULTS

Among elderly Canadians, the age-standardized prevalence of stroke, CIND, and dementia were 8%, 17%, and 8%, respectively. Alone or combined, they affected one fourth of the elderly. Among stroke survivors, 64% had cognitive impairment compared with 21% among stroke-free persons. Among the cognitively impaired, 25% had a stroke compared with 4% among the cognitively normal. The incidence rates of stroke, CIND, and dementia were 3, 6, and 3 per 100 person-years, respectively. Compared with cognitively normal subjects, the adjusted risk for incident stroke was 1.3 (95% confidence interval [CI], 0.9 to1.9) in patients with CIND and 2.3 (95% CI, 1.7 to 3.2) in patients with dementia regardless of whether "questionable stroke" was included.

CONCLUSIONS

Stroke and cognitive impairment pose risk for each other. CIND is highly prevalent, and some of its subtypes may represent treatable preludes to stroke and/or dementia.

Ischaemic and haemorrhagic stroke in the dog

Cerebrovascular disease results from any pathological process of the blood vessels supplying the brain. Stroke, characterised by its abrupt onset, is the third leading cause of death in humans. This rare condition in dogs is increasingly being recognised with the advent of advanced diagnostic imaging. Magnetic resonance imaging (MRI) is the first choice diagnostic tool for stroke, particularly using diffusion-weighted images and magnetic resonance angiography for ischaemic stroke and gradient echo sequences for haemorrhagic stroke. An underlying cause is not always identified in either humans or dogs. Underlying conditions that may be associated with canine stroke include hypothyroidism, neoplasia, sepsis, hypertension, parasites, vascular malformation and coagulopathy. Treatment is mainly supportive and recovery often occurs within a few weeks. The prognosis is usually good if no underlying disease is found.

Management of blood pressure after acute ischemic stroke: An evidence-based guide for the hospitalist

Hospitalists are frequently called upon to manage blood pressure after acute ischemic stroke. A review of both post infarction cerebral perfusion physiology and the data from randomized trials of antihypertensive therapy is necessary to explain why consensus guidelines for blood pressure management after stroke differ from those of other hypertensive emergencies. The peri-infarct penumbra is the central concept in understanding post ischemic cerebral perfusion. This area of impaired cerebral blood flow is dependent on mean arterial blood pressure and acute reduction of blood pressure may expand the area of infarction. Review of clinical trials fails to show benefit from reduction of blood pressure after ischemic stroke and current guidelines suggest antihypertensive therapy be employed if the systemic blood pressure is greater than 180/105 mmHg after tPA is employed, or 220/120 mmHg when tPA is not used. Induced hypertension remains a promising but unproven therapy in the acute setting, but the evidence for long term control of blood pressure to less than 140/80 mmHG for secondary prevention of stroke is strong. Adherence to guidelines is poor but it is recognized that current evidence is limited by a lack of trials in which blood pressure is titrated to a pre-specified goal, as is common in clinical practice.

Ischaemic stroke in dogs and humans: a comparative review

Cerebrovascular accidents, also known as strokes, are one of the major causes of disability and mortality among adult humans. The increased availability of magnetic resonance imaging in veterinary medicine means they are being increasingly recognised in dogs, too. Cerebrovascular accident is defined as the sudden onset of non-progressive, focal brain dysfunction as a result of ischaemic infarction or haemorrhage. Focal ischaemic stroke is caused by interruption of the arterial blood flow to a dependent area of brain parenchyma by a thrombus or an embolus. Once the diagnosis of ischaemic stroke is confirmed, potential sources of thrombosis or embolism should be investigated and treated accordingly. Dogs with ischaemic stroke tend to recover within several weeks with supportive care only.

Hyperosmolar Hyperglycemic State

Hyperosmolar hyperglycemic state (HHS) is the most serious acute complication of type 2 diabetes mellitus. Emergency department management focuses on prompt diagnosis and restoration of hemodynamic stability with appropriate fluid therapy while maintaining electrolyte homeostasis. Identification of any precipitating illness is essential. The emergence of HHS as a critical presentation of type 2 diabetes mellitus in adolescents is highlighted.

Stroke and neurodegenerative disorders. 1. acute stroke evaluation, management, risks, prevention, and prognosis11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors(s) or upon any organization with which the author(s) is/are associated

This self-directed learning module highlights recent developments in the acute care of stroke patients, prediction of outcome after stroke, evaluation of risk factors, secondary prevention of stroke, and the evaluation of the young adult with stroke. It is part of the study guide on stroke and neurodegenerative disorders in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article contains sections on the acute evaluation and management of the stroke patient, prediction of functional outcome after stroke, and secondary prevention of stroke. Special emphasis is given to the evaluation of the young adult with stroke.

OVERALL ARTICLE OBJECTIVES

(a) To summarize the acute evaluation and management of stroke, particularly in the young stroke patient; and (b) to review the risk factors for stroke and secondary prevention measures.