Review Question - QID 215168

A 37-year-old man presents to the emergency department with agitation and palpitations. His mother brought him in when she thought he was behaving bizarrely. The patient states he feels fine and does not need help from anyone. His past medical history is significant for depression, multiple suicide attempts, hypertension, obesity, severe asthma, and polysubstance abuse. He is unsure about which medications he takes. His temperature is 101°F (38.3°C), blood pressure is 82/68 mmHg, pulse is 177/min, respirations are 24/min, and oxygen saturation is 99% on room air. Physical exam reveals an agitated man. The patient’s neurological exam reveals symmetric strength and sensation throughout with intact cranial nerves. His abdomen is non-tender, and his breath sounds are clear bilaterally. His pupils are 3 mm, symmetric, and reactive to light. He demonstrates a bilateral tremor in his upper extremities. Laboratory studies are ordered as seen below.

Serum:
Na+: 139 mEq/L
Cl-: 100 mEq/L
K+: 3.0 mEq/L
HCO3-: 15 mEq/L
Blood urea nitrogen (BUN): 20 mg/dL
Glucose: 299 mg/dL
Creatinine: 1.1 mg/dL
Ca2+: 10.2 mg/dL

The patient begins vomiting in the emergency department and subsequently demonstrates seizure activity. Which of the following is the most likely etiology of this patient’s symptoms?