gms | German Medical Science

Objective: Diabetes insipidus centralis with hypernatremia is a common phenomenon after aneurismal subarachnoid hemorrhage (SAH) known for adverse effects on outcome. Possible underlying pathomechanism is a hypothalamic dysregulation through direct injury to the anterior hypothalamic nuclei. In this preliminary prospective study, we analyzed serial Copeptin (COP) levels as a marker of arginin-vasopresin secretion after SAH to determine severity of hypothalamic impairment.

Methods: Prospectively, 20 patients (3 male/17 female; 52.4±11 years) with confirmed aneurysmal SAH were included. COP was determined at days 1, 2, 3, 4, 5, 7 and 10 after SAH, sodium levels and serum osmolarity were determined trice daily beginning from admission. Moderate hypernatremia was defined by sodium levels between 145 and 150 mmol/l, sever hypernatremia was defined by sodium levels above 150 mmol/l with a minimum of two consecutive readings.

Results: Eleven patients showed no sign of hypernatremia (NH), seven patients showed only mild hypernatremia and two patients a severe form. Sodium levels were elevated immediately after SAH within the first 48 hours with elevated serum osmolarity indicating a loss of free water consistent with a central diabetes insipidus. Maximum sodium level at 36 hours was 157 mmol/l vs. 143 mmol/l (p<0.05) in SH and NH, respectively. COP levels were lowest at day 1 and 2 (4.5 pmol/l both) in SH compared to NH confirming an impaired secretion of AVP. Due to the small group size statistical significance could not be achieved (p=0.126).

Conclusions: This preliminary analysis provides evidence that COP is a predictive marker of hypernatremia and central diabetes inipidus in patients suffering from aneurismal SAH. Larger patient series are required to determine reference ranges and to adapt intensive care treatment strategies.