Preoperative management of Graves' disease (GD) typically includes antithyroid drugs, β-blockers, and short-term iodine. However, intensified therapy may result in excessive elevation of thyroid-stimulating hormone (TSH). Whether a TSH threshold (≥10.0 μIU/mL) can determine greater operative difficulty in such patients is unclear. Therefore, we assessed this association in patients with GD who underwent total thyroidectomy. This retrospective cohort study included consecutive patients with GD who underwent total thyroidectomy at a single center between 2009 and 2022 (n = 1516). The primary analysis comprised a complete case-cohort design (n = 1407; TSH ≥ 10.0 group, n = 48; TSH < 10.0 group, n = 1359). Primary outcomes included intraoperative blood loss, enlargement ratio (ER; estimated preoperative thyroid weight/preadmission thyroid weight), and operative time. Secondary outcomes were perioperative complications and resected thyroid weight. Multivariable linear or logistic regression included prespecified covariates. Rare events were modeled using Firth's penalized logistic regression. For temporal context, we compared preadmission and preoperative TSH levels. Preoperative TSH was modeled as four clinically defined categories based on the institutional reference range to address heterogeneity within the TSH < 10.0 μIU/mL category. Of 1407 patients, 48 (3.4%) had preoperative TSH ≥ 10.0 μIU/mL. Unadjusted analyses indicated that the TSH ≥ 10.0 group had greater blood loss (median, 52 mL vs. 34 mL; p < 0.001), higher ERs (1.137 vs. 1.029), longer operative times (129 minutes vs. 112 minutes), and heavier resected thyroids (131.8 g vs. 97.0 g). Adjusted models indicated that TSH ≥ 10.0 was independently associated with greater blood loss (β = 53.03 mL; p < 0.001) and higher ERs (β = 0.12; p = 0.002). Dichotomized analyses indicated that TSH ≥ 10.0 increased the odds of ER ≥ 1.1 (adjusted odds ratio [aOR] 2.60; p = 0.004) and operative times ≥ 120 minutes (aOR: 2.29; p = 0.018). Preadmission TSH ≥ 10.0 μIU/mL was more common in the TSH ≥ 10.0 group (20.8% vs. 3.2%), indicating earlier elevation. Preoperative TSH ≥ 10.0 μIU/mL was independently associated with greater blood loss and higher ERs in patients with GD who underwent total thyroidectomy. Avoiding iatrogenic hypothyroidism and marked TSH elevation during preoperative preparation may improve operative conditions.

Extreme Hormonal Instability in Graves’ Disease Requiring Nonstandard Management of Severe Iatrogenic Hypothyroidism

Disclosure: M.P. Reyes: None. P. Ginier: None. M. Koteles: None.Introduction: Iodine-induced hyperthyroidism (Jod-Basedow phenomenon) occurs when excessive iodine triggers thyrotoxicosis in individuals with nodular thyroid disease. Repeated iodinated contrast exposure can cause severe complications. Identifying high-risk patients and monitoring thyroid function post-contrast exposure is essential. Clinical Case: A 75-year-old male with no prior thyroid disease underwent two iodinated contrast-enhanced CT scans: an abdominal/pelvic CT on 11/29/24 for abdominal pain and vomiting, and a CTA chest on 12/3/24 to rule out pulmonary embolism due to new-onset atrial fibrillation. Combined, these delivered ∼80 g of iodine. The patient was asymptomatic prior to imaging but subsequently developed palpitations, tremor, weight loss, and heat intolerance.On presentation, he had atrial fibrillation with rapid ventricular response. Urinary iodine levels were significantly elevated, with a spot urine iodine of 1512 µg/L on 12/12/24 and 684 µg/L on 12/18/24, reflecting recent high iodine exposure from contrast-enhanced imaging. A follow-up 24-hour urinary iodine test on 12/20/24 showed a level of 972 µg, further confirming ongoing iodine excess. Laboratory tests showed TSH <0.01 µIU/mL, free T4 4.7 ng/dL, and free T3 7.4 ng/dL. Thyroid antibodies were negative. A 2.2 cm left-lobe thyroid nodule was found on ultrasound. Due to recent iodine exposure, radioactive iodine uptake was not performed, as iodine saturation would have rendered the test uninterpretable. RAIU typically becomes reliable four to six weeks post-exposure.A presumptive diagnosis of Jod-Basedow hyperthyroidism was made. Methimazole 40 mg/day and beta-blockade were started, leading to partial improvement. He was readmitted with recurrent atrial fibrillation after missing a beta-blocker dose. Follow-up thyroid function tests showed a shift to hypothyroidism (TSH 10.53 µIU/mL, free T4 0.38 ng/dL), necessitating methimazole discontinuation. Further evaluation of the thyroid nodule via fine-needle aspiration and assessment of abdominal lesions were deferred until stable euthyroidism. Clinical Lessons This case illustrates how high-dose iodinated contrast can unmask thyroid autonomy, causing severe hyperthyroidism. The patient’s course, marked by new-onset atrial fibrillation, readmission, and hypothyroidism, highlights the importance of thorough risk assessment and post-contrast thyroid function monitoring. Baseline thyroid testing and ultrasound should be considered in high-risk individuals. Monitoring with thyroid function tests at two and four weeks post-exposure is crucial for detecting iodine-induced dysfunction. Careful antithyroid medication titration is necessary to avoid overtreatment and iatrogenic hypothyroidism. Recognizing Jod-Basedow hyperthyroidism in high-risk patients is vital to prevent arrhythmias and optimize thyroid management.Presentation: Monday, July 14, 2025

