INCREASED ACTIVITY OF THE SYMPATHETIC NER VUS SYSTEM AND NEUROENDOCRINE CHANGES IN PATIENTS WITH IDIOPATHIC TRIGEMINAL NEARALGIA

Whereas most investigations point toward peripheral mechanisms such as a mechanic irritation of the trigeminal nerve, a central aetiopathoge nesis of trigeminal neuralgia is considered possible. Little attention has been paid to the potential role of the sympathetic nervous system and neuroendocrinological changes in trigeminal neuralgia. For this r eason, we examined the plasma level of the catecholamines norepinephri ne and epinephrine, as well as cortisol and ACTH in 16 patients (55.3 +/- 8.3 years) with trigeminal neuralgia at different times during the day (7.00, 13.00, 17.00 and 23.00). Morning (p < 0.01) and evening va lues (p < 0.01) of plasma norepinephrine as well as the daily mean Val ue (dmv) (p < 0.01) were significantly higher in patients with trigemi nal neuralgia than in the control group. Moreover, morning, afternoon and daily mean epinephrine values were also significantly elevated. Th e daily mean norepinephrine levels correlated with the intensity of th e 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 = 0.72, p < 0.001). In addition to elevated catecholamines, trigeminal neuralgia patients als o demonstrated significantly increased morning, evening and daily mean (p < 0.05) values of plasma cortisol and ACTH. Thus, patients with tr igeminal pain have an increased sympathetic nervous system activity fo r an extended period of time without a direct link to pain attacks whi ch suggests that the sympathetic nervous system itself plays a role in the induction and maintenance of trigeminal pain. However, the meanin g of the elevated cortisol and ACTH levels remains unclear, some paral lels to the cluster headache are noticed and may point to a central in volvement of trigeminal neuralgia due to a dysregulation of the hypoth alamic-pituitary-adrenal axis.