A 64-year-old woman is brought to the emergency department due | Uworld | Step 2ck

A 64-year-old woman is brought to the emergency department due to sudden-onset headache associated with nausea, vomiting, and a sensation that the "room is spinning." The patient first noticed the symptoms yesterday when she awoke, and they have not improved. She has had no ear pain, hearing loss, fever, or chills. She was recently prescribed hydrochlorothiazide and lisinopril for hypertension. Medical history also includes type 2 diabetes mellitus and hyperlipidemia. The patient does not use tobacco or alcohol. Blood pressure is 124/76 mm Hg and pulse is 86/min. Neurologic examination with the patient lying still shows pure rotatory nystagmus but no extremity weakness or sensory loss. Walking causes worsening of symptoms, and the patient falls toward the left side. Finger-stick glucose is 145 mg/dl. Complete blood count and serum electrolytes are within normal limits.