This study assesses the management of hyperthyroidism in primary care clinics, focusing on adherence to clinical guidelines and resulting treatment outcomes. This study retrospectively reviews medical records of patients with overt hyperthyroidism attending 11 primary care clinics between 1st January 2023 and 31st December 2023. Patients are identified through laboratory results, electronic medical records, or pharmacy records. Eligible cases include adults diagnosed with overt hyperthyroidism with at least 12 months of follow-up. Data were collected and analysed descriptively. A total of 143 patients were included, with a mean age of 49.0 ± 14.8 years, predominantly female (73.4%) and Malay (81.1%). While 96.5% of cases were correctly diagnosed, documentation of aetiology (52.4%) and treatment counselling (28.7%) was suboptimal. Thyroid function monitoring was inconsistent, with only 52.4% undergoing repeat testing within 2-6 weeks. ATD therapy was appropriately initiated in 65.0% of cases, but side effect counselling was documented in only 11.9%. Within 18 months, 59.4% achieved euthyroidism, and 62.2% avoided iatrogenic hypothyroidism. Despite appropriate diagnosis and treatment initiation, gaps exist in monitoring, documentation, and referrals. Future efforts should focus on strengthening adherence to guidelines and improving patient tracking systems to enhance hyperthyroidism management in primary care.

INTRODUCTIONCarbimazole is a commonly used antithyroid medication for the treatment of hyperthyroidism. Dosage recommendations typically vary based on the severity of biochemical hyperthyroidism, particularly free thyroxine (FT4) levels. However, real-world dosing practices may deviate from guideline-based recommendations, potentially leading to suboptimal outcomes such as persistent hyperthyroidism or iatrogenic hypothyroidism. This study evaluates whether adherence to recommended dosing based on initial FT4 levels is associated with appropriate thyroid function outcomes at six weeks. METHODOLOGYWe conducted a retrospective observational study involving 125 patients with confirmed hyperthyroidism. Patients were categorized based on whether their initial carbimazole dose was lower than, consistent with, or higher than the recommendations outlined in the American Thyroid Association guidelines. Thyroid function outcomes at 6 weeks were classified as euthyroid, hypothyroid, or persistent hyperthyroid based on repeat thyroid function tests. A chi-square test was performed to evaluate the association between dosing appropriateness and thyroid outcome. RESULTThe mean age of participants was 48.9 years (SD = 15.0). Based on initial FT4 values, 23.2% were within 1–1.5× upper normal limit (UNL), 23.2% were 1.5–2× UNL, and 53.6% were &gt;2× UNL. Among the 63 patients who received a correct dose, 58.6% became hypothyroid, and 35.0% became euthyroid. In contrast, 52.5% of those given a lower dose achieved euthyroidism, while only 17.2% became hypothyroid. Higher-than-recommended doses resulted in 24.1% hypothyroid outcomes. The chi-square test demonstrated a statistically significant association between dose category and thyroid outcome (p = 0.003). CONCLUSIONInitial carbimazole dosing based on FT4 levels is significantly associated with short-term thyroid outcomes. Interestingly, lower-than-recommended doses were more likely to achieve euthyroidism without excessive hypothyroidism. These findings suggest the need to re-evaluate dosing strategies to optimize early treatment outcomes and reduce the risk of overtreatment in hyperthyroid patients.

