Abstract
Chronic Daily Headache (CDH) is uncommon in Indian children compared to their adult counterpart. This is a retrospective study looking at the headache phenomenology of CDH in Indian children and adolescents. The validity of the case definitions of subtypes of chronic primary headaches mentioned in the HIS 2004 classification have been evaluated. 22 children (age range 8-15 years; M : F-16 : 6) diagnosed as having primary CDH using a modified definition seen between 2002 and 2003 have been studied. CDH has been defined as daily or near daily headaches > 15d/month for > 6 weeks. The rationale for this modified definition has been discussed. Majority of children (15/22) had a more or loss specified time of onset of regular headache spells resembling New Daily Persistent Headache (NDPH) but did not fulfil totally the diagnostic criteria of NDPH as laid down by IHS 2004. In all cases headache phenomenology included a significant vascular component. Headache phenomenology closely resembled Chronic Tension Type Headache (CTTH) in 4 patients and Chronic Migraine in 3 patients. However, in no patient in these groups, a history of evolution from the episodic forms of the diseases could be elicited. Heightened level of anxiety mostly related to academic stress and achievement was noted in the majority (19/22). Only a minority of patients (3/22) had anxiety and depression related to interpersonal relationships in the family. Medication overuse was not implicated in any patient. CDH in children in India is very much different from CDH in adults with the vast majority of patients exhibiting overlapping features of migraine and tension-type headache. There is need for a modified diagnostic criteria and terminology for chronic primary headaches in children.
Keywords
Introduction
Headaches occurring daily or on near daily basis are common in adult neurological practice. The concept of Chronic Daily Headache (CDH) is now widely accepted. CDH forms a major bulk of all primary headaches in adults in both population based as well as clinic-based studies from different parts of the world (1–6). CDH remains a relatively unexplored entity in India with a single report from a clinic based study in the adult (7).
Chronic Daily Headache (CDH) is uncommon in Indian children compared to their adult counterpart. The commonly employed definition of CDH is difficult to use as therapeutic interventions are often made early due to parental anxiety and this tends to modify the clinical picture. Furthermore, subtype classification seems difficult due to overlapping features of primary headache types in individual cases as evident from past experience of the present author and highlighted in a number of previous publications (8–10).
The present study is a retrospective one looking at the headache phenomenology of CDH in Indian children and adolescents. The usefulness of the case definitions of the subtypes of chronic primary headaches mentioned in the IHS 2004 classification (11) will be evaluated.
Materials and methods
Twenty-two children (age 8–15 years; M:F−16 : 6) diagnosed as having primary CDH (6.3% of all primary headaches seen in the age group) using a modified definition, seen between 2002 and 2003 have been studied. CDH has been defined as daily or near daily headaches ≥ 15d/month for ≥ 6 weeks or headache for 3 days or more per week for ≥ 6 weeks with individual headache spells lasting > 1 h. Ophthalmic diseases and sinus diseases were carefully excluded. All patients underwent neuroimaging studies revealing normal results. CSF studies were done in 5 cases with normal results. The rationale for adopting this modified definition has been briefly mentioned above and would be further commented upon in the discussion. The 5 patients in whom CSF study was undertaken had a near specified onset of chronic headache preceded by a brief febrile illness within a week, preceding the headache onset and hence was the need for exclusion of CNS infection. No patient in the study had received any form of prophylactic treatment specially for migraine. Patients receiving migraine prophylactic drugs, tranquilisers and antidepressants on a regular basis were carefully excluded. This is a major reason for employing a modified definition of CDH (reducing the time frame from 3 months to 6 weeks). Patients included in the study received only simple analgesics on as and when needed basis.
Identification of stressors, psychiatric diagnoses (employing DSM IV criteria) and other contributory factors, if any, were all based on structured interview of patients and parents (7). Attempt was made to assess the temporal course of the events when headache became daily. The questioniare employed had been a modified version of the one employed in earlier study of CDH in adults (7) and one carried out in relation to childhood migraine (briefly reported) (12). The present questionnaire incorporated specific situations relating to children like schooling condition, examination stresses, parental and other family member relationship, socio-economic class, family educational status and parental aspirations regarding children's education and career. Medication overuse was assessed as per experience from study of CDH in adults in India (7). Analgesic overuse was considered when daily intake was ≥ 600 mg of Aspirin or equivalent for ≥ 5 days/week or when daily intake of ergotamine was ≥ 1 mg for ≥ 3 days per week.
