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