Q. A 32-year-old male marathon runner presents to the emergency department via ambulance following a witnessed seizure. The patient just completed running 42 kilometers (26.2 miles) in approximately 3 hours, and collapsed. He was taken to the medical tent and intravenous access was established by paramedics on the scene. A short time later, he had a witnessed tonic?clonic seizure which lasted for 2 minutes, and resolved after he received 2.5 mg of intravenous midazolam. His serum sodium was assessed by a portable electrolyte analyzer and found to be 98 mmol/L. The patient was given 3 percent hypertonic saline bolus of 100 mL and transported to the emergency department. The rhythm strip in the ambulance was described as normal sinus with no acute changes observed. His vital signs on presentation are a blood pressure of 112/59 mm Hg, heart rate of 71/min, temperature of 37.7 degrees Celsius (100 degrees Fahrenheit), respiratory rate of 17/min, and oxygen saturation of 99 percent on room air. He weighs 65.3 kg (144 lb), is 175 cm (5 ft 9 in) tall, and has a BMI of 21 kg/m2. He is obtunded and not following commands but is able to maintain his airway. His pupils are equal, round, and reactive to light. His cardiorespiratory and abdominal exam are normal, and he does not have any edema. A second 100 ml bolus of 3 percent hypertonic saline is given in the emergency department. You order an electrocardiogram (EKG) and a metabolic panel. Laboratory Results: Sodium 110 mmol/L Potassium 3.5 mmol/L Chloride 100 mmol/L Bicarbonate 28 mmol/L Urea nitrogen 6.8 mmol/L Creatinine 1.4 mg/dL Glucose 65 mg/dL Based on this patient’s history and physical examination, and laboratory results, what is the most likely complication to occur?