Attempt was made to subclassify chronic headaches in children in the recommended categories proposed by the IHS (11). However, difficulty in classification occurred as deviation from standardized case definitions occurred in most subjects. As such the suffix ‘like’ has been used against individual subtypes of chronic headache while describing the headache phenomenology of the subjects studied.
Observations
1. Headache Phenomenology
Three clinical patterns were recognized.
A. New Daily Persistent Headache – like pattern
Noted in 15 of 22 children. The phenomenology includes:
Near specified onset time.
No significant headache history in past.
Frequency and severity near maximal from onset.
Regular headache spells (daily: 9 cases; 4–6 days/ week: 6 cases).
Dull pressing quality universal.
Superimposed pulsatile headaches lasting (30–120 mins) intermittently (1–3 spells/day in all).
Mostly holocranial headache – but frontal (15/15), bitemporal (12/15) or occipital headaches (4/15) at times in all. None had hemicranial headaches. Site variations were noted in individual subjects on different days of headache or even during a single day.
Mild nausea at times – no vomiting.
No photo/phonophobias.
Pulsatile pains exacerbated by physical activity (15/15) and reading (12/15).
Pericranial/cervical muscle tenderness in 11/15.
Migraine in at least one first degree relative in all.
A preceding brief febrile illness in 5/15 subjects.
Phenomenology resembled New Daily Persistent Headache (NDPH) in adults (IHS 2004) (11).
B. Chronic Migraine – like pattern
Noted in 3 of 22 children. The phenomenology includes:
Resembled Chronic Migraine (CM) in adults (IHS 2004) (11), – but always bilateral (bitemporal).
No h/o transformation.
Past history of episodic pulsatile headache ≥ 1 h duration and in bitemporal distribution fulfilling IHS diagnostic criteria for migraine without aura as applicable to children for 2–5 years preceding chronic headache but infrequent. (1–5 headache days/month).
Unspecified onset of chronic phase.
No specific transforming factor identifiable in any subject.
Nearly continuous dull tightness/heaviness with several pulsatile exacerbations during each headache day lasting > 1 h.
Exacerbation by physical activity and reading in all.
Mild nausea at times of pulsatile exacerbations – no vomiting.
C. Chronic Tension Type Headache – like pattern
Noted in 4/22 patients. The phenomenology includes:
Resembled Chronic Tension Type Headache (CTTH) in adults (IHS 2004) (11).
Past history of occasional episodic TTH fulfilling IHS diagnostic criteria of infrequent episodic TTH (2 cases experienced less than 10 episodes) for 1–2 years.
No clear h/o transformation.
Unspecified onset of chronic phase.
No nausea/photophobia/phonophobia.
Exacerbation with reading.
2. Medication overuse
None.
3. Psychiatric comorbidity
Uniform in 3 different subtypes.
Generalized Anxiety disorder and mixed anxiety and depressive disorder related to academic achievement stress – noted in 19/22 cases.
Mixed anxiety and depressive disorder related to interpersonal relationship in family – noted in 3/22 cases.
Major depression as defined in DSM IV – none.
Although DSM IV criteria has been used to assess psychiatric comorbidity in the present series, slightly different terminology has been used in depicting the results as in many subjects the diagnostic criteria laid down to delineate subcategories of anxiety disorders and mood disorders in the DSM IV could not be strictly adhered to. While 8/22 subjects fulfilled the diagnostic criteria for Generalized Anxiety Disorder (GAD), 14 subjects exhibited features not totally fulfilling the diagnostic criteria for either GAD or major depression. This latter category is included in the Appendix of DSM IV as ‘mixed anxiety and depressive disorder’ and is also highlighted in the ICD10. Similar observations were made in our earlier study with CDH in adults (7) and by Verri et al. (13) No subject in the present series fulfilled the diagnostic criteria for major depression. This aspect would be highlighted further later in the article.
