A patient presents with an intense retro-orbital headache and elevated blood pressure. What is the most appropriate next step in management?

In the scenario described, the patient exhibits symptoms of an intense retro-orbital headache coupled with elevated blood pressure. These symptoms could indicate elevated intracranial pressure or possibly a serious condition such as a subarachnoid hemorrhage or intracranial mass.

The most appropriate next step in management, in this case, is a lumbar puncture. Performing a lumbar puncture allows for the analysis of cerebrospinal fluid (CSF), which can help determine if there is bleeding (such as blood in the CSF could suggest a hemorrhagic stroke) or any signs of infection (like meningitis) that might explain the patient's symptoms.

This procedure not only aids in diagnosis but can also be therapeutic in certain scenarios, alleviating pressure created by excessive CSF. It is important to note that a lumbar puncture is contraindicated in cases of increased intracranial pressure due to risks of herniation; however, if there is a reasonable suspicion of something urgent like a hemorrhage, imaging would typically be performed first to rule out such risks.

In summary, following the presentation of intense headache and hypertension, a lumbar puncture becomes the pivotal step to evaluate the underlying cause of these symptoms.