mrcem2-1210

mrcem2-1210

A 45-year-old woman presents with a severe headache that has been ongoing for the past 3 hours. She describes it as the ‘most intense headache she has ever experienced’. She also complains of sensitivity to light and stiffness in her neck. There is no history of any head injury. Initially, she was treated conservatively and her symptoms improved. However, on the third day, she had a seizure and lost the ability to move her left arm. Physical examination reveals weakness in the left arm but normal sensation. A CT scan of her head shows a localized area of decreased density in the right frontal lobe, with a loss of distinction between grey and white matter and surrounding swelling.

What is the most likely cause of her current condition?