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.
Primary or secondary headache or both?
The general rules for attribution to another disorder apply with some adaptation to 8. Headache attributed to a substance or its withdrawal.
- When a new headache occurs for the first time in close temporal relation to exposure to or withdrawal from a substance, it is coded as a secondary headache attributed to exposure to or withdrawal from that substance. This remains true when the new headache has the characteristics of any of the primary headache disorders classified in Part One of ICHD-3.
- When a pre-existing headache with the characteristics of a primary headache disorder becomes chronic, or is made significantly worse (usually meaning a two-fold or greater increase in frequency and/or severity), in close temporal relation to exposure to or withdrawal from a substance, both the initial headache diagnosis and a diagnosis of 8. Headache attributed to a substance or its withdrawal (or one of its types or subtypes) should be given, provided that there is good evidence that exposure to or withdrawal from that substance can cause headache.
- Certain subforms of headache attributed to exposure to a pharmacologically active substance occur some hours after the exposure and only in a patient with a primary headache disorder, phenomenologically resembling the primary headache type. They are presumed to be mechanistically distinct, responding to a non-physiological stimulus, and therefore are regarded as secondary. Diagnoses should be given for both the primary headache disorder and the appropriate subform of 8.1 Headache attributed to use of or exposure to a substance.
People with 1. Migraine are physiologically and perhaps psychologically hyperresponsive 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.
Associations between headache and substances are often anecdotal, many based on reports of adverse drug reactions. The fact of association with headache does not prove causation, or eliminate the need to consider other aetiologies. Because common events happen commonly, an association between headache and an exposure to a substance may be mere coincidence. Headache can occur by chance. Headache may be a symptom of a systemic disease, and drugs given to treat such a condition will be associated with headache. In trials of drugs for acute migraine, in particular, headache as well as associated symptoms are listed as adverse drug reactions despite being symptoms of the treated disorder rather than an outcome of treatment. Some disorders may predispose to drug-related headache: alone, neither the drug nor the condition would produce headache.
The general criteria for the headache disorders listed here are:
- Headache fulfilling criterion C
- Use of, exposure to or withdrawal from a substance known to be able to cause headache has occurred
- Evidence of causation demonstrated by at least two of the following:
- headache has developed in temporal relation to use of, exposure to or withdrawal from the substance
- either of the following:
- a) headache has significantly improved or resolved in close temporal relation to cessation of use of or exposure to the substance
- b) headache has significantly improved or resolved within a defined period after withdrawal from the substance
- headache has characteristics typical for use of, exposure to or withdrawal from the substance
- other evidence exists of causation
- Not better accounted for by another ICHD-3 diagnosis.