Resident Physician, Department of Emergency Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USAUnited States
Professor, Department of Emergency Medicine and Pediatrics, Medical College of Georgia, Augusta University, Augusta, Georgia, USAUnited States
Also available as PDF (figures and tables appear in the PDF).
In this mini-review, the authors introduce and discuss the 3rd edition of the International Classification of Headache Disorders (ICHD-3), an important tool in the diagnosis and management of headaches and other causes of orofacial pain, such as the cranial neuropathies.
Keywords: International Classification of Headache Disorders (ICHD); Headaches; Headaches classification; Emergency department; Emergency medicine; Differential diagnosis of headache; Headache management; Primary headaches; Secondary headaches; Cranial neuropathies; ICHD-3; Emergency depart- ment; Secondary head- aches
his year saw the publication of the third edition of the In-
ternational Classification of Headache Disorders (ICHD-3), T a comprehensive diagnostic guide which categorizes and clinically
defines all types of headaches as they are presently understood.
This follows the publication of the beta edition in 2013, which
was available online for the past several years both as a tool for
diagnosis and classification, and to promote field testing and evi-
dence- and clinical-based feedback before finalization of the new 1-2 edition.1-2 In either case, the ICHD-3 is a very helpful guide for any
clinicians who manage patients presenting with headache.1-2
Despite its utility, and the availability of the beta ver-
sion in a user-friendly online format since 2013, many clinicians
are unaware of this helpful and important resource. Headache is a
prevalent disorder worldwide across many settings, and a particu-
larly common chief complaint in the emergency department.3-7 Be-
cause of the extensive array of various headache diagnoses, which
can have significant overlap in presentation and sometimes subtle points of diagnostic differentiation, the ICHD-3 is a resource
meant to be easily accessible and frequently referred back to when-
ever it is needed to assist in diagnosing specific headache disor- 1-2 ders.1-2 While this would be less important if all headaches were
best managed in a similar fashion, therapeutic management in fact
cc Copyright 2018 by Purdy-Payne EK. This is an open-access article distributed under Creative Commons Attribution 4.0 International License (CC BY 4.0), varies significantly depending on the specific type of headache.
Therefore, accurate diagnosis is an important factor in therapeutic
outcome, and such a resource can help clinicians effect a positive
impact on the lives of untold numbers of patients.3
Detailed delineations and diagnostic descriptions of spe-
cific headache types are provided in the International Classification
of Headache Disorders (ICHD-3), which, while the full document
published in Cephalalgia is over 200 pages, is also presented in an
easily-accessible, outline-based format online at www.ichd-3.org.2
The goal of this mini-review, therefore, is not to restate these di- 1-2 agnostic criteria; but to increase awareness of this useful clinical
resource, and present some of its higher yield information via sim-
plified tables and an algorithm.
3-7 The ICHD-3 classification reference has three main sections. Part
one covers primary headaches, part two covers secondary head-
aches, and part three covers painful cranial neuropathies, as well as 1-2 other facial pains and headaches.
The differentiation between primary and secondary
headaches are relatively simple and easy to understand; a primary
headache is due to the actual headache condition itself and cannot
be attributed to another etiology, while a secondary headache is a
symptom of another underlying condition. In cases where a head-
ache otherwise meets diagnostic criteria for a primary headache
type, such as migraine, but is due to an underlying cause, it only re-
ceives one diagnosis—that of the secondary headache disorder.1,2
The third section, cranial neuropathies and other facial
pains, describes an array of disorders which are attributed to dys-
function or afferent activation of isolated craniofacial nerves, rath-
er than true headaches. While the craniofacial pains are indistinct
categories from the headaches, the clinical differentiation is not
always so distinct—there is quite a bit of overlap in some of the
presentations, and some headache types have even changed cate-
gories between the prior edition and the current one. For example,
what is now known as recurrent painful ophthalmoplegic neurop-
athy was previously categorized an ophthalmoplegic migraine.1,2
The first section of the ICHD-3, primary headaches, include four
subtypes—migraine, tension-type headache, trigeminal autonomic
cephalalgias, and other primary headache disorders. Each of these
four headache classifications is further sub-classified as well.1,2
Migraine headaches with and without aura are subject to
specific diagnostic criteria which specify not only what types of
headaches can be diagnosed as migraines, but also when accompa-
nying neurologic symptoms can be defined as an aura. In the sim-
plest of terms, they are unilateral, pulsating, moderate-to-severe,
and accompanied by either nausea and vomiting, or photophobia 1,2 and phonophobia.1,2 In the emergency department setting, antido-
paminergic medications such as have been shown to be the most
efficacious treatment, and are often administered alongside other
analgesics and adjunct treatments, sometimes including diphenhy-
dramine to reduce the incidence of akathisia.5
Tension-type headaches also have specific diagnostic cri-
teria, including mild-to-moderate pressure-type pain in a bilateral
distribution, and may occur with or without pericranial tenderness.
