Effect of Distance from Target on Hypopituitarism After Stereotactic Radiosurgery for Pituitary Adenomas

IntroductionDelayed hypopituitarism is the most common complication after stereotactic radiosurgery (SRS) for pituitary adenomas. The aim of this study was to investigate the relationship between the distance from the hypothalamic-pituitary axis to the treatment target and anterior pituitary function preservation after SRS. MethodsBetween 2007 and 2020, consecutive adult patients who underwent single-session SRS for pituitary adenomas with ³6 months of follow-up were included. Distance measurements between hypothalamic-pituitary axis structures and the SRS target volume were quantified on MRI. The primary outcome was anterior pituitary function preservation. Outcomes were compared using multivariable regression and area under the receiver operator characteristic curve (AUROC) analyses. ResultsThe study cohort comprised 224 patients, who were categorized by preservation (n=168) and no preservation (n=56) of anterior pituitary function after SRS. Independent predictors of anterior pituitary function preservation were a greater distance between the center of the pituitary gland and center of the SRS target (OR=1.101 [1.000–1.213], p=0.050), and a shorter clinical follow-up duration (OR=0.985 [0.977–0.993], p<0.0001). The adjusted AUROC for the distance from the center of the pituitary gland and center of the SRS target in predicting anterior pituitary function preservation was 0.595. The sensitivity, specificity, positive predictive value and negative predictive value in predicting anterior pituitary function preservation at the optimal cut-off distance of 15mm were 30.0%, 88.0%, 89.9% and 26.2%, respectively.ConclusionsGreater distance between the normal pituitary gland and the SRS target is associated with anterior pituitary function preservation and increasing this distance should be a goal of adenoma resection. Larger prospective, multi-center studies are necessary to corroborate this finding and establish the effects of distance on hypopituitarism after SRS for pituitary adenomas.

Practical and nursing aspects of endocrine conditions

Endocrinology nursing is an ever-evolving specialty. This chapter provides expert and innovative practice-based nursing information. It provides nursing care for thyroid surgery and disorders, facilitating investigation and education about pituitary function and specialist nurse management of different conditions. Education on visual field deficits and minimum driving standards are covered. The full roles of the nurse in pituitary surgery is explained, from pre-op to post-op care. Diabetes insipidus is covered. Responsibilities and possible pathways for managing male fertility, testosterone replacement, and gender dysphoria are all described. Finally, role development and nurse led clinics are examined.

Pituitary

This chapter covers the pituitary gland. It starts with the anatomy and physiology, then moves on to imaging, and pituitary function. It then covers common tests, including ITT, glucagon, ACTH stimulation, arginine, clomiphene, hCG, and TRH. It then begins to cover disorders of pituitary function, with treatment, hormone replacement, and investigation all included. Pituitary tumours are described, along with investigation, diagnosis, and treatment. Other disorders, including Cushing’s disease, cysts, inflammatory conditions are all included. Complications from other conditions are also described.

Deterioration of pituitary function without relapse after steroid therapy for IgG4-related hypophysitis

Summary IgG4-related hypophysitis is an autoimmune hypophysitis associated with IgG4-related disease. Swelling of the pituitary gland is responsive to steroid therapy, but the prognosis of pituitary function after the treatment remains unclear. The present case implies that transiently improved pituitary function can re-worsen during long-term follow-up in IgG4-related hypophysitis. A 71-year-old male patient with IgG4-related hypophysitis visited a nearby hospital with malaise, anorexia, and polyuria. Pituitary dysfunction was suspected, so he was referred to our hospital for further examination. Imaging studies and laboratory data showed swelling of the pituitary gland and panhypopituitarism, which dramatically improved following steroid therapy. There was no evidence of relapsing IgG4-related disease during prednisolone tapering. Pituitary function was examined after 4 years under treatment with low-dose prednisolone; surprisingly, anterior pituitary function had worsened again. Our case suggests a need for continuous monitoring of pituitary function after steroid therapy for IgG4-related hypophysitis. This report illustrates the natural course of pituitary function in IgG4-related hypophysitis and may be informative when considering the introduction of steroid therapy. Learning points Steroid therapy is an effective first-line therapy for pituitary dysfunction and pituitary swelling in IgG4-related hypophysitis. Pituitary function can worsen again during follow-up, despite transient improvement after steroid therapy in IgG4-related hypophysitis. Continuous monitoring of pituitary function is necessary for IgG4-related hypophysitis, regardless of disease activity.

