Perianesthetic Management of Patients With Thyroid-Stimulating Hormone-Secreting Pituitary Adenomas

The effect of preoperative TSH levels on perioperative complications in patients undergoing pituitary surgery

INTRODUCTION

Pituitary surgery involves special conditions for the anaesthetist due to the anatomical localisation and the role of the pituitary gland in hormonal balance. The aim of this study was to retrospectively investigate the effect of TSH levels on perioperative complication rates in patients undergoing pituitary surgery.

METHODS

In this study, patients who underwent pituitary surgery at Izmir Katip Celebi University Ataturk Training and Research Hospital between January 2017 and November 2022 were retrospectively screened. Two patients out of the 137 were excluded from the study as they underwent simultaneous aneurysm surgery along with pituitary tumor surgery. A total of 135 patients meeting the criteria were analyzed. Patients were divided into three groups according to TSH levels. Perioperative complication rates and mortality rates were compared between the three groups.

FINDINGS

The study included a total of 135 patients, with an age range of 16-76 years. Among the groups with low-normal-high TSH levels, there were no statistically significant difference observed, in postoperative complications, such as epistaxis, rhinorrhea, postoperative nausea/vomiting, seizures, hypertension, and hypotension. When looking at the incidence of postoperative diabetes insipidus, a significant difference was found between the groups. When examining the mortality rates on the 28th day, a significant difference was found between the groups, with a mortality rate of 25% in the high TSH group (p < 0.5).

CONCLUSIONS

The risk of perioperative mortality is higher in patients with TSH levels above normal.

Recent advancements in the molecular biology of pituitary adenomas

INTRODUCTION

Pituitary adenomas are a common and diverse group of intracranial tumors arising from the anterior pituitary that are usually slow-growing and benign, but still pose a significant healthcare burden to patients. Additionally, they are increasing in both incidence and prevalence, leading to a need for better understanding of molecular changes in the development of these tumors.

AREAS COVERED

A PubMed literature search was conducted using the terms 'pituitary adenoma' in combination with keywords related to secretory subtype: lactotroph, somatotroph, corticotroph, gonadotroph and null cell, in addition to their transcription factor expression: PIT1, TPIT, and SF-1. Articles resulting from this search were analyzed, as well as relevant articles cited as their references. In this review, we highlight recent advances in the genetic and epigenetic characterization of individual pituitary adenoma subtypes and the effect it may have on guiding future clinical treatment of these tumors.

EXPERT OPINION

Understanding the molecular biology of pituitary adenomas is a fundamental step toward advancing the treatment of these tumors. Yet crucial knowledge gaps exist in our understanding of the underlying molecular biology of pituitary adenomas which can potentially be addressed by turning to differentially activated molecular pathways in tumor relative to normal gland.

Central Hyperthyroidism due to Thyroid-Stimulating Hormone-Secreting Pituitary Microadenoma in an Adolescent Boy: Case Report and Review of the Literature

Thyroid-stimulating hormone- (TSH-) secreting pituitary adenoma (TSH-oma) is a rare cause of secondary hyperthyroidism and can be misdiagnosed as primary hyperthyroidism. We report a case of a 15-year-old male patient who was one of two monozygotic twins and exhibited hyperthyroidism syndrome. The laboratory results showed secondary hyperthyroidism, with increased levels of free T3 (FT3) and free T4 (FT4) and no TSH inhibition. Magnetic resonance imaging (MRI) and histopathological examination of the pituitary gland confirmed pituitary microadenoma. The patient was treated with methimazole, propranolol, and somatostatin analogs to restore euthyroidism before undergoing an endoscopic transsphenoidal resection of the pituitary tumor. After surgery, the hyperthyroidism symptoms improved, thyroid hormones normalized, and MRI of the pituitary gland showed the complete removal of the tumor with no recurrence after 2 years of follow-up.

Immediate postoperative measurement of thyroid-stimulating hormone as an early predictor of remission in thyroid-stimulating hormone-secreting pituitary adenomas

OBJECTIVE

Thyroid-stimulating hormone (TSH)-secreting pituitary adenoma (TSHoma) is a rare type of pituitary adenoma; thus, little is known about TSHomas. The purpose of this study was to analyze clinical characteristics and therapeutic outcomes of TSHomas based on a single-center experience. The authors also searched for reliable preoperative and early postoperative factors that could predict long-term endocrinological remission.