BackgroundA significant number of patients with primary hypothyroidism report persistent symptoms and decreased quality of life (QoL) despite biochemically adequate levothyroxine replacement. Individual variations in thyroxine conversion, autoimmune inflammation, and psychological factors have all been implicated as a potential cause.MethodsIn this cross-sectional study we have examined the association of numerous demographic, disease-specific, and laboratory parameters as well as three patient reported outcome measures with thyroid-dependent QoL as measured by the Underactive Thyroid-Dependent Quality of Life Questionnaire. Patients were stringently selected to minimize the confounding effect of comorbidities or inadequate hormone replacement. We used validated questionnaires to assess somatosensory amplification, depression, and symptom number. Determinants of QoL were evaluated using uni- and multivariable linear modeling, and mediation analysis.ResultsOur final sample consisted of 157 patients. 70.7% had Hashimoto’s, whereas 29.3% had iatrogenic hypothyroidism. Mean age was 49.5 ± 14.5 years, disease duration: 11.2 ± 8.2 years, thyroxine dose: 1.2 ug/kg bodyweight, TSH: 1.8 ± 0.9 mIU/L. Thyroid-specific biomarkers including TSH, FT3, FT4, rT3, SPINA-GD, anti-TPO, and SHBG had no association with thyroid-dependent QoL. Somatosensory amplification was a strong predictor of the presence and perceived bother of the most common hypothyroidism-associated symptoms. In our final multivariable model (r2 = 0.31) the factors associated with thyroid-dependent QoL were somatosensory amplification (p = 0.002), BMI (p = 0.021), and depression (p < 0.001).ConclusionThese results suggest that psychological factors, particularly somatosensory amplification, might play a major role in influencing QoL in hypothyroid individuals on adequate levothyroxine replacement. Our findings do not corroborate a significant role for autoimmune inflammation or tissue-level hypothyroidism.

Thyroid scintigraphy is a key tool for diagnosing and staging hyperthyroidism in cats, but follow-up scintigraphic studies after radioiodine treatment are limited. This multicentric study evaluated 99mTc-pertechnetate scintigraphy findings in 234 hyperthyroid cats before and 6 months after radioiodine treatment. Based on serum T4 and TSH concentrations, 165 (70.5%) became euthyroid, 54 (23.1%) had subclinical hypothyroidism, and 15 (6.4%) developed overt hypothyroidism. On post-treatment scintigraphy, all cats showed reduced size and radionuclide uptake of "hot" thyroid nodules. Of 99 cats with unilateral nodules, 60 (61%) recovered function in the contralateral lobe. Among 135 cats with bilateral nodules, both lobes remained visible in 108 (80%). Persistent "hot" nodules with high thyroid/salivary (T/S) ratios or thyroidal pertechnetate uptake (TcTU) occurred in 26 (11%) cats, all of which were euthyroid. Conversely, 24 (10.4%) cats had minimal or absent thyroid tissue with 17 (71%) being hypothyroid, but seven (29%) were euthyroid. As a diagnostic test for iatrogenic hypothyroidism, TcTU showed the highest sensitivity (62.3), with the T/S ratio (7.3) and background-corrected T/S ratio (30.4) being much lower (p < 0.01). While follow-up scintigraphy aids in assessing thyroid tumor destruction and residual function, its diagnostic utility for differentiating euthyroidism and hypothyroidism is limited, especially for cats with mild (subclinical) hypothyroidism.

HER2-positive metastatic breast cancer represents a significant therapeutic challenge. Its prognosis has been altered thanks to significant advances in targeted anti-HER2 therapies. These treatments, such as trastuzumab and pertuzumab, have significantly improved the management of this pathology, enhancing patient survival, but are also responsible for adverse effects. Hypothyroidism, although less frequent than other complications, is an important side effect to recognize and manage. This clinical case presents a 47-year-old patient with HER2-positive metastatic breast cancer treated with chemotherapy combined with a dual anti-HER2 blockade using trastuzumab and pertuzumab, along with letrozole. After 52 cycles of dual blockade, the patient developed overt hypothyroidism. Levothyroxine replacement therapy improved her symptoms. This case illustrates the clinical importance of endocrine monitoring in patients receiving targeted anti-HER2 therapies, highlighting the need for a multidisciplinary approach to optimize the management of adverse effects and the quality of life of patients. A diagnostic delay of hypothyroidism can potentially impact the prognosis of the disease.

