TSH Response Research Articles

A-041 Metoclopramide Stimulation Test can Rule Out Prolactinoma in Patients with Moderate Hyperprolactinemia

Abstract Background Prolactinoma is the main cause of hyperprolactinemia once physiological and pharmacological causes are excluded. Prolactin (PRL) and thyrotropin (TSH) response to dopaminergic antagonists has been previously used in prolactinoma diagnosis. Current guidelines only recommend baseline PRL concentration in diagnosis, considering values exceeding 250 ng/mL highly suggestive of prolactinoma. However, subtler hyperprolactinemia is much more frequent, and magnetic resonance imaging (MRI) studies are necessary to detect potential prolactinomas. Our aim was to examine the utility of a metoclopramide (MCP) stimulation test as a screening tool to evaluate the need for pituitary MRI studies in patients with moderate hyperprolactinemia. Methods We retrospectively selected 67 moderate hyperprolactinemia patients (<250 ng/mL), with a MCP test and a pituitary MRI within the same assistance. We excluded patients with pharmacological treatments affecting dopaminergic axis. According MRI results we classified them in patients with microadenoma (<10 mm; n=23), with macroadenoma (≥10 mm; n=5) or without adenoma (n=39). Maximum relative increases over baseline concentrations were calculated for PRL (ΔPRLMax) and TSH (ΔTSHMax). The Research Ethic Committee approved the study. Results ΔPRLMax exceeds baseline PRL capability to identify patients with an adenoma (AUC=0.8718 vs 0.7756). ΔPRLMax below 220% identifies 100% of these patients with 71% of specificity (Table 1). Screening with MCP test would have avoided 42% of MRI, resulting in 34% costs saving. Analysis of TSH response only slightly increased the specificity when considered as a secondary criterion. Test length can be reduced from 60 to 30 minutes without losing screening capability. Conclusions A shortened MCP test is a useful and cost-effective screening tool to avoid unnecessary MRI. Its simplicity allows its performance in almost any clinical facility, allowing to easily rule out prolactinoma in an important percentage of patients, something of upmost importance specially in regions were MRI facilities are scarce.

Total thyroxine and thyroid-stimulating hormone responses of healthy cats to different doses of thyrotropin-releasing hormone.

Thyrotropin-releasing hormone (TRH) stimulation can be used as a test of thyroid function and pituitary thyrotropin (thyroid-stimulating hormone, TSH) reserve, but optimal stimulation testing protocols in cats are unreported. We randomly divided 6 healthy young adult cats into 3 groups of 2 and administered 3 different intravenous doses of TRH (0.01, 0.05, 0.1 mg/kg) at weekly intervals in our crossover study. Serum TSH and thyroxine (T4) concentrations were measured using chemiluminescent immunoassay before, and at 30 and 60 min after, TRH administration. All cats were monitored for 4 h post-TRH administration for side effects. All 3 TRH doses induced significant TSH (0.01 mg/kg, p = 0.001; 0.05 mg/kg, p = 0.002; 0.1 mg/kg, p = 0.006) and total T4 (0.01 mg/kg, p = 0.008; 0.05 mg/kg, p = 0.006; 0.1 mg/kg, p = 0.001) responses. Lower TRH doses (0.01 and 0.05 mg/kg) caused fewer side effects (1 of 6 cats) than did the highest dose (3 of 6 cats), and may be safer in cats than the previously reported higher dose (0.1 mg/kg) of TRH. Our results do not support the use of maropitant to prevent side effects of a TRH stimulation test in cats.

Retrospective Evaluation of Gastrointestinal Signs in Hypothyroid Dogs.

Few observations about gastrointestinal (GI) signs in hypothyroid dogs (hypo-T dogs) are available. We aimed to evaluate the prevalence and characteristics of concurrent GI signs in hypo-T dogs, describe clinicopathological, hepato-intestinal ultrasound findings in hypo-T dogs, investigate changes in GI signs after thyroid replacement therapy (THRT). Medical records of suspected hypo-T dogs from two hospitals were retrospectively reviewed. The inclusion criteria were: (1) having symptoms and clinicopathological abnormalities related to hypothyroidism (i.e., mild anemia, hyperlipemia); (2) not being affected by systemic acute disease; (3) not having received any treatment affecting thyroid axis. Hypothyroidism had to be confirmed using low fT4 or TT4 with high TSH and/or inadequate TSH-stimulation test response; otherwise, dogs were assigned to a euthyroid group. Clinical history, GI signs, hematobiochemical parameters, and abdominal ultrasound findings were recorded. Hypo-T dogs were assigned to the GI group (at least 2 GI signs) and not-GI group (1 or no GI signs). Follow-up information 3-5 weeks after THRT was recorded. In total, 110 medical records were screened: 31 dogs were hypo-T, and 79 were euthyroid. Hypo-T dogs showed a higher prevalence of GI signs (44%), especially constipation and diarrhea (p = 0.03 and p = 0.001), than euthyroid dogs (24%) (p = 0.04). Among hypo-T dogs, no difference in hematological parameters between GI and non-GI groups was found. Hypo-T dogs had a higher prevalence of gallbladder alterations than euthyroid dogs (20/25; 80% and 32/61; 52% p = 0.04). The hypo-T GI group showed a significant improvement in the GI signs after THRT (p < 0.0001). Specific investigation for concurrent GI diseases in hypo-T dogs was lacking; however, improvement in GI signs following THRT supports this association between GI signs and hypothyroidism.

