Headache

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Editor-In-Chief: Robert G. Schwartz, M.D. [mailto:RGSHEAL@aol.com], Piedmont Physical Medicine and Rehabilitation, P.A.; Associate Editor-In-Chief:

Overview
A headache (cephalgia in medical terminology) is a condition of pain in the head; sometimes neck or upper back pain may also be interpreted as a headache. It ranks amongst the most common local pain complaints.

The vast majority of headaches are benign and self-limiting. Common causes are tension,Neck pain, migraine, eye strain, dehydration, low blood sugar, and sinusitis. Much rarer are headaches due to life-threatening conditions such as meningitis, encephalitis, cerebral aneurysms, extremely high blood pressure, and brain tumors. When the headache occurs in conjunction with a head injury the cause is usually quite evident. A large percentage of headaches among females are caused by ever-fluctuating estrogen during menstrual years. This can occur prior to, during or even midcycle menstruation.

Treatment of uncomplicated headache is usually symptomatic with over-the-counter painkillers such as aspirin, paracetamol (acetaminophen), or ibuprofen, although some specific forms of headaches (e.g., migraines, Barre lieou) may demand other, more suitable treatment. It may be possible to relate the occurrence of a headache to other particular triggers (such as stress or particular foods), which can then be avoided.

Pathophysiology
The brain in itself is not sensitive to pain, because it lacks pain-sensitive nerve fibers. Several areas of the head can hurt, including a network of nerves which extend over the scalp and certain nerves in the face, mouth, and throat. The meninges and the blood vessels do have pain perception. Headaches often result from traction to or irritation of the meninges and blood vessels. The muscles of the head may similarly be sensitive to pain.

Types
There are five types of headache: vascular, myogenic (muscle tension), cervicogenic, traction, and inflammatory.

Vascular
The most common type of vascular headache is migraine. Migraine headaches are usually characterized by severe pain on one or both sides of the head, an upset stomach, and, for some people, disturbed vision. It is more common in women. While vascular changes are evident during a migraine, the cause of the headache is neurologic, not vascular. Barre-Lieou is an excellent example. After migraine, the most common type of vascular headache is the "toxic" headache produced by fever.

Other kinds of vascular headaches include cluster headaches, which cause repeated episodes of intense pain, and headaches resulting from high blood pressure (rare).

Muscular/myogenic
Muscular (or myogenic) headaches appear to involve the tightening or tensing of facial and neck muscles; they may radiate to the forehead. Tension headache is the most common form of myogenic headache. Myofascial pain is a common cause of muscular headache.

Cervicogenic
Cervicogenic headaches originate from disorders of the neck Neck pain, including the anatomical structures innervated by the cervical roots C1–C3. Cervical headache is often precipitated by neck movement and/or sustained awkward head positioning. It is often accompanied by restricted cervical range of motion, ipsilateral neck, shoulder, or arm pain of a rather vague non-radicular nature or, occasionally, arm pain of a radicular nature.

Traction/inflammatory
Traction and inflammatory headaches are symptoms of other disorders, ranging from stroke to sinus infection. Specific types of headaches include:
 * Tension headache
 * Migraine,
 * Idiopathic intracranial hypertension (headache with visual symptoms due to raised intracranial pressure)
 * Ictal headache
 * "Brain freeze" (also known as: ice cream headache)
 * Thunderclap headache
 * Vascular headache
 * Toxic headache
 * Coital cephalalgia (also known as: sex headache)
 * Hemicrania continua
 * Rebound headache (also called medication overuse headache, abbreviated MOH)
 * Red wine headache
 * "Spinal headache" (or: post-dural puncture headaches) after lumbar puncture or related procedure that will lower the intracranial pressure
 * Hangover (caused by heavy alcohol consumption)

A headache may also be a symptom of sinusitis.

Like other types of pain, headaches can serve as warning signals of more serious disorders. This is particularly true for headaches caused by inflammation, including those related to meningitis as well as those resulting from diseases of the sinuses, spine, neck, ears, and teeth.

Diagnosis
While, statistically, headaches are most likely to be harmless and self-limiting, some specific headache syndromes may demand specific treatment or may be warning signals of more serious disorders. Some headache subtypes are characterized by a specific pattern of symptoms, and no further testing may be necessary, while others may prompt further diagnostic tests.

