Anterior Pituitary Hormones in Blood and Cerebrospinal Fluid of Patients in Neurocritical Care
Authors: Beyer Henriette ,   Department of Neurosurgery, Technical University Munich, School of Medicine, Klinikum rechts der Isar, Munich, Germany, Lange Nicole ,   Department of Neurosurgery, Technical University Munich, School of Medicine, Klinikum rechts der Isar, Munich, Germany, Podtschaske Armin H ,   Department of Anesthesiology, Technical University Munich, School of Medicine, Klinikum rechts der Isar, Munich, Germany, Martin Jan ,   Department of Anesthesiology, Technical University Munich, School of Medicine, Klinikum rechts der Isar, Munich, Germany, Albers Lucia ,   Department of Medical Informatics, Statistics and Epidemiology, Technical University Munich, School of Medicine, Klinikum rechts der Isar Munich, Germany, Werder Alexander von ,   Department of Neuroendocrinology, Technical University Munich, School of Medicine, Klinikum rechts der Isar, Munich, Germany, Ruland Jürgen ,   Department of Clinical Chemistry, Technical University Munich, School of Medicine, Klinikum rechts der Isar, Munich, Germany, Schneider Gerhard ,   Department of Anesthesiology, Technical University Munich, School of Medicine, Klinikum rechts der Isar, Munich, Germany, Meyer Bernhard ,   Department of Neurosurgery, Technical University Munich, School of Medicine, Klinikum rechts der Isar, Munich, Germany, Kagerbauer Simone M ,   Department of Anesthesiology, Technical University Munich, School of Medicine, Klinikum rechts der Isar, Munich, Germany, Gempt Jens ,   Department of Neurosurgery, Technical University Munich, School of Medicine, Klinikum rechts der Isar, Munich, Germany
Published: July 2022

Background: Anterior pituitary hormones in blood follow a circadian rhythm, which may be influenced by various factors such as intracranial pathologies. In cerebrospinal fluid (CSF), pituitary hormones have been collected only selectively and circadian rhythm has not yet been investigated. This pilot study analysed diurnal variations of anterior pituitary hormones in patients in neurocritical care to determine whether circadian rhythmicity exists in these patients. Possible influences of intracranial pathologies were also investigated. Blood and CSF concentrations were assessed simultaneously to explore the value of blood concentrations as a surrogate parameter for CSF levels. Methods: Blood and CSF samples of 20 non-sedated patients were collected at 06:00, noon, 18:00 and midnight, and analysed for adrenocorticotropic hormone (ACTH), cortisol, thyroid-stimulating hormone (TSH) and insulin-like growth factor-1 (IGF-1) concentrations at each of the four time points. ACTH and IGF-1 were measured by sandwich chemiluminescence immunoassay. Cortisol and TSH were measured by electrochemiluminescence immunoassay. Results: Results showed inconsistent circadian rhythms. Less than 50% of the patients showed a circadian rhythmicity of ACTH, cortisol, TSH or IGF-1. Significance of diurnal variations was only present for blood concentrations of TSH. Correlations between blood and CSF concentrations were strong for cortisol and TSH. Conclusions: CSF concentrations were only in the measurable range in some of the patients. No clear circadian rhythmicity could be identified, except for TSH in blood. Absence of significant diurnal variations could be explained by the underlying pathologies or disturbing influences of the intensive care unit. Blood concentrations of cortisol and TSH may be suitable surrogate parameters for CSF.