Thyroid nodules are highly prevalent, particularly among women. Palpation detects nodules in 2–7% of cases, whereas high-resolution ultrasound (US) identifies them in 20–76% of individuals. In most cases, thyroid nodules are benign and incidentally detected, causing no clinical symptoms. But when clinical symptoms begin to appear, it is necessary to make a decision on the tactics of further management. Surgical treatment is often used,&amp;nbsp;including hemithyroidectomy or total thyroidectomy, poses several limitations, such as prolonged hospital stay, airway obstruction, recurrent laryngeal nerve paralysis, iatrogenic hypothyroidism, and challenges associated with reoperation. Microwave ablation is used today, is a minimally invasive method used to treat various benign and malignant tumors, including those of the thyroid, liver, and lungs.

Hyperthyroid cats that are azotemic and hypothyroid after surgical or medical treatment have poor outcomes, and supplementation with levothyroxine (LT4) improves survival. However, the effect of LT4 supplementation on survival of nonazotemic, hypothyroid radioiodine (RI)-treated hyperthyroid cats is unknown. Radioiodine treated hyperthyroid cats with iatrogenic hypothyroidism or azotemia have shorter survival times than euthyroid, nonazotemic cats and supplementation of LT4 improves survival times of hypothyroid cats. One hundred seventeen RI treated hyperthyroid cats. Prospective cohort study. Radioiodine treated cats were screened for azotemia and iatrogenic hypothyroidism using TSH stimulation test; LT4 supplementation was offered to all hypothyroid cats with decision to treat based on owner preference. The log rank test was used to compare survival times between groups, and the Mann-Whitney U test was used to compare age and renal variables. Data are presented as median [range]. Euthyroid azotemic cats (934 [759-2035] days) and nonsupplemented hypothyroid cats (azotemic and nonazotemic combined, 1232 [238-2363] days) had shorter survival times than euthyroid nonazotemic cats (1616 [663-3369] days, P = .003 and P = .002, respectively). Levothyroxine supplemented hypothyroid nonazotemic cats had longer survival times than nonsupplemented hypothyroid nonazotemic cats (1037 [300-2401] days vs 768 [34-1014] days; P = .027). Levothyroxine supplementation was not associated with prolonged survival times in hypothyroid azotemic cats vs nonsupplemented hypothyroid azotemic cats (771 [718-1558] days vs 152 [82-1852] days, respectively, P = .991). Levothyroxine supplementation in nonazotemic cats with iatrogenic hypothyroidism (diagnosed based on TSH stimulation test results) improved survival times, although randomized controlled trials are needed.

AimThe present guideline (GL) is aimed to improve and standardize the treatment of primary hypothyroidism in non-pregnant adults and to offer all the patients the best possible care across the Italian country.Target populationNon-pregnant adults with hypothyroidism.Excluded populationThis GL does not cover the treatment of hypothyroidism in children and adolescents under 18 years of age, in women who are pregnant or breastfeeding, nor in subjects with central hypothyroidism. Also patients who require suppressive therapy with levothyroxine after thyroidectomy for thyroid cancer and those with transient iatrogenic hypothyroidism were not considered in this GL.MethodsThe direct costs and the utilization of resources over time were evaluated for the implementation of the appropriate management within the National Health Service. Recommendations were based on the analysis, according to the GRADE methodology, of the evidence from literature. Patients preferences were collected and verified by means of specific bibliographic research and the active participation of two patients’ representatives in the GL development group.ResultsThe present GL provides 4 formal graded recommendations and 16 ungraded indications for good clinical practice. An elevated agreement was consistently obtained among the panel members.ConclusionsThe present GL provides operative recommendations—based on the best available evidence and cost-effectiveness analysis—for the treatment of adult patients with primary hypothyroidism. The expected benefits from the dissemination, application and implementation of this GL are the improvement of the quality of care, its homogenization across the national territory and the rationalization of health expenditure in the respect of patient preferences.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40618-025-02652-y.

