What is Cluster Headache (Cluster Headache)?

Cluster headaches are the most common type of a specific group of primary headaches called trigeminal autonomic cephalgias (TACs). However, this specific type of headache is quite rare, affecting only about 0.1% of people. This rarity makes them difficult to study. Despite their infrequency, cluster headaches are considered among the most severe types of headaches, making timely recognition and treatment vital.

It’s believed that there’s a genetic aspect to cluster headaches. In fact, close relatives of someone suffering from cluster headaches are 18 times more likely to also be diagnosed. Yet, how exactly it is passed down within families is unclear. Some families show signs of an autosomal recessive pattern, while others show a dominant pattern.

Similar to other headaches falling under trigeminal autonomic cephalgias (TACs), cluster headaches are characterized by short, intense, one-sided headaches. They also come with at least one physical symptom on the same side, like tearing, nasal blockage, redness in the whites of the eyes or a sensation of fullness in the ear. Sometimes, the nasal blockage can mislead doctors to diagnose it as sinusitis and prescribe decongestants, which doesn’t help in this case. These headaches can happen irregularly, from every other day to as much as eight times a day. Interestingly, they usually strike at roughly the same hours each day, frequently during the night. For most patients, these daily cluster headache episodes may persist for weeks or months and then disappear for several months to years.

What Causes Cluster Headache (Cluster Headache)?

The exact origin of cluster headaches remains uncertain and several ideas have been proposed and tested. Finding definitive answers is difficult due to the small number of people who actually suffer from this condition. Some research suggests there may be a genetic link, as certain genetic locations have been associated with cluster headaches.

There is a known link between the trigeminovascular system, a set of specific nerve fibers involved in a type of reflex, and a part of the brain called the hypothalamus. However, the way these parts interact to cause cluster headaches remains a mystery. A family connection has been observed, leading to significant research into the genetics of the condition and how it may relate to body chemistry.

A definite connection has been found between the widening of blood vessels and the onset of pain. The activation of the trigeminovascular system can cause the surrounding nerves to trigger this widening. However, it’s then believed that one side of the trigeminal nerve gets activated, though this has not been confirmed with imaging. Also, even when the entire trigeminal nerve root is removed, the number or frequency of attacks doesn’t change. This doesn’t discount the role of the trigeminovascular system, but merely suggests there are other parts involved.

The hypothalamus is certainly linked with cluster headaches. The rhythmic occurrence of these attacks, typically at night, and the seasonal variation suggest the involvement of the hypothalamus, our body’s biological clock. This notion is further supported by studies revealing lower levels of the hormone melatonin and a loss of normal daily rhythm in cluster headache patients. Specific brain scans have revealed activation within a particular part of the hypothalamus during an attack. Notably, though, stimulating the hypothalamus doesn’t trigger attacks. Interestingly, some research suggests that stimulating the hypothalamus might actually stop an attack from happening.

The parasympathetic nerve fibers, which are involved in the trigeminal reflex, might also have a role in the pain and symptoms like eye watering, runny nose, and facial reddening seen in cluster headaches. Like the hypothalamus, the exact way this reflex is activated in cluster headaches is not yet understood.

Certain risk factors for cluster headaches have been identified and these include being male, aged over 30, alcohol consumption, having had previous brain surgery or trauma, and a family history of the condition.

Risk Factors and Frequency for Cluster Headache (Cluster Headache)

Cluster headaches are a medical condition that affects about 0.1% of people. Although they can start at any age, they usually begin around the age of 30. Men are three times more likely to have cluster headaches than women, but recent studies show that this gap has narrowed. The improvements in correctly identifying cluster headaches could be one reason for this change, as in the past, women were often mistakenly diagnosed with migraines instead of cluster headaches. It’s worth noting that approximately 88% of people with cluster headaches are smokers.

