The profile of refractory chronic cluster headache.

Introduction: Chronic cluster headache (CCH) is a relatively rare primary headache disorder whose management is often challenging. The prevalence of refractory CCH (rCCH) is unknown. Our aim is to describe the frequency of rCCH within a population of CCH, define the clinical profile of the refractory patients and the treatments they underwent.

Methods: We conducted a cross-sectional study through a review of the medical records of CCH patients in six hospitals in Madrid, Spain. Data on epidemiological, clinical presentation, treatment and disease activity at the moment were collected. The European Headache Federation diagnostic criteria were used for rCCH definition. High disease activity was defined as having at least 3 severe attacks per week that impact quality of life despite treatment. Non-rCCH and rCCH groups were compared.

Results: 88 CCH patients were analyzed, 68.2% (60/88) met rCCH criteria at some point in their evolution. A longer diagnostic delay (4.6 ± 7.1 vs. 3.2 ± 3.7 years, p = 0.017) was observed in rCCH. All rCCH patients tried therapies without established evidence from randomized clinical trials. OnabotulinumtoxinA and galcanezumab were initiated in 77.3% (68/88) and 5.7% (5/88), but discontinued in 52.9% (36/68) and 60.0% (3/5), respectively. Occipital nerve stimulation (ONS) was implanted in 29.6% (26/88), with 50.0% (13/26) still active. Other treatment options are described and discussed. Despite treatment, 60.2% (53/88) still have high disease activity.

Conclusion: CCH is a disorder with poor prognosis, meeting refractoriness criteria in more than half. OnabotulinumtoxinA and ONS could be the effective in refractory patients.