Adult-onset spontaneous feline hypothyroidism (SH) is considered rare, but its prevalence is unknown. This study aimed to screen laboratory submissions for cats with laboratory suspected SH (LSSH) and to identify laboratory abnormalities associated with LSSH. Submissions to a commercial laboratory in Germany between January 2022 and April 2023 were prospectively screened for cats aged 3–12 years with low total thyroxine (TT4); in these cats, thyrotropin (TSH) was measured. Iatrogenic hypothyroidism was excluded by contacting submitting veterinarians. Creatinine, triglyceride and cholesterol concentration and red blood cell count (RBC) of cats with LSSH (low TT4, TSH &gt; 0.53 ng/mL; i.e., [one sided TSH reference change value (76%) of TSH upper reference interval (RI)] + [TSH upper RI] = 0.53) were compared to euthyroid cats (TT4 within RI) and cats with suspected non-thyroidal illness (SNTIS) (low TT4, normal TSH (&lt;0.3 ng/mL; upper RI)) by non-parametric tests. p &lt; 0.05 was significant. In total, 31,572 submissions of cats were included, 25,169 (79.7%) were euthyroid, 3818 (12.1%) had SNTIS and 61 (0.2%) had LSSH. Cats with LSSH had higher creatinine (p = 0.002) and lower RBC count (p &lt; 0.0001) than euthyroid cats as well as higher creatinine (p = 0.00035) than cats with SNTIS. Azotaemia (creatinine &gt; 140 µmol/L) and anaemia (RBC &lt; 7.2 × 1012/L) were present in 28/49 (57%) and 19/44 (43%) cats with LSSH, respectively. There was no difference between LSSH and SNTIS for the remaining parameters. In cats with low TT4, azotaemia and anaemia might indicate the presence of SH and reinforce the need for TSH testing. Hypercholesterolaemia and hypertriglyceridaemia are not indicators of SH.

Abstract Disclosure: L.G. Amato: None. P.H. Carani: None. L.D. Volpi: None. A. Rahal: None. E.M. Volpi: None. Introduction: Thyroid nodules are quite prevalent worldwide, with papillary thyroid carcinoma (PTC) being the most common histological subtype of thyroid malignant neoplasm, accounting for approximately 85% of thyroid cancers. When this carcinoma is less than 10 mm in its longest axis, it is defined as papillary thyroid microcarcinomas (mPTCs) which has had an increasing proportion of thyroid cancers and with a disease-specific survival of patients having this diagnosis more than 99% after 10 years of follow-up. Most guidelines concerning thyroid cancer care recommend a lobectomy as the first-line treatment strategy for low-risk unifocal mPTC but often results in aggressive overtreatment. Thyroid surgery comes with significant costs and morbidity rates caused by iatrogenic hypothyroidism and recurrent laryngeal nerve damage, resulting in poor quality of life, justifying the growing search for minimally invasive and effective methods in the treatment of mPTC and in this context Radiofrequency thermal ablation (RFA), a minimally invasive treatment that preserves thyroid function have been proposed for patients with low-risk mPTC. Clinical case: From April 2018 to January 2024, 143 patients with mPTC, were submitted to RFA and patient's follow-up were dated 1, 3, 6, 12 and 18 months after the procedure. During the follow-up we observed 3 (2%), complications, 1 case of permanent paralysis unilateral vocal cord, 1 Horner Syndromes and 1 case of transient paralysis, with total reversal. In all cases there was a reduction in the volume of the node after 6 months of the procedure. Conclusion: The reported incidence rate of postoperative hypothyroidism in patients underwent hemithyroidectomy is 10.9-48.8%, therefore, risks of complications with radioablation in our series were lower than those previously described during hemithyroidectomy. Radiofrequency thermal ablation (RFA) is a minimally invasive treatment that preserves thyroid function with a lower incidence of complications compared to thyroidectomy or lobectomy, and and should be considered the selection procedure for low-risk thyroid microcarcinomas. Presentation: 6/3/2024

