CASE 5

A 38-year-old man with altered mental status is brought to the emergency department (ED) by ambulance. The patient had been found sprawled on the stoop of an apartment building when residents called the police. The patient was unresponsive when the paramedics arrived, and they were unable to obtain any additional history from the patient or from any of the onlookers at the scene. The patient was wrapped in blankets and an intravenous (IV) line was inserted, which provided 0.5 L of normal saline during transit to the ED. When the patient was found, the temperature outside was about 35°F (1.7°C), with winds reaching speeds of 10-15 miles per hour (16.1-24.1 kilometers per hour).

On his arrival to the ED, the patient's vital signs are a blood pressure of 88/40 mm Hg, heart rate of 38 bpm, and a respiratory rate of 24 breaths/min. An oral thermometer reading is unsuccessful, but a rectal probe records a temperature of 85.4°F (29.7°C). Repeated attempts to obtain an oxygen saturation measurement via a finger pulse oximeter are not successful. On initial examination, the patient appears to be a homeless, disheveled man with the faint smell of alcohol on his breath. His clothing is stained and extensively worn. He looks older than the stated age on his identification card. In the ED, he is mildly arousable and has trouble following simple commands. He has intact gag and corneal reflexes and does not fight the examiner during the tests. He responds appropriately to painful stimuli. His pupils are equal, round, and reactive to light. No obvious signs of head trauma are noted, and his oropharynx, nares, and ears are unremarkable. His cardiac examination is notable for marked bradycardia of 45 bpm, but no murmurs, rubs, gallops, or extra heart sounds are otherwise noted. A lung examination reveals rhonchi and dullness to percussion in the right lower lung field, but otherwise normal lung sounds. His abdomen is soft, nontender, and nondistended, and normal bowel sounds are heard. The patient's skin is cold and his fingers and toes have a bluish tinge, with a delayed capillary refill time. A brief skin survey reveals some minor abrasions, but no major wounds or erosions. The patient is unable to provide any additional information about his past medical, family, medication, social, or allergy history. His pockets contain an identification card, but no other useful information.

Routine blood work is ordered. The results of his metabolic panel are all within normal limits. His blood glucose level is 104 mg/dL (5.77 mmol/L). His complete blood cell count (CBC) reveals a small elevation in the white blood cell (WBC) count, but it is otherwise unremarkable. A portable chest radiograph shows a small consolidation of the right lower lobe that is consistent with pneumonia.

An electrocardiogram (ECG) is performed