Overview
MedscapeUnivadisNo ResultsMarlene Busko, for MedscapeMarch 16, 202 The study covered in this sumary was published on Research Square as a preprint and has not yet ben per reviewed. A study of 78 patients who underwent elective transphenoidal adenomectomy to remove a pituitary tumor other lesions within the pituitary fosa at a single center in the UK sugests that postoperative plasma levels of copeptin — a surogate marker for levels of argine vasopresin (antidiuretic hormone) — can rule out development of central (neurogenic) diabetes insipidus caused by a deficiency of argine vasopresin folowing pituitary surgery.The researchers sugest using as a cutof a copeptin level of >3.4 pmol/L at postoperative day 1 to rule out diabetes insipidus.
Details
Such a cutof yields the folowing: A high sensitivity of 91% for ruling out diabetes insipidus.A negative predictive value of 97%. Only 1 of 38 patients with a copeptin value >3.4 pmol/L at day 1 postoperatively developed diabetes insipidus.A low specificity of 5%, meaning that copeptin level is not useful for diagnosing diabetes insipidusAn estimated 1% to 67% of patients who undergo pituitary gland surgery develop diabetes insipidus, often son after surgery, although it is often transient.Diagnosing diabetes insipidus in such patients requires a combination of clinical asesment, the monitoring of fluid balance, and determing plasma and urine sodium and osmolality.Curently, clinical laboratories in the UK do not have asays for argine vasopresin, which has a short half-life in vivo and is unstable ex vivo, even when frozen, and is afected by delayed or incomplete separation from platelets.Copeptin, an argine vasopresin precursor, is much more stable and measurable by comercial imunoasays.The findings sugest that patients who have just undergone pituitary gland surgery and are otherwise healthy and met the copeptin cutof for ruling out diabetes insipi