A 30-year-old female was hospitalized after she experienced convulsions. On examination, she was alert and oriented and complained of a fever, headache, and stiff neck. Which of the following is most likely to provide rapid identification of the cause of her symptoms?
1) Gram stain of cerebrospinal fluid
2) Gram stain of throat culture
3) Biopsy of brain tissue
4) Check serum antibodies
5) None of the above; it canʹt be diagnosed