Concomitant Persistent Pain in Classical Trigeminal Neuralgia – Evidence for Different Subtypes

OBJECTIVE: To describe the clinical characteristics in classical trigeminal neuralgia (TN) with concomitant persistent pain and to investigate whether TN with concomitant persistent pain represents a distinct phenotype. BACKGROUND: There has been much debate about the possible pathophysiological and clinical importance of concomitant persistent pain in TN. This has led to subgrouping of TN into forms with and without concomitant persistent pain in the recent 3rd International Classification of Headache Disorders beta classification. METHODS: In this cross-sectional study, data on the clinical characteristics were systematically and prospectively collected from consecutive TN patients. RESULTS: A total of 158 consecutive TN patients were included. Concomitant persistent pain was present in 78 patients (49%). The average intensity of concomitant persistent pain was 4.6 (verbal numerical rating scale). The concomitant persistent pain was present at onset or early in the disease course. Patients with concomitant persistent pain were on average 6.2 (P = .008) years younger at onset, but the 2 groups had the same duration of disease (P = .174). There was a preponderance of women in TN with (P < .001) but not in TN without concomitant persistent pain (P = .820). Right-sided pain was more prevalent than left-sided in TN without (P = .007) but not in TN with concomitant persistent pain (P = .907). TN with concomitant persistent pain more frequently had sensory abnormalities (P < .001) and less frequently responded to sodium channel blockers (P = .001). There were no significant differences in other clinical characteristics. CONCLUSIONS: Concomitant persistent pain is very prevalent in TN and is not a consequence of paroxysmal pain. Findings support that the 3rd International Classification of Headache Disorders beta division of TN with and without concomitant persistent pain is clinically and scientifically important.