What are the other Names for this Condition? (Also known as/Synonyms)

• TCH (Thunderclap Headache)

What is Thunderclap Headache? (Definition/Background Information)

• A Thunderclap Headache (TCH) is defined as a sudden-onset powerful headache that is extremely painful and lasting a minimum period of 5 minutes; the pain intensity shoots to a maximum within a minute
• It is important to note that Thunderclap Headaches have to be immediately addressed as a medical emergency, since they may forebode certain life-threatening conditions such as a ruptured aneurysm or brain stroke
• Thunderclap Headaches are generally uncommon. Based on the underlying cause, these are classified as primary or secondary:
  • Primary TCH is not associated with an identified cause; it is observed in nearly 75% of the cases
  • Secondary TCH is associated with a variety of conditions including subarachnoid hemorrhage (most common cause), artery dissection, brain strokes, and head injury
• Apart from the sharp and painful headaches, some individuals also present nausea, vomiting, dizziness, and altered vision and mental status. A diagnosis of Thunderclap Headaches may involve a host of radiological studies including computed tomography and magnetic resonance imaging scans
• The treatment of Thunderclap Headaches is mostly symptomatic, in case of Primary TCH. Promptly addressing and managing the underlying condition causing Secondary TCH can help alleviate the headaches in others
• The prognosis of the condition depends on the type of Thunderclap Headache, whether primary or secondary. With adequate treatment, the prognosis of Primary TCH is generally good. The prognosis of Secondary TCH is based on the severity and type of the underlying condition causing it

Who gets Thunderclap Headache? (Age and Sex Distribution)

• Thunderclap Headaches are rare, but may be observed in individuals of any age
• According to some reports, the incidence of the condition is reportedly 430 cases per a million population each year
• Both males and females are affected
• Individuals of all racial and ethnic groups may be affected, and no preference is noted

What are the Risk Factors for Thunderclap Headache? (Predisposing Factors)

No risk factors are clearly established for Primary Thunderclap Headache. The risk factors for Secondary Thunderclap Headache may include a host of factors such as:

• Brain aneurysms
• Brain stroke (ischemic or hemorrhagic); 1 in 4 stroke patients present headaches, although TCH is rare among them
• Cerebral venous sinus thrombosis; another common condition resulting in TCH
• Cervical artery dissection; it is also associated commonly with TCH
• Colloid cyst of the third ventricle
• Head injury
• Hydrocephalus
• Hypertensive crisis, or a severe increase in blood pressure
• Hypertensive encephalopathy
• Infections affecting the brain including meningitis and encephalitis
• Pituitary gland impairment (due to infarction or hemorrhage)
• Pregnancy complications, especially around childbirth
• Retroclival hematoma, or localized bleeding in the skull that may be due to injury or spontaneous occasionally
• Reversible cerebral vasoconstriction syndrome
• Sinusitis
• Spontaneous intracranial hypotension, when fluid pressure inside the skull is lower than normally observed
• Subarachnoid hemorrhage; these account for anywhere between 10% to 25% of all Thunderclap Headaches
• Swollen blood vessel in the brain

The following factors are known to trigger Thunderclap Headaches in some individuals (some may have a history of migraines):

• Use of certain illegal drugs
• Severe physical stress due to hard labor
• Sexual activity
• Sudden exposure to hot or cold water, especially while taking a bath or diving into water
• Trauma to the head

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Thunderclap Headache? (Etiology)

The exact cause of Thunderclap Headache (TCH) is not clearly known. It seems to develop spontaneously and suddenly, like the “clap of a thunder” and can involve the head, neck, and even the upper back region.

• If TCH is not associated with a known condition, it is termed Primary TCH. These account for about three-fourths of all Thunderclap Headache cases. Primary TCHs are also called idiopathic TCHs, non-specific headaches, or uncertain headache disorders. A history of migraine headaches may precede TCH in some individuals
• Secondary TCH is often the result of an underlying condition and account for the remaining one-fourth of the cases. The most common among these conditions causing Secondary TCH include subarachnoid hemorrhage, followed by cerebral venous thrombosis (CVT) and carotid/vertebral artery dissection
• Some other conditions potentially causing Secondary TCH include trauma to the head, ruptured blood vessels in the brain, a bulging blood vessel in the brain (aneurysm), ischemic or hemorrhagic strokes, infections affecting the brain, vasoconstriction syndrome, and extremely high blood pressures

What are the Signs and Symptoms of Thunderclap Headache?