  • People have a 14 to 39 times higher chance of being diagnosed with cluster headaches if they have a close relative, such as a parent or sibling, with the condition.
  • If a more distant relative has cluster headaches, their risk is still 2 to 8 times higher than average.
  • Patients who have had a head injury also report a higher incidence of cluster headaches.
  • Between 30 to 80% of people with cluster headaches also suffer from sleep apnea, a condition that disrupts breathing during sleep.

Signs and Symptoms of Cluster Headache (Cluster Headache)

Cluster headaches are a severe type of headache that require an in-depth understanding of a patient’s history to diagnose. Patients often describe the pain as exceptionally intense, almost explosive, and one-sided. It’s commonly felt above or behind the eye. Unlike other types of pain that ebb and flow, this pain is steady and very severe, leading patients to feel restless. They may even be seen shifting or swaying back and forth due to the intensity of the pain. Additionally, patients with cluster headaches usually experience at least one symptom on the same side as the pain. These symptoms include watery eyes or a red-eye, nasal congestion or a runny nose, swelling around the eye or on the face, and partial eyelid drooping or a smaller pupil.

  • Red or watery eyes – 90% of patients
  • Nasal congestion or runny nose – 84% of patients
  • Swelling around the eye or on the face – 59% of patients
  • Partial drooping or a smaller pupil – not known

Light and sound sensitivity, if present, usually occur on just the side with the headache, contrasting migraines, which always affect both sides. Up to a third of patients may also experience pain from normally non-painful stimuli; this is more common in women, those with recent attacks, individuals who first began experiencing these headaches at a younger age, and those also struggling with depression or migraines. While the pain is often so intense that patients entertain thoughts of ending their life, the actual risk of suicide resulting from these headaches is low.

Unlike people with migraines, those suffering from cluster headaches have a hard time keeping still during an attack. They may pace, sway, or even go so far as to hit their heads to distract from the intensity of the headache. Attack duration can vary widely, lasting from 15 minutes to 3 hours. These attacks can happen up to eight times a day, though usually, patients experience two attacks daily, more often at night. Most patients will experience these clusters of headaches for weeks or months at a time, followed by headache-free periods that could last months or even years. This pattern of headache patterns and headache-free periods can continue for up to fifteen years. If these cluster periods last for a year without any relief, the condition is considered chronic.

Certain activities or environmental factors are known to trigger cluster headache attacks in some people. These may include watching television, consuming alcohol, hot weather, experiencing stress, using nitroglycerin, engaging in sexual activity, or exposure to glare.

  • Watching television
  • Alcohol
  • Hot weather
  • Stress
  • Use of nitroglycerin
  • Sexual activity
  • Glare

Testing for Cluster Headache (Cluster Headache)

Generally, diagnosing cluster headaches relies on a combination of symptoms and their duration. Doctors may use a questionnaire that asks about the length of the headache and the presence of symptoms like swollen or watery eyes. This questionnaire can correctly identify cluster headaches 81% of the time and almost always rules out other conditions.

Yet, cluster headaches are often misdiagnosed, and sometimes patients won’t receive a proper diagnosis for years. It’s therefore essential that doctors consider the possibility of cluster headaches in their diagnosis.

The International Classification of Headache Disorders has specific criteria to diagnose cluster headaches. These include having at least five attacks characterized by severe one-sided pain in and around the eye or temple lasting between 15 and 180 minutes. During a part of these headache periods, the pain might be less severe, or the attacks might last a shorter or longer time.

To meet the diagnostic criteria, patients also need to have either one or both of the following: symptoms on the same side as the headache like red or watery eyes, sweating on the forehead and face, a stuffy or runny nose, swollen eyelids, small pupils, or a drooping eyelid and a feeling of restlessness. These attacks occur with varying frequency, between once every two days and eight times per day, and they can’t be better explained by another diagnosis.

There are further criteria to recognize episodic and chronic cluster headaches. Episodic ones occur in periods lasting from seven days to one year and are separated by pain-free intervals of at least three months, while chronic cluster headaches occur without any breaks, or with breaks shorter than three months, persisting for a minimum of one year.

