1st April 2022

A 43-year-old man presents to A&E with a sudden onset headache

A 43-year-old man presents to A&E with a sudden onset headache. He describes a 10/10 pain which “hit me like a truck” about 4 hours ago, whilst he was at the gym. He has vomited several times since it began. He has no history of headache disorder. He is tachycardic at 110bpm, and his blood pressure is raised to 182/101 mmHg on assessment. His observations are otherwise normal, and routine blood tests show no abnormalities. A subarachnoid haematoma is suspected – initial CT head shows no bleeding, and so the patient is admitted for a lumbar puncture. 

What CSF finding would confirm subarachnoid haematoma?

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