June 2021 Quiz

A 78-year-old patient is brought to the ED for evaluation and management of increasing confusion and lethargy. The patient started treatment with levofloxacin for community-acquired pneumonia 5 days ago. Fever and respiratory symptoms improved, but the patient developed large-volume diarrhea with poor oral intake over the past several days. Medical history includes hypertension, type 2 diabetes, chronic atrial fibrillation, nephrolithiasis, and hypothyroidism. Outpatient medications are hydrochlorothiazide, metopolol, lisinopril, metformin, and levothyroxine. After 2 L of crystalloid in the ED, the patient developed a seizure, which rapidly responded to lorazepam. On arrival to the ICU, the patient is lethargic and disoriented. Temperature is 37.8°C; BP, 103/60 mm Hg; pulse 108/min; and respirations, 16/min. Mucous membranes are dry, and cardiac exam demonstrates an irregularly irregular rhythm. Left lung coarse crackles are present. There is no peripheral edema. WBC count is 13,100/μL (13.1 x 109/L) and hemoglobin 10.2 g/dL (102 g/L). Other admission laboratory values are displayed below (Figure 1). Urinalysis shows a specific gravity 1.023, pH 7.4, and hyaline casts only on microscopic exam. CT head is normal, and chest radiograph demonstrates a left lower lobe infiltrate with ipsilateral hilar prominence.