Thunderclap headaches live up to their name, grabbing your attention like a boom of thunder. The pain of these sudden, severe headaches peaks within 60 seconds and usually fades over several hours. Some of these headaches, however, can last for more than a week.

Thunderclap headaches are uncommon, but they can be a warning sign of potentially life-threatening conditions — usually having to do with bleeding in and around the brain. That's why it's so important to seek emergency medical attention if you experience a thunderclap headache.

Thunderclap headaches are dramatic. The pain strikes suddenly and severely. Some people describe the pain as the worst headache they've ever experienced. The pain peaks within 60 seconds and usually lasts several hours — although some thunderclap headaches may linger for up to 10 days.

Some thunderclap headaches appear for no obvious physical reason. In other cases, potentially life-threatening conditions may be responsible, including:

• Bleeding between the brain and membranes covering the brain
• A bulge in a blood vessel in the brain, which may rupture
• A tear in the lining of an artery that supplies blood to the brain
• A tear in the membrane that surrounds the brain and spinal cord, leading to a leak of cerebrospinal fluid
• A cyst that blocks the flow of cerebrospinal fluid
• Death of tissue or bleeding in the pituitary gland
• Infection, such as meningitis or encephalitis

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

The following tests are commonly employed to determine if any underlying condition is causing thunderclap headaches.

CT scan
Diagnosis often starts with a CT scan of the head to search for an underlying cause for the headache. CT scans use an X-ray unit that rotates around your body and a computer to create cross-sectional images (like slices) of your brain and head.

Spinal tap
Sometimes a spinal tap (lumbar puncture) is needed as well. With this procedure, the doctor removes a small amount of the fluid that surrounds your brain and spinal cord. The cerebrospinal fluid sample can be tested for protein, white blood cells and other substances.

MRI
In some cases, magnetic resonance imaging (MRI) may be done for further assessment. With this imaging study, a magnetic field and radio waves are used to create cross-sectional images of the structures within your brain.

Angiography
To obtain a picture of the blood vessels inside your head, your doctor may have you undergo a magnetic resonance angiogram or a CT angiogram, in which contrast material is injected intravenously during an MRI or CT scan.

There's no single treatment for thunderclap headaches. Treatment is aimed at the underlying problem causing the headaches — if one is found. If no identifiable cause can be found and you have recurring thunderclap headaches, your doctor may suggest preventive medicine to be taken on a daily basis. With or without treatment, thunderclap headaches usually stop happening within a few days or weeks.