Rebound following oxygen therapy in cluster headache

Background: Rapid recurrence of a new cluster headache attack following oxygen treatment was named the ‘rebound effect’ by Kudrow (1981). It has never been studied properly. To study this effect, we defined it as a more rapid than usual (for the individual patient) recurrent cluster headache attack after complete relief following oxygen therapy, or an increase in the number of attacks per 24 hours while using oxygen therapy as acute attack treatment. We reviewed the literature and searched our cluster headache study databases. Case series: In our eight patients with rebound cluster headache, the effect was experienced following 87.5% of oxygen treated attacks. Duration until the next cluster headache attack was on average 894 minutes shorter and frequency was on average 1.6 cluster headache attacks per day higher than without oxygen therapy. Conclusion: Although the 1981 trial reported a prevalence of 25%, rebound cluster headache following oxygen therapy is rarely reported nowadays. This may be due to better techniques in oxygen application, the use of higher oxygen flow rates or underreporting. The few literature data and data on our eight patients did not provide clues about the mechanism of the rebound effect. Further study, applying the proposed definition, seems useful.