Finally, patients should undergo brain imaging, such as an MRI or CT scan, to rule out any structural issues that could be causing the headaches. It is also essential to rule out problems with the pituitary gland because certain types of tumors can cause symptoms similar to cluster headaches.

Treatment Options for Cluster Headache (Cluster Headache)

There are two main strategies for treating cluster headaches: stopping an ongoing attack, and preventing future ones.

For Immediate Relief

A famous treatment for cluster headaches is using pure oxygen. This is a highly recommended solution exclusive for cluster headaches. About two-thirds of patients find relief through this, with results usually showing in less than 10 minutes. The great thing about oxygen therapy is that it has no side effects. Unfortunately, the downside is that insurance often doesn’t cover this treatment, which can make it hard to access.

Another highly recommended treatment is Triptans, which can be given as a shot under the skin or as a nasal spray. If regular shots are not bearable, nasal spray Triptans can be given on the opposite side to where the headache is located. Taking these medicines through mouth isn’t suggested as they typically take longer to work than the duration of a headache.

Alternatives include intranasal lidocaine (effective for about a third of patients who try it), octreotide, and ergotamine. Sadly, between 10% to 20% of patients with chronic cluster headaches eventually become resistant to these drugs. It’s recommended to avoid triggers like alcohol. Though there’s no proof that quitting smoking will lessen the risk of getting these headaches, patients are still advised to stop smoking.

For Preventing Attacks

The only highly recommended treatment for stopping cluster headaches before they happen is a suboccipital blockade, which has minor side effects like temporary injection site discomfort and low-level headaches.

A common preventative drug is verapamil, recommended initially for patients suffering chronic cluster headaches and short-term episode cluster headaches. Verapamil is usually given once daily, and regular heart monitoring is advised when using this drug. Despite its popularity among professionals, it is only a level C recommendation.

Also recommended as a preventive therapy for occasional cluster headaches and brief active cluster periods are glucocorticoids. These work for roughly 70 to 80% of the patients. However, they do have severe long-term side effects, so they aren’t prescribed for long durations when other helpful alternatives are available. They are particularly useful when other preventive therapies take time to kick in. There’s no one method that’s proven to be more effective than others.

Other medical options include lithium, valproic acid, melatonin, and intranasal capsaicin.

Electrical stimulation has been widely studied and has shown excellent results, particularly for patients resistant to drugs. It can be applied to the sphenopalatine ganglion, occipital nerve, or vagus nerve. Deep brain stimulation of the hypothalamus has produced positive results. Alongside this, vagus nerve stimulation can be done using a non-implanted device.

When doctors are trying to diagnose cluster headaches, they may need to rule out other similar conditions also known as TACs (Trigeminal Autonomic Cephalgias). These include:

  • Paroxysmal hemicrania: a headache on one side of the head that lasts from 2 to 30 minutes and usually responds to a medication called indomethacin.
  • SUNCT syndrome: a very rare kind of headache on one side of the head that lasts from 5 seconds to 4 minutes. These headaches can happen multiple times a day and are generally difficult to treat.
  • SUNA: another type of unilateral neuralgiform headache with automated symptoms.
  • Hemicrania continua: yet another type of persistent headache.
  • Probable trigeminal autonomic cephalgia: a headache linked to the trigeminal nerve, which is responsible for sensations in the face and for functions such as biting and chewing.

Additionally, other types of headaches may also need to be considered:

  • Tension headache: a headache on both sides of the head characterized by a dull or squeezing pain and often associated with fatigue, tender muscles around the head and neck, or sleep issues.
  • Trigeminal neuralgia: an unpredictable headache causing sharp electrical or stabbing pain that lasts only a few seconds.
  • Primary stabbing headache: Brief, stabbing headaches that can last from 1 to 10 seconds and do not have other symptoms common with cranial issues.
  • Migraine: a commonly experienced, throbbing headache usually on one side of the head that causes individuals to prefer quiet, dark spaces. Other symptoms include tiredness, nausea, sensitivity to light and sound, and vomiting.

