Aside from publishing ground-breaking insights into the mechanisms of neurological disease, JNNP also publishes many manuscripts that focus on common hard-to-manage clinical problems, things that neurologists come across on a daily basis. In this issue of JNNP, there is a very interesting paper from Bakker and colleagues http://jnnp.bmj.com/content/85/8/885.abstract that concerns one of the most feared neurological disorders, namely subarachnoid haemorrhage (SAH). This condition is due to rupture of a cerebral aneurysm and the condition is commonly fatal. Many of you would have heard about patients who have had emergency surgery for this condition and survived and possibly of others who died despite treatment or in whom the diagnosis was missed.

In my current cohort of final year medical students, all were able to provide clear descriptions of how SAH presents and how you diagnose and treat this condition, which is reassuring. There does however remain one area of contention. If someone has a CT scan of the brain which does not show any evidence of acute bleeding but has evidence of ‘old blood’ in their spinal fluid (obtained by lumbar puncture), how far do you go looking for an aneurysm?

In this paper, Bakker et al have addressed this very issue . Patients who were CT negative but lumbar puncture positive, were put through a rigorous set of additional tests. This included a CT angiogram and in patients who were CT angio negative, a follow-up formal cerebral angiogram. The key finding was that >40% of patients who were investigated in this way had evidence of an aneurysm. This is a very significant proportion and it demonstrates the lengths to which one needs to go to detect these abnormalities. Overall, patients in this study had a favourable outcome, which underscores the benefits of intense investigations in this potentially fatal condition.