Abstract A. Newman: None. G.K. Adler: None. Exogenous thyrotoxicosis is caused by excess consumption of thyroid hormone preparations, primarily levothyroxine (T4) or mixed T4-T3 preparations (e.g. desiccated thyroid). Herein, we report the case of a 42-year-old man with bipolar II disorder and anxiety who presented with muscle weakness and inability to stand. Medications were notable for lithium carbonate, alprazolam, doxepin, hydroxyzine, and propranolol (80 mg/day in divided doses). In addition, he had been started on liothyronine for treatment-resistant bipolar II disorder 3 months prior to admission. Liothyronine had been titrated up to 150 mcg daily according to a protocol recommending initiation at 25 mcg daily with weekly dose escalation by 25 mcg increments until psychiatric response, thyrotoxic adverse effects or 150 mcg maximum daily dose. Medications were taken as prescribed based on the patient’s family’s count of remaining pills. TSH on lithium and prior to starting liothyronine ranged from 3.4 to 6.3 mIU/mL (assay reference range: 0.28 – 3.89) with normal free T4, consistent with euthyroidism to mild subclinical hypothyroidism. Physical exam on presentation was notable for normal vital signs with heart rate of 88 bpm, BMI of 36.3 kg/m2, bilateral upper extremity action tremor, no hyperreflexia, and mild, diffuse muscle weakness with proximal predominance. Labs revealed TSH &amp;lt; 0.01 mIU/mL (0.50-5.70), low free T4 of 0.5 ng/dL (0.9-1.7), total T3 &amp;gt; 500 ng/dL (80-200), negative thyroid peroxidase and TSH receptor antibodies, and lithium level in the therapeutic range. Liothyronine was discontinued and thyroid function tests were repeated every 12 hours. His total T3 fell rapidly, with an initial half-life of about 12 hours. The patient was discharged after 2 days, with a total T3 of 123 ng/dL (80-200). Due to concern for transient iatrogenic central hypothyroidism, levothyroxine was initiated on discharge. In outpatient telemedicine follow up, he reported improvement in muscle strength and ambulation over a 2–4-week timeframe. TSH levels normalized and levothyroxine was tapered. This is an unusual case of isolated T3 thyrotoxicosis due to chronic excess liothyronine use. Propranolol likely masked the signs and symptoms of thyrotoxicosis expected with liothyronine supplementation at a dose four times higher than his predicted daily endogenous triiodothyronine production. However, his presenting weakness may represent thyrotoxic myopathy, previously described only in T4 thyrotoxicosis such as Graves disease. This case demonstrates that the cardiovascular masking effect of beta-blockade in T3 thyrotoxicosis may not extend to other adverse effects of chronic excess liothyronine use, such as thyrotoxic myopathy, and that any supraphysiologic treatment with thyroid hormone should be undertaken with care and close monitoring. Sunday, June 2, 2024

Abstract Disclosure: A. Mubashir: None. F. Sajid: None. M. Sattar: None. Myxedema Coma is a life-threatening complication of hypothyroidism and often presents with multi-organ failure. However, reversible cardiomyopathy and acute renal failure are rare. Here, we present a case of iatrogenic hypothyroidism leading to myxedema coma with reversible organ failure. Case Presentation: A 58-year-old male with a past medical history of iatrogenic hypothyroidism after total thyroidectomy for follicular thyroid cancer, noncompliant with levothyroxine for the past three years, was brought to the hospital due to worsening mental status, low energy, and cold extremities for three days. On admission, vital signs were within normal limits. Laboratory studies revealed Random Glucose 113 (74-200 mg/dl), Na 134 (135-149 mmol/l), TSH: 217 (0.39-4.08 MCIU/ml), Free T4 &amp;lt;0.25 (0.58-1.64 ng/dl), Free T3 1.01 (2.53-3.87 pg/ml), BUN 53.3 (7-21 mg/dl), Creatinine 4.9 (0.5-1.3mg/dl). Urinalysis was positive for protein of 300 mg/dl (negative). Urine studies showed hematuria, total protein/cr 3.18 (&amp;lt;0.10), with increased total protein of 60/24 hours (0-12 mg/dl), suggesting glomerular etiology. Additionally, Bence Jones protein and monoclonal band were negative, interpreted as mild glomerular proteinuria. FeNa &amp;gt;2%, Urine sodium of &amp;gt;40 (20-40mmol/l) suggest acute tubular necrosis. EKG showed normal sinus rhythm with low voltage. To rule out diastolic dysfunction, an echocardiogram was performed, which revealed depressed systolic function with an ejection fraction of 31-35% and a large pericardial effusion with echocardiographic features of tamponade. He also had global cardiomyopathy with akinesis, especially in the inferior segments. He was treated with IV levothyroxine. Repeat imaging in one month showed an increase in ejection fraction to 55% with moderate-sized pericardial effusion and no echocardiographic features of tamponade. Global cardiomyopathy had also resolved. However, left ventricular systolic function was borderline, with delayed diastolic expansion of the right ventricle. Repeat creatinine was 2mg/dl. The patient’s condition greatly improved, and he was discharged with follow-up with endocrinology, nephrology, and cardiology. Discussion: In the available literature, diastolic dysfunction is associated with severe hypothyroidism. However, reversible global cardiomyopathy with decreased systolic function is rare. The pathogenesis of this myopathy is not well understood. Similarly, known mechanisms of renal injury in hypothyroidism include renal hypoperfusion, rhabdomyolysis, decreased kidney-to-body weight ratio, truncated tubular mass, and altered glomerular architecture. While the need to perform a renal biopsy or the use of goal-directed therapy for dilated cardiomyopathy remains questionable in such cases, reversible complications of severe hypothyroidism should be investigated in patients with suspected myxedema. Presentation: 6/2/2024

