Read below about thunderclap headache, including causes, treatment options and remedies. Or get a personalized analysis of your thunderclap headache from our A.I. health assistant. At Buoy, we build tools that help you know what’s wrong right now and how to get the right care.

This symptom can also be referred to as:
Lone splitting headache

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Thunderclap Headache Symptoms

A thunderclap headache is a severe headache that occurs abruptly and reaches maximal intensity within one minute of onset. A thunderclap headache is different from other headaches because of the speed with which it develops. While other severe headaches may require evaluation, a thunderclap headache is particularly worrisome as it might be a sign of a serious or impending bleed in the brain. Other causes of thunderclap headache include stroke, serious problems with arteries and veins in the brain, infection in the brain, or very high blood pressure. All thunderclap headaches should be evaluated emergently by a physician and will likely require brain imaging. Once the cause of the headache is determined, your doctor will discuss treatment possibilities which include surgery, medications, and other interventions.

Symptoms that can be associated with thunderclap headaches include:

  • Nausea
  • Vomiting
  • Loss of consciousness
  • Altered consciousness
  • Facial droop
  • Weakness
  • Neck stiffness
  • Neck pain
  • High blood pressure
  • Seizures
  • Fever

Thunderclap Headache Causes Overview

The most concerning cause of thunderclap headache is an aneurysm rupture leading to bleeding in the brain. An aneurysm is a bulge in a blood vessel in the brain due to a weakening in the wall. The bulge can spontaneously rupture and cause bleeding in the brain. A thunderclap headache can also be a warning sign of impending aneurysm rupture. Therefore, a thunderclap headache always requires emergent medical evaluation. Other causes of thunderclap headache include stroke or other problems with arteries or veins in the brain, infection in the brain, or very high blood pressure. All require emergent medical evaluation. Bottom line: if you experience a headache that reaches maximal intensity within 1 minute of onset, seek immediate medical attention.

Bleeding

  • Aneurysm Rupture: An aneurysm is a bulge that forms in a blood vessel in the brain due to a weakening in the wall. The bulge can rupture and cause bleeding in the brain. Most commonly, the vessel bleeds into the subarachnoid space, a compartment in between the brain and the skull. Aneurysms can also bleed into the brain tissue itself. Either of these scenarios can lead to severe thunderclap headache symptoms, and typically involve lost or altered consciousness.
  • Aneurysm Warning Headache: Sometimes, an aneurysm can cause a thunderclap headache days or weeks before it ruptures and causes bleeding. Almost half of patient with bleeding into the subarachnoid space due to aneurysm rupture report a similar warning headache.

Problems with blood vessels in the brain:

  • Arteries in the brain: An ischemic stroke is when a clot forms or travels to an artery in the brain, blocking blood flow to some part of the brain tissue. An ischemic stroke may present with a thunderclap headache, as well as neurologic symptoms such as slurred speech or weakness on one side of the body.
  • Veins in the brain: A blood clot can form in the veins in the head and present with thunderclap headache symptoms, as well as neurologic symptoms such as problems with vision or weakness on one side of the body.
  • Arteries in the neck: The walls of the main artery in the neck can tear, leading to cervical artery dissection. This may present with thunderclap headache as well as one-sided neck pain with or without neurologic symptoms such as blurry vision or facial droop.
  • Arterial Spasm: The narrow arteries in the brain can spasm, temporarily blocking blood flow to parts of the brain and leading to thunderclap headache symptoms. Unlike other problems on the list, this is reversible, and typically patient experience complete symptom resolution followed by headache recurrence. The thunderclap headache may be indistinguishable from that associated with stroke or aneurysm rupture.

Other causes:

  • Infection: Bacterial and viral infections in the brain are typically associated with headaches that have gradual onset but can also present with thunderclap headache. Other symptoms include fever and neck stiffness.
  • High Blood Pressure: Very high blood pressure can cause a variety of symptoms including headache, chest pain, blurry vision, or change in mental status. Typically, the headache associated with high blood pressure is a throbbing headache with gradual onset, but high blood pressure may also present with thunderclap headache.

A.I. Health Assistant Causes for Thunderclap Headache

The list below shows results from the use of our A.I. Health Assistant by Buoy users who experienced thunderclap headache. This list does not constitute medical advice.

  1. 1.Subarachnoid Hemorrhage

    Subarachnoid hemorrhage is bleeding in the area between the brain and the thin tissues that cover the brain. It's typically caused by a ruptured aneurysm (out-pouching of an artery's wall).

    Indefinite

    Rarity:
    Rare
    Top Symptoms:
    new headache, being severely ill, nausea or vomiting, severe headache, vision changes
    Symptoms that always occur with subarachnoid hemorrhage:
    new headache, being severely ill
    Urgency:
    Emergency medical service
  2. 2.Carotid Artery Dissection

    A carotid artery dissection is the tearing of the walls of the carotid arteries, which deliver blood to the brain from the aorta. This is a medical emergency.

    About 10% have recurrence

    Rarity:
    Rare
    Top Symptoms:
    new headache, history of headaches, steady headache, neck pain on one side, headache near one temple
    Urgency:
    Emergency medical service

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  3. 3.Cerebral Venous Thrombosis

    Cavernous sinus thrombosis is a blood clot in an area at the base of the brain that contains a vein, which carries blood from the brain to the heart. This area is called the cavernous sinus.

    Indefinite

    Rarity:
    Ultra rare
    Top Symptoms:
    fatigue, headache, nausea or vomiting, loss of appetite, being severely ill
    Symptoms that always occur with cerebral venous thrombosis:
    being severely ill
    Urgency:
    Emergency medical service
  4. 4.Stroke or Tia (Transient Ischemic Attack)

    A stroke is a medical emergency. Strokes happen when blood flow to the brain is stopped.

