Abstract
Considering the high frequency of headaches in childhood, it is surprising that this is only the sixth book on the subject in 35 years. The difficulty in eliciting a verbal history from very young children and in those distressed during an attack, makes diagnosis particularly difficult. Further, the absence of any objective criteria or tests emphasize the uncertainties of precise categorization. The general use of criteria set out by the International Headache Society (IHS) has facilitated some measure of uniformity in clinical trials; but as the several authors of this book point out, the IHS criteria are far from universally accepted, as repeated attempts to modify them has testified; and they are of limited value in the clinic.
Thus, childhood headache remains a difficult field, riddled with even more imprecision than exists with adult headaches. Dr Abu-Arafeh, a paediatrician from Stirling in Scotland, has, with 11 co-authors, covered the main areas in 14 chapters. Pain mechanisms, pathophysioiology, inheritance, migraine, episodic and chronic tension headaches are the major topics covered, with added chapters on rarer and organic headaches, and sections on medical, dietary, and psychological treatments. Dr Abu-Arafeh's input is unusually large, with contributions to seven of the 14 chapters. His choice of other authors from Finland, England, Holland and the USA is a fair balance of international opinion.
Most major headaches are described, but with too much overlap and repetition. The coverage is wide but not deep in either basic scientific appraisal or in clinical detail. There are many useful tables condensing the criteria for diagnosis and subclasses of headache mechanisms. But many of these are speculative rather than factual. The reader looks in vain for a detailed critique of spreading depression and the evidence is sparse that this attractive concept actually occurs consistently in human migraine, as compared to its demonstration in animal models in response to artefactual stimuli. A plausible case is made out for CNS hyperexcitability as a background to migraine, and for the putative role of glutamates and nitric oxide in migraine genesis. But their exact role is unclear, and whether these are only links in a chain of events rather than initiating events, or even essential links are not spelled out clearly. Indeed Ramadan in this chapter concludes by saying: ‘a threshold for neuronal activation is set, environmentally, genetically, or both…the lowered threshold triggers a cascade, with events either in parallel or in series.’ A wordy if not, I think, a very enlightening generalization.
Clinical descriptions are poor. Referral to much literature of the 1960–70 period has been overlooked and would have remedied this shortcoming. I found no detailed account of the symptoms of headache, the terms used by patients to describe them, nor what the victims look like during various attacks. The inexperienced need a detailed description of the nature, quality, and evolution of pain and associated symptoms in all the headache types. He will search for these in vain. The account of Familial hemiplegic migraine (p. 37) is shallow and inchoate, with no clear description of this fascinating neurological picture that develops over several days or more, and is as worrying as it is intriguing to witness in its evolution. We are informed elsewhere (p. 59) that the disorder may be sporadic or familial, which makes a nonsense of the name Familial hemiplegic migraine; clearly the writer confuses the quite separate, more common nonfamilial hemiplegic migraine. Several chromosomal links (19p13, 1q31, 1q21–23) exist with mutations in the voltage-gated calcium channel genes, as described. But we are not told that it is a far step to extrapolate from this to the inheritance of common or classic migraine. There are other clinical mistakes; for example under retinal migraine we read the visual field defect may be a ‘homonomus (sic) hemianopia’– a certain indication of involvement of the visual cortical pathways, not the retina.
The usual array of drug and non drug treatments are well described by Hämäläinen. The highly doubtful scientific basis for both bio-behavioural treatments and exclusion diets is sceptically but fairly appraised, though dietary factors are quoted as being accountable in between 8 and 12% of childhood cases. By contrast, the editor in the last chapter states that exclusion diets may be helpful. The limitations of prophylactic drugs in children are sensibly emphasized. Psychological treatment is discussed by Osterhaus, ‘regardless of the diagnostic classification of the headache type’– an interesting if unconventional approach to rational therapeutics. Physical-behavioural, cognitive, and behavioural components are elaborated with illustrative case reports, and a three page long table of published studies. Osterhaus rightly states that: ‘scientific endorsement of psychological therapies…is tentative’, and she emphasizes ‘the major differences in techniques used so that it is impossible to draw conclusions on their relative efficacy.’ The final chapter argues the case for headache clinics and repeats much stated elsewhere in the book about assessments, diagnostic tests and management.
This book sketches the most important areas of childhood headache, and will be useful for the trainee new to the field. But there is too much inexact speculation about abdominal migraine, cyclical vomiting, traumatic headache, and other supposed migraine equivalents, without the necessary critical appraisal. Too much reliance is placed throughout on the IHS criteria, which are at best arbitrary generalizations, decided over a conference table, but not in the clinic. The fact that in many disorders, there may be marked similarities with migraine does not necessarily constitute proof of identity. Several spelling errors (Artaeus for Aretaeus, Avicinna for Avicenna (both on p. 1.) seratonin for Serotonin (p. 37) positive for positron (p. 62), etc. would have been eliminated by more careful editing. However, the text is attractively printed with good illustrations, and the case reports are an asset. Despite its descriptive limitations, this is one of the better recent texts on the subject.