Altered sympathetic thermoregulation in patients with hypothalamic dysfunction following resection of suprasellar tumors

In patients with suprasellar tumors, both the tumor and its surgical resection may produce hypothalamic dysfunction including thermoregulatory disturbances. We quantitated skin sympathetic nerve activity using microneurography in eight patients with hypothalamic dysfunction following resection. Skin sympathetic nerve activity, skin blood flow (by laser Doppler flowmetry), sweating, blood pressure, and pulse rate were monitored during changes of core (tympanic) temperature in the patients and seven healthy controls. Core temperature was decreased by 0.3 °C and increased by 0.5 °C relative to baseline using a cooling/heating blanket. The increase in sympathetic nerve activity in response to cooling did not differ between controls and patients (41.0±13.1 vs. 38.1±7.7 bursts min °C−1), but an increase upon heating in controls (45.1±5.4 bursts min °C−1) was absent in the patients (−26.0±17.5 bursts (min °C−1). Skin blood flow during heating increased significantly in controls but not in patients (35.6±14.6 vs. 15.8±5.8 ml min 100 g tissue °C−1). The patients thus showed impaired heat loss during body temperature elevation. Microneurography proved to be a sensitive measure of hypothalamic autonomic function.