Thunderclap headaches live up to their name, grabbing your attention like a clap of thunder. The pain of these sudden, severe headaches peaks within 60 seconds and can start fading after an hour. Some thunderclap headaches, however, can last for more than a week.

Thunderclap headaches are often a warning sign of potentially life-threatening conditions, usually linked to bleeding in and around the brain. That's why it's so important to seek emergency medical attention if you experience a thunderclap headache.

Some people may also experience thunderclap headaches as part of a potentially recurring headache disorder, known as primary thunderclap headache. But this diagnosis should only be made after a thorough medical evaluation and elimination of other possible underlying causes.


Thunderclap headaches are dramatic. Symptoms include pain that:

  • Strikes suddenly and severely — sometimes described as the worst headache ever experienced
  • Peaks within 60 seconds
  • Lasts anywhere between an hour and 10 days
  • Can occur anywhere in the head, and may involve the neck or lower back
  • Can be accompanied by nausea, vomiting or loss of consciousness

When to see a doctor

Seek immediate medical attention for any headache that comes on suddenly and severely.


Some thunderclap headaches appear as a result of no obvious physical reason.

In other cases, potentially life-threatening conditions may be responsible, including:

  • Bleeding between the brain and membranes covering the brain, often due to an abnormal bulge or ballooning in a blood vessel (aneurysm)
  • A rupture of a blood vessel in the brain
  • A tear in the lining of an artery (for example, carotid or vertebral artery) that supplies blood to the brain
  • Leaking of cerebrospinal fluid, which when present is usually due to a tear of the covering around a nerve root in the spine
  • A tumor in the third ventricle of the brain that blocks the flow of cerebrospinal fluid
  • Loss of blood supply to or bleeding in the pituitary gland
  • A blood clot in the brain
  • Severe elevation in blood pressure
  • Infection such as meningitis or encephalitis
March 25, 2015
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