Case 345

History A 64-year-old man was brought to the emergency department after being found unresponsive at home, with family reporting progressive confusion following heavy alcohol intake the previous day. On arrival, he was nonverbal and unresponsive to stimuli. Vital signs showed a normal heart rate and blood pressure, with oxygen saturation measured at 80%. Arterial blood gas analysis revealed a pH of 6.86 (reference range, 7.35–7.45), bicarbonate level of 5.4 mmol/L (reference range, 20–28 mmol/L), and anion gap of 28 mmol/L (reference range, 4–12 mmol/L). Lactate level was elevated, at 7.8 mmol/L (reference range, 1–2 mmol/L). Creatinine level was 1.45 mg/dL (128 µmol/L) (reference range, 0.7–1.3 mg/dL [62–115 µmol/L]). Blood glucose level was 282 mg/dL (15.7 mmol/L) (reference range, 70–99 mg/dL [3.9–5.5 mmol/L]), and white blood cell count was 18.8 × 10 9 /L (reference range, 4.5 × 10 9 /L to 11 × 10 9 /L). Liver function test results were within normal limits. Results of initial noncontrast head CT and CT angiography of the head performed at an outside institution were interpreted as normal. Brain MRI was performed without intravenous contrast material approximately 8 hours after initial presentation. Brain MRI included axial diffusion-weighted imaging ( Figs 1 – 3 ), T2-weighted fluid-attenuated inversion recovery (FLAIR) imaging ( Fig 4 ), and susceptibility-weighted imaging ( Fig 5 ).