Autonomic nervous system and neuroendocrine changes in patients with idiopathic trigeminal neuralgia

To investigate sympathetic nervous system and neuroendocrine changes in idiopathic trigeminal neuralgia, we determined the plasma level of the catecholamines norepinephrine and epinephrine, as well as cortisol and ACTH in 16 patients (55.3 +/- 8.3 years) with trigeminal neuralgia at four different times during the day (7.00, 13.00, 17.00 and 23.00). Morning and evening values of plasma norepinephrine as well as the daily mean value (dmv) were significantly higher (p < 0.01) in patients with trigeminal neuralgia than in an age- and gender-matched control group. Moreover, morning, afternoon and dmv epinephrine values were also significantly elevated. The dmv norepinephrine levels correlated with the intensity of the attacks (r = 0.68, p < 0.01), the frequency of the attacks (r = 0.75, p < 0.01) and the duration of the disease (r = 0.78, p < 0.01). In addition to elevated catecholamines, trigeminal neuralgia patients also demonstrated significantly increased morning, evening and daily mean values of plasma cortisol. Thus, patients with trigeminal pain have an increased sympathetic nervous system activity for an extended period of time without a direct link to pain attacks, which suggests that the sympathetic nervous system itself is at least co-activated in trigeminal neuralgia and perhaps plays a role in the induction and maintenance of trigeminal pain. The neuroendocrine changes are similar to cluster headache and point to a central dysregulation of the hypothalamic-pituitary-adrenal axis, possibly due to the cyclic phenomena in idiopathic trigeminal neuralgia.