Sleep disorders in acromegaly: preliminary data demonstrating a high prevalence of restless leg syndrome (RLS)
S Cannavo1, R Condurso2, S Squadrito1, G Romanello1, I Arico2, G Mento2, F Trimarchi1 & R Silvestri2
Sleep related breathing disorders (SRBD), due to bone mass and soft tissue swelling of the upper airways, are frequently reported by acromegalic patients, but sleep disorders other than SRBD were rarely studied in acromegaly. We evaluated 38 acromegalics (14 M, 24 F, age 52.8±2.3 yrs) by a structured interview for insomnia, excessive daytime sleepiness (EDS), SRBD, sleep related movement disorders (SRMD), circadian sleep disorders and parasomnias. Epworth sleepness scale (ESS) and RLS diagnostic interview were performed in patients reporting EDS and specific sensory symptoms. Grouping by symptoms, snoring was reported in 28, EDS in 20, apneas in 13, RLS in 10, insomnia in 7, periodic leg movements sleep (PLMS) in 4, bruxism in 1, nightmares in 1, delayed sleep phase in 1 cases. We selected 21 cases for video-polysomnography (PSG) and 19 for portable monitoring. So far, 14 standardized PSG have been obtained (4 M, 10 F, age 60.0±2.9 yrs, BMI 30.6±1.6 kg/m2). Ten PSG were positive for PLMS (PLMS index 26.5±10.0, v.n. <5), 6 for snoring, 6 for RLS, 5 for sleep apnea syndrome (SAS) (apnea-hypopnea index 9.5±5.0, SaO2 96±1% v.n. 9799). Sleep efficiency (SE) was overall reduced (65.1±3.8%), expecially in patients with RLS (59.0±6.1%). In patients with RLS the EDS was generally mild (ESS 7.5±2.1, v.n. <10), but more severe than that overall reported in non acromegalic patients with SAS. Nocturnal sleep latency (SL) was longer in RLS patients (33.8±12.8) than in other cases (18.5±7.4). In conclusion, acromegalics sleep poorly, and are fatigued during daytime. In our study the prevalence of RLS is dramatically increased (26%) in comparison with that reported in general population. Based on these data, a role for sleep related somatostatinergic and dopaminergic mechanisms could be hypothesized in acromegaly. Moreover, despite snoring is quite frequent, the prevalence of SAS is less than that shown in previous studies and it is usually mild to moderate.