A reference center study in thyrotropin-secreting pituitary adenomas: clinicopathological, therapeutic and long-term follow-up outcomes.

This study aims to analyze the clinicopathological features, diagnostic steps, and therapeutic results of TSHomas and to reveal the effective factors on remission. The clinical, radiological, and pathological features and surgical and endocrinological results of 41 TSHoma cases followed between 2005 and 2022 were retrospectively analyzed. The factors affecting the surgical cure were investigated by comparing the groups with and without remission. A total of 41 patients (23 male,18 female) were included in the study and the mean age was 42 (31.5-49). Palpitation and headache were the most common complaints. The time from the onset of symptoms to diagnosis was 8 (3-20) months. There were 8 patients with a preoperative clinical and biochemical diagnosis of TSH + GH co-secretion. In the TRH stimulation test, a blunted TSH response was obtained in 18 patients (90.0%). Complete suppression could not be obtained in any of the patients who underwent the T3 suppression test. The median maximum tumor diameter was 19.0 mm (6.8-41). There was microadenoma in 4 (9.8%) patients and macroadenoma in 37 patients (92.8%). Remission was achieved in 31 (75.6%) of 40 patients who underwent endoscopic transsphenoidal surgery (eTSS). The Ki-67 labeling index was 2% (1.00-4.00) in the entire patient group. Preoperative use of antithyroid drugs appears to be significantly associated with surgical cure. Diagnosis of TSHoma is still full of challenges and dynamic tests remain important. Recognition and good management of inappropriate TSH secretion states affect subsequent surgical outcomes.

Possible Association Between Thyroid Nodule Formation and Developmental Alterations in the Pituitary-Thyroid Hormone Axis in Children and Adolescents: The Fukushima Health Management Survey.

Background: We previously found low thyrotropin (TSH) levels in children and adolescents with thyroid nodules, including papillary thyroid cancer, although it is generally accepted that high TSH levels are a risk factor for formation and growth of thyroid nodules in adults. To clarify the reasons for the discrepancy, we precisely analyzed the features of pituitary-thyroid hormone (TH) actions in children and adolescents with or without nodules at different ages. Methods: Among the 4955 participants who participated in a second screening by thyroid ultrasound examination in the Fukushima Health Management Survey, 721 and 2849 euthyroid participants aged 6-20 years without or with nodules, including thyroid cancer, were selected for evaluation of TH regulation. The responsivity of TSH to THs was assessed by two thyroid feedback quantile-based indices (T4FQI and T3FQI). Logistic regression analyses were conducted to calculate the odds ratios (ORs) of serum concentrations related to thyroid functions for positive thyroid nodules compared with negative nodules. Results: The feedback indices declined in a sex-specific manner with aging. In particular, T3FQI, the index for TSH response to free triiodothyronine (fT3), started to decline after ∼10 and 15 years of age in female and male participants, respectively. Compared with the absence of nodules, the age- and sex-adjusted ORs (confidence intervals) for logTSH, free thyroxine (fT4), fT3, T4FQI, T3FQI, and thyroglobulin levels were 0.586 (0.501-0.685), 1.036 (0.595-1.805), 1.059 (0.842-1.332), 0.569 (0.454-0.715), 0.564 (0.443-0.719), and 1.01 (1.005-1.014), respectively. Associations between the presence of nodules and either low logTSH or low feedback indices were observed in participants aged between 12 and 17 years among the total cohort. Conclusions: The relationships between the levels of TSH and THs changed in a sex-dependent manner in children and adolescents. The age-dependent shift in the pituitary-TH set point may be associated with age-dependent nodule formation during restricted periods of growth and maturation in both young female and male participants.

P290. Effect of Repetitive Transcranial Magnetic Stimulation on Chronobiological Hypothalamic-Pituitary-Thyroid Axis Activity in Major Depression

We previously demonstrated that the difference between 11 PM and 8 AM TSH response to protirelin (TRH) tests on the same day (ΔΔTSH test) is an improved measure in detecting hypothalamic-pituitary-thyroid (HPT) axis dysregulation in depression. This chronobiological index is normalized after successful antidepressant treatment. The present study aimed at assessing the effects repetitive transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal cortex (DLPFC) on the HPT axis activity in treatment resistant depressed inpatients (TRDs).

