Thunderclap Headaches


What is a thunderclap headache?

A thunderclap headache is an extremely painful headache that comes on suddenly, like a clap of thunder. This type of headache reaches its most intense pain within 1 minute and lasts at least 5 minutes.

Thunderclap headaches strike without any warning. Some of these headaches are benign (not dangerous). But they can also be a sign of very serious underlying conditions that involve bleeding in and around the brain.

It is important to seek medical attention immediately to rule out life-threatening causes of a thunderclap headache.

How common is a thunderclap headache?

Thunderclap headaches are rare. They occur in less than 50 out of 100,000 adults each year.

Symptoms and Causes

What causes a thunderclap headache?

Some thunderclap headaches have no known cause and are not dangerous. Others occur because of a problem with the blood vessels in the brain or due to injury or heavy exertion. Causes of thunderclap headaches include:

  • Torn or ruptured blood vessels in the brain
  • Stroke (blocked or bleeding blood vessel)
  • Brain aneurysm (bulging or bleeding blood vessel)
  • Head injury that causes a brain bleed
  • Vasculitis (swollen blood vessel)
  • Infection in the brain such as encephalitis or meningitis
  • Sudden severe rise in blood pressure
  • Late-term pregnancy complications including rise in blood pressure and bleeding in the brain’s pituitary gland during pregnancy or soon after delivery
  • Spasms in the blood vessels around the brain (vasoconstriction syndrome)

What are the symptoms of a thunderclap headache?

The main symptom of a thunderclap headache is sudden and severe pain in the head. This pain reaches its most intense point within 60 seconds and lasts at least 5 minutes. Other symptoms may include:

  • Numbness
  • Weakness
  • Speech problems
  • Nausea and/or vomiting
  • Seizures
  • Change in vision
  • Confusion
  • Change in sensation

Diagnosis and Tests

How is a thunderclap headache diagnosed?

Doctors usually diagnose thunderclap headaches with an imaging test called a CT-Angiogram scan. This test shows a doctor the blood vessels in and around the brain to see what is causing the pain.

Sometimes doctors take a sample of spinal fluid from the back in a test called a spinal tap. This test enables doctors to see if there is blood in the spinal fluid to help determine the cause of the headache.

Magnetic resonance imaging (MRI), another type of imaging test, may be ordered if the CT and spinal fluid are normal.

Management and Treatment

How is a thunderclap headache managed or treated?

Treatment for thunderclap headaches depends on the cause. If a thunderclap headache is not associated with an urgent underlying condition, your doctor may treat it with medication. A non-steroidal anti-inflammatory (NSAID) medicine can help reduce swelling. Other drugs can manage blood pressure. If the thunderclap headache is caused by spasms in the brain’s blood vessels, IV or oral nimodipine (Nimotop®, Nymalize®) may be given.

Some thunderclap headaches require surgery to repair torn or ruptured blood vessels or remove a blockage. Your doctor will determine the best treatment option based on the cause of the headache.


Can thunderclap headaches be prevented?

Because they come on without warning, it is difficult to prevent thunderclap headaches. Managing underlying health conditions and avoiding triggers are the best ways to keep them from occurring. If you have high blood pressure or vascular problems, it is important to work with your doctor to follow a regular treatment plan.

Maintaining a healthy diet and active lifestyle helps keep blood pressure from rising to levels that could cause a condition involving a thunderclap headache. In addition, quitting smoking and controlling cholesterol levels can help reduce the risk of blood vessel problems.

What are the risk factors for a thunderclap headache?

People with certain inherited (passed down in a family) conditions such as weak blood vessels or a tendency to develop blood clots have a higher risk of thunderclap headaches.

Some people with high blood pressure may be more likely to experience thunderclap headaches. These people may be at higher risk of having a blood vessel rupture in the brain.

For some people, activities such as heavy exertion and sexual activity can trigger thunderclap headaches. Once you identify these triggers, avoiding them can help reduce the number of headaches you experience. Your doctor can provide treatment options, including medications, to reduce your likelihood of repeated thunderclap headaches.

Outlook / Prognosis

What is the prognosis (outlook) for people with a thunderclap headache?

The prognosis for a thunderclap headache depends on the specific cause. Doctors can often successfully manage and treat these headaches when they are diagnosed promptly.

Some people experience ongoing thunderclap headaches throughout their lives. These headaches are usually not associated with an underlying condition. People can often manage them with medication.

Living With

When should I call the doctor or seek emergency care?

Go to the emergency room if you are experiencing a thunderclap headache for the first time. It is urgent to determine if a dangerous condition is the underlying cause so it can be treated quickly if necessary. Some conditions associated with a thunderclap headache can be fatal without prompt treatment.

What questions should I ask my doctor?

Some questions you may want to ask your doctor about thunderclap headaches include:

  • What is causing my headache?
  • What are my options for treatment?
  • How long will it take for treatment to work?
  • What are the risks and side effects of treatment?
  • How can I prevent future thunderclap headaches?

When can I go back to my regular activities?

If a thunderclap headache isn’t caused by a serious underlying condition, people typically resume their usual activity as soon as the headache passes. The lengths of these headaches vary, but medications often provide relief within hours.

Recovery times vary for people when an underlying condition causes a thunderclap headache. People who need brain surgery may require several weeks or even months of recovery before they return to normal activities.

Last reviewed by a Cleveland Clinic medical professional on 08/16/2018.


  • American Headache Society. Thunderclap headaches. ( Accessed 11/18/2021.
  • American Migraine Foundation. Thunderclap headaches. ( Accessed 11/18/2021.
  • U.S. National Library of Medicine. Focus on the management of thunderclap headache: from nosography to treatment. ( Accessed 11/18/2021.

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