Headache

Headache is a term used to describe aching or pain that occurs in one or more areas of the head, face, mouth, or neck. It may be a disorder in its own right or may be a symptom of some other disease or condition. Headaches can be chronic, recurrent, or occasional. The pain can be mild or severe enough to disrupt daily activities. Headaches involve the network of nerve fibers in the tissues, muscles, and blood vessels located in the head and at the base of the skull.

Other Names

 * Cephalalgia is a term for headache derived from Greek words for head (cephal-) and pain (-algia).
 * Cephalodynia
 * Encephalalgia

Types

 * Primary headache accounts for about 90% of all headaches. There are three types of primary headache: tension headache, cluster headache, and migraine headache.
 * Tension headache is the most common type of primary headache. Episodes usually begin in middle age and are often associated with the stresses, anxiety, and depression that can develop during these years. There is an association between childhood abuse, domestic violence and adult headaches.
 * Cluster headaches occur daily over a period of weeks, sometimes months. They may disappear and then recur during the same season in the following year.
 * Migraine headaches, sometimes called simply migraines, are typically one-sided (unilateral), "throbbing", preceded by an aura or prodrome of altered sensations, and occur more frequently in women than in men.
 * Secondary headache is associated with an underlying condition such as cerebrovascular disease, head trauma, infection, tumor, and metabolic disorder (e.g., diabetes, thyroid disease). Head pain also can result from syndromes involving the eyes, ears, neck, teeth, or sinuses. In these cases, the underlying condition must be diagnosed and treated. Also, certain types of medication can produce headache as a side effect. Severe, sudden, and debilitating secondary headache that develops after a blow to the head, that interferes with normal activity, or that accompanies other symptoms (e.g., convulsions, disorientation, dizziness, loss of consciousness, pain in the eye or ear, fever) demands immediate medical attention.

Tension Headache
The typical tension headache is one that produces a dull, steady, achy pain on both sides of the head. However, a small proportion of tension-headache patients report that their pain, when at its worst, does at times develop a pulsating quality, a phenomena which physicians sometimes call a tension-vascular headache. This represents one more area where the distinction between tension headaches and migraines becomes somewhat blurred, and tends to support the theory that the two headache types are not actually separate conditions, but opposite ends of the common spectrum of primary headache activity. Many tension headache sufferers describe their pain as producing a sensation of pressure or tightness around the head, as though a band were pulled tightly around it. Others compare the feeling to having their head clamped in an ever-tightening vise. The pain usually begins gradually and increases steadily over a period of hours, but while severe and distracting, it rarely becomes overwhelming and physically debilitating, as in a migraine.

Cluster Headache
A person experiencing cluster headache most often experiences one to three attacks per day, though sometimes more. Typical attacks last from 30 to 180 minutes, on average, and usually occur daily during a cluster period. Attacks often come in the early morning hours and waken the person from sleep. The pain of cluster headaches usually is located around one eye and is almost always on one side of the head (unilateral). There can be nasal stuffiness and tearing with the headache. The pain is excruciating for most people. Lying down often makes cluster headaches worse. Some people pace the floor and move about, unable to find relief.

Migraine
The classic symptom of a migraine headache is severe, throbbing or pulsating pain, often on one side of the head. The onset of a migraine is often preceded by a prodrome in which people might feel irritable, unduly tired, or even yawn excessively for hours before the pain begins. Other people experience an aura before the migraine, which takes the form of visual disturbances or alterations in taste or smell.

Tension Headache
Tension headaches are caused by stress, muscular tension, vascular dilation, postural changes, protracted coughing or sneezing, and fever. Physical and mental conditions that can lead to chronic muscular tension and headache include anxiety, arthritis in the neck or spine, depression, or disorders with the temporal-mandibular joint. Some researchers believe that a low level of endorphins (painkilling compounds found in the brain) may cause frequent, severe, or chronic headache pain.

Recent studies have shown that environmental triggers may cause headaches in some people. These factors include changes in atmospheric pressure and altitude, inclement weather (e.g., heavy rain or snow), and high winds.

It is estimated that 75% to 90% of all people who complain of chronic or frequent headaches suffer from tension headaches. These are the most common type of primary headache, and while they share some characteristics with the more serious migraine, they also display certain distinct differences that set them apart.

Like migraines, tension headaches seem to be more common in women than in men. Unlike migraines, which often make their initial appearance during adolescence, tension headaches usually begin in middle age. As such, their onset often is equated with the development of adult stresses, anxieties and depression that can characterize mid-life. The name "tension headache" therefore can be said to describe a response by the body to emotional strains and pressures, rather than to excessive muscular tightness and resultant constriction of the scalp arteries, as was once widely presumed. In many cases, researchers have found that people with frequent headaches, which are generally not migraines, also exhibit varying degrees of depression, anxiety, and worry. They may have current or past experiences with childhood or interpersonal violence and abuse.