There may also be medical conditions that could masquerade as TACs. These include:

  • Vascular abnormalities such as dissection of the carotid artery, brain aneurysms, blood clot in the brain, a brain cavernous hemangioma (a cluster of abnormal blood vessels in the brain), brain arteriovenous malformations (an abnormal connection between arteries and veins in the brain), and brain dural arteriovenous fistulas (abnormal connections between blood vessels in the brain).
  • Inflammatory or infectious diseases such as temporal arteritis (inflammation of blood vessels in the temples), dental abscesses, and sinus infections.
  • Tumors such as meningiomas, prolactinomas and growth hormone tumors, and nasopharyngeal carcinoma (a type of cancer in the upper part of the throat).

What to expect with Cluster Headache (Cluster Headache)

About a quarter of people who get a cluster headache may never have another one. However, between 15% and 20% of these patients could have chronic cluster headaches, with 10% to 20% developing resistance to medication. This condition often improves after around 15 years.

The condition can have negative effects on mental health, lead to physical discomfort, and reduce the quality of life. While many patients may think about suicide, it’s rare for them to actually act on these feelings.

Possible Complications When Diagnosed with Cluster Headache (Cluster Headache)

Patients who have this condition often also suffer from mental health issues like depression, anxiety, and aggressive behavior. There are rare cases of suicide attempts associated with these conditions, which can add to the overall stress and strain of the disease. Additionally, there’s evidence that the condition can affect the body’s autonomic function, which is typically not noticeable but can include slow or rapid heart rate, high blood pressure, and heart rhythm problems like AV block and SA block.

A very worrying outcome of this body’s system dysfunction can be a higher risk of blood pressure instability. Similar to sleep apnea patients, individuals could face a higher risk of not having the normal decrease in blood pressure that occurs during sleep. This could potentially lead to damage to the organs in the body and an increased risk of heart disease. Furthermore, there’s a higher risk of an abnormal ankle-brachial index (ABI), indicating an increased likelihood of peripheral artery disease. This confirms an increased threat of heart disease as well.

Preventing Cluster Headache (Cluster Headache)

Alcohol is often the culprit behind pain attacks. Many people recognize this and choose to stop drinking alcohol on their own. However, others might need support and advice on how to stop. While there’s no direct proof that giving up smoking reduces the number of pain attacks, it’s still good health advice to quit smoking.

It’s also important for patients to know about certain drugs that can cause pain attacks, particularly ones that dilate blood vessels. Patients might need assistance in managing their overall lifestyle and mental health support could also be suggested.

Lastly, patients are advised to keep a record of their headaches. This diary can help monitor their symptoms and how well their treatment is working.

Frequently asked questions

Cluster headaches are a type of primary headache called trigeminal autonomic cephalgias (TACs). They are rare, affecting only about 0.1% of people, but are considered among the most severe types of headaches. They are characterized by short, intense, one-sided headaches accompanied by physical symptoms on the same side, such as tearing, nasal blockage, redness in the eyes, or a sensation of fullness in the ear.

Cluster headaches affect about 0.1% of people.

The signs and symptoms of Cluster Headache include: - Severe and intense pain, often described as explosive and one-sided, felt above or behind the eye. - Steady and very severe pain that does not ebb and flow, leading to restlessness. - Shifting or swaying back and forth due to the intensity of the pain. - Symptoms on the same side as the pain, such as watery eyes or a red-eye, nasal congestion or a runny nose, swelling around the eye or on the face, and partial eyelid drooping or a smaller pupil. - Light and sound sensitivity, usually occurring on the side with the headache. - Pain from normally non-painful stimuli, more common in women, those with recent attacks, individuals who first began experiencing these headaches at a younger age, and those also struggling with depression or migraines. - Low risk of suicide resulting from these headaches, despite the intensity of the pain. - Difficulty keeping still during an attack, often pacing, swaying, or hitting their heads to distract from the headache. - Attack duration varying from 15 minutes to 3 hours, with up to eight attacks a day. - Clusters of headaches lasting for weeks or months, followed by headache-free periods that could last months or even years. - Possible chronic condition if cluster periods last for a year without relief. - Triggers for cluster headache attacks, including watching television, consuming alcohol, hot weather, experiencing stress, using nitroglycerin, engaging in sexual activity, or exposure to glare.

