Clinical pattern and response to treatment of primary stabbing headache: Retrospective case series study from a Portuguese tertiary hospital.

Objectives: This retrospective case series study aimed to investigate the demographic and clinical patterns of primary stabbing headache (PSH). In addition, we tried to identify subgroups of treatment responses in a neurology outpatient consultation at a Portuguese tertiary hospital.

Methods: Clinical records were retrospectively reviewed and patients meeting the International Classification of Headache Disorders, 3rd edition, criteria for PSH were identified from January 2014 to December 2020. We collected data regarding demographic characteristics, clinical features of the headache, primary headache comorbidities, and information about treatment-related do PSH.

Results: Of 1857 patients, 32 (1.7%; mean [SD] age of onset 56 [3.5] years) had the final diagnosis of PSH. Regarding headache characteristics, 20 patients (62.5%) reported episodes of stabbing in fixed locations and 12 (37.5%) in multiple areas; the duration of each attack was between ≤5 s (seven [21.9%]), 5-60 s (20 [62.5%]), and ≥60 s (five [15.6%]). In all, 18 patients (56.3%) had an episodic course (vs. six of 32 [18.8%] an acute course and eight of 32 [25%] a chronic course). In all, 17 patients started medical treatment (53.1%), with total or partial improvement in 10 (58.8%) of them. It was found that patients with pain in fixed locations had a better response to treatment when compared to patients with multiple locations, in a statistically significant way (eight of 11 vs. two of six, p = 0.023).

Conclusion: In our sample, the mean age of onset of PSH was >50 years and there was a wide range of PSH duration. The duration of each attack (>5 s), the pain in fixed locations, non-daily episodes of the pain in each attack, and the intermittent course of headache were the most prevalent clinical features. Finally, patients with stabbing in localized areas had a better response to treatment.