Headache

A common response to a headache is to apply pressure to the forehead with one's hand
ICD-10	G43.-G44., R51.
ICD-9	339, 784.0
DiseasesDB	19825
MedlinePlus	003024
eMedicine	neuro/517 neuro/70
MeSH	D006261

A headache or cephalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck.^[1] The brain tissue itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the pain-sensitive structures around the brain. Several areas of the head and neck have these pain-sensitive structures, which are divided in two categories: within the cranium (blood vessels, meninges, and the cranial nerves) and outside the cranium (the periosteum of the skull, muscles, nerves, arteries and veins, subcutaneous tissues, eyes, ears, sinuses and mucous membranes).

There are a number of different classification systems for headaches. The most well-recognized is that of the International Headache Society. Treatment of a headache depends on the underlying etiology or cause, but commonly involves analgesics.

[edit] Differential diagnosis

Headaches are most thoroughly classified by the International Headache Society's International Classification of Headache Disorders (ICHD), which published the second edition in 2004.^[2] This classification is accepted by the WHO.^[3]

Other classification systems exist. One of the first published attempts was in 1951.^[4] The National Institutes of Health developed a classification system in 1962.^{[citation needed]}

Headaches can also be classified by severity and acuity of onset. Headaches that are sudden and severe are known as thunderclap headaches.^[5]

[edit] ICHD-2

The International Classification of Headache Disorders (ICHD) is an in-depth hierarchical classification of headaches published by the International Headache Society. It contains explicit (operational) diagnostic criteria for headache disorders. The first version of the classification, ICHD-1, was published in 1988. The current revision, ICHD-2, was published in 2004.^[6]

The classification uses numeric codes. The top, one-digit diagnostic level includes 14 headache groups. The first four of these are classified as primary headaches, groups 5-12 as secondary headaches, cranial neuralgia, central and primary facial pain and other headaches for the last two groups.^[7]

[edit] NIH

The NIH classification consists of brief definitions of a limited number of headaches.^[8]

[edit] Serious causes

Causes of headache can be divided into serious and benign causes. An overview of serious causes follows:

Infection

Many infections can affect the head or neck and present with a headache as their primary symptom including: meningitis, encephalitis, and a brain abscess among others. The patients affected by meningitis tend to be young and the first symptoms they experience are mild, flu-like. The headache caused by meningitis is severe and generally accompanied by photophobia and a certain level of discomfort when willing to bend the neck forward. Occasionally, when meningitis is caused by a meningococcal infection, a rash may appear as well. The headache provoked by meningitis is likely to worsen with fever which is a result of the immune system trying to fight against the infection.

Increased intracranial pressure

Anything that increases the pressure inside the skull can lead to a headache. Example of conditions that may do this include: masses such as brain tumors and idiopathic intracranial hypertension.

Intracranial bleeding

Bleeding inside the skull may lead to both increased pressure as well as an inflammatory reaction, both of which result in pain. Bleeding conditions include: intracranial hemorrhage, subdural hematoma, and subarachnoid hemorrhage. A sub-arachnoid hemorrhage may also cause severe headaches. This condition occurs due to a bleed in the space between the brain and the arachnoid layer of the meninges. The headache caused by a sub-arachnoid hemorrhage is usually accompanied by photophobia, confusion or nick stiffness and may be similar to the symptoms caused by meningitis. Headaches caused by this condition tend to occur suddenly and are often described as being like a very hard hit over the back of the head.^[9]

Strokes can cause headaches although they normally first result in other symptoms than headaches. A haemmorrhagic stroke causes a sudden, severe and persistent headache, along with confusion while speaking and understanding, sudden vision trouble, dizziness, and a loss of balance. ^[10] Although strokes and migraines are rarely related, in people younger than 40 years, a long-term untreated migraine can cause a stroke. Headaches caused by brain tumors are more likely to come later in the development of the tumor. Usually, headaches due to brain tumors appear gradually over a period of weeks and can feel worse when lying down, coughing, and bending forward. The headache caused by temporal arteritis is frequently described more as a head pain than ache, and it might get worse when the inflamed blood vessel of the scalp is touched. Pseudotumor Cerebri is a condition which causes symptoms that mimic the symptoms of a real tumor, although it does not exist. The headache caused by this condition is usually accompanied by nausea, vomiting and pulsating intracranial noises and it may completely resolve once the causative agent has been removed. ^[11]

Others

• Temporal arteritis
• Glaucoma
• Severe hypertension

[edit] Pathophysiology

The brain in itself is not sensitive to pain, because it lacks pain receptors. However, several areas of the head and neck do have nociceptors, and can thus sense pain. These include the extracranial arteries, large veins, cranial and spinal nerves, head and neck muscles and the meninges.^[12]

Headache often results from traction to or irritation of the meninges and blood vessels. The nociceptors may also be stimulated by other factors than head trauma or tumors and cause headaches. Some of these include stress, dilated blood vessels and muscular tension. Once stimulated, a nociceptor sends a message up the length of the nerve fiber to the nerve cells in the brain, signaling that a part of the body hurts. ^[13]

It has been suggested that the level of endorphins in one's body may have a great impact on how people feel headaches. Thus, it is believed that people who suffer from chronic headaches or severe headaches have lower levels of endorphins compared to people who do not complain of headaches.