Headache associated with specific symptoms may warrant urgent medical attention, particularly sudden, severe headache or sudden headache associated with a stiff neck; headaches associated with fever, convulsions or accompanied by confusion or loss of consciousness; headaches following a blow to the head, or associated with pain in the eye or ear; persistent headache in a person with no previous history of headaches; and recurring headache in children.

The most important step in diagnosing a headache is for the physician to take a careful history and to examine the patient. In the majority of cases the diagnosis will be tension headache or migraine, both of which can be managed on the basis of a clear-cut clinical picture. Where doubt remains, or if there are abnormalities detected on examination, further investigations are justified. Computed tomography (CT/CAT) scans of the brain or sinuses are commonly performed, or magnetic resonance imaging (MRI) in specific settings. Blood tests may help narrow down the differential diagnosis, but are rarely confirmatory of specific headache forms. For mixed headaches (headaches with several components) diagnostic testing that addresses each suspected aspect may be required. Examples include EMG/NCV, Diagnostic musculoskeletal ultrasonography and Thermography.

Complete Differential Diagnosis of Causes of Headache
Causes include

Treatment
Not all headaches require medical attention, and respond with simple analgesia (painkillers) such as paracetamol/acetaminophen or members of the NSAID class (such as aspirin/acetylsalicylic acid or ibuprofen).

In recurrent unexplained headaches, healthcare professionals may recommend keeping a "headache diary] with entries on type of headache, associated symptoms, precipitating and aggravating factors. This may reveal specific patterns, such as an association with medication, menstruation or absenteeism or with certain foods. While it can be time consuming and complex, taking the effort to both determine the root cause of each headache type that the afflicted may have and then customize treatment for one aspect at a time can be quite fruitful. This is sometimes referred to as reducing total load.

It was reported in March 2007 by two separate teams of researchers that stimulating the brain with implanted electrodes appears to help ease the pain of cluster headaches. Since cluster headache is ultimately an autonomic nervous system generated headache, evaluation for Barre lieou may offer an effective, non-invasive alternative.

Prevention
Some forms of headache, such as migraine, may be amenable to preventative treatment. On the whole, long-term use of painkillers is discouraged as this may lead to "rebound headaches" on withdrawal. Caffeine, a vasoconstrictor, is sometimes prescribed or recommended as a remedy or supplement to pain killers in the case of extreme migraine. This has led to the development of paracetamol/caffeine analgesic. One popular herbal preventive treatment for migraines is Feverfew. Magnesium, Vitamin B2, and Coenzyme Q10 are "natural" supplements that have shown some efficacy for migraine prevention(5).

Manipulative therapy
A controversial approach to headache treatment is chiropractic care. Most research supporting the chiropractic adjustment (also known as spinal manipulation by the scientific community) has been self-funded by the chiropractic profession.

The most compelling study of chiropractic efficacy is Nelson's randomized trial, comparing chiropractic to medical care, which included the drug amitriptyline, for the treatment of Migraine Headache. During the 4-week trial, both groups reduced in symptoms. After withdrawal of treatment, the medical group relapsed or got worse, whereas the group receiving chiropractic care maintained their improvements. The amitriptyline is more cost-effective as it is cheaper than the cost of visiting a doctor, but freedom from symptoms or a reduction in frequency only happened in the chiropractic group.

Independent (non-chiropractic) researchers reviewed research on many different types of behavioral and physical treatments for tension-type and cervicogenic headaches and found that cervical spinal manipulation was associated with improvement in cervicogenic headache outcomes (but not for tension-type headache), and was superior to soft-tissue therapies like massage.

Reducing Total Load
Reducing the total number of things that can trigger a headache can be one of the most effective approaches toward headache relief. With this approach the patient and doctor try to identify all of the factors that contribute to that person's headache and whittle away at them one at a time. Treatment therefor is specific to those factors that contribute that person's headache. Cerviogenic nerve irritation with degenerative disc disease and cycle (hormonal) headaches may be important for one patient, however stress and a history of sinus infections may be more important for another. The next patient may have all of these factors and more. In each case an individualized treatment plan is required.