16th August 2024

A 28-year-old female is brought to hospital by her family as an urgent referral by the GP

A 28-year-old female is brought to hospital by her family as an urgent referral by the GP. They report that she has become acutely disturbed in her behaviour in the preceding 24 hours and has stopped sleeping. She had previously been well but complained of headache and fever in the previous week, which progressed to sleeplessness.

On review, she is extremely agitated and clearly responding to unseen stimuli within the room. Her speech is nonsensical. Abdominal examination reveals fullness in the pelvis.

The cardiac monitor demonstrates sinus tachycardia, interspersed with periods of bradycardia without compromise of blood pressure or neurological state. She is febrile at 38.2℃.

Which is the single most specific investigation to isolate the causative diagnosis?

Select the SINGLE most appropriate option from the list below. Select ONE option only.