Bexarotene-induced central hypothyroidism assessed by TRH stimulation test in cutaneous T-cell lymphoma patients.

Bexarotene-induced central hypothyroidism (CH), for which levothyroxine (LT4) replacement is recommended, has been shown to be caused by pituitary but not hypothalamic disorder experimentally, though the underlying mechanism in humans remains unclear. Here, the pathophysiology of bexarotene-induced CH was examined using a TRH stimulation test in cutaneous T-cell lymphoma (CTCL) patients. In this retrospective longitudinal observational study, serum TSH and free T4 (F-T4) levels were measured in 10 euthyroid patients with CTCL during 24 weeks of bexarotene treatment. TRH stimulation testing was performed following CH diagnosis, with LT4 replacement dosage adjusted to maintain F-T4 at the pre-treatment level. After one week of bexarotene administration, all 10 patients developed CH, based on combined findings of low or low-normal F-T4 with low or normal TSH levels. TSH peak response after a stimulation test at one week was reached at 30 minutes. However, that was <4 μIU/mL in all patients, indicating a blunted though not exaggerated and delayed TSH response. In eight who continued bexarotene for 24 weeks, median LT4 replacement dosage was 125 (range, 75-150) μg/day. TSH level at 30 as well as 15, 60, 90, and 120 minutes after TRH stimulation was significantly correlated with LT4 replacement dosage (ρ = -0.913, p = 0.002), whereas TSH and F-T4 basal levels at one week were not. These results suggest that pituitary hypothyroidism is responsible for bexarotene-induced CH, while TSH levels after TRH stimulation precisely reflect residual pituitary-thyroid function in patients receiving bexarotene.

Iodide-sensitive Graves' hyperthyroidism and the strategy for resistant or escaped patients during potassium iodide treatment.

The effectiveness of potassium iodide (KI) (100 mg/day) was evaluated in 504 untreated patients with Graves' hyperthyroidism (GD). Initial response to KI within 180 days, the effect of additional methylmercaptoimidazole (MMI) or radioactive iodine (RI) in resistant or escaped patients, and long-term prognosis were evaluated. Serum fT4 levels became low or normal in 422 patients (83.7%, KI-sensitive group) without serious side effects. Among these patients, serum TSH levels became high (n = 92, hypothyroid) or normal (n = 78) in 170 patients (33.7%) (KI-sensitive with a recovered TSH response, Group A), but remained suppressed in 252 patients (50.0%) (KI-sensitive with TSH suppression, Group B). Serum fT4 levels decreased but remained high in 82 patients (16.3%) (KI-resistant, Group C). Older patients, or those with small goiter and mild GD were more KI-sensitive with a recovered TSH response than others. Escape from KI effect occurred in 0%, 36% and 82% in Group A, B and C, respectively. Patients in Group B and C were successfully treated with additional low-dosage MMI or RI. After 2-23 years' treatment (n = 429), remission (including possible remission) and spontaneous hypothyroidism were significantly more frequent in Group A (74.3% and 11.1%, respectively,) than in Groups B (46.3% and 2.8%, respectively) or C (53.6% and 1.5%, respectively) (p < 0.0001). In conclusion, a high KI sensitivity with a recovered TSH response was observed in about a third of the patients in GD associated with a better prognosis. Additional MMI or RI therapy was effective in escaped or KI-resistant patients with suppressed TSH level.

A Hidden Link between Subclinical Hypothyroidism and Depression: A literature Review

The association between Subclinical hypothyroidism and Depression is recognised. It is found that patients with Thyroid disorders are more prone to develop depressive symptoms and depression may be accompanied by various subtle thyroid abnormalities. The most commonly documented abnormalities are elevated T4 levels, Low T3, elevated rT3, a blunted TSH response to TSH, Positive anti thyroid autoantibodies and elevated CSF TRH concentrations. It is also found that thyroid hormone supplements appear to accelerate and enhance the clinical response to antidepressants. It is found out that Depression is associated with changes in Hypothalamic-pituitary axis as thyroid hormones act on the central nervous system. Mild thyroid dysfunction causes depression in younger patients (&lt;60 years old) diagnosed by depressive scale. It was found that differences in age group may cause depressive episodes. Depressive episodes such as anxiety and the risk of committing suicide are considerable factors that differ according to the age of the individuals.SCH was found to be associated with depression in the younger adults (&lt;60 years old). The only difference between SCH and normal thyroid function is TSH.In depressive disorder and subclinical hypothyroidism sex differences have also been recognised. Association between subclinical hypothyroidism and Depression is assessed by various depressive scores such as Beck Depression Inventory and Hamilton depression rating scale. As Subclinical hypothyroidism is associated with low mood, Serum levels of TSH, FT3, FT4 and Hamilton depression, treatment with Levothyroxine showed significant decrease is TSH levels and Hamilton scores were decreased. Since the prevalence of depressive symptoms in hypothyroidism is high TSH cut-off levels is used,TSH cut off value for hypothyroidism is based on associated symptoms,TSH cut-off value is 2.5 MIU/L is optima

