A patient develops slurred speech, blurry vision, and blood pressure of 200/90 mmHg during dental treatment. What is the most likely diagnosis?

The combination of severely elevated blood pressure (200/90 mmHg), slurred speech (dysarthria), and visual disturbance (blurry vision) are classic warning signs of a cerebrovascular accident (CVA/stroke). Hypertensive crises can cause ischemic or hemorrhagic stroke. Anaphylaxis typically presents with hypotension, urticaria, and bronchospasm. Vasovagal reactions cause hypotension and bradycardia. Seizures may cause altered consciousness but not typically slurred speech with hypertension. Immediate emergency medical services (EMS) activation is required for suspected CVA.