Despite these findings, many physicians and researchers still believe strongly that stress-induced muscular tension in the head, neck and shoulders can bring on tension headaches. This is supported by evidence of muscular tenderness in areas of the neck, the base of the skull, scalp, forehead, face, jaw, shoulders or upper arms in many tension-type headache sufferers. Others show signs of pronounced clenching of the teeth, suggesting that problems related to the temporomandibular joint (TMJ) are causative factors, along with cervical disorders, such as arthritis or degenerative disease of the neck and/or spine, leading to chronic muscular contraction.

Cluster Headaches
There are several well-known triggers associated with cluster headaches, including drugs that dilate or constrict blood vessels and alcohol. These only trigger headaches during a cluster period, however, suggesting that more is involved than simply vascular issues. Recent imaging studies have found abnormalities in parts of the hippocampus in cluster headache patients, even when not in a cluster period. Since the hippocampus is also involved in circadian rhythm, and daily and annual circadian rhythm events are often coincident with cluster periods, these imaging studies support the hypothesis of central influences perhaps acting in concert with peripheral ones.

The fact that some of the triggers also cause blood vessels to dilate or open up to increase blood flow, or involve medications which make blood vessels constrict or narrow to reduce blood flow, contributes to the belief that changes in the structure of blood vessels in the head may at least be partly responsible.

Other Causes
Other, less common causes of headache include:


 * Brain Tumors
 * Many people with brain tumors have headaches. Their pain may be worse in the morning as a result of pressure buildup in the brain after lying flat all night. Headaches caused by brain tumors usually increase with coughing or straining, and are often accompanied by nausea and vomiting. CT (computer tomography) scans or MRI (magnetic resonance imaging) scans can help differentiate between cluster headaches and those caused by brain tumors.


 * Infections
 * Meningitis, an infection of the coverings of the brain, or brain abscess, a collection of infected tissue in the brain, also can lead to headaches. Such patients may have a stiff neck, fever, abnormal laboratory test or neurological examination results. CT scans, MRIs or a spinal tap, a procedure in which cerebrospinal spinal fluid is drawn for examination, may be necessary to make the diagnosis.


 * Other infections that can cause headaches are sinusitis (sinus infection), ear infections, dental disease and infections of the eye.


 * Cerebral Aneurysm
 * An aneurysm is a widening of a blood vessel wall that can rupture, leading to bleeding in the brain, known as subarachnoid hemorrhage. The pain this causes has often been described as the worst headache of one's life. CT and MRI scans are used to make the diagnosis. Other tests include angiography (procedure in which a catheter is threaded upward through successive arteries to the neck and brain, where a contrast dye is injected into the blood to facilitate x-ray images) and spinal tap, which can disclose the presence of blood in the cerebrospinal spinal fluid.


 * Temporal Arteritis
 * An inflammation of an artery, temporal arteritis usually occurs in older persons, and is associated with headache, muscular and joint aches, weight loss, malaise, fever and sometimes jaw pain. Its most worrisome symptom is transient visual loss, which may lead to permanent blindness if the disorder goes undiagnosed.


 * Patients typically complain of tenderness when the scalp or sides of the head are touched. Laboratory studies may show an elevation of the patient's ESR (erythrocyte sedimentation or "sed" rate), indicating inflammation. Some patients with temporal arteritis also have low blood iron levels (anemia). Most patients with suspected temporal arteritis are sent for a biopsy, in which a surgeon removes a small piece of the inflamed artery for microscopic examination to ensure correct diagnosis. Treatment involves steroids, mainly prednisone, often for an extended period to control the inflammation and prevent blindness.


 * Trigeminal Neuralgia


 * Trigeminal Neuralgia is most common in people over 40. The disorder may have many causes. Multiple sclerosis, tumors and blood vessel abnormalities may be responsible for a few cases, but in most instances the cause remains obscure.


 * One of the more commonly prescribed drugs used to treat trigeminal neuralgia is carbamazepine (Tegretol, Carbatrol). Three-quarters of all patients respond favorably to its use. Other medications that may be beneficial include gabapentin (Neurontin), tramadol (Ultram) and phenytoin (Dilantin). Pain medications also may be necessary during prolonged attacks.

Diagnosis
Physicians typically diagnose tension-type headache on the basis of observed differences between its symptoms and those that characterize migraines, cluster headaches and other kinds of chronic craniofacial pain. With all patients who complain of abnormally frequent head pain, however, the physician usually will perform a thorough physical examination, including a medical history and one or more diagnostic procedures, to rule out any underlying serious medical problems that may be producing the headaches.

Diagnosis of tension or cluster headache is based on symptoms and a thorough medical examination, including the following:


 * Blood tests including thyroid, liver, and kidney function tests
 * Eye examination
 * Family history
 * History of interpersonal violence and abuse
 * Medical history (including medications and characteristics of the headache)
 * Neurological examination
 * Sleep habits

Imaging studies of the brain may be necessary to rule out any serious underlying medical problem, such as brain tumor, stroke, infection, and vascular malformation (e.g., aneurysm).

