MRCP2-0793

MRCP2-0793

Lena is a 23-year-old woman who has been brought to the emergency department by her roommate after being found collapsed on the floor surrounded by unmarked bottles. Lena has a history of depression and had been arguing with her boyfriend earlier in the day. Her friend was concerned for her safety and brought her to the hospital. Lena is unsure of what was in the bottles she was found with.

Upon arrival at the emergency department, Lena was disoriented and unable to recall why she was there. She began experiencing nausea and vomiting, and after an hour, she became extremely drowsy and unresponsive.

Physical examination did not reveal any significant findings, and her skin color was normal. There was no tenderness in her abdomen, but her respiratory rate was elevated at 30 breaths per minute.

Blood tests showed a hemoglobin level of 140 g/L, platelet count of 250 * 109/L, and a white blood cell count of 7.0 * 109/L. Her electrolyte levels were within normal limits, but her bicarbonate level was low at 12 mmol/L. Her measured osmolarity was elevated at 350 mOsm/kg. Liver function tests were normal.

Arterial blood gases showed a pH of 7.27, pO2 of 13.7 kPa, pCO2 of 3.2 kPa, and an HCO3 level of 12.

An ECG showed sinus tachycardia with no abnormalities in the QRS complex.

What substance is likely responsible for Lena’s symptoms?