The International Classification of Headache Disorders (ICHD) is a detailed hierarchical classification of all headache-related disorders published by the International Headache Society. [1] It is considered the official classification of headaches by the World Health Organization, and, in 1992, was incorporated into the 10th edition of their International Classification of Diseases (ICD-10). [2] Each class of headache contains explicit diagnostic criteria—meaning that the criteria include quantities rather than vague terms like several or usually—that are based on clinical and laboratory observations. [2]
The ICHD was first published in 1988 (now known as the ICHD-1). A second version, the ICHD-2, was published in 2004. The most current version, ICHD-3, was published in 2018. [3] [4]
teeth, mouth or other facial or cervical structures
Migraine is a genetically influenced complex neurological disorder characterized by episodes of moderate-to-severe headache, most often unilateral and generally associated with nausea and light and sound sensitivity. Other characterizing symptoms may include vomiting, cognitive dysfunction, allodynia, and dizziness. Exacerbation of headache symptoms during physical activity is another distinguishing feature. Up to one-third of migraine sufferers experience aura, a premonitory period of sensory disturbance widely accepted to be caused by cortical spreading depression at the onset of a migraine attack. Although primarily considered to be a headache disorder, migraine is highly heterogenous in its clinical presentation and is better thought of as a spectrum disease rather than a distinct clinical entity. Disease burden can range from episodic discrete attacks to chronic disease.
Headache, also known as cephalalgia, is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches.
Cluster headache is a neurological disorder characterized by recurrent severe headaches on one side of the head, typically around the eye(s). There is often accompanying eye watering, nasal congestion, or swelling around the eye on the affected side. These symptoms typically last 15 minutes to 3 hours. Attacks often occur in clusters which typically last for weeks or months and occasionally more than a year.
Tension headache, stress headache, or tension-type headache (TTH), is the most common type of primary headache. The pain usually radiates from the lower back of the head, the neck, the eyes, or other muscle groups in the body typically affecting both sides of the head. Tension-type headaches account for nearly 90% of all headaches.
A medication overuse headache (MOH), also known as a rebound headache, usually occurs when painkillers are taken frequently to relieve headaches. These cases are often referred to as painkiller headaches. Rebound headaches frequently occur daily, can be very painful and are a common cause of chronic daily headache. They typically occur in patients with an underlying headache disorder such as migraine or tension-type headache that "transforms" over time from an episodic condition to chronic daily headache due to excessive intake of acute headache relief medications. MOH is a serious, disabling and well-characterized disorder, which represents a worldwide problem and is now considered the third-most prevalent type of headache. The proportion of patients in the population with Chronic Daily Headache (CDH) who overuse acute medications ranges from 18% to 33%. The prevalence of medication overuse headache (MOH) varies depending on the population studied and diagnostic criteria used. However, it is estimated that MOH affects approximately 1-2% of the general population, but its relative frequency is much higher in secondary and tertiary care.
Intracranial pressure (ICP) is the pressure exerted by fluids such as cerebrospinal fluid (CSF) inside the skull and on the brain tissue. ICP is measured in millimeters of mercury (mmHg) and at rest, is normally 7–15 mmHg for a supine adult. This equals to 9–20 cmH2O, which is a common scale used in lumbar punctures. The body has various mechanisms by which it keeps the ICP stable, with CSF pressures varying by about 1 mmHg in normal adults through shifts in production and absorption of CSF.
Occipital neuralgia (ON) is a painful condition affecting the posterior head in the distributions of the greater occipital nerve (GON), lesser occipital nerve (LON), third occipital nerve (TON), or a combination of the three. It is paroxysmal, lasting from seconds to minutes, and often consists of lancinating pain that directly results from the pathology of one of these nerves. It is paramount that physicians understand the differential diagnosis for this condition and specific diagnostic criteria. There are multiple treatment modalities, several of which have well-established efficacy in treating this condition.
Chronic paroxysmal hemicrania (CPH) is a severe debilitating unilateral headache usually affecting the area around the eye. It normally consists of multiple severe, yet short, headache attacks affecting only one side of the cranium. Retrospective surveys indicated that paroxysmal hemicrania was more common in women. However, subsequent prospective research showed an equal prevalence between females and males, with a ratio close to 1:1. Unlike in migraine, it has no neurological symptoms associated with it. CPH headaches are treated through the use of non-steroidal anti-inflammatory drugs, with indomethacin found to be especially effective in eliminating symptoms.
Sexual headache is a type of headache that occurs in the skull and neck during sexual activity, including masturbation or orgasm. These headaches are usually benign, but occasionally are caused by intracranial hemorrhage and cerebral infarction, especially if the pain is sudden and severe. They may be caused by general exertion, sexual excitement, or contraction of the neck and facial muscles. Most cases can be successfully treated with medication.
Antimigraine drugs are medications intended to reduce the effects or intensity of migraine headache. They include drugs for the treatment of acute migraine symptoms as well as drugs for the prevention of migraine attacks.
Mixed tension migraines are also known as mixed migraines or mixed headaches. They combine characteristics of tension headaches and migraines.
Atypical trigeminal neuralgia (ATN), or type 2 trigeminal neuralgia, is a form of trigeminal neuralgia, a disorder of the fifth cranial nerve. This form of nerve pain is difficult to diagnose, as it is rare and the symptoms overlap with several other disorders. The symptoms can occur in addition to having migraine headache, or can be mistaken for migraine alone, or dental problems such as temporomandibular joint disorder or musculoskeletal issues. ATN can have a wide range of symptoms and the pain can fluctuate in intensity from mild aching to a crushing or burning sensation, and also to the extreme pain experienced with the more common trigeminal neuralgia.
New daily persistent headache (NDPH) is a primary headache syndrome which can mimic chronic migraine and chronic tension-type headache. The headache is daily and unremitting from very soon after onset, usually in a person who does not have a history of a primary headache disorder. The pain can be intermittent, but lasts more than 3 months. Headache onset is abrupt and people often remember the date, circumstance and, occasionally, the time of headache onset. One retrospective study stated that over 80% of patients could state the exact date their headache began.
The NIH classification of headaches consists of brief, relatively vague glossary-type definitions of a limited number of headaches.
The classification of all headaches, including migraines, is organized by the International Headache Society, and published in the International Classification of Headache Disorders (ICHD). The current version, the ICHD-3 beta, was published in 2013.
Atypical facial pain (AFP) is a type of chronic facial pain which does not fulfill any other diagnosis. There is no consensus as to a globally accepted definition, and there is even controversy as to whether the term should be continued to be used. Both the International Headache Society (IHS) and the International Association for the Study of Pain (IASP) have adopted the term persistent idiopathic facial pain (PIFP) to replace AFP. In the 2nd Edition of the International Classification of Headache Disorders (ICHD-2), PIFP is defined as "persistent facial pain that does not have the characteristics of the cranial neuralgias ... and is not attributed to another disorder." However, the term AFP continues to be used by the World Health Organization's 10th revision of the International Statistical Classification of Diseases and Related Health Problems and remains in general use by clinicians to refer to chronic facial pain that does not meet any diagnostic criteria and does not respond to most treatments.
Migraine may be treated either prophylactically (preventive) or abortively (rescue) for acute attacks. Migraine is an complex condition; there are various preventive treatments which disrupt different links in the chain of events that occur during a migraine attack. Rescue treatments also target and disrupt different processes occurring during migraine.
Orofacial pain (OFP) is a general term covering any pain which is felt in the mouth, jaws and the face. Orofacial pain is a common symptom, and there are many causes.