Hypothyroidism, a prevalent endocrine disorder, results from insufficient thyroid hormone production or release, affecting metabolism. However, disparities in comorbidities and treatment trajectories may exist between endogenous and exogenous hypothyroidism. Data from the Korean National Health Insurance Service from 2004 to 2018. Endogenous hypothyroidism was defined as cases with two or more diagnostic codes for hypothyroidism coupled with a history of thyroid hormone intake exceeding 60 days. To eliminate iatrogenic hypothyroidism, individuals with diagnosis codes for thyroid cancer, treatment codes for thyroid surgery, or radiotherapy were excluded. Hypothyroidism-related comorbidities were defined as new occurrences of the corresponding diagnosis code after the diagnosis of hypothyroidism during the entire study period. The age-standardized incidence of endogenous hypothyroidism among men was 0.2 per 1,000 person-years in 2004, increasing to 0.8 in 2018. Among women, the incidence increased from 1.6 per 1,000 person-years in 2004 to 3.7 in 2018. When comparing age groups of 20s-50s and 60s-90s, both sexes in the 60s-90s demonstrated a more rapid increase in incidence than those in the 20s-50s age range. Patients with endogenous hypothyroidism demonstrated a higher incidence of mood disorders across all age groups and cerebrovascular disease in individuals ≥60 years old, regardless of sex. In Republic of Korea, endogenous hypothyroidism incidence has been increased in recent years. The incidence of endogenous hypothyroidism is increasing more rapidly in men than in women, especially in the elderly. Patients with endogenous hypothyroidism seem to have a heightened risk for cerebrovascular disease and mood disorders.

Abstract Objective Multiple criteria for successful radioiodine remnant ablation (RRA) under thyroid-stimulating hormone (TSH)-stimulation have been inconsistently employed, resulting in difficulties in efficacy comparison and iatrogenic hypothyroidism. Establishing an optimal standard for successful RRA is a priority. Methods Five existing criteria for successful RRA under endogenous TSH-stimulation were retrieved and then compared in a cohort of 51 patients with papillary thyroid cancer post RRA. Criterion A, a negative diagnostic 131I whole-body scan (DxWBS); Criterion B, a negative DxWBS and serum thyroglobulin (Tg) &lt; 2 ng/mL, irrespective of anti-thyroglobulin antibody (TgAb) level; Criterion C, Tg &lt; 2 ng/mL with TgAb ≤ 46 IU/mL; Criterion D, a negative DxWBS and Tg &lt; 1ng/mL with TgAb ≤ 100 IU/mL or a negative DxWBS with TgAb &gt; 100 IU/mL; Criterion E, a negative DxWBS and Tg ≤ 1 ng/mL with TgAb ≤ 46 IU/mL. Non-TSH-stimulated DxWBS was compared to TSH-stimulated DxWBS. Results Success rates of 98.0% (50/51), 78.4% (40/51), 78.0% (32/41), 64.7% (33/51) and 56.1% (23/41) were achieved regarding the criteria A, B, C, D, and E, respectively. The success rate of RRA by criterion A was significantly higher than those by other criteria. The similar success rates of RRA by criteria B and C were higher than that by criterion E. The success rate of RRA regarding non-TSH stimulated DxWBS was comparable to that of TSH-stimulated DxWBS, with a negative predictive value of 98.0%. Conclusions Compared with negative TSH-stimulated DxWBS criterion, the success rate of RRA decreases when the cut-off value of serum Tg is introduced. A negative non-TSH-stimulated DxWBS seems promising in predicting a successful RRA.

