There are some patient complaints that cause a fair amount of angst for physicians, because certain words conjure up fear of missing a potentially fatal diagnosis that might be curable if found early. It has been drilled into most medical students that a person complaining of "the worst headache of their life" likely has a subarachnoid hemorrhage due to a brain aneurysm - that is, the sudden rupture of a malformation of a brain artery - and action needs to be taken immediately. Even with improved technology, the diagnosis of a brain aneurysm rupture hasn't changed much in a generation. However, not all people with headaches need an MRI, CT scan and/or a lumbar puncture. Unfortunately, people sometimes exaggerate "the worst headache of your life, and the art of medicine is appreciating the severity of a patient's pain and deciding how aggressive to be in trying to make the diagnosis. Brain aneurysms are common and it is estimated that up to 1% of people have them. A brain aneurysm causes no problem unless it leaks blood into brain tissue or into the subarachnoid space, the area that bathes the brain and spinal cord with nutrient rich cerebrospinal fluid (CSF). Blood from a ruptured aneurysm is very irritating when it leaks into the brain and it causes an intense headache. Blood leaking from a ruptured aneurysm into the cerebrospinal fluid causes inflammation of the meninges, the membranes that surround the brain, resulting in a stiff and painful neck. Before a disastrous bleed occurs from a ruptured aneurysm, a patient will often develop an intense sentinel, or "warning," headache due to a tiny leak in the brain. In the time between the initial small leak and the large bleed there is an opportunity to make a difference in a patient's life. If a sentinel bleed occurs, two things need to happen: First, the patient needs to seek treatment from a doctor. Second, the doctor needs to recognize the situation as more than just a bad headache. This is when doctor angst happens. Most people will suffer from a significant headache in their lifetime, but how many need aggressive clinical evaluation, treatment, or even surgery for a possible brain aneurysm? Patients who have leaking blood that irritates brain appear in markedly ill health. They lie very still, avoid light, and may complain of significant nausea and vomiting. In this regard they act similar to patients with a migraine headache condition. Blood in the cerebrospinal fluid causes inflammation and patients complain of a stiff neck and won't voluntarily flex their neck. The pain does not mimic that of a pulled neck muscle. The stiff neck more closely resembles a sign of the condition meningitis.