Review Question - QID 214493

A 24-year-old woman presents to the emergency department altered. She was at a night club with her friends when they noticed her somnolent in the corner of the club. They had left her alone as she was conversing with a new acquaintance. Her temperature is 98.1°F (36.7°C), blood pressure is 102/63 mmHg, pulse is 53/min, respirations are 9/min, and oxygen saturation is 95% on room air. Physical exam is notable for a somnolent woman who becomes quite agitated when sternal rub is performed. She has bilateral pinpoint pupils which are responsive to light. She is moving all extremities. An ECG is performed as seen in Figure A. Laboratory studies are ordered as seen below.

Serum:
Na+: 139 mEq/L
Cl-: 102 mEq/L
HCO3-: 25 mEq/L
BUN: 20 mg/dL
Glucose: 58 mg/dL
Creatinine: 1.1 mg/dL
Ca2+: 8.8 mg/dL
AST: 22 U/L
ALT: 30 U/L
Creatine kinase: 1,290 U/L

The patient is observed, and roughly 8 hours later she is back to her baseline. Which of the following is the mechanism of the etiology of this patient’s symptoms?