Introduction and Lecture Objectives
This lecture covers the topic of Transient Ischemic Attacks (TIA), and we will focus on several key points:
- Definition of TIA, also known as a mini-stroke or warning stroke.
- Calculating the likelihood of a complete stroke occurring after a TIA.
- Explaining the ABCD2 scoring system, which helps determine the severity of the condition and whether the patient needs to be hospitalized or can be followed up externally.
- Necessary tests (Work-up) and treatment protocols.
Clinical Case Presentation
We will start with a real-life case that occurs daily in hospitals: a 60-year-old man with a medical history of hypertension and diabetes. The patient arrived at the emergency department with sudden weakness on the right side of the face, arm, and leg, along with difficulty speaking and articulating words.
Upon clinical examination, his blood pressure was high (190/100), and he had a leftward gaze deviation with severe weakness on the right side. In such cases, the initial assumption is either a Transient Ischemic Attack (TIA) or a complete stroke.
First Step: CT Scan
The most important test to perform immediately is a brain CT scan without contrast. The primary goal is to rule out any bleeding in the brain, as the treatment protocol for bleeding differs completely from that of a clot or ischemic stroke.
In this patient's case, the scan showed no bleeding but indicated a possible clot and ischemia in a major artery, the middle cerebral artery (MCA). This was later confirmed through a CT angiogram and MRI, which revealed an acute clot in a branch of the internal carotid artery.
Medical History and the Importance of TIA
When asked later, "Have you experienced these symptoms before?" the patient mentioned that three days prior, he felt the same weakness on the same side, but the symptoms disappeared completely after 15 minutes, so he did not seek medical attention, thinking the problem had resolved. Medically, this means the patient had a TIA before the major stroke occurred. If it had been addressed at the time, the major stroke might have been prevented.
Definition of Transient Ischemic Attack (TIA)
TIA is characterized by a sudden onset (Rapid onset) within seconds or minutes. It consists of neurological symptoms resulting from temporary ischemia and clotting in the arteries without leaving a permanent effect or causing cell death in the brain.
- Duration: Symptoms usually resolve within less than an hour (typically 20-30 minutes).
- Old Definition: Previously included any symptoms resolving within less than 24 hours, but the modern approach depends on the absence of effects in imaging.
- Statistics: In America, for example, there are between 200,000 to 500,000 cases annually. More importantly, 15% of patients with complete strokes have experienced a warning TIA before the stroke.
Pathophysiology (Anatomy & Pathogenesis)
The brain is nourished through the carotid arteries, which branch from the aorta. The carotid artery in the neck divides into internal and external branches. The internal carotid artery supplies blood to the eye and brain (through the middle and anterior cerebral arteries).
Causes of Temporary Clotting:
- Cardiac Source: Such as atrial fibrillation, where a small clot forms in the heart and travels to the brain.
- Carotid Artery Stenosis: Presence of plaques and fats in the neck artery.
- Hypercoagulability: Particularly in young individuals (under 50 years) who do not suffer from hypertension or diabetes.
- Traditional Risk Factors: Advanced age (over 55), gender (males more), smoking, diabetes, and high cholesterol.
Clinical Symptoms and FAST Criteria
People and medical teams are educated with the acronym FAST for quick response to symptoms:
- F (Face): Weakness or drooping on one side of the face (ask the patient to smile).
- A (Arm): Weakness in the arm (ask the patient to raise their hands).
- S (Speech): Difficulty speaking or heaviness in the tongue.
- T (Time): Time is a very critical factor for medical intervention.
Differential Diagnosis
Not every sudden weakness is a TIA; there are similar conditions (Mimics) that need to be ruled out:
- Hypoglycemia: Can give symptoms similar to a stroke and disappear once sugar is administered to the patient.
- Seizures: Sometimes after a seizure, there is temporary weakness called Todd's Paralysis.
- Migraine: Migraine headaches may be accompanied by weakness, but it is usually gradual and not as sudden as an ischemic attack.
- Brain Tumors: May press on certain centers and give similar symptoms.
- Syncope: Resulting from problems with blood pressure or heartbeats.
Risk Assessment and ABCD2 Scoring System
After diagnosing the condition as a Transient Ischemic Attack (TIA), the most important question arises: What is the likelihood of a complete stroke occurring in the coming hours or days? To answer this question, we use the ABCD2 scoring system, a global standard that helps doctors decide whether to admit the patient to the hospital or follow up externally.
Components of the Score (Criteria):
- A (Age): Age 60 years or older (1 point).
- B (Blood Pressure): Blood pressure at arrival 140/90 mmHg or higher (1 point).
- C (Clinical Features): Clinical symptoms:
- Weakness on one side of the body (2 points).
- Speech and language disturbance without muscle weakness (1 point).
- D (Duration): Duration of symptom persistence:
- More than 60 minutes (2 points).
- Between 10 to 59 minutes (1 point).
- Less than 10 minutes (0 points).
- D (Diabetes): History of diabetes (1 point).
Interpretation of Results and Decision-Making:
- 0-3 points: Low risk. Tests can be done outside the hospital if rapid facilities are available.
- 4-5 points: Moderate risk. Strongly advised to admit the patient to the hospital.
- 6-7 points: Very high risk. The likelihood of a stroke within the first two days reaches 8%, and the patient should be admitted immediately.
Necessary Tests (Work-up)
The goal of the tests is to search for the "source" of the temporary stroke to prevent its permanent recurrence:
- Blood Tests: Blood sugar, cholesterol and lipids, and clotting functions.
- Electrocardiogram (ECG): To search for atrial fibrillation.
- Cardiac Monitoring (Telemetry/Holter): If the initial ECG is normal, the patient is placed under continuous monitoring for 48 hours in the hospital, or a "Holter" device at home for two to four weeks, as atrial fibrillation may be intermittent and not appear in the instantaneous ECG.
- Carotid Artery Ultrasound: To ensure there is no narrowing in the neck arteries.
- Heart Imaging (Echocardiogram):
- TTE (Transthoracic): Initial external examination.
- TEE (Transesophageal): A more precise examination performed if there is a high suspicion of a clot inside the heart that was not detected in the external examination, especially in young individuals.
- Brain MRI: To ensure there is no small clot, tumors, or abscesses that mimic TIA symptoms.
Treatment and Preventive Protocol
Treatment depends on the test results and the identified cause:
- Antiplatelet Drugs: Such as aspirin or Plavix. If the patient is already taking aspirin and experiences a stroke, we may need to add another medication or change the protocol.
- Blood Thinners (Anticoagulants): Used only if atrial fibrillation or a clot inside the heart is confirmed.
- Cholesterol Medications (Statins): Given in high doses to prevent future clots.
- Control of Risk Factors: Regulating blood pressure, diabetes, quitting smoking, and exercising.
- Surgical Intervention: If severe narrowing (more than 70%) is found in the carotid artery, the patient may require surgery to clean the artery (Endarterectomy) or the placement of a stent.
Conclusion and Important Points
- TIA is a golden opportunity to prevent a stroke that could cause permanent disability.
- The disappearance of symptoms does not mean the end of the problem; it is a warning sign that requires immediate attention to the emergency department.
- Half of the strokes that occur after a TIA happen within the first 48 hours, so speed in evaluation (especially for those with a high score) is key to survival.
- Accurate diagnosis requires cooperation between emergency, neurology, and cardiology doctors to reach the true cause and prevent disaster before it happens.
[The lecture is over]