A Hidden Link between Subclinical Hypothyroidism and Depression: A literature Review

The association between Subclinical hypothyroidism and Depression is recognised. It is found that patients with Thyroid disorders are more prone to develop depressive symptoms and depression may be accompanied by various subtle thyroid abnormalities. The most commonly documented abnormalities are elevated T4 levels, Low T3, elevated rT3, a blunted TSH response to TSH, Positive anti thyroid autoantibodies and elevated CSF TRH concentrations. It is also found that thyroid hormone supplements appear to accelerate and enhance the clinical response to antidepressants. It is found out that Depression is associated with changes in Hypothalamic-pituitary axis as thyroid hormones act on the central nervous system. Mild thyroid dysfunction causes depression in younger patients (&lt;60 years old) diagnosed by depressive scale. It was found that differences in age group may cause depressive episodes. Depressive episodes such as anxiety and the risk of committing suicide are considerable factors that differ according to the age of the individuals.SCH was found to be associated with depression in the younger adults (&lt;60 years old). The only difference between SCH and normal thyroid function is TSH.In depressive disorder and subclinical hypothyroidism sex differences have also been recognised. Association between subclinical hypothyroidism and Depression is assessed by various depressive scores such as Beck Depression Inventory and Hamilton depression rating scale. As Subclinical hypothyroidism is associated with low mood, Serum levels of TSH, FT3, FT4 and Hamilton depression, treatment with Levothyroxine showed significant decrease is TSH levels and Hamilton scores were decreased. Since the prevalence of depressive symptoms in hypothyroidism is high TSH cut-off levels is used,TSH cut off value for hypothyroidism is based on associated symptoms,TSH cut-off value is 2.5 MIU/L is optimal

Analytical validation of the LiCA® high-sensitivity human thyroid stimulating hormone assay

BackgroundWe aimed to assess the analytical characteristics of a new high-sensitivity human thyroid stimulating hormone (hTSH) assay on a light-initiated chemiluminescent immunoassay system (LiCA Smart) and examine the utility of this assay in the context of profoundly low TSH levels (<0.01 mIU/L). MethodsAnalytical validations included precision, linearity, reportable range, analytical sensitivity, interference, reagent lot-to-lot and between-instrument variability, and method comparisons. Additionally, a cross-sectional study was performed to evaluate the assay for the detection of profoundly low TSH levels in comparison to those of two other ultrasensitive hTSH assays. ResultsWithin-run and within-lab imprecisions (%CV) were < 5% at all concentrations studied. A satisfactory linearity (R = 0.998, change in recovery < 5%) was verified over the entire measuring range. Method comparisons demonstrated a reasonable agreement (R > 0.99, median bias < 5%) between LiCA and Cobas, ADVIA, UniCel or Architect. The limit of quantitation was 0.0019 mIU/L. Comparative measurements of 236 patient samples with profoundly low TSH levels (<0.01 mIU/L) by LiCA, Cobas, and Architect revealed that the detection rate observed with LiCA (67.8%) was significantly higher than that with Cobas (28.0%) or Architect (21.7%). In a further comparative follow-up of patients with overt hyperthyroidism who were receiving treatment, an earlier recovery response of TSH was observed in LiCA. ConclusionsThe LiCA Smart hTSH is a precise and highly sensitive fourth-generation assay. The assay demonstrated superior detection sensitivity for profoundly low TSH levels and was acceptable for clinical use.

Mild progressive osseous heteroplasia overlap syndrome with PTH and TSH resistance appearing during adolescence and not early childhood

Progressive osseous heteroplasia (POH), a genetic disorder, is associated with Albright's hereditary osteodystrophy (AHO), pseudohypoparathyroidism, and primary osteoma cutis and has common features of superficial ossification and GNAS-inactivating mutations. Disorders due to GNAS-inactivating mutations are classified as "inactivating parathyroid hormone (PTH)/PTHrP signaling disorder type 2." This study reports a case of mild POH overlap syndrome to improve understanding of genotype-phenotype correlations. A 13-year and 6-month-old Japanese boy was referred to our hospital with a chief complaint of the lower limb length difference. He underwent clinical, biochemical, radiological, and genetic studies. He showed sporadic GNAS mutation, deep ectopic ossification, small for gestational age (SGA), congenital tooth defect, and lack of AHO features; he met the diagnostic criteria for POH, and mild PTH and TSH resistance was detected. He had constant hyperphosphatasemia and hypocalciuria. At the age of 10 years, he occasionally experienced high iPTH levels. The pituitary stimulation test showed a normal response of all hormones at 3 years of age, but TSH response was decreased (previously 0.770, peak value 4.144 μIU/mL) in the TRH loading test at age 13 years and 6 months. DNA analysis showed a heterozygous p.D189MfsTer14 mutation of GNAS. The parents did not carry this mutation. We report a rare case of POH overlap syndrome with PTH/TSH resistance that appeared in adolescence rather than early childhood. Cases diagnosed with POH in early childhood also require reassessment during adolescence. Further studies of the GNAS heterozygous mutation p.D189MfsTer14 may reveal factors involved in POH overlap syndrome.

