Secondary headache attributed to exposure to or overuse of a substance.

BACKGROUND: Secondary headaches attributed to exposure to or the overuse of a substance are classified under chapter eight in the International Classification of Headache Disorders 3rd edition. Three distinct sub-chapters consider: 1. Headache attributed to exposure to a substance, 2. Medication overuse headache, and 3. Headache attributed to substance withdrawal. Headache attributed to exposure to a substance refers to a headache with onset immediately or within hours after the exposure, while medication overuse headache is a headache occurring on 15 or more days per month that has developed as a consequence of regular usage of acute headache medication(s) for more than three consecutive months in a patient with a pre-existing primary headache disorder. The withdrawal of caffeine, oestrogen, and opioids is most often associated with the development of headache. DISCUSSION: Despite the current headache classification, there is no certainty of a causal relationship between the use of any substance and the development of headache. Some substances are likely to provoke headache in patients that suffer from a primary headache disorder like migraine, tension-type headache or cluster headache, while others were described to cause headache even in people that generally do not get headaches. Toxic agents, such as carbon monoxide (CO) are difficult to investigate systematically, while other substances such as nitric oxide (NO) were specifically used to induce headache experimentally. If a patient with an underlying primary headache disorder develops a headache, in temporal relation to exposure to a substance, which is significantly worse than the usual headache it is considered secondary. This is even more the case if the headache phenotype is different from the usually experienced headache characteristics. Medication overuse headache is a well-described, distinct disease entity with only marginally understood pathophysiology and associated psychological factors. Managing medication overuse headache patients includes education, detoxification, prophylactic treatments and treating comorbidities, which is reflected in available guidelines. Viewing medication overuse headache as a separate entity helps clinicians and researchers better recognise, treat and study the disorder. CONCLUSION: Identification of substances that may cause or trigger secondary headache is important in order to educate patients and health care professionals about potential effects of these substances and prevent unnecessary suffering, as well as deterioration in quality of life. Treatment in case of medication overuse and other chronic headache should be decisive and effective.

The applicability of web-based solutions in headache epidemiology research.

BACKGROUND: Epidemiological research of headache is vital but resource consuming prerequisite for evidence-based development in the field. Rapid evolution of information technology may provide new opportunities for population-based surveys. The aim of this study was to evaluate the applicability of web-based solutions in epidemiological studies of primary headaches. METHODS: An online survey was conducted among 20-64 year old Estonian citizens, using a previously validated headache questionnaire. The participants were accessed through most popular portals and e-mail domains to get the maximum coverage of Estonian digital community. The resulting one-year headache prevalences were compared to those acquired in parallel from a population-based cross-sectional person-to-person study in Estonia. RESULTS: Five thousand seven hundred eight entries were made by 5347 participants in the online study. Of the participants, 3896 (72.9%) had no headache, 1436 (26.8%) had only one and 15 (0.3%) had more than one type of headache. The study sample demographics were statistically significantly different from Estonian population and the prevalences were adjusted by age, gender, education and habitat. The proportion of headache sufferers was smaller in the online study sample (23.1% vs 41.0% in the population-based parallel person-to-person study). Among the headache sufferers the proportions of different headache diagnoses were similar across the two studies with the exceptions of episodic migraine and episodic tension-type headache. There were less migraine and more tension-type headache sufferers in the online study sample. DISCUSSION: This is the first study addressing applicability of web-based solutions in headache related large epidemiological studies. Online approach presents a much faster means of data collection, larger samples, has mechanisms of avoiding data contamination and distinguishes the proportions of most primary headache disorders among the headache sufferers. However, the present online survey was significantly biased towards the people without headache, leading to underestimation of headache prevalence. This stems from the shortcomings related to method of sampling, access and engagement. CONCLUSION: Online headache epidemiology research could be a resource saving alternative to person-to-person studies, however, further research is needed to overcome the problems related to methods of sampling, access and engagement.

The prevalence of primary headache disorders in the adult population of Estonia.

OBJECTIVE: To estimate the one-year prevalence of primary headaches, most importantly migraine and tension type headache, but also other primary headaches, in Estonia. METHODS: A population-based random sample of 2162 subjects in Tartu City and Tartu County were interviewed by telephone or face to face using a previously validated questionnaire. RESULTS: Of the 2162 contacted participants, 1215 (56%) fully completed the study. Of these, 502 (41.3%) reported headache during the previous year. The prevalences adjusted by weighting by age, gender, education, marital status and habitat were the following: All headaches 41.0%, all migraine 17.7%, all tension-type headache 18.0%, trigeminal autonomic cephalalgias 0.4%, other primary headaches 2.5%, and chronic headaches 2.7%. CONCLUSION: The 1-year prevalences of primary headache disorders in Estonia are comparable to the previous findings in other European countries.

Medication-overuse headache: a widely recognized entity amidst ongoing debate.

Medication overuse in primary headache disorders is a worldwide phenomenon and has a role in the chronification of headache disorders. The burden of disease on individuals and societies is significant due to high costs and comorbidities. In the Third Edition of the International Classification of Headache Disorders, medication-overuse headache is recognized as a separate secondary entity next to mostly primary headache disorders, although many clinicians see the disease as a sole complication of primary headache disorders. In this review, we explore the historical background of medication-overuse headache, its epidemiology, phenomenology, pathophysiology and treatment options. The review explores relevant unanswered questions and summarizes the current debates in medication-overuse headache.