4. Comparative Study with Adult CDH in India
See (Table 1).
Comparative Study of Childhood and Adult CDH
Discussion
From the results of the present study and a previous one reported by the author (7), it is apparent that CDH in children (8–15 years) is relatively uncommonly seen in a busy general neurology outpatient department in India. Children with primary headache disorders below the age of 8 years are seldom seen in the author's clinic as in the author's institute they are generally managed by the paediatricians. Perhaps dedicated paediatric headache specialists may encounter more of such cases. Still then, CDH in children poses a significant diagnostic and therapeutic challenge to the clinician. The major problem is that classification systems reflect what is known in adults and hence ‘shoe horning’ children into adult criteria may be problematic and was indeed the experience of the present author.
The present study is the first of its kind to be reported from India (and perhaps from Asia as well). There are indeed major differences in the social structure and healthcare delivery systems between India and developed western countries. These differences need to be borne in mind to fully appreciate the methodology and some of the study findings. The hospital mostly caters to the need of the middle and upper middle class people living in the southern part of the metropolis. All patients hailed from families with good educational background (at least one parent having had university education). These parents mostly have 1–2 children who are generally overcared for. The aspirations of parents relating to their children are always high but with limited job opportunities and limited availability of good schooling, competitions are high. This pose as a major stressor for children and their parents alike and remains a constant one throughout the year and year after year not particularly related to examination times. Combined with this remains the lack of a nationalized health care delivery system giving people the freedom to choose and change doctors and hospitals at any time they wish. This results in high percentage of clinic drop outs of patients with chronic diseases like CDH – a fact noted earlier (7). The problem is relevant to the present study in more than one way. Parents of children with chronic primary headache remain so much worried that they move from one centre to another and most often are started on some form of regular prophylactic medication which tend to modify the original headache phenomenology. The present study aimed at looking at the headache phenomenology of only those subjects who have not been on any form of regular medication. To satisfy this criterion, it seemed necessary to adopt a modified definition of CDH reducing the time frame from 3 months to 6 weeks. It is unusual in the experience of the present author to encounter a child having chronic headache for more than 3 months who have not been started on some form of regular medication in the social class of people who attend the institute's neurology out-patient clinic. As most patients in the study had been having chronic headache for 8 weeks or longer (mean 8.7 weeks), it is also unlikely that the modified inclusion criteria would have influenced the observations made. Non-inclusion of treated patients also probably partly accounts for the relatively small number of patients recruited in the study.
Globally, only a handful of studies have looked into the problem of CDH in children (8). Abu-Arafeh (14) reported on 115 children and adolescents, from Glasgow, UK, with CDH of whom 93 (81%) subjects fulfilled the IHS criteria for diagnosis of CTTH. However about a third of these patients also suffered from migraine like headaches (without aura) and nearly half of patients reported migrainous features during headache like photo/phonophobia and nausea. These features highlight the overlapping phenomenology in most children with CDH. Gladstein and Holden (15) noted difficulty in categorizing nearly 45% of their children either into CM or CTTH category but preferred to classify_them as ‘mixed headache’ to illustrate the overlapping phenomenology. Koenig et al. (10), on behalf of the Pediatric Committee of the American Headache Society reported on the only multicentre study surveying 189 consecutive patients. Females predominated though male gender was associated with greater disability. Family history of migraine was common and medication overuse recorded in many (44%). The problem of classification was stressed because of overlapping features of primary headache types. Nearly one quarter of patients reported two separate headache types with distinguishing characteristics.
Continuous ‘base line’ headache with superimposed episodic spells were common in the migranous type, than in the tension type category. These authors concluded that children and adolescents with chronic primary headache seem to have a single syndrome that in many cases paroxysmally worsen and gather migranous features. Hershey (9) also expressed the view that in children, the majority of CDH appear to be migraine related.
