Home Introduction Prefaces Introduction to the classification How to Use This Classification Subcommittees and working groups The Classification Table of contents Part I: The primary headaches Part II: The secondary headaches Part III: Cranial neuralgias, facial pain and other headaches Appendix Definition of Terms

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5. HEADACHE ATTRIBUTED TO HEAD AND/OR NECK TRAUMA 6. HEADACHE ATTRIBUTED TO CRANIAL OR CERVICAL VASCULAR DISORDER 7. HEADACHE ATTRIBUTED TO NON-VASCULAR INTRACRANIAL DISORDER 8. HEADACHE ATTRIBUTED TO A SUBSTANCE OR ITS WITHDRAWAL 8.1. Headache induced by acute substance use or exposure  8.2. Medication-overuse headache (MOH) 8.3. Headache as an adverse event attributed to chronic medication [code to specify substance] 8.4. Headache attributed to substance withdrawal Bibliography9. HEADACHE ATTRIBUTED TO INFECTION 10. HEADACHE ATTRIBUTED TO DISORDER OF HOMOEOSTASIS 11. HEADACHE OR FACIAL PAIN ATTRIBUTED TO DISORDER OF CRANIUM, NECK, EYES, EARS, NOSE, SINUSES, TEETH, MOUTH OR OTHER FACIAL OR CRANIAL STRUCTURES 12. HEADACHE ATTRIBUTED TO PSYCHIATRIC DISORDER 

IHS	Diagnosis	ICD-10
8	HEADACHE ATTRIBUTED TO A SUBSTANCE OR ITS WITHDRAWAL	G44.4 or G44.83
Coded elsewhere	7.1.2 Headache attributed to intracranial hypertension secondary to metabolic, toxic or hormonal causes , 7.3.2 Headache attributed to aseptic (non-infectious) meningitis , 10.3.6 Headache attributed to acute pressor response to an exogenous agent .

General comment

Primary or secondary headache or both?

When a new headache occurs for the first time in close temporal relation to substance exposure, it is coded as a secondary headache attributed to the substance. This is also true if the headache has the characteristics of migraine, tension-type headache or cluster headache. When a pre-existing primary headache is made worse in close temporal relation to substance exposure, there are two possibilities, and judgment is required. The patient can either be given only the diagnosis of the pre-existing primary headache or be given both this diagnosis and the diagnosis of headache attributed to the substance. Factors that support adding the latter diagnosis are: a very close temporal relation to the substance exposure, a marked worsening of the pre-existing headache, very good evidence that the substance can aggravate the primary headache and, finally, improvement or resolution of the headache after termination of effect of the substance.

Definite, probable or chronic?

A diagnosis of Headache attributed to a substance usually becomes definite only when the headache resolves or greatly improves after termination of exposure to the substance. When exposure to a substance ceases but headache does not resolve or markedly improve after 3 months, a diagnosis of A8.5 Chronic post-substance exposure headache, described in the appendix, may be considered. However, such headaches have not been documented and the criteria are proposed only for research purposes.

In the particular case of 8.2 Medication-overuse headache, a period of 2 months after cessation of overuse is stipulated in which improvement (resolution of headache, or reversion to its previous pattern) must occur if the diagnosis is to be definite. Prior to cessation, or pending improvement within 2 months after cessation, the diagnosis 8.2.8 Probable medication-overuse headache should be applied. If such improvement does not then occur within the 2 months, this diagnosis must be discarded.

Introduction

Migraineurs are physiologically and perhaps psychologically hyper-responsive to a variety of internal and external stimuli. Alcohol, food and food additives and chemical and drug ingestion and withdrawal have all been reported to provoke or activate migraine in susceptible individuals. The association is often based on anecdotal data and reports of adverse drug reactions.

The fact that these stimuli are associated with headache does not prove causation or eliminate the need to consider other aetiologies. Because common events happen commonly, the association between a headache and an exposure to a substance may be mere coincidence. Headache can occur just on the basis of chance. Headache can be a symptom of a systemic disease, and drugs given to treat such a condition will be associated with headache. In acute migraine drug trials, headache, as well as associated symptoms, is listed as an adverse drug reaction despite that it is a symptom of the treated disorder and not the result of treatment. Some disorders may predispose to substance related headache. Alone, neither the drug nor the condition would produce headache. A nonsteroidal anti-inflammatory drug may produce headache by inducing aseptic meningitis in susceptible individuals.

Finally, some acute or chronic substance exposures have been proven to be causally related to headache.

Sitemap

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IHS vs. ICD-10

To facilitate headache diagnosis in daily practice, the classification provides the corresponding WHO ICD-10NA codes for each IHS code.

IHS Subcommittee

The Classification Subcommittee prepares and revises the International Classification of Headache Disorders.

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Cephalalgia

Cephalalgia is the official journal of the IHS. It contains original papers on all aspects of headache. The journal provides an international forum for original research papers, review articles and short communications.www.cephalalgia.org

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