Prospective analysis of salivary melatonin levels in patients with symptomatic pineal cysts

BACKGROUND: Melatonin (ML) is synthesized in the pineal gland and is subject to a circadian rhythm. It significantly influences the sleep-wake cycle. Patients with non-hydrocephalic symptomatic pineal cysts (PC) suffer from a variety of symptoms including cephalgias and sleep disorders. However, the underlying pathomechanism remains unclear. Among others, a disturbed ML secretion due to the cyst is being discussed. However, the data regarding ML levels in patients with symptomatic PC is still insufficient. METHODS: As part of a prospective study in non-hydrocephalic patients with symptomatic PC, we examined the preoperative ML level in the saliva in a half-hour rhythm between 08:30 p.m. and 01:00 a.m.. In addition, symptoms, in particular sleep quality and headache, were recorded over a week using a diary. We analyzed the relationship between symptoms and the ML levels including their time course during early night hours. RESULTS: A total of ten female patients were included. The average diameter of the PC was 11 mm. Patients were able to sleep through the night on an average of 2.5 out of 7 days (range 0 - 6 days), problems falling asleep occurred on an average of 3.6 out of 7 days (range 0 - 7 days). Headaches occurred on an average of 5.5 out of 7 days (range 2 - 7 days). The severity of the headaches ranged from 3 to 7 on the visual analog scale (VAS). Four patients (40%) reported nausea. There was no significant correlation between ML levels and the recorded symptoms. However, the ML values showed a lack of increase during the night. In six patients, ML levels were within the normal range at 8:30 p.m. (p = 0.001). After 10:00 p.m. only two patients (p < 0.0001), and after 00:30 a.m. all patients had pathologic ML levels (p < 0.0001). Of these patients, two had ML values above, and seven below the normal range. CONCLUSIONS: The ML levels in patients with symptomatic PC show a deficient nocturnal increase, which may provide an explanation for the symptoms.