Although factual details had been somewhat different, the present study also highlights the overlapping phenomenology in most children with CDH. The major finding has been the rather specified onset of chronic headache in majority of the children in the present study. This is similar to the situation described in adults as New Daily Persistent Headache (NDPH) and included in the IHS 2004 classification (11). It is true that children in the present series did not fulfil the diagnostic criteria for NDPH in toto; but it was indeed the closest resembling pattern recognized by the IHS. The fundamental nature of the headache phenomenology mentioned by Koeing et al. (10) of one with a baseline headache with episodic migranous exacerbations was very much apparent in this group in the present study. It was of interest to note reading as an exacerbating factor in all classes of chronic headaches in children in India. Occurrence of NDPH like headache phenomenology as a major subtype of CDH in children has only been recognized recently. In the series reported by Bigal et al. (16) NDPH like headache was the second commonest subtype of CDH noted in adolescents and appeared about twice as common as in adults. CM emerged as the commonest subtype in this study but comparatively was less frequent than its incidence in adults with CDH. These workers ofcourse noted the phenomenon of transformation from episodic to chronic migraine in adolescents just as it occurs in adults – with or without medication overuse. This last finding is at variance with the observations made in the present study. The higher age group in the series by Bigel et al. (16), (13–17 years) compared to the present study (8–15 years), probably accounts for this.
Chronic migraine (CM) is largely a transformed phenomenon from episodic migraine (without aura) in adults. In the small group of children who were labelled as having chronic migraine (CM) purely on the basis of headache phenomenology and past history of episodic migraine, such transforming phenomenon was not encountered. It was unclear in them at what point the episodic variety changed to the chronic form but in contrast to the NDPH like patients, the onset time could not be specified. A similar situation existed in relation to subjects thought to be having chronic tension type headache (CTTH).
Another major difference from adult CDH and the study of Koenig et al. (10) in children, and Bigel et al. (16) in adolescents, has been the absence of medication overuse headache in the present series. In fact the prevalence of medication overuse on the whole is less even in adults with CDH in India than in the West specially the US (7).
Tension arising out of desire for academic achievement was noted in many Croatition children with chronic tension-type of headache (17). Although detailed personality trait was not assessed in the present study, using DSM IV, criteria, most children in the present series revealed evidence of anxiety disorders related to academic performance irrespective of their headache phenomenology. Eight subjects fulfilled the diagnostic criteria of generalized anxiety disorder (GAD) but the rest 14 could be considered to have a mixed anxiety and depressive disorder. This aspect has been commented upon earlier in the article. In contrast to adults with CDH, however, none, had any major depressive feature (7).
Another clinical feature worth mentioning has been the presence of perieranial/cervical muscle tenderness in subjects in the present series. The IHS classified tension-type headache into two categories (11), those with and those without pericranial muscle tenderness. The present study reveals a very different picture in children. 11/15 children having a NDPH like headache phenomenology and 2/3 children with CM like phenomenology but none with CTTH like phenomenology, demonstrated pericranial muscle tenderness. The significance is not clear but corroborates with the findings of Antilla et al. in Finnish children (18) with headache where muscle tenderness was commoner in children with migraine than with tension type headache.
The present study clearly highlights one thing and that is the difficulty in classifying chronic headaches in children purely on phenomenological basis. This has been stressed by other workers as well as mentioned earlier. The IHS in the current classification has avoided the use of the term Chronic Daily Headache (CDH) probably to avoid a ‘mixed bag’ diagnosis. Judging by the variability and overlapping nature of headache phenomenology in children with chronic primary headache syndrome, it seems rational to retain the term CDH at least while dealing with headaches in children. The pathophysiological mechanism to explain this overlapping nature of chronic headache syndromes in children is not known. It is possible that this pehnomenon may be related to maturation difference (between children and adults) in the trigemino-vascular system, its connection with the somatic trigeminal pathway and the brain stem pain modulatory pathway involving the periaqueductal grey.
Conclusion
CDH in children in India is very different from CDH in adults with the vast majority of patients exhibiting overlapping features of migraine and tension type headache. There is need for a separate classification system and diagnostic criteria for chronic primary headaches in children. Because of increased occurrence of combined features, the term Chronic Daily Headache needs to be retained in classifying primary childhood headache disorders.