Melatonin secretion after head injury: a pilot study.
OBJECTIVE
To investigate the circadian rhythm of serum melatonin in patients with traumatic brain injury (TBI) during Intensive Care Unit (ICU) stay and its relationship with core body temperature fluctuations and measures of severity of their condition.


METHODS
The pilot study was conducted in the ICU of a general hospital in Athens, Greece. Blood melatonin was determined in eight patients consecutively admitted at the ICU following severe head injury, eight times per day during the first and second day following admission. Core body temperature was recorded at hourly intervals. Patients were also assessed with the Glasgow Coma Score (GCS) and the APACHE II score.


RESULTS
Melatonin concentrations were lower than the normally reported values. Mean night-time melatonin levels were higher than mean daytime levels both on the first and second days, although not statistically significant. Diurnal variation of melatonin was associated with the GCS. Thus, patients with low GCS (n = 4) did not exhibit a consistent diurnal variation of melatonin, whereas those with high GCS (n = 4) retained the normally expected fluctuations.


CONCLUSIONS
ICU-treated TBI patients exhibit reduced melatonin levels and a circadian secretion profile which is related to the severity of the injury. Patients with more severe head trauma exhibit a clearly disrupted pattern of melatonin secretion, whereas those with less severe trauma preserve a relatively intact diurnal rhythm. Furthermore, the diurnal secretion pattern of melatonin appeared to be dissociated from the circadian rhythm of core body temperature. These preliminary findings may have implications for the management of TBI patients.
Paparrigopoulos
Thomas
T
Sleep Research Unit, Department of Psychiatry, Athens University Medical School, Eginition Hospital, Athens, Greece. tompaparrigopoulos@teledomenet.gr
Melissaki
Antigoni
A
Tsekou
Hara
H
Efthymiou
Anna
A
Kribeni
Georgia
G
Baziotis
Nikos
N
Geronikola
Xenia
X
D000328:Adult; D001831:Body Temperature / Q000502:physiology; D001930:Brain Injuries / Q000097:blood* / Q000503:physiopathology; D002940:Circadian Rhythm; D005260:Female; D015600:Glasgow Coma Scale; D006115:Greece; D006801:Humans; D015601:Injury Severity Score; D008297:Male; D008550:Melatonin / Q000097:blood*; D008875:Middle Aged; D010865:Pilot Projects
D008550:Melatonin