Two Cases of Anti-PIT-1 Hypophysitis Exhibited as a Form of Paraneoplastic Syndrome

Abstract Background: Anti-pituitary-specific transcription factor 1 (PIT-1) hypophysitis (anti-PIT-1 antibody syndrome) is a newly defined clinical entity, demonstrating an adult-onset hypopituitarism, and is a thymoma-associated autoimmune disease characterized by acquired GH, PRL, and TSH deficiencies due to autoimmunity against PIT-1 (1, 2). This disease is defined by an acquired specific GH, PRL, and TSH deficiencies and the presence of circulating anti-PIT-1 antibody and/or PIT-1-specific T cells (2). As the etiology, ectopic expression of PIT-1 in thymoma plays a causal role in the development of the disease (3); however, it is unknown whether this disease is involved in other conditions. Here, we report two PIT-1 hypophysitis cases, exhibiting as a form of paraneoplastic syndrome with malignancies other than thymoma. Clinical Case: A 79-year-old woman (case 1) and an 86-year-old man (case 2) were referred to us on suspicion of anti-PIT-1 hypophysitis because of acquired GH, PRL, and TSH deficiencies. In both patients, the endocrinological evaluation revealed extremely low basal levels and blunted responses of GH, PRL, and TSH to the provocative stimuli. In contrast, the secretion of HPA and HPG axis were preserved in both patients. Magnetic resonance imaging of the pituitary gland showed slight atrophy in case 1 and normal size in case 2. Interestingly, computed tomography imaging revealed no evidence for thymomas in both patients. On the other hand, case 1 was complicated with diffuse large B-cell lymphoma (DLBCL) of the bladder with multiple bilateral cervicals, axillary, para-aorta, and internal and external peri iliac lymphadenopathies. Case 2 was diagnosed with malignancy with multiple metastases of unknown origin with para-aortic and para-gastric lymphadenopathies, and vertebral body infiltrates. Because circulating anti-PIT-1 antibody was detected, both patients were diagnosed with anti-PIT-1 hypophysitis. Circulating PIT-1-reactive T cells were detected in case 1 using Enzyme-Linked Immunospot assay. Interestingly, the PIT-1 protein was ectopically expressed in the DLBCL tissue of case 1, while DLBCL tissues derived from control patients without anti-PIT-1 hypophysitis were negative for PIT-1. In case 2, the materials were not available because of the situation of the best supportive care. Conclusion: These data show that anti-PIT-1 hypophysitis is associated not only with thymoma but also with other malignancies. Additionally, the ectopic expression of PIT-1 in the DLBCL tissues and presence of PIT-1- reactive T cells suggested that the underlying mechanisms were similar to those observed in thymoma (3). Thus, anti-PIT-1 hypophysitis is defined as a form of paraneoplastic syndrome. Reference: (1) J Clin Invest. 2011;121(1):113-119., (2) Endocr Rev. 2020;41(2)., (3) Sci Rep. 2017;7:43060.

TRH Stimulation Testing in Older Individuals with Persistent Subclinical Hypothyroidism: A Randomized, Double-Blind, Cross-Over Study of Levothyroxine and Liothyronine Administration