Most guidelines recommend treating these headaches with over-
the-counter analgesics, including combination formulations, some 1,2 of which contain caffeine.1,2 That being said, while the differen-
tiation between a migraine and tension-type headaches is sharply
demarcated in the ICHD-3, many clinicians and researchers have
pointed out the subtlety of patients’ presentations in real-life prac-
tice, and that in many cases, the presentation may be more blurred
or a combination of two or more headache types. In addition, ten-
sion-type headaches have shown favorable responses to treatments
primarily used to treat migraines. This data has led some to believe
that they may, in fact, lie on the same spectrum and should there-
fore be managed similarly.6
The third section of the primary headaches classification
covers the trigeminal autonomic cephalalgias, which include cluster
headaches, paroxysmal hemicrania, short-lasting unilateral neural-
giform headaches, hemicrania continua, and probable trigeminal
autonomic cephalalgia; each of which is characterized by sharp
pain occurring in a unilateral distribution, associated with ipsilateral autonomic symptoms. Despite these similarities, their timing and
other diagnostic criteria are quite distinct from each other, as are 1,2 their management recommendations.1,2 The ICHD-3 should be al-
ways consulted for differentiation of these disorders, as their simi- 1,2 lar features yet important distinctions would be almost impossible
to memorize other than by clinicians specialized in this particular
area.
The fourth category of primary headaches is for other
primary headache disorders, and includes a number of less com-
mon headache conditions, including a primary cough headache,
primary exercise headache, primary headache associated with sexu-
al activity, primary thunderclap headache, cold-stimulus headache,
an external-pressure headache, primary stabbing headache, num-
mular headache, hypnic headache and new daily persistent head- 1,2 ache. While many of these headaches occur secondary to other
stimuli, they are still classified as primary headaches because they 1,2 do are not the result of any other disorder.1,2 A helpful diagnos-
tic algorithm for primary headaches (Algorithm 1), and a table in-
cluding the primary headache classifications, current management,
prophylaxis recommendations, and mimics (Table 1), are provided
in this mini-review.
1,2
The classification of secondary headaches is much more extensive,
due to the vast array of underlying conditions which can produce
a headache. Subcategories include headaches attributed to trauma
or injury to the head and/or neck, cranial or cervical vascular dis-
orders, non-vascular intracranial disorder, a substance or its with-
drawal, infection, a disorder of homeostasis, a disorder of various
structures of the head and neck, or psychiatric disorder. These
categories, too, are further divided into sub-categories, which are
generally, the specific medical diagnoses which have produced a 5 1,2 headache.1,2
A secondary headache is a headache which is present be-
cause of another medical condition, and generally, carry a high-
er-level of concern for clinicians because the underlying etiology is
sometimes a life-threatening condition such as bacterial meningitis
or intracranial hemorrhage. The biggest challenge associated with
secondary headaches is in differentiating them from the primary
headache etiologies, which they frequently mimic and which are al-
most universally less worrisome. Failure to recognize and act upon
a secondary headache will frequently have serious consequences 1,2 and complications, depending on the etiology.1,2 See Table 2 for
a selection of these secondary headaches which may mimic more
common primary headaches, as well as their emergent manage-
ment.
