[Sodium regulation disorder, hypothermia, and circadian rhythm disturbances of the body temperature and sleep-wakefulness as sequelae of acute subdural hematoma].

We reported an 11-year-old boy who suffered from transient hypernatremia, hypothermia, and circadian rhythm disturbances of sleep-wakefulness and body temperature from the age of 4 years, as sequelae of acute subdural hematoma. T1-weighted magnetic resonance imaging (MRI) of the brain revealed low intensity consistent with necrotic change in the whole left cerebral hemisphere, hypothalamic region, and the right-sided brain stem including tegmentum, while the pituitary structure was well preserved. Anterior pituitary function was almost normal. ADH (antidiuretic hormone) was neither stimulated by hyperosmolality nor suppressed by hyposmolality but continued to be secreted at almost constant level approximating the normal basal state. This pattern seemed to be due to complete destruction of the osmoreceptor located in the anterior hypothalamus. He exhibited a dispersed-type sleep with differentiated stages of NREM (non-rapid eye movement), although the percentage of sleep was higher at night than in the daytime. It is suggested that circadian rhythm of sleep-wakefulness and differentiation of NREM sleep stages are regulated by different neuromechanisms. Brain stem lesion on MRI may be connected with the pathogenesis of the dispersed-type sleep with special respect to amplitude reduction of sleep-waking circadian rhythm. Circadian rhythm of body temperature (BT) was irregular in amplitude, phase, and period without synchronization with sleep-wakefulness rhythm. Hypothermia was also demonstrated at the basal state, while BT increased when he suffered from respiratory infection. It is likely that hypothermia in our case is caused by the BT shift to the lower side due to malfunction of BT integrating system including preoptic area and anterior hypothalamus.(ABSTRACT TRUNCATED AT 250 WORDS)