Relationships between intracranial pressure and diurnal prolactin secretion in primary empty sella

The role of the intracranial pressure (ICP) in the development and/or maintenance of the primary empty sella has been evaluated by recording the ICP during sleeping and waking periods in 11 women who had this syndrome. Concomitantly, plasma PRL levels, measured at 2-hour intervals during a 24-hour period, were compared with the changes in ICP. Daily PRL variations were also measured in 5 normally cycling and 5 postmenopausal women. ICP was abnormally increased in 8 patients with PES. In 3 of them, increased values were recorded during waking and sleeping periods, while in 5 subjects abnormal values were observed only during sleep. In the remaining 3 patients the ICP was normal in all conditions tested. 8 patients with elevated ICP presented an absent or blunted nocturnal PRL increase. In 3 patients with normal ICP, the circadian periodicity of PRL was preserved. The normalization of ICP obtained in 4 patients by a surgical shunting procedure was accompanied by the return to normal of the circadian PRL periodicity. Our observations demonstrate that the finding of a normal ICP during wakefulness is not sufficient to rule out an actual increase in ICP, since a rise in the CRF pressure can occur during sleep. Our data also demonstrated a correlation between an abnormal rise in ICP and an absent or blunted nocturnal increment in PRL secretion.