A 61-year-old man with a history of EtOH dependence, recurrent C. diff colitis, and a recent left humeral fracture presents to the ED complaining of nausea, non-bloody emesis, and diffuse abdominal pain. The patient is intoxicated on arrival. He is unable to give a reliable history of ingesting moonshine, antifreeze or other medications such as metformin. His initial blood glucose was 40 mg per deciliter and a dose of glucagon and oral glucose were administered by EMS. In the ED, the patient’s blood pressure was 108/39 mmHg. He was afebrile and non-tachycardic. His respiratory rate was 31. His weight was 158 kg (approx. 350 lbs). The patient was oriented to person, but not place or date. Initial laboratory data included: Na 142 mmol/L, K 3.5 mmol/L, Cl 103 mmol/L, HCO3 2 mmol/L, BUN 48 mg/dL, Cr 4 mg/dL (baseline 1.3 mg/dL 2 months prior), glucose 124 mg/dL, Ca 7.8 mg/dL and albumin 3 g/dL. An ABG showed pH 6.8/PCO2 18/PO2 109.
Thoughts regarding the differential diagnosis?