Abstract
Mainardi et al. (1) report several more cases of airplane headache (AH). This report is now the largest series of case reports on AH. Several isolated reports have contributed to the literature over the past several years since the first description of this entity in 2004, including one discussion by Evans et al. published in 2007 (2).
Mainardi et al. (1) suggest that AH appears exclusively in relation to airplane flights, in particular during the landing phase. Up to their report, 37 cases were described in the literature, and with their direct observation of three more subjects with AH they were able to study a total of 75 patients suffering from AH. They have confirmed the stereotypical nature of the attacks: short duration, lasting less than 30 min in up to 95% of cases, the clear relationship with the landing phase, unilateral pain, male preponderance, and the absence of accompanying signs and/or symptoms.
They proposed provisional diagnostic criteria for AH in a prior paper (3) and support its recognition as a new form of headache, to be included in next edition of International Classification of Headache Disorders (IHCD) under ‘Chapter 10: Headache attributed to disorder of homoeostasis’.
Like other authors and papers in the past, they postulate that it is conceivable to consider barotrauma as a main mechanism involved in the pathophysiology of AH in the absence of other pathological disorders. By validating this disorder in the classification – or even in the appendix of the new edition of the ICHD – they feel that this would lead to further studies directed at improving the understanding of its pathophysiology and potential therapies. I could not agree more with their conclusions in this regard.
As usually occurs in the medical literature, descriptive case reports are usually the first opportunity for clinicians to acquaint their colleagues with new entities or variations on well-described neurological disorders. Such case reports are extremely popular among clinicians, particularly neurologists.
To advance science, and headache medicine in particular, it is important that we know what we are studying. For this reason, I believe, in large part, the ICHD (4) came about to allow research in the headache field to progress. By using operational criteria, usually with low sensitivity and high specificity, it has been possible to study disorders in a logical and scientific way. In the current circumstance, however, with only a few case reports in the past it is difficult to determine if the reported cases are simply observations for a specific trigger for a primary headache disorder, or are related to transient inner ear trauma. If these are simply triggers, this disorder, as described, requires no further study or explanation other than to indicate that flying in airplanes can lead to aggravation of underlying headache disorders.
On the other hand, observational and descriptive neurology has led to remarkable understandings in many neurological disorders, many of which today are being studied of the molecular genetic level. AH deserves further study, quantification and elucidation, under the new headache classification criteria. Perhaps AH can be studied prospectively with a methodology that will allow clinicians and researchers alike to determine whether these disorders are unique or not.
Clinicians on a daily basis are drawn to understand the peculiarities of the patients they see and treat. Evidence-based medicine does a lot to direct care and allows us to make rational decisions about investigation and treatment of various disorders. Individual cases leave most of us short as to what to do; however, most of these cases fall within an evidence-free zone, or are so uncommon and rare that they cannot be studied on a large scale or even classified properly.
I would say that AH, as a disorder, is ready to fly. I suspect that if most neurologists asked their patients, ‘Do you ever have headaches on an airplane?’, many would say ‘Yes’. If the identification of this disorder helps identify new or unique entities, and facilitates better classification, diagnosis and management, then this case series and all of those reported in the past decade will have served our patients well, as well as clinical neurology.
Finally, besides reporting on AH, I have had a personal experience with this disorder on a few occasions. It occurs shortly before landing, and does not necessarily require long distances of travel; the pain is extremely severe, usually around the eye and frontal area and into the temple. It is intense, sharp and sometimes throbbing. Attempts to clear the middle layer by maneuvers to open the Eustachian tubes are generally not successful. Based on my knowledge of AH, I suspect that people with this disorder have more than one reason to cheer when the airplane lands safely!
I congratulate the authors on this excellent clinical paper and know that time and further study will decide eventually as to whether AH will truly fly in the face of close scrutiny and evidence.