Imaging studies that may be performed include:


 * computed tomography (CT scan) or magnetic resonance imaging (MRI scan) to examine the tissues and structures around, on, and in the brain


 * Electroencephalogram (EEG) to measure brain activity


 * X-rays or magnetic resonance angiography (MRA) to evaluate the brain's blood vessels

Laboratory and imaging tests can help rule out secondary causes of headache, such as the following:


 * Brain tumor
 * Cerebral aneurysm
 * High blood pressure (hypertension)
 * Infection (e.g., meningitis, sinusitis, ear infection)
 * Temporal arteritis
 * Trigeminal Neuralgia

Treatment
Tension Headache


 * Many patients with tension headaches do not seek medical attention or advice, instead choosing to treat themselves with nonprescription analgesics and over-the-counter pain medications. While this works for some people, others, whose tension headaches are severe enough or sufficiently frequent to compel them to seek professional treatment, obtain relief through a course of doctor-prescribed antidepressant or anxiety-reducing medications, such as amitriptyline, nortriptyline or desipramine.


 * When headaches are severe, symptomatic treatment with aspirin, acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) can be helpful. In such cases, care must be taken to avoid medication overuse, as this can lead to "rebound headaches." Due to potentially severe gastrointestinal side effects, NSAIDs should only be used as instructed.


 * Some patients report beneficial results from secondary treatments that help reduce the effects of stress and tension on the body, such as massage, meditation and the use of biofeedback techniques. In some cases, patients also may benefit from the effects of psychotherapy as a means of learning how to cope with stress and tension.

Cluster Headache


 * Treating cluster headache involves addressing the severe, sometimes unbearable, pain during the headache, and disrupting or shortening the cluster episode. Acute treatment medications are similar to those used for migraine. Sumatriptan can be given in injectable or nasal form for rapid onset. The other oral triptans may also be effective. Dihydroergotamine mesylate (DHE, marketed as Migranal is another option. It is delivered as a nasal spray and takes effect quickly. DHE is also available in an injectable form. It is also useful in migraine. Side effects include nausea and dizziness.


 * Narcotics may be helpful, although the onset of most oral agents may not be rapid enough, given the severity and brief duration of the headache. In addition, narcotics are not recommended as a first-line abortive treatment for the reason that a cluster period may go on for months with attacks on a daily basis and therefore the patient would risk serious addiction if treated with narcotics. Breathing 100% oxygen during the acute headache has been found helpful for many patients, if the oxygen is provided with sufficient flow (at least 10 liters per minute) and with a proper non-rebreather mask.  Oxygen provided through a concentrator machine is usual not sufficient, and unfortunately, many patients give up on oxygen prematurely because of under-dosing. (P. Goadsby, UCSF Medical Center, personal communication). Greater occipital nerve block has also been found useful, when attempted at the beginning of a cluster period.  When the diagnosis of cluster is made, and other medications do not work well, a tank of oxygen can be kept for home use.

Migraine Headache
 * Treatment of migraine headache also involves techniques to avoid or shorten the severity and duration of the pain. There are many options available for lowering the frequency of migraines, including beta blockers such as propranolol, calcium channel blockers such as verapamil, antidepressants such as amitriptyline and sertraline, or methysergide (marketed as Deseril). Drugs to treat migraines in progress include over-the-counter analgesics and prescription medications such as sumatriptan (marketed as Imitrex) and ergot alkaloids (marketed as Cafergot and Mioranal). Cannabis was once widely used as a remedy for migraine headaches, but current federal (US) law prohibits its use.

Prevention

 * Prednisilone(Prednisone)
 * This is a steroid medication that is taken initially in high doses, then tapered over days to weeks, depending on the response. This medication is best if used for short periods of time, as long term steroid use is associated with many complications.


 * Lithium carbonate
 * This medication is taken orally, usually twice a day in order to interrupt the cluster. Laboratory testing including lithium levels need to be followed closely. Side effects include tremor, increased thirst and gastrointestinal symptoms.


 * Verapamil
 * This is a medication that can also be effective in migraine. It can be taken twice daily in a sustained oral preparation. Side effects include dizziness and constipation.

Clinical Trials/Research
Many clinical trials investigating the safety and efficacy of treatments for headache that are currently recruiting patients are listed at

History
Headaches are described in the Bible and in other ancient medical writings from Egypt, Babylonia, Greece, Rome, India, and China. Severe chronic headaches were once treated by one of the oldest known surgical procedures, trephining, in which a hole is drilled in the skull.

Epidemiology
In the United States, over 45 million people—including more than the 33 million sufferers of asthma, diabetes, and heart disease—experience chronic, recurring headaches. Of these, 28 million suffer migraine every year.

Approximately 75% to 90% of all people who complain of chronic or frequent headaches suffer from tension headache. Tension headache is more prevalent among women than men. Cluster headaches primarily affect men between the ages of 20 and 40.

Interesting Facts
Headaches have played a prominent role in literature, with many prominent fictional characters suffering from them.

George Gershwin, a renowned composer and pianist, experienced severe headaches that were caused by a brain tumor that proved fatal soon after the development of symptoms.

Other historical figures who suffered from headaches include Thomas Jefferson, Alexander Graham Bell, Elvis Presley, and Charles Darwin.

Related Videos
In this video from NHS Choices, Dr. Anne McGregor describes common causes of headaches, the differences between a normal headache and more severe forms such as a migraine, and treatment options.