Pituitary function after transsphenoidal surgery including measurement of basal morning cortisol as predictor of adrenal insufficiency

Introduction: Patients with pituitary adenomas undergoing transsphenoidal surgery require pre- and post-surgery examination of pituitary hormones. There is currently no consensus on how to evaluate the adrenal axis post-surgery. The aims of this study were to investigate factors that may predict postoperative adrenal insufficiency (AI) and to investigate the overall effect of transsphenoidal surgery on the pituitary function. Methods: One-hundred-and-forty-three consecutive patients who had undergone transsphenoidal surgery for pituitary adenomas were included. Data on tumour size, pituitary function pre-surgery, plasma basal cortisol measured within 48 hours post-surgery and pituitary function 6 months post-surgery were collected. Patients with AI prior to surgery, perioperative glucocorticoid treatment, Cushing’s disease and no re-evaluation after 1 month were excluded (n=93) in the basal cortisol analysis. Results: Low plasma basal cortisol post-surgery, tumour size and previous pituitary surgery were predictors of AI (all p<0.05). A basal cortisol cut-off concentration of 300 nmol/L predicted AI 6 months post-surgery with a sensitivity and negative predictive value of 100%, specificity of 81% and positive predictive value of 25%. New gonadal, thyroid and adrenal axis insufficiencies accounted for 2%, 10% and 10%, respectively. The corresponding recovery rates were 17%, 7% and 24%, respectively Conclusion: Transsphenoidal surgery had an overall beneficial effect on pituitary endocrine function. Low basal plasma cortisol measured within 48 hours after surgery, tumour size and previous surgery were identified as risk factors for AI. Measurement of basal cortisol post-surgery may help identifying patients at risk of developing AI.

Transcriptional and Genomic Regulation of Pituitary Function by Thyroid Hormone Receptor Beta

Background : The pituitary is a key target for thyroid hormone but underlying transcriptional mechanisms are poorly understood. Thyroid hormone modifies expression of hormones, including growth hormone (GH) and thyroid-stimulating hormone (TSH, thyrotropin). Wider transcriptome responses are undefined. Thyroid hormone receptor beta (TRb) encoded by THRB are expressed in the anterior pituitary and THRB mutations cause human resistance to thyroid hormone. Method: To investigate genomic genomic regulation by TRb, we derived Thrb-HAB knockin mice that express TRb protein with a tag that is biotinylated in vivo in presence of an R26-BirA allele. Specific, sensitive streptavidin pull-down facilitated Chromatin-Affinity-Purification-sequencing (ChAPseq) to identify genomic TRβ binding sites in pituitary of male mice. Hypo- and hyperthyroidism were produced using methimazole (MMI) in drinking water for 4 weeks with/without added thyroid hormone (T3) for the 4th week. Pituitaries from wild type and Thrb-KO mice were also isolated for RNA-sequencing (RNA-seq). Selected expression changes were confirmed by quantitative PCR. Epigenetic changes were determined by ChIPseq for histone acetylation and methylation and open chromatin analysis (ATAC-seq). Results: Transcriptome analysis revealed genes with statistically different expression induced by T3, including known response genes such as Tshb, Hr and Gh. Responses were impaired in Thrb-KO mice. T3 induced recruitment of TRb binding, chromatin opening and specific histone acetylation marks. Conclusion: Most T3 response genes in pituitary depend to some extent upon TRb. T3-dependent chromatin modifications indicate properties of TRb-dependent enhancer regions and a critical role for TRb in transcriptional regulation of pituitary function.