Introduction
The term stroke refers to a spectrum of conditions affecting the brain’s vasculature that can lead to sudden brain tissue compromise and ultimately brain tissue death. An acute stroke is an emergency in which early intervention can significantly improve outcome. The emergency department (ED) technician (EDT) plays a crucial role in the multidisciplinary response to stroke recognition and treatment.
There are 17 million new stroke cases worldwide annually. Strokes are the fifth-leading cause of death in the United States and the second-leading cause of death worldwide. The stroke mortality rate has been declining over recent years due to treatment advances, but as mortality has dropped, more patients are living with stroke-related disabilities.
A stroke may be:
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Thrombotic: a clot occurs at the site of arterial wall damage (50%).
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Embolic: a clot formed at a distant site travels from that site, impacting an artery supplying the brain (30%).
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Hemorrhagic: an artery bleeds into brain tissue, disrupting the function in the area of the bleed (20%).
Thrombotic and embolic strokes are described as “ischemic” strokes. This means that they occur from lack of blood flow to the area downstream from the blockage. The focus of treatment in these strokes is to restore the blood flow as quickly as possible. By documenting the patterns of dysfunction on the clinical examination, the provider can often infer the location of the blood vessel blockage.
Initial Assessment and Triage
An important role of the EDT is to help the treatment team with the early recognition and response to strokes. Although most stroke patients arrive by ambulance, many will arrive unannounced.
The most common recognizable signs of an acute stroke are described by the acronym FAST ( Table 14.1 ). There are, however, multiple other findings of a stroke not covered by the FAST evaluation, including loss of vision, inability to speak (aphasia), and confusion. A severe headache associated with stroke-like findings suggests a hemorrhagic stroke. Any concerns that a patient is having a stroke should be raised to the nurse or provider, following the hospital’s stroke protocol. Though these protocols vary among hospitals, they will facilitate rapid brain imaging and neurologic evaluation.
| F | Facial droop: Ask the patient to smile. If one side droops lower than the other, start to think that the patient is having a stroke. |
| A | Arm drifting: Ask the patient to raise their arms. If one arm drifts lower, again, recognize that this is a potential stoke. Dizziness, loss of balance, and one-sided weakness are commonly associated with stroke. |
| S | Speech: If speech is slurred or confused, you must rule out stroke vs. altered mental status. |
| T | Time: Time is brain cells. The longer it takes to get this patient treated, the more brain cells will die, resulting in potential hemiparesis or hemisensory loss. |
An example of a stroke protocol is shown in Fig. 14.1 .
Ischemic Stroke
Approximately 700,000 US patients experience an acute ischemic stroke annually. The overall mortality of acute ischemic strokes is 15%, but severe strokes have a 75% mortality. Half of patients who experience an ischemic stroke will have a permanent disability, such as weakness or speech difficulties, and will be dependent on others for care.
Ischemic strokes are most often a result of atherosclerosis (plaques of fatty materials on the inside of blood vessel walls). When one of these plaques fissures, an acute clot at that site can form that will compromise flow to downstream tissue. The symptoms and examination findings of a stroke patient vary with the clot’s location and the area of the brain it supplies. Brain tissue deprived of blood ceases to function normally, and the physician’s physical examination will document the patient’s deficits and allow the physician to determine where the clot is located even before seeing damage documented on the brain computed tomography (CT) scan ( Fig. 14.2 ).
Hemorrhagic Stroke
Hemorrhagic strokes are caused by bleeding into the brain or spinal fluid. Although hemorrhagic strokes only comprise about 20% of all strokes, they are more lethal, with a mortality rate of 30% to 55% in the first month.
The major causes of hemorrhagic strokes are from vessel malformations, excessively elevated blood pressures, or tumors. There are two major types of vessel malformations: intracranial aneurysms (ICAs) or arteriovenous malformations (AVMs). An ICA is an outpouching or “ballooning” of the blood vessel, making it prone to rupture. It accounts for 80% of bleeding around the brain; its major risk factors are smoking, high blood pressure, and family history. An AVM is a disorganized collection of arteries and veins that are also prone to bleed ( Fig. 14.3 ). Extremely elevated blood pressures can put excess pressure on the vessels of the brain, causing bleeding into the brain. Tumors in the brain may have weakened blood vessels, making them prone to bleeding as well.
Diagnosis
The diagnosis of an acute stroke is complicated by the fact that many patients with prior strokes present with new symptoms that could either represent an acute new stroke or an exacerbation of their prior stroke symptoms caused by another disease process. Table 14.2 outlines conditions that could mimic an acute stroke. After completing a history and careful neurologic examination, the physician will order a noncontrast brain scan (i.e., CT)
