Abstract
Dear Sir,
We have with considerable interest read Pareja and co-workers’ communication (1) on the nomenclature concerning Hemicrania continua and the more recently observed variant without indomethacin responsiveness.
In recent years, some turbulence has been created around the Hemicrania continua (HC)-picture, when an apparently indomethacin non-responsive HC-variant appeared on the firmament. According to some investigators, this headache, nevertheless, seemed to ‘meet the phenotype’ (of HC) (2). It should be emphasized that the original, genuine HC-picture persists, as previously perceived, unassailed/unstained, through this, actually rather low-energy, upheaval. The common clinical traits of the two headaches, the original and the new one, are: unilaterality and chronicity of the headache. Besides, there are more than just occasional, regional autonomic features in HC (3). However, the typical autonomic features of cluster headache and chronic paroxysmal hemicrania (CPH): symptomatic side conjunctival injection, lacrimation and nasal secretion are far less frequently present in HC and less marked when present. It has been felt that these features are, possibly, not constant and domineering enough in HC to demand a separate emphasis within the limited space of a term, at the expense of other, probably more important, solitary components. This also seems to concern the new variety.
The decisive point is that indomethacin, by definition, exerts an absolute effect in HC. A case of indomethacin non-responsive HC is accordingly an impossibility. It is not surprising that there presently seems to be a growing understanding that there are two headaches, not only one. The present dispute seems to concern the nature of the non-indomethacin responsive variant rather than its very existence. There are two factions in this matter: one claiming non-affinity between the two forms of headache; the other claiming that they are twins. We favor the former view. How then should the interrelationship between the two headaches be expressed in categorical terms? Pareja and co-workers have come up with two proposals for naming the new variety: (a) ‘Hemicrania generis incerti’ (4), and (b) ‘Hemicrania incerta’ (1). Neither of them may seem quite flawless, at face value. In our estimation, the first term (4) may seem to be the better one.
In taxonomy, clarity and as much as possible of attainable, useful information should characterize the various terms. We are on line with Pareja and co-workers (1) as for the word ‘hemicrania’. This is so essential that it should be kept for the new appellation. The crucial lack of indomethacin effect in the new variety is clearly also important. This should, therefore, be alluded to in the appellation for the new variety.
It is highly relevant that the new variety headache as well is protracted. However, and this is important, if the protractedness is referred to by employing the term ‘continua’, as in HC, the word itself, ‘continua’, is so loaded in this respect that it instantaneously will bring the flight of thoughts back to HC. If one wants to sever every link to HC, and that is what we feel should be done, and, as we understand it, that is also Pareja and co-workers’ intention, the contagious word ‘continua’ must be avoided. It should be substituted by another, analogous word: ‘chronic’ is probably the best alternative.
Scrutiny of the terms proposed for the new variety (1,4): ‘Hemicrania incerta’(1), i.e. ‘the hemicrania’ is appropriately alluded to. However, there is a contradictio in adjecto, in the real sense of the term: ‘incerta’. For the unwitting reader, and maybe even for the specialist, it may seem as though it is the ‘hemicrania’ that is at stake (‘incerta’); and that it is not the essence/nature of the hemicrania that is referred to. For the latter reason alone, the term: ‘Hemicrania incerta’ is unfortunate. In addition, there is no mention of indomethacin responsiveness or of the chronicity of the disorder. These further imperfections concerning the term are far from being unimportant.
As for the term ‘Hemicrania generis incerti’ (4), one is not left with doubt about the hemicrania. It is not its very presence that is dubious; it is its nature/essence that is undefined and imprecise. However, even this term renders no information as to the lack of indomethacin efficacy or the chronicity of the headache. These setbacks concerning the term are of more than just marginal importance.
The term for the new variety ought to be substantially upgraded.
We have previously proposed the term: ‘indomethacin non-responsive chronic hemicrania’ (5). This term covers three capital qualities of the new variety. Autonomic features are part of both headaches, but are not incorporated into either of the terms. This term has at least one major disadvantage: It contains four, or even five, words. It can, however, be abbreviated to one single word: ‘NIRCH’. In this form, it ought to be palatable for common usage for the new variety, as it identifies it. This term constitutes a counterpart to the term: HC, pinpointing both likenesses and distinguishing features.
The fact that a headache is unilateral and chronic does not in itself imply that such a headache has anything to do with HC. There may be several non-indomethacin responsive, unilateral headaches with protracted course, not only one. It is, therefore, important that this new term is kept open for future, similar headaches. It would seem to be important that ‘NIRCH’ is incorporated into the new international classification. It may seem to be an important headache, in all probability more important than HC itself (2).