The timing and nature of a headache can be a vital clue to intracranial bleeding.br br Neurosurgeon Dr Moventhiran Ramakrishnan said in cases of hypertensive bleeds, the headache often appears suddenly - you could be having breakfast, feeling fine and within minutes be struck with a headache and weakness.br br But with an aneurysm rupture, there’s a unique warning sign - a headache that appears one to two weeks before the major event, in someone who’s never had migraines before. This is called a sentinel hemorrhage - a small leak that irritates the brain, quietly sounding the alarm.br br When the full rupture happens, it triggers what patients describe as a thunderclap headache - the worst headache they’ve ever experienced.br br Watch now to understand the signs your brain may be sending.