Graves. disease in females of childbearing age is common. Radioiodine therapy (RAIT) is a definitive treatment for such a condition. The effect of radiation on germ cells and iatrogenic hypothyroidism following radioiodine therapy may cause a bad pregnancy outcome. We present an unfortunate case of miscarriage of early pregnancy in 7th gestational weeks following 7 months of RAIT and an approach to the clinical question .How to manage Graves. disease with RAIT in women of childbearing potential.. Maintenance of an adequate interval and achieving euthyroid status after RAI ablation in Graves. disease in patients willing to conceive can reduce the risk of miscarriage and assure a good pregnancy outcome. Bangladesh J. Nuclear Med. 26(2): 201-203, 2023

Clinicians commonly use thyroid-stimulating hormone (TSH) concentrations to diagnose thyroid disorders in humans and dogs. In cats, canine TSH chemiluminescent immunoassays (CLIA) assays are commonly used to measure TSH, but these TSH-CLIAs cannot measure low TSH concentrations (< 0.03 ng/mL) and therefore cannot distinguish between low-normal concentrations and truly low TSH concentrations (characteristic of hyperthyroidism). Our aim was to evaluate a novel TSH assay based on bulk acoustic wave (BAW) technology that has lower functional sensitivity (0.008 ng/mL) than TSH-CLIAs. 169 untreated hyperthyroid cats, 53 cats treated with radioiodine (131I), 12 cats with chronic kidney disease (CKD), and 78 clinically healthy cats. Serum concentrations of T4, TSH-CLIA, and TSH-BAW were measured in all cats. Untreated hyperthyroid cats were divided into 4 severity groups (subclinical, mild, moderate, and severe), whereas 131I-treated cats were divided into euthyroid and hypothyroid groups. Test sensitivity, specificity, and positive predictive value for identifying hyperthyroidism were higher for TSH-BAW (90.5%, 98.9%, and 86.9%) than TSH-CLIA (79.9%, 76.7%, and 21.7%; P < .001). Test sensitivity for identifying 131I-induced hypothyroidism was only 45.5% for T4 versus 100.0% for both TSH-CLIA and TSH-BAW (P = .03), whereas TSH-BAW had a higher positive predictive value (100%) than did either TSH-CLIA (81.2%) or T4 (71.9%). Serum TSH-BAW alone or together with T4 is a highly sensitive and specific diagnostic test for evaluating feline hyperthyroidism and iatrogenic hypothyroidism. Finding low serum TSH-BAW concentrations is most useful for diagnosing subclinical and mild hyperthyroidism, in which serum T4 remains within or only slightly above the reference interval.

BackgroundHyperthyroid cats commonly have systemic hypertension, with a reported prevalence of 7% to 48%. Although hypertension might be expected to resolve once treatment restores euthyroidism, it can persist or only first develop after treatment.ObjectivesTo determine the proportion of hyperthyroid cats with hypertension (systolic blood pressure [SBP] ≥160 mm Hg), persistence or first development of hypertension after successful radioiodine treatment, and correlation of post‐treatment hypertension with azotemia or hypothyroidism.AnimalsFour hundred one hyperthyroid nonazotemic cats were included in the study.MethodsProspective, cross‐sectional and before‐and‐after studies. All hyperthyroid cats had SBP measured by Doppler; 255 had SBP rechecked 6 months after successful radioiodine (131I) treatment.ResultsOf untreated hyperthyroid cats, 108/401 (27%) were hypertensive. A higher proportion of hypertensive cats were nervous/excited compared with normotensive cats (47% vs 12%; P < .001). Of the initially hypertensive cats, 87/108 cats were reexamined after 131I treatment; 43/87 (49%) cats normalized SBP, whereas 44/87 (51%) remained hypertensive. Of the initially normotensive cats, 16/168 (9.5%) first developed hypertension after successful 131I treatment. 7/60 (12%) of the 131I‐treated hypertensive cats were azotemic and 9/60 (15%) were hypothyroid. A higher proportion of cats remaining hypertensive had nervous/excited demeanor than did normotensive cats (50% vs 17%; P < .001).Conclusions/Clinical ImportanceHypertension, when present, resolves in many hyperthyroid cats after successful treatment. Hyperthyroid cats uncommonly develop new hypertension after treatment. Persistent or newly detected hypertension was unrelated to azotemia or iatrogenic hypothyroidism. More frequently perceived nervousness/anxiety in radioiodine‐treated hypertensive cats suggests that many of these cats might have “situational” hypertension, as hyperthyroid‐induced hypertension should resolve after treatment.