ENDOCRINOLOGIC AND POLYSOMNOGRAPHIC FINDINGS IN KLEINE-LEVIN-SYNDROME- NO EVIDENCE FOR HYPOTHALAMIC AND CIRCADIAN DYSFUNCTION

Five subjects-four men, ages 17-28, and one woman, age 30-with Kleine- Levin syndrome were investigated during symptomatic (SP) and asymptoma tic (ASP) periods. Investigations comprised medical history, MRI, poly somnography, 24-hour hormone profile of human growth hormone, melatoni n, TSH, cortisol and FSH (in the woman only) assessed every 2 hours, a ctimetry, and sleep logs. Medical history confirmed presence of the th ree symptoms diagnostic of of typical Kleine-Levin syndrome: hypersomn ia, excessive food intake, and psychic alteration. MRIs of the brain w ere normal in all patients. Symptomatic periods were triggered by unsp ecific events, such as infection, sleep deprivation, and alcohol. Poly somnography revealed low sleep efficiency during SPs, decreased amount of slow-wave sleep, and high frequency of stage shifts, indicating sl eep fragmentation. Mean 24-hour growth hormone levels were reduced dur ing the SPs in only two patients. Their hGH peaks were dissociated fro m slow-wave sleep during attacks and intervals, often occurring during wake time. Twenty-four-hour melatonin levels were increased during th e SPs in all patients, but were lower in two patients during the noctu rnal sleep period. Cortisol, TSH and FSH did not reveal important diff erences between attacks and intervals. Except for hGH, all hormones ha d normal circadian excretion during symptomatic and asymptomatic perio ds. Amplitude of nocturnal activity as assessed by actimetry was signi ficantly increased in two patients, whereas amplitude of daytime activ ity was significantly reduced in three patients. Actimetry and sleep l ogs demonstrated prolonged sleep phases during SPs. Our investigation could confirm changes of sleep structure described in the literature. The neuroendocrinological findings could not confirm decreased hGH and cortisol and increased TSH levels during SPs, as previously reported in single cases by many authors. Endocrinological findings did not sup port an underlying circadian disorder in KLS.