Metabolic complications of nonfunctioning pituitary macroadenomas: a mini review

• Main Authors: Lora Stanka Kirigin Biloš, Milan Vrkljan
• Format: Article
• Language: English
• Published: VBZ 2016-09-01
• Series: Endocrine Oncology and Metabolism
• Subjects: nonfunctioning pituitary adenomas; metabolic complications; diabetes mellitus; glucose intolerrance; dyslipidemia; hyperlipoproteinemia; obesity; pituitary; adenoma
• Online Access: http://eom.hdeo.eu/wp-content/uploads/2016/10/vol2-iss3-2KiriginBilos.pdf

Nonfunctioning pituitary macroadenomas (NFMA) make up 20% of pituitary adenomas. Previous studies have shown that patients treated for NFMA have disturbances in sleep characteristics, circadian movement rhythm, subjective sleep quality, and decreased quality of life. Furthermore, studies have shown that NFMA patients have an increased risk for the metabolic syndrome and insulin resistance. Despite these findings, long-term studies on the metabolic outcomes of NFMA patients are scarce. The purpose of this review is to familiarize clinicians with the potential metabolic complications of nonfunctioning pituitary adenomas, with an emphasis on pituitary macroadenomas. Patients with NFMA have an increased risk for developing the metabolic syndrome and have adverse metabolic outcomes, but the exact mechanisms involved remain unknown. The adverse metabolic profile of these patients could be the result of hypothalamic damage or intrinsic imperfections in hormone replacement therapy. However, because the optimal doses of levothyroxine, hydrocortisone and rhGH are not known and are variable between patients, and because the effects of these hormones are difficult to quantify at the tissue level, the metabolic effects of these replacement strategies are difficult to determine. This represents a limiting factor in designing studies to determine the metabolic complications of individual hormone deficiencies in patients with NFMA. From a clinical perspective, this represents a challenge in the outpatient management NFMA patients as the notion of adequate and stable hormone replacement is frequently challenged. Furthermore, the benefits of long-term rhGH therapy are still unknown, and it is still unclear which patients should receive rhGH substitution therapy. Despite these uncertainties, it is evident that patients treated for nonfunctioning pituitary adenomas should receive proper follow-up that includes cardiovascular risk assessment and treatment of metabolic complications as they arise. Patients should be informed of this potential complication so that lifestyle modifications can be made early in the course of their treatment.