Neurologic Emergencies: Stroke and TIA (EMT)
This lesson covers stroke and Transient Ischemic Attack (TIA), two of the most time-sensitive neurological emergencies encountered by EMTs. A stroke, formerly known as a Cerebrovascular Accident (CVA), is a "brain attack" caused by an interruption of blood flow to the brain, leading to the death of brain cells. Rapid identification and transport are critical to patient outcomes. A TIA, or "mini-stroke," involves a temporary blockage with symptoms that resolve on their own, but it serves as a major warning sign for a future stroke.
Types of Stroke
There are two main types of stroke: ischemic and hemorrhagic.
Ischemic Stroke (87% of all strokes)
Pathophysiology: Occurs when a blood vessel supplying the brain is blocked, typically by a blood clot (thrombus or embolus). This is often due to atherosclerosis, a condition where plaque builds up in the arteries.
Embolus: A clot that forms elsewhere in the body and travels to the brain.
Thrombus: A clot that forms directly in an artery supplying the brain.
Symptoms: Can range from mild to severe, including paralysis on one side of the body (hemiparesis), aphasia (difficulty speaking), and altered mental status.
Hemorrhagic Stroke (13% of all strokes)
Pathophysiology: Occurs when a weakened blood vessel in the brain ruptures, causing bleeding into the surrounding brain tissue. This bleeding increases pressure within the skull (intracranial pressure), damaging brain cells.
Causes: Often associated with uncontrolled hypertension (high blood pressure) or an aneurysm (a weak, bulging spot on an artery wall).
Prognosis: Cerebral hemorrhages are often fatal.
Transient Ischemic Attack (TIA)
A TIA occurs when blood flow to the brain is temporarily blocked. The symptoms are the same as a stroke but are transient, typically resolving within minutes to hours. While the symptoms disappear, a TIA is a critical warning sign that a major stroke may be imminent, and the patient requires urgent medical evaluation.
Stroke Assessment for EMTs
Time is critical in stroke care ("Time is Brain"). Rapid identification using a validated prehospital stroke scale is essential.
Cincinnati Prehospital Stroke Scale (CPSS)
This simple tool assesses for three key findings:
Facial Droop: Ask the patient to smile or show their teeth. Does one side of the face not move as well as the other?
Arm Drift: Ask the patient to close their eyes and hold both arms straight out in front of them for 10 seconds. Does one arm drift down or not move at all?
Abnormal Speech: Ask the patient to say a simple phrase, such as "The sky is blue in Cincinnati." Is their speech slurred, do they use the wrong words, or are they unable to speak?
If any one of these signs is abnormal, the probability of a stroke is high.
Other Stroke Signs and Symptoms
Sudden weakness or numbness in the face, arm, or leg, especially on one side of the body.
Sudden confusion, trouble speaking, or difficulty understanding speech.
Sudden trouble seeing in one or both eyes.
Sudden trouble walking, dizziness, or loss of balance or coordination.
Sudden severe headache with no known cause.
Management of Stroke and TIA
Prehospital management focuses on supportive care and rapid transport to an appropriate facility (a designated stroke center).
Primary Assessment: Ensure a patent airway, adequate breathing, and circulation.
Oxygenation: Administer oxygen only if the patient is hypoxic (SpO2 < 94%) to maintain a saturation of 94% or greater.
Blood Glucose: Check the patient's blood glucose level. Hypoglycemia can mimic stroke symptoms.
Last Known Well Time: Determine the exact time the patient was last seen in their normal state of health. This is a critical piece of information for determining treatment options (e.g., thrombolytic therapy) at the hospital.
Rapid Transport: Transport the patient promptly to a designated stroke center, providing pre-arrival notification to the receiving facility. Keep the patient in a position of comfort and be prepared to manage the airway if their condition deteriorates.
Critical Thinking Questions
A 72-year-old female presents with sudden onset of slurred speech and right-sided arm weakness. Her husband states she was "perfectly fine" 30 minutes ago. What is your primary diagnosis, and what is the single most important piece of historical information to obtain and relay to the hospital?
You are assessing a patient for a possible stroke using the Cincinnati Prehospital Stroke Scale. Describe how you would assess for facial droop and arm drift.
Explain the fundamental difference between an ischemic stroke and a hemorrhagic stroke in terms of their underlying pathophysiology. Why might the prehospital management be similar despite these differences?
A patient reports stroke-like symptoms that completely resolved 15 minutes before your arrival. What is this event called, and why is it still considered a medical emergency requiring transport?
During your assessment of a potential stroke patient, you find their blood glucose level is 40 mg/dL. How does this finding change your differential diagnosis and immediate treatment plan?