Diabetes mellitus Quiz: Ace Your Exams

A 78-year-old man is brought to the emergency department by his daughter due to persistent confusion at home. Over the past several days, the patient has appeared more sleepy and is harder to arouse. He has also experienced urinary incontinence more frequently, and he moans when his abdomen is palpated. His daughter had to call an ambulance to bring him to the hospital because he was too weak to stand on his own. The patient has a history of Alzheimer dementia, type 2 diabetes, and heart failure with reduced ejection fraction. Medications include aspirin, insulin glargine, lisinopril, metoprolol, atorvastatin, and metformin. His temperature is 38.0°C (100.4°F), pulse is 115/min, respirations are 18/min, and blood pressure is 95/60 mmHg. Physical examination shows an ill-appearing, lethargic man with dry mucous membranes and an absent jugular venous pulsation. The abdomen is mildly tender just proximal to the pubic symphysis. Laboratory studies show the following:  
 

Laboratory value	Result
Hemoglobin	12 g/dL
Hematocrit	36 %
Leukocyte count	14,000/mm3
Platelet count	400,000/mm3
Sodium	127 mEq/L
Potassium	4.5 mEq/L
Chloride	100 mEq/L
Bicarbonate	20 mEq/L
Blood urea nitrogen	45 mg/dL
Creatinine	3.0 mg/dL
Glucose	800 mg/dL
Serum osmolality	340 mOsm/kg

Which of the following processes is most likely contributing to this patient’s acute illness?