Abstract Background: Subclinical hypothyroidism is common in older individuals. To better understand the underlying physiology, we examined the pituitary-thyroid axis using thyrotropin releasing hormone (TRH) stimulation testing both at baseline and after levothyroxine (LT4) and liothyronine (LT3) supplementation. Methods: We conducted a randomized, double-blind, cross-over study in men and women aged 70 years and over without anti-thyroid peroxidase antibodies with persistent subclinical hypothyroidism, defined as having a TSH level between 4.5 and 19.9 µIU/mL with a normal free thyroxine (FT4) level at two consecutive time points. The primary outcome measures were TSH serum concentration area under the curve (AUC), maximum TSH serum concentration (Cmax), and change in free thyroxine (∆FT4) and total triiodothyronine (∆TT3) levels following TRH stimulation, each measured at three time points: once at baseline and once each after achieving euthyroid TSH levels with the two thyroid preparations. The maximal change in TSH (∆TSH); FT4 and TT3 AUCs; and time to maximal TSH, FT4, and TT3 (Tmax) were also analyzed. Results: Thirteen participants [mean (SD) age 77 (5) years], 4 women and 9 men, completed TRH stimulation testing at baseline and after achieving a TSH level of 0.5-1.5 µIU/mL with each therapy. Baseline mean TSH was 4.84 (1.29) µIU/mL. The mean LT4 dose was 105 (36) µg/day and LT4 dose was 34 (9) µg/day. After TRH stimulation, the mean TSH AUC (0-180) at baseline was 3099.5 (1424.4) µIU*min/mL, and significantly decreased after both LT4 [631.4 (315.2), p&amp;lt;0.001] and LT3 [631.5 (317.3), p&amp;lt;0.001]. There was no difference in TSH AUC (0-180) between LT4 and LT3 treatment arms. Baseline mean TSH Cmax was 27.2 (14.5) µIU/mL and significantly decreased after LT4 [5.5 (3.0), p&amp;lt;0.001] and LT3 [5.4 (2.9), p&amp;lt;0.001], with no difference between the LT4 and LT3 treatment arms. The ∆FT4 was 0.11 (0.07) ng/dL at baseline and decreased significantly on LT3. The ∆TT3 was 0.32 (0.09) ng/mL at baseline and significantly decreased on both LT4 and LT3, with no difference between treatment arms. Conclusions: Older individuals with antibody-negative persistent subclinical hypothyroidism have a heterogeneous TSH response to TRH stimulation. Our data show a significantly diminished response to TRH stimulation after thyroid hormone replacement, and they support the pharmacodynamic equivalence of LT4 and LT3 treatment.

Thyrotropin Secreting Adenoma in a Patient with Autoimmune Hypothyroidism: Case Report of a Challenging Diagnosis

Clinical presentation: We describe a case of a 47-year-old woman with a longtime primary autoimmune hypothyroidism with a progressive rising of TSH levels despite increasing of LT4 therapy. LT4 dose was increased up to 2.9 mcg/kg/day causing an excess of circulating fT4 a minor increase of fT3 concentrations without, however, achieving TSH normalization. The patients was asymptomatic and during the long observation period she had two term pregnancies. A withdrawal of thyroid hormone replacement therapy appropriately induced a further increase of TSH levels and a decrease of fT3 and fT4 below the normal range. LT4 therapy was then resumed and, because TSH levels failed to normalize, central hyperthyroidism or thyroid hormone resistance were suspected. Thyroid levels of first grade relatives were normal, and TSH response to TRH was positive, leaving the diagnosis unclear. The magnetic resonance imaging (MRI) of sellar region revealed a pituitary macroadenoma. The remaining pituitary function was normal. The patient underwent transphenoidal surgery (TNS) and histological examination showed positive immunostaining for TSH, and a mild positivity for GH. After surgery, TSH levels quickly fall down and her replacement therapy could finally be optimized.

English

BACKGROUND Patients with DM are at increased risk of thyroid disease, especially those with poor glycaemic control. The following mechanisms are thought to be responsible. In patients with DM, the nocturnal TSH peak is blunted or abolished; the TSH response to TRH, from the hypothalamus, is impaired thus leading to hypothyroidism. We wanted to study the thyroid disorders in type 2 diabetic and non-diabetic patients attending a tertiary care hospital. METHODS This is an analytical observational study conducted among 100 type 2 diabetic and 100 non-diabetic patients attending medicine OPD in the Department of General Medicine of Narayan Medical College &amp; Hospital, Jamuhar, Distt. Rohtas over a 6- month period from Oct 2019 to April 2020. RESULTS The mean age of group A and group B was found to be 51.79 ± 10.374 and 49.86 ± 9.538 respectively. In group A (diabetes mellitus patients), 71 (71 %) patients were euthyroid whereas in group B (healthy individuals) 84 (84 %) patients were euthyroid. In Group A (diabetes mellitus group) either subclinical or overt hypothyroidism was seen in 26 (26 %) patients and hyperthyroidism was seen in 3 (3 %) patients. In Group B (healthy individuals) either subclinical or overt hypothyroidism was seen in 14 (14 %) patients and hyperthyroidism was seen in 2 (2 %) patients. CONCLUSIONS The comparison of the patients of control and cases groups on the basis of whether they had a normal or abnormal thyroid function test showed that patients with diabetes mellitus type 2 (Group A) were more likely to be having abnormal thyroid function test as compared to healthy individuals (Group B) and this difference was found to be statistically significant (p = 0.027). KEYWORDS Type 2 DM, Hypothyroid, Hyperglycaemia, Hyperthyroid