Certain risk factors for cluster headaches have been identified, including being male, aged over 30, alcohol consumption, having had previous brain surgery or trauma, and a family history of the condition. Additionally, certain activities or environmental factors can trigger cluster headache attacks in some people, such as watching television, consuming alcohol, hot weather, experiencing stress, using nitroglycerin, engaging in sexual activity, or exposure to glare.

The other conditions that a doctor needs to rule out when diagnosing Cluster Headache are: - Paroxysmal hemicrania - SUNCT syndrome - SUNA - Hemicrania continua - Probable trigeminal autonomic cephalgia - Tension headache - Trigeminal neuralgia - Primary stabbing headache - Migraine - Vascular abnormalities such as dissection of the carotid artery, brain aneurysms, blood clot in the brain, a brain cavernous hemangioma, brain arteriovenous malformations, and brain dural arteriovenous fistulas - Inflammatory or infectious diseases such as temporal arteritis, dental abscesses, and sinus infections - Tumors such as meningiomas, prolactinomas and growth hormone tumors, and nasopharyngeal carcinoma.

Patients with suspected cluster headaches should undergo the following tests to properly diagnose the condition: 1. Questionnaire: A questionnaire that asks about the duration of the headache and the presence of symptoms like swollen or watery eyes can help identify cluster headaches. 2. Diagnostic Criteria: The International Classification of Headache Disorders has specific criteria to diagnose cluster headaches, including the presence of at least five attacks characterized by severe one-sided pain in and around the eye or temple lasting between 15 and 180 minutes. Patients also need to have symptoms on the same side as the headache, such as red or watery eyes, sweating on the forehead and face, a stuffy or runny nose, swollen eyelids, small pupils, or a drooping eyelid. 3. Brain Imaging: Patients should undergo brain imaging, such as an MRI or CT scan, to rule out any structural issues that could be causing the headaches. This is important to rule out problems with the pituitary gland, as certain types of tumors can cause symptoms similar to cluster headaches.

Cluster headaches can be treated through two main strategies: stopping an ongoing attack and preventing future ones. For immediate relief, pure oxygen therapy is highly recommended and has no side effects, although it may not be covered by insurance. Triptans, which can be administered as a shot or nasal spray, are also effective for immediate relief. Other alternatives include intranasal lidocaine, octreotide, and ergotamine. To prevent cluster headaches, suboccipital blockade and verapamil are highly recommended. Glucocorticoids can also be used as a preventive therapy, but they have severe long-term side effects. Other medical options include lithium, valproic acid, melatonin, and intranasal capsaicin. Electrical stimulation of various nerves and deep brain stimulation of the hypothalamus have also shown positive results.

The side effects when treating Cluster Headache include: - Temporary injection site discomfort and low-level headaches from suboccipital blockade. - Regular heart monitoring is advised when using verapamil, a common preventative drug. - Severe long-term side effects from glucocorticoids, which are not prescribed for long durations when other alternatives are available. - Side effects from electrical stimulation, such as applying to the sphenopalatine ganglion, occipital nerve, or vagus nerve. - Mental health issues like depression, anxiety, and aggressive behavior are often associated with Cluster Headache.

Approximately 25% of people who experience a cluster headache may never have another one. However, between 15% and 20% of patients may develop chronic cluster headaches, and 10% to 20% may become resistant to medication. The condition often improves after around 15 years.

A neurologist.

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