Stroke is a disease that affects the arteries leading to and within the brain and is the number five cause of death and a leading cause of disability in the United States,1 is the third most common cause of death in high-middle developed countries, and is the leading disease between the causes of years lived with disability worldwide.8 The five main categories of strokes reported by the American Stroke Association (ASA) are ischemic, hemorrhagic, transient ischemic attack (TIA), cryptogenic, and brainstem.
An ischemic stroke is as an episode of neurologic dysfunction caused by focal cerebral, spinal, or retinal infarction.16 Ischemic stroke accounts for 87% of all strokes.1 Ischemic stroke results in a core region of infarcted tissue surrounded by a penumbra that is electrically silent in the setting of marginal perfusion.14 Ischemia of the penumbra will progress to permanent infarction once regional cerebral blood flow decreases below a critical level for a sufficient time.4 The duration of time for which an individual’s penumbra can withstand decreased perfusion varies tremendously and depends on several factors, including health of collateral circulation.6,13 Factors that affect collateral flow and cerebral perfusion include individual vascular anatomy and modifiable elements such as blood pressure and a patient’s volume status.12,2,15
Fatty deposits lining the vessel walls, called atherosclerosis, are the main cause for ischemic stroke. Fatty deposits can cause two types of obstruction:1
In June 1996, the Food and Drug Administration approval of alteplase transformed the emergency assessment and treatment of patients with acute ischemic stroke.10 Thrombolysis with tissue plasminogen activator (tPA) is now a cornerstone in treating a patient with acute ischemic stroke.11,7 This treatment should be given as soon as possible, preferably within 4.5 hours after symptom onset and within 60 minutes after patient arrival at the hospital.11
Intracerebral hemorrhage is the second most common subtype of stroke and, in comparison with ischemic stroke, mortality is higher and functional outcomes are worse.5 Hemorrhagic strokes makeup about 13 % of stroke cases and are caused by a weakened vessel that ruptures and bleeds into the surrounding brain.1 Ruptured blood vessels are weakened through either an aneurysm or AV malformation. Higher blood pressures after intracerebral hemorrhage are associated with increased fatality rates and worse functional outcomes.3 The two types of hemorrhagic strokes are intracerebral hemorrhage and subarachnoid hemorrhage.1
Current management focuses on reversal of severe coagulopathy, blood pressure control, and neurosurgical intervention for herniation or ventricular obstruction.9 Diagnosing a stroke as ischemic versus hemorrhagic before administration of a thrombolytic agent is critical to prevent worsening of the bleed.
TIA is a temporary blockage of blood flow to the brain and since it doesn’t cause permanent damage, it is often ignored.1 Patients experiencing a TIA can exhibit the same signs and symptoms of a stroke, but they are transient and temporary. This condition should not be ignored, and follow-up with a practitioner with neurologic experience is recommended. Signs and symptoms of a TIA could be a precursor to a stroke.
According to Vidale et al., about 25% to 40% of acute cerebral ischemia have no identifiable causes and are classified as cryptogenic strokes. Cryptogenic strokes are a category of conditions in which an identifiable cause of the event is not found. Collaboration by neurologists, cardiologists, electrophysiologists and others may reveal the answers needed to provide targeted treatment for preventing recurrent strokes.1
Only a half-inch in diameter, the brain stem controls all basic activities of the central nervous system: consciousness, blood pressure, breathing and all motor control throughout the body.1 Brain stem strokes can have complex symptoms, and they can be difficult to diagnose. A person may have vertigo, dizziness and severe imbalance without the hallmark of most strokes: weakness on one side of the body. A unique sign and symptom of a brain stem stroke is “locked in syndrome” which renders the victim with the ability to move only their eyes.
No matter the type and location of stroke, it is important to get the patient experiencing a stroke into a facility that can diagnose and treat promptly.