BÜYÜME HORMONU TEDAVİSİ ALAN ÇOCUKLARIN KLİNİK ÖZELLİKLERİ: TEK MERKEZ DENEYİMİ

Objective: In this study, we aimed to investigate the clinical features of children who received growth hormone (GH) treatment with a diagnosis of GH deficiency (GHD). Material and Methods: The clinical features of children treated with GH treatment between 01.06.2013-31.12.2018 in a tertiary healthcare service were retrospectively analyzed. Children with isolated GHD and children with panhipopituitarism were compared. Results: In total, 70 boys 118 children were included in the study. 78 (66.3%) of patients were treated with GH due to isoleted GHD, 14 (11.9%) due to bio-inactive GH syndrome, 9 (7.6%) due to panhypopituitarism, 6 (5.1%) due to GH neurosecretory dysfunction, 6 (5.1%) due to Turner syndrome and 5 (4.2%) due to off-label reasons.There were no significant diffrence between groups of isoleted GHD and panhipopituitarism regarding gender, age of diagnosis and oxological features at diagnosis. Serum IGF-1 SDS, IGFBP-3 SDS, TSH and pik GH response to klonidine test were lower in panhipopituitarism group (p=0.026, p=0.002, p=0.009 ve p=0.005, respectively). Significantly higher growth rates in the first 2 years in the patient with panhypopituitarism were determined (p<0.001 and p=0.005, respectively). A correlation was found between the growth rate in the first year and age of diagnosis, GH stimulation test responses, serum IGFBP-3 SDS and difference between chronologic age and bone age. Conclusion: Patients with panhypopituitarism had more significant laboratory findings for GHD at admission and better GH treatment responses in follow-up compared to patients with isolated GHD.

MON-723 Identification of Thyrotrope Signature Genes and Regulatory Elements

Recent genome wide association studies have begun to identify loci that are risk factors for sporadic pituitary adenomas, but the genes associated with these loci are unknown. In general, ~90% of GWAS hits are in noncoding regions, making it difficult to transition from genetic mapping to a biological understanding of risk factors. Recent studies that identify enhancer regions by undertaking large scale functional genomic annotation of non-coding elements like Encyclopedia of DNA Elements (ENCODE) have begun to yield a better understanding of some complex diseases. Dense molecular profiling maps of the transcriptome and epigenome have been generated for more than 250 cell lines and 150 tissues, but pituitary cell lines or tissues were not included. Epigenetic and gene expression data are emerging for somatotropes, gonadotropes and corticotropes, but there is very little available data on thyrotropes. We identified the transcription factors and epigenetic changes in chromatin that are associated with differentiation of POU1F1-expressing progenitors into thyrotropes using cell lines that represent an early, undifferentiated Pou1f1 lineage progenitor (GHF-T1) and a committed thyrotrope (TαT1). TαT1 is an excellent cell line for this purpose because it responds to TRH, retinoids, and secretes TSH in response to diurnal cues. We have also used genetic labeling and fluorescence activated cell sorting to purify thyrotropes from pituitaries of young mice and analyzed gene expression using single cell transcriptomics. We used the Assay for TransposaseAccessible Chromatin with sequencing (ATACseq) and Cleavage Under Target and Release Using Nuclease (CUT&RUN) to identify POU1F1 binding sites and histone marks associated with active enhancers, H3K27Ac and H3K4Me1, or inactive regions, H3K27Me3, in GHF-T1 and TαT1 cells. We integrated DNA accessibility, histone modification patterns, transcription factor binding and RNA expression data to identify regulatory elements and candidate transcriptional regulators. We identified POU1F1 binding sites that were unique to each cell line. For example, POU1F1 binds sites in and around Cga and Tshb only in TαT1 cells and Twist1 and Gli3 only in GHFT1 cells. POU1F1 binding sites are commonly associated with bZIP factor consensus binding sites in GHFT1 cells and Helix-Turn-Helix or basic Helix-Loop-Helix in TαT1 cells, suggesting classes of transcription factors that may recruit POU1F1 to unique sites. We validated enhancer function of novel elements we mapped near Tshb, Gata2, and Pitx1 by transfection in TαT1 cells. Finally, we confirmed that an enhancer element near Tshb can drive expression in thyrotropes of transgenic mice. These data extend the ENCODE analysis to an organ that is critical for growth and metabolism. This information could be valuable for understanding pituitary development and disease pathogenesis.

