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Symptoms of a Brain Aneurysm

Medical Author: Benjamin Wedro, MD, FACEP, FAAEM
Medical Editor: Charles Patrick Davis, MD, PhD

What Are Brain Aneurysm Symptoms?

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 patient complaining of "the worst headache of their life" likely has a subarachnoid hemorrhage due to a leaking brain aneurysm and action needs to be taken immediately. Even with improved technology, the diagnosis of a brain aneurysm hasn't changed much in a generation. However, not all patients with headaches need a CT scan and/or a lumbar puncture. Unfortunately, the worst headache term is sometimes exaggerated by patients 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.
  • An 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 is very irritating when it leaks into the brain and it causes an intense headache.
  • Blood leaking 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 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 medical care.
  • Second, the physician needs to recognize the situation as more than just a bad headache. This is when physician angst happens.

Most people will suffer from a significant headache in their lifetime, but how many need to be aggressively evaluated for a possible brain aneurysm? Patients who have leaking blood that irritates brain appear markedly ill.

  • They lie very still, avoid light, and may complain of significant nausea and vomiting. In this regard they act similar to patients with migraine headaches.
  • 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. Symptoms more closely resemble meningitis.

Diagnosis of a Brain Aneurysm

For a patient with a potential leaking brain aneurysm, a CT scan of the head is the first step.

  • If blood is present in the brain, the diagnosis is confirmed. The next step is to get the neurosurgeons and interventional radiologists involved to figure out where the blood vessel damage is and how to prevent further bleeding.
  • Up to 5% of patients who have subarachnoid hemorrhages from brain aneurysms can have a normal CT scan. The next step is usually a lumbar puncture where a needle is placed into the lower back to retrieve cerebrospinal fluid and determine if blood is present. If the cerebrospinal fluid appears normal, there is very little risk of a brain aneurysm. There is some controversy about performing a lumbar puncture after a negative CT scan.

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