The signs and symptoms of Thunderclap Headache include the following:

• Sudden and explosive headache pain that is completely unexpected
• The pain may be ‘very high’ to ‘completely unbearable’ and reaches its maximum pain intensity within a minute of onset (within 30 to 60 seconds)
• It can last anywhere from 5 minutes to up to several hours; in some, the pain episodes may repeat for more than a week (from 7 to 14 days)
• The head is commonly involved; the pain may involve any part of the head. Pain may even be felt on the neck and upper back
• In some, the onset of TCH may be preceded by migraine headaches that occur intermittently to frequently (days to weeks before TCH onset)
• The headache may be accompanied by nausea and vomiting, fever, stiff neck, vision changes, numbness, dizziness, seizures, weakness, and changed mental state, depending on the underlying cause

Other signs and symptoms of the underlying condition, if any, causing Thunderclap Headaches may also be noted.

How is Thunderclap Headache Diagnosed?

It is important to immediately evaluate and diagnose the cause of Thunderclap Headache (TCH), where possible, since many of the conditions, such as bleeding in the brain, brain aneurysms, stroke, or vasculitis, causing the secondary forms of TCH are potentially life-threatening and mandating prompt medical attention. A diagnosis of Primary TCH is made by excluding conditions that can potentially cause Secondary TCH.

A diagnosis of Thunderclap Headache is made based on the information gathered from the following:

• Complete physical examination and evaluation of one’s presenting signs and symptoms
• Thorough analysis of personal and family medical history, including one’s history of migraine (if any)
• Neurological examination by a qualified healthcare provider
• Imaging tests such as MRI and CT scans (of the head and neck region)
• Magnetic resonance angiography (MRA) scans
• Lumbar puncture, if needed
• Transcranial doppler studies
• Differential diagnosis to rule out other conditions that may manifest with similar signs and symptoms

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Thunderclap Headache?

The complications of Thunderclap Headache may include the following:

• The headaches may be excruciatingly painful
• Poor performance at school or work
• Risk for accidents while driving or operating machinery
• Complications that arise from an underlying condition, if any present
• Thunderclap Headaches may be recurrent: In about 35% of the individuals, TCH may recur for many months and years
• Side effects of treatment and medications used

How is Thunderclap Headache Treated?

The treatment of Thunderclap Headache is dependent on the underlying (neurological) cause. If the cause is unknown, then the treatment is mostly symptomatic with the intent of reducing pain and discomfort. The treatment measures may include:

• Close clinical monitoring
• Arterial blood pressure monitoring
• Administration of pain medication, non-steroidal anti-inflammatory drugs (NSAIDs), blood pressure medication, etc.
• Surgical procedures to treat blood vessel tears or blockages
• Other symptomatic therapies

Additionally, treatment for the underlying condition causing TCH is necessary.

How can Thunderclap Headache be Prevented?

It is difficult to prevent the onset of Thunderclap Headaches, because these are known to develop suddenly. However, the following points may be considered to lower one’s risk, particularly if it is associated with an underlying disorder.

• Keep a diary to record migraine headaches on a regular basis, also of any other associated symptoms that may occur with the headaches
• Keeping track of any triggering factors; avoiding such triggering factors that have been identified previously
• Undertake prompt treatment for any longstanding headache/migraine, high blood pressure, or even mild head injuries
• Maintaining a healthy lifestyle and optimum body weight, which includes ‘no smoking’ (or consumption of other tobacco-based products), keeping blood pressure under check, staying physically fit, controlling cholesterol levels, reducing stress, etc.
• Be careful while driving (always wear a seat belt), while performing any physical tasks/job-related activities, or while exercising with weights - all factors that puts one at risk for a potential traumatic head injury
• Regular medical screening at periodic intervals with tests and physical examinations are recommended, including an annual eye checkup

What is the Prognosis of Thunderclap Headache? (Outcomes/Resolutions)

The prognosis for Thunderclap Headache is mostly dependent on the underlying cause and its severity, if any identified. The prognosis of Primary TCH is usually good with suitable treatment/medications.

• Individuals with chronic TCHs are able to manage the condition through adequate treatment and medications. Some cases are known to be recurrent and exist throughout one’s lives
• In some, the TCH can be an emergency situation and the overall outcome is based on speedy diagnosis and prompt management of the underlying condition
• Without early appropriate treatment for some of the underlying conditions causing TCH, such as subarachnoid hemorrhage or ruptured brain aneurysm, the prognosis may be poor

Additions and Relevant Useful Information for Thunderclap Headache:

The following DoveMed website link is a useful resource for additional information:

https://www.dovemed.com/health-topics/neurological-institute/