SAT-244 Inflammatory Rathke Cleft Cyst Caused Hypothalamic Panhypopituitarism

Background: Hypothalamic panhypopituitarism was a rare disease which was caused by brain tumors such as Rathke cyst, germinoma, malignant lymphoma and craniopharyngioma, and vascular accidents such as thrombosis and hemorrhage. We have found a rare case of hypothalamic panhypopituitarism occurred by the inflammation of Rathke cyst. Case presentation: A 77-year-old woman was admitted to our hospital because of severe headache, nausea, vomiting and fever. Hyponatremia (Na 131 meq/L) and increased CRP level (0.20 mg/dl) and no finding of gastroenterological examination and abdominal CT scanning were observed. Endocrinological examination revealed low levels of anterior pituitary hormones such as GH, LH, FSH and ACTH and increased PRL levels and low level of serum cortisol. Simultaneous CRH, TRH and LH-RH stimulations tests indicated low responses of TSH, LH, FSH and PRL and hyperesponse of ACTH (from 2.4 to 251 pg/ml). Radiological examination by enhanced MRI revealed high intensity of T2-weighted images and low and partial high intensities of T1-weighted images in swelling of pituitary gland and vanishment of high intensity of posterior lobe in T2-weighted images suggesting that the inflammatory wall of Rathke cyst. We searched previous data of ACTH and cortisol levels which showed normal level of ACTH (55.2 pg/ml) and cortisol 18.8 μ;g/dl) when headache and nausea arouse on 50 days before. Based on above results patient was diagnosed as hypothalamic hypopituitarism due to inflammatory Rathke cyst. Therefore, patient was treated with hormone replacement therapy by 20 mg of hydrocortisone. After these treatment, polyuria, urinary low osmotic pressure and hypernatremia appeared due to partial diabetes insipidus caused by the impairment of posterior lobe in pituitary gland, and diagnosed by the examination of vasopressin test. This patient was also treated by the oral desmopressin acetate hydrate (60 μ;g/day), and has been well-tolerated in the outpatient clinic. Conclusion: These results suggested that inflammatory Rathke cyst with inflammatory changes in hypothlamo-pituitary system raised a rare case of hypothalamic panhypopituitarism.Reference: Nishioka H. et al.: Clin Endocrinology (Oxf) 2006:64:184–188

SAT-268 Thyrotropin Secreting Pituitary Adenoma Initially Misdiagnosed as Primary Hyperthyroidism in a Taiwanese Man

Background:TSH (Thyrotropin) secreting pituitary adenoma (TSHoma) account for less than 1% of all causes of hyperthyroidism and 1% of all functioning pituitary tumors. Definite diagnosis and treatment of TSHoma are clinical challenges in practice. Here we report laboratory data, imaging findings, endocrine dynamic test, and treatment outcomes in a 50-year-old Taiwanese man with pituitary plurihormonal adenoma secreting TSH and LH.Clinical case:The patient was initially diagnosed as goiter with primary hyperthyroidism and DM while medical check-up by primary care physician in 2014. He had no significant hyperthyroidism symptoms and signs except goiter and mild palpitation. He received propylthiouracil and Metformin. Two years later, he visited to Endocrinologist’s clinic for poor glycemic control. Central hyperthyroidism was diagnosed due to measurable TSH level in the presence of increased serum thyroid hormone level. Moreover sella MRI revealed left sided pituitary lesion. He was referred to Taipei Veteran General Hospital for further management. There was no family history of thyroid disease. Physical examination was not remarkable except diffuse grade 3 goiter and tachycardia (HR 100~115 bpm). Follow up laboratory data showed TSH 4.89; range 0.4~4.0 uIU/ml, free T4: 3.05; range 0.9~1.8 ng/dl, T4: 16.02; range 4.50~12.50 μg/dl, T3: 249; range 58~159 ng/dl, free T3: 8.0; range 2.3~4.3 pg/ml. Two times of TRH stimulation test showed blunted TSH response. Normal limit of thyroid autoantibodies level were found. Thyroid sonography revealed heterogenous echogenicity with increased size and vascularity of both lobes. I-131 uptake was homogenous uptake (94%). Other pituitary hormones level were within normal limit except mild elevation of testosterone 12.69 ng/ml. Sella MRI with contrast showed macroadenoma (size 10x10x7.6 mm) at left pituitary gland. Taken together, he was diagnosed as central hyperthyroidism related to left sided pituitary macroadenoma. Surgery was performed after one year of definite diagnosis due to personal reason. TSH level returned to normal ranges (0.799 uIU/ml) in 1st post operative day. Histologically, the pituitary mass was compatible with plurihormonal adenoma and immunohistochemistry showed positivity for TSH (4+) and LH (3+). Post operative condition was well. Antithyroid agent was discontinued after operation. His blood glucose became well controlled after operation.Clinical lessons:A biochemical hallmark of TSHoma is an escape of TSH from the feedback loop that is detectable TSH levels in the presence of increased serum thyroid hormone level. Diagnosis of TSHoma was frequently unrecognized and thus much delayed despite its relatively straightforward. Physician should keep in mind that the importance interpretation of simple laboratory tests to avoid delay diagnosis and unnecessary treatments.