The thirdsection in the International Classification of Headache
Disorders (ICHD-3) is dedicated to the cranial neuropathies, oth-
er facial pains, and other headaches. Many, but not all of these
conditions, are characterized by neuropathic-type pain in a specific
Algorithm 1. Diagnosis of Primary Headaches
Table 1. Primary Headaches, Management, Prophylaxis, and Mimics
Unilateral, pulsating, severe, 4-72 hours, migrainous features, with or without aura Migraine analgesic, and an antiemetic
Management adjuncts to consider: diphenhydramine (for prevention or treatment of akathisia), corticosteroids (for prevention of recurrence)
Tension-type Bilateral, tightening or pressure-like, with or with- Over-the-counter analgesics, may consider Antidepressants, physical Many types of secondary headache out pericranial tenderness formulation with caffeine therapy, biofeedback headaches
Severe, stabbing, with fluctuations ipsilateral Cluster parasympathetic headache autonomic symptoms
neuralgiform IV lidocaine or corticosteroids Anti-epileptics, gabapentin
stabbing Short stabbing burts, no autonomic symptoms Indomethacin, COX-2 inhibitors anti-depressants, neuralgiform headache at-
thunderclap Severe, sudden onset, maximal at onset Rule out emergent causes rhage or othervascular
Small, well-circumscribed area of mild pain Over-the-counter analgesics
Hypnic Onsets exclusively during sleep (2-4 am), usually headache moderate bilateral pain
Occur daily for at least 3 months in patients with
limited prior headache history, variable features
Ischemic stroke or TIA, Neuroleptics or other anti-dopaminergics, Antiepileptics, botulinum intracranial hemorrhage, combined with an over-the-counter toxin injections giant cell arteritis, central venous sinus thrombosis
Management alternatives to consider: sub-dissociative ketamine infusions, triptans
Lasts 2-30 minutes, occurs several times Cluster headaches per day Indomethacin Indomethacin Continuous pain with waxing and waning Migraine
15-180 minutes, several Suboccipital corticosteroid Migraine, paraoxysmal per day during 'cluster 100% oxygen, subcutaneous/nasal triptan injections hemicrania periods'
Short stabbing bursts which last a few seconds Primary stabbing headand occur many times aches, trigeminal neuralgia per day
Indomethacin, tricyclic Short-lasting unilateral
gabapentin tacks, cranial neuralgias
Acute intracranial hemor-
problems
Only for severe or refrac- Underlying structural tory cases lesion
Variable, depends on Analgesics formulation containing caffeine Lithium features
Similar to migraine headaches Underlying structral lesion
Table 2. Selected Secondary Headaches which Mimic Primary Headaches, and their Emergent Management
Migraine, certain cranial Giant cell arteritis with migraine); may also have scalp tenderness, neuropathies
Migraine, encephalopathy, intracranial hemorrhage, Central venous ings including seizures, vision changes, focal Anticoagulation, antiepileptic prophylaxis, monitoring ischemic stroke, or other sinus thrombosis deficits, alterations of mental status or level of and management of intracranial pressure intracranial vascular problems
Medication overuse Migraine or tension-type headache headaches
Tension-type headaches, Headache onsets in neck before spreading to
occipital neuralgia head, may have bony tenderness and/or signs
cranial nerve distribution, including trigeminal neuralgia, occipital
neuralgia, optic neuritis and other, lesser-known neuropathies. This
section also includes a category dedicated to headaches without a
clear-cut etiology or not fitting specific diagnostic criteria for any
other headache diagnosis. Again, the most current diagnostic cri-
teria for each of these conditions, as determined by the ICHD-3 a
panel of experts, are provided for the clinician.1,2 The treatments
for these conditions range from local anesthetics, to antiepileptics
and tricyclic antidepressants, to surgical interventions, depending
on the nerve involved and the underlying cause.8
rd In summary, the 3rd edition of the International Classification of
Headache Disorders (ICHD-3) is an extremely valuable tool in the
diagnosis and therapeutic management of the complex spectrum
of head and face pain syndromes. Because therapeutic success is
most likely to occur when the type or cause of a headache or face
pain is correctly identified, a precise diagnosis is critical.
The authors have no conflicts of interest to disclose.