Reversible cerebral vasoconstriction syndrome (RCVS) and headache attributed to aeroplane travel (AH): Does a link exist?

To the Editor:

We read the interesting paper by Hiraga et al. (1) concerning the occurrence of RCVS precipitated by airplane landing in a 74-year-old woman. During the descent of the aircraft, the patient developed a severe headache, which apparently met the clinical criteria of the International Classification of Headache Disorders 3 beta version (2) for the diagnosis of 10.1.2 Headache attributed to aeroplane travel (AH). In this particular case, the headache continued for 48 h after landing; notwithstanding the spontaneous disappearance of the pain, the patient was referred to hospital three days after the onset of the headache. There, she underwent brain magnetic resonance angiography (MRA), which demonstrated segmental vasoconstriction of brain vessels; a control MRA, performed six days later, gave normal results, allowing the diagnosis of RCVS.

Along with a previous report (3), this case proposes the possible role of RCVS in the pathophysiology of AH, which appears to be related to a variety of multimodal contributing factors (4).

However, the different clinical features of these two forms do not support the role of RCVS. AH sufferers experience recurrent attacks over several different flights and, by definition, AH spontaneously improves and disappears within 30 min of completion of the ascent or descent of the aeroplane (2), although we have found that in a subgroup of AH sufferers a much milder phase of headache could persist for several hours (4) and our preliminary, unpublished data show that this occurs in 27% of AH sufferers. Headache due to RCVS, instead, is similar to 4.4 Thunderclap headache and could “recur over a span of days to two to three weeks” (5), but it does not recur repeatedly. In a recent paper, half of the patients with RCVS developed a mild-moderate, persistent headache feature clearly different from AH (5). Furthermore, in 12 out of 78 patients with AH, which usually treat the attacks, the use of nafazoline is completely effective (data on file). Given the vasoconstrictive action of this drug, should RCVS be involved, we could expect a worsening of the pain instead. However, it cannot be excluded that in rare instances an isolated attack of headache with AH features could be a secondary form due to RCVS. But this possibility is, in our opinion, restricted to a headache of strong intensity lasting for hours in a flyer who did not present previously, nor will present further AH-like episodes.

In conclusion, although we disagree with the authors when they state that “RCVS during air travel may have been previously overlooked as AH”, we do believe that patients who report the persistence of a strong headache during several hours from the onset of a typical AH attack should be investigated with particular caution to rule out a possible secondary pathology, including RCVS.