title: Systemic illness.
abstract: Systemic illnesses are associated with alterations in the hypothalamic-pituitary-peripheral hormone axes, which represent part of the adaptive response to stressful events and may be influenced by type and severity of illness and/or pharmacological therapy. The pituitary gland responds to an acute stressful event with two secretory patterns: adrenocorticotropin (ACTH), prolactin (PRL) and growth hormone (GH) levels increase, while luteinizing hormone (LH), follicle-stimulating hormone (FSH) and thyrotropin (TSH) levels may either decrease or remain unchanged, associated with a decreased activity of their target organ. In protracted critical illness, there is a uniformly reduced pulsatile secretion of ACTH, TSH, LH, PRL and GH, causing a reduction in serum levels of the respective target-hormones. These adaptations are initially protective; however, if inadequate or excessive they may be dangerous and may contribute to the high morbidity and mortality risk of these patients. There is no consensus regarding the type of approach, as well as the criteria to use to define pituitary axis function in critically ill patients. We here provide a critical approach to pituitary axis evaluation during systemic illness.
authors.affiliation: Department of Biomedical Sciences and Advanced Therapies, University of Ferrara, Ferrara, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Bondanelli
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Zatelli
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Ambrosio
authors.forename: Ettore C
authors.initials: EC
authors.lastname: degli Uberti
mesh_terms: D000818:Animals; D016638:Critical Illness; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology*; D010901:Pituitary Function Tests; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D013961:Thyroid Gland / Q000503:physiopathology