    Indefinite

    Rarity:
    Common
    Top Symptoms:
    dizziness, leg numbness, arm numbness, new headache, stiff neck
    Symptoms that never occur with stroke or tia (transient ischemic attack):
    bilateral weakness
    Urgency:
    Emergency medical service
  5. 5.Viral Encephalitis

    Encephalitis is irritation and swelling (inflammation) of the brain, most often due to viral infections. Encephalitis caused by the herpes simplex virus is the leading cause. Several other causes of encephalitis (St. Louis, California, Japanese and Eastern Equine encephalitis infections) are transmitted by bites from an infected mosquito.

    Indefinite

    Rarity:
    Rare
    Top Symptoms:
    fatigue, being severely ill, loss of appetite, new headache, vomiting
    Symptoms that always occur with viral encephalitis:
    being severely ill
    Urgency:
    Hospital emergency room

Thunderclap Headache Treatments and Relief

All thunderclap headaches require emergent medical evaluation. There are no appropriate ways to treat a thunderclap headache at home. The first step in diagnosing and treating a thunderclap headache is obtaining imaging of the brain such as a CT scan. A doctor may also order a spinal tap or other blood tests to help determine the cause of the thunderclap headache. Depending on the cause of the thunderclap headache, surgery may be warranted. Other treatments may include medications and pain control.

All thunderclap headaches warrant emergency treatment. Although some causes of thunderclap headache are less concerning than others, seek emergency treatment to determine the cause of the headache and receive the appropriate intervention.

Medical professional treatments include:

  • Imaging: There are multiple ways to obtain images of the brain, including CT scan, MRI, or MR angiography which looks specifically at the blood vessel in the brain. In most cases of thunderclap headache, doctors will order imaging to help determine the cause of the headache and guide appropriate treatment.
  • Spinal Tap: In some cases, bleeding in the brain may not appear on imaging. If a doctor is particularly concerned for brain bleeding but does not see anything on imaging, he or she may order a spinal tap to look for signs of bleeding. A doctor may also order a spinal tap if he or she is concerned for a brain infection.
  • Surgery: In some instances, aneurysms require surgical intervention. Your doctor will discuss the risks and benefits of surgical repair of an aneurysm or a bleed due to an aneurysm.
  • Endovascular Intervention: Some aneurysms can be repaired by inserting a small metal coil into the blood vessel to block the weakness and prevent the aneurysm from bursting. Some strokes can be reversed by removing the clot from the blocked blood vessel. These procedures are known as endovascular interventions, because they treat the problem by going inside the blood vessel. Your doctor will discuss the risks and benefits of endovascular intervention if it is indicated.
  • Medications: If the headache is determined to be due to an infection or due to high blood pressure, your doctor might prescribe antibiotics or blood pressure lowering medications to treat the condition. If stroke is the cause of the headache, a doctor may prescribe blood thinners to treat the problem.
  • Pain Control: It is important to determine the cause of a thunderclap headache, and not simply treat the pain of the headache. However, once the cause is determined, your doctor may prescribe pain medication to help relieve headache symptoms.

FAQs About Thunderclap Headache

Here are some frequently asked questions about thunderclap headache.

How long do thunderclap headaches last?

A thunderclap headache does not have a defined period during which it lasts. It is a headache that reaches its maximal intensity within one minute of onset, and is rated very highly in severity. A thunderclap headache is a dangerous symptom. If you suspect you are having a thunderclap headache, go to the nearest emergency department.

Why am I nauseous when I have a thunderclap headache?

A thunderclap headache can have multiple causes. The classical explanation is an aneurysm (dilated arterial blood vessel) that is at risk of bursting within the brain. Many of the other causes, however, are just as dangerous, and warrant immediate medical evaluation and care. Nausea is a common symptom of increased pressure within the brain.

Are thunderclap headaches a warning sign of a brain aneurysm?

Yes. They are classically known as "sentinel headaches," or headaches that predict the presence of an unruptured aneurysm within the brain. This is a medical emergency; it should be evaluated for risk of rupture and treatment should begin as soon as possible because a rupture can be life-threatening.

What are the differences between a thunderclap headache and a migraine?

A thunderclap headache reaches maximal intensity within one minute and may affect both sides of the head. A migraine is usually one-sided, gradual in onset, and may be precipitated by changes in vision. A thunderclap headache may disappear quickly or not at all. A migraine is generally helped by silence and darkness. Most people with migraines have had them in the past and can recognize them readily.

What does a thunderclap headache feel like?

A thunderclap headache is commonly referred to as "the worst headache I've ever had in my life," as it is intense and extremely rapid in onset. It can be immediately debilitating, and either constant or it can decrease in intensity. If it does decrease in intensity or disappear, you should still seek immediate medical care.

Thunderclap Headache Symptom Checker Statistics

  • People who have experienced thunderclap headache have also experienced:

    • 16% Headache
    • 8% Headache That Worsens When Head Moves
    • 8% Severe Headache
  • People who have experienced thunderclap headache had symptoms persist for:

    • 53% Less Than a Day
    • 28% Less Than a Week
    • 7% Over a Month
  • People who have experienced thunderclap headache were most often matched with:

    • 33% Subarachnoid Hemorrhage
    • 33% Carotid Artery Dissection
    • 33% Cerebral Venous Thrombosis
  • Source: Aggregated and anonymized results from visits to the Buoy AI health assistant (check it out by clicking on “Take Quiz”).

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