A 42-year-old woman presents to emergency complaining of a severe global headache. Temperature is 100 F. Her neck is stiff. She has history hypertension managed with hydrochlorothiazide. Neurologic examination shows an enlarged right pupil. She was recently diagnosed and treated for herpes labialis. A CT of the head is shown.
Which of the following is the most likely explanation for this patient’s findings?
Anterior communicating artery aneurysm
Encephalitis
Meningitis
Pituitary apoplexy
Posterior communicating artery aneurysm