METHODS

The clinical, radiological, and pathological characteristics and surgical and endocrinological outcomes of 31 consecutive cases of TSHomas that were surgically treated between 2005 and 2017 were reviewed retrospectively. Preoperative factors were evaluated for their ability to predict long-term remission by comparing remission and nonremission groups. TSH and free thyroxine levels were measured at 2, 6, 12, 18, and 24 hours after surgery to determine whether they could predict long-term remission.

RESULTS

Gross-total removal of tumor was achieved in 28 patients (90.3%), and 26 patients (83.9%) achieved endocrinological remission by surgery alone based on long-term endocrinological follow-up (median 50 months, range 32-81 months). The majority of the tumors were solid (21/31, 67.7%), and en bloc resection was possible in 16 patients (51.6%). Larger tumor size and tumor invasion into cavernous sinus and sphenoid sinus were strong predictors of lower rates of endocrinological remission. Immediate postoperative TSH level at 12 hours after surgery was the strongest predictor, with a 0.62 μIU/mL cutoff. Postoperative complications included CSF rhinorrhea in one patient and epistaxis in another patient, who underwent additional surgical treatment for the complications.

CONCLUSIONS

Tumor size and extent are major prognostic factors for both extent of resection and endocrinological remission. The consistency of TSHomas was more likely to be solid, which makes extracapsular dissection more feasible. Long-term remission of TSHomas could be predicted even during the early postoperative period.

A 2019 update on TSH-secreting pituitary adenomas

Thyrotropin-secreting pituitary adenomas (TSH-omas) present with signs and symptoms of hyperthyroidism and they are characterized by elevated serum levels of free thyroid hormones with measurable TSH levels. TSH-omas are very infrequent, accounting for less than 1% of all pituitary adenomas, thus representing a very rare cause of hyperthyroidism. For this reason, data collected on these rare disorders are relatively few, but some new researches shed new light on the etiopathogenesis, the diagnosis and the treatment of such a remarkable disease. Since the same biochemical picture is present in the syndromes of thyroid hormone resistance (RTH), in particular in the form of pituitary RTH, failure in distinguishing these clinical entities may lead to improper patient management. Conversely, early diagnosis and correct treatment of TSH-omas may prevent the occurrence of neurological and endocrinological complications, thus leading to a better rate of cure. In the present short review article, the most relevant recent advances in the pathophysiology of TSH-omas are described.

Neuroanesthesiology Update

We provide a synopsis of innovative research, recurring themes, and novel experimental findings pertinent to the care of neurosurgical patients and critically ill patients with neurological diseases. We cover the following broad topics: general neurosurgery, spine surgery, stroke, traumatic brain injury, monitoring, and anesthetic neurotoxicity.

High Prevalence of Radiological Vertebral Fractures in Patients With TSH-Secreting Pituitary Adenoma

Background

Bone loss and high risk of fractures have been reported in patients with primary hyperthyroidism, whereas data on skeletal health in TSH-secreting adenoma (TSH-oma) are scant, and the risk of fractures in this specific clinical context has not been investigated so far. In this cross-sectional study, we aimed at evaluating for the first time, to our knowledge, the prevalence and determinants of radiological vertebral fractures (VFs) in patients with TSH-oma.

Methods

Twenty-two patients (10 males, 12 females; median age 47 years) with TSH-oma and 44 patients (20 males, 24 females; median age 49 years) with nonfunctioning pituitary adenoma (NFPA) were retrospectively evaluated for thoracic VFs using a morphometric approach on lateral chest X-ray routinely performed in the presurgical diagnostic workup.

Results

The prevalence of VFs was significantly higher in TSH-oma vs NFPA (59.1% vs 22.7%; P = 0.003), the difference being still significant (odds ratio, 10.5; P = 0.005) after correction for the size of pituitary adenomas and biochemical parameters. In TSH-oma, the prevalence of VFs was significantly associated with older age (P = 0.007) and higher serum free T4 values (P = 0.02). In 20 patients, data on presurgical medical therapies of TSH-oma were available. All patients not treated with somatostatin receptor ligands were fractured compared with 25% of those who were treated with these drugs (P = 0.001). No significant (P = 0.25) association between VFs and treatment with methimazole was found.

Conclusions

This study provides the first evidence, to our knowledge, that patients with TSH-oma may develop VFs in close relationship with severity of hyperthyroidism.