Headache

A headache (cephalalgia 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, 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 an 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) 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.

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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

Main article: vascular headache

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. 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.

Cervicogenic

Cervicogenic headaches originate from disorders of the neck, 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
• Cluster 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 a "primary headache" which means that the headache, whilst unpleasant is not a occurring as a manifestation of a more serious condition. The main types of primary headache are tension headache, migraine and the trigeminal autonomic cephalalgias of which cluster headache is an example. As it is often difficult for patients to recall the precise details regarding each headache, it is often useful for the sufferer to fill-out a "headache diary" detailing the characteristics of the headache. When the headache does not clearly fit into one of the recognized primary headache syndromes or when atypical symptoms or signs are present then further investigations are justified.^[1] 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.

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. 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.^[2]

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).^[3]

The Placebo Effect and Alternative headache treatments

Headache treatment trials are notoriously difficult to design as headache is probably one of the most profoundly placebo-sensitive conditions in medicine. For this reason, many documented treatment strategies that have not been validated by double blind placebo controlled trials are the subject of much controversy. The question is not whether acupuncture for example can reduce headache, but whether one needs an experienced therapist performing the procedure according to strict methodology to achieve pain relief. A well-blinded trial of acupuncture in tension type headache showed that acupuncture helps, but not significantly more than a procedure performed "incorrectly". Other controversial treatments frequently rejected by the scientific medical community include homeopathy, magnetic field treatment, and chiropractic care. Most research supporting the chiropractic adjustment (also known as spinal manipulation by the scientific community) has been endorsed by the chiropractic, but not the medical profession.^{[citation needed]} Many neurologists are opposed to spinal manipulation as it may precipitate an arterial tear such as a carotid artery dissection which should be suspected if spinal manipulation is followed by headache exacerbation particularly unilaterally, and may precipitate a stroke.

The most cited study of chiropractic efficacy is Nelson's randomized, but not double-blinded trial, comparing chiropractic to medical care,^[4] 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.

Independent (non-chiropractic) researchers reviewed research on many different types of behavioral and physical treatments for tension-type and cervicogenic headaches^[5] 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.

Massage therapy

As a stand alone therapy treatment or in conjunction with other conservative modalities (chiropractic, acupuncture, physical therapy, proprioceptive therapy) massage therapy is a very effective and safe choice for treating and preventing Tension Headaches. A thorough study in 2002 chronicled the change in chronic headache frequency, duration and intensity over an 8-week trial period. Marked reduction in headache frequency and duration was noted but the intensity remained unchanged.^[6]

References