[edit] Headaches in children

Children can suffer from the same types of headaches as adults do although their symptoms may vary. Some kinds of headaches include: tension headaches, migraines, chronic daily headaches, cluster headache and sinuses headaches. ^[14] It is actually common for headaches to start in childhood or adolescence, for instance, 20% of adults who suffer headaches report that their headaches started before age 10 while 50% report they started before age 20. The incidence of headaches in children and adolescents is very common. One study reported that 56% of boys and 74% of girls between 12 and 17 indicated having experienced a form of headache within the past month. ^[15]

The causes of headaches in children include either one factor or a combination of factors. Some of the most common factors include: genetic predisposition, especially in the case of migraine; head trauma, produced by accidental falls; illness and infection, for example in the presence of ear or sinus infection as well as colds and flu; environmental factors, which include weather changes; emotional factors, such as stress, anxiety, and depression; foods and beverages, caffeine or food additives; change in sleep or routine pattern; loud noises. Also, excess physical activity or sun may be a trigger specifically of migraine. ^[16]

Although most cases of headaches in children are considered to be benign, when they are accompanied with other symptoms such as speech problems, muscle weakness, and loss of vision, a more serious underlying cause can be suspected. They include: hydrocephalus, meningitis, encephalitis, abscess, hemorrhage, tumor, blood clots, and head trauma. In these cases, the headache evaluation may include CT scan or MRI in order to look for possible structural disorders of the central nervous system. ^[17]

Some measures can help prevent headaches in children. Some of them are: drinking plenty of water throughout the day avoiding caffeine; getting enough and regular sleep; eating balanced meals at the proper times; and reducing stress and excess of activities. ^[18]

[edit] Diagnosis approach

The American College of Emergency Physicians have guidelines on the evaluation and management of adult patients who have a nontraumatic headache of acute onset.^[12]

While, statistically, headaches are most likely to be primary (non serious and self-limiting), some specific secondary headache syndromes may demand specific treatment or may be warning signals of more serious disorders.^{[citation needed]} Differentiating between primary and secondary headaches can be difficult.

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.

[edit] Imaging

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.^[19] Neuroimaging (noncontrast head CT) is recommended if there are new neurological problems such as decreased level of consciousness, one sided weakness, pupil size difference, etc. or if the pain is of sudden onset and severe, or if the person is known HIV positive.^[12] People over the age of 50 years may also warrant a CT scan.^[12]

[edit] Treatment

An old advertisement for a headache medicine.

[edit] Acute headaches

Not all headaches require medical attention, and most respond with simple analgesia (painkillers) such as paracetamol/acetaminophen or non-steroidal anti-inflammatory drugs like aspirin, ibuprofen, or diclofenac.^{[citation needed]}

[edit] Chronic headaches

In recurrent unexplained headaches keeping a "headache diary" with entries on type of headache, associated symptoms, precipitating and aggravating factors may be helpful. 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.^[20]

Acupuncture has been found to be beneficial in chronic headaches^[21] of both tension type^[22] and migraine type.^[23] Whether or not there is a difference between true acupuncture and sham acupuncture however is yet to be determined.^[23]

One type of treatment, however, is usually not sufficient for chronic sufferers and they may have to find a variety of different ways of managing, living with, and seeking treatment of chronic daily headache pains. ^[24]

There are however two types of treatment for chronic headaches meaning acute abortive treatment and preventive treatment. Whereas the first is aimed to relieve the symptoms immediately, the latter is focused on controlling the headaches that are chronic. From this reason, the acute treatment is commonly and effectively used in treating migraines and the preventive treatment is the usual approach in managing chronic headaches. The primary goal of preventive treatment is to reduce the frequency, severity, and duration of headaches. This type of treatment involves taking medication on a daily basis for at least 3 months and in some cases, for over 6 months. ^[25] The medication used in preventive treatment is normally chosen based on the other conditions that the patient is suffering from. Generally, medication in preventive treatment starts at the minimum dosage which increases gradually until the pain is relieved and the goal achieved or until side effects appear.

To date, only amitriptyline, fluoxetine, gabapentin, tizanidine, topiramate, and botulinum toxin type A (BoNTA) have been evaluated as "prophylactic treatment of chronic daily headache in randomized, double-blind, placebo-controlled or active comparator-controlled trials. Antiepileptics can be used as preventative treatment of chronic daily headache and includes Valproate. ^[26]

Psychological treatments are usually considered in comorbid patients or in those who are unresponsive to the medication.

[edit] Epidemiology

During a given year, 90% of people suffer from headaches. Of the ones seen in the ER, about 1% have a serious underlying problem.^[27]

[edit] History

An 1819 caricature by George Cruikshank depicting a headache.

The first recorded classification system that resembles the modern ones was published by Thomas Willis, in De Cephalagia in 1672. In 1787 Christian Baur generally divided headaches into idiopathic (primary headaches) and symptomatic (secondary ones), and defined 84 categories.^[8]

[edit] References

[edit] Further reading

• Gorman, Christine; Park, Alice (7 October 2002), The New Science of Headaches, Time, http://www.time.com/time/covers/1101021007/story.html, retrieved 22 February 2010 

[edit] External links

• National Headache Foundation
• IHS - The International Headache Classification (ICHD-2)
• American Headache Society
• Withdrawal related headache information
• HealthyCase - Headache or Cephalalgia

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Headache".