Thyroxine Replacement Therapy Research Articles

Role of TSH Inhibition Therapy in the Postoperative Management of Patients with Differentiated Thyroid Cancer

Objective: To investigate the effect of TSH inhibition therapy in the postoperative management of patients with differentiated thyroid cancer. Methods: Seventy patients diagnosed with differentiated thyroid cancer were selected for the study. TSH inhibition therapy was administered to the research group, while thyroxine replacement therapy was provided to the control group during the postoperative management phase. This allowed for a comparative analysis between the two groups. Results: In comparison with the control group, the research group exhibited significant decreases in serum TSH, T3, and T4 levels after treatment, while FT4 and FT3 levels significantly increased (P < 0.05). Additionally, significant decreases in Tg, VEGF, TSGF, CD44V6, and sIL-2R levels were observed in the research group after treatment (P < 0.05). No significant differences were found in pre-treatment thyroid function between the two groups (P > 0.05). Conclusion: The application of TSH inhibition therapy in the postoperative management of patients with differentiated thyroid cancer demonstrates promising outcomes.

Profound postinduction hypotension precipitated by immune checkpoint inhibitors: a case report

BackgroundWith the increasing use of immune checkpoint inhibitors (ICIs) in cancer therapy, perioperative healthcare professionals need to be vigilant about potential immune-related adverse events (irAEs). We report a case of severe postinduction hypotension in a patient undergoing laparotomy due to suspected intraabdominal bleeding from gastric cancer and Krukenberg tumors, caused by unrecognized hypothyroidism precipitated by ICIs.Case presentationA 65-year-old Chinese female with a history of gastric adenocarcinoma and Krukenberg tumors, previously treated with nivolumab, presented to the emergency room with abdominal pain and hypotension. Despite ruling out other causes, including hypovolemia and anaphylaxis, her hypotension persisted. The patient was found to have severe hypothyroidism, likely an irAE from the use of nivolumab. Thyroxine replacement therapy resolved the hypotension, and the patient recovered uneventfully after surgery.ConclusionsThis case underscores the importance of considering irAEs, such as hypothyroidism, in patients treated with ICIs. Perioperative healthcare providers must remain vigilant for potential complications and promptly recognize and manage irAEs to optimize patient outcomes.

Thyroxine restores hippocampal neurogenesis and synaptogenesis in a male rat model of carbimazole-induced hypothyroidism: a histological study

BackgroundAdult-onset hypothyroidism has a deleterious effect on hippocampal cognitive and memory functions. This study was performed to evaluate the possible therapeutic effect of thyroxine on hippocampus degeneration in an adult male rat model of carbimazole-induced hypothyroidism and the potentiality of spontaneous recovery. Thirty-two adult male albino rats were divided equally into four groups, as follows: I (control group), II (hypothyroidism group) received carbimazole (20 mg/kg) orally once daily for 4 weeks; III (recovery group) rats were managed as in group II, then left untreated for an additional 4 weeks to assess spontaneous recovery; and IV (thyroxine-treated group): hypothyroidism was induced as in group II, then rats received levothyroxine (20 µg/kg/day) orally for 4 weeks. Rats and their corresponding controls were sacrificed after 4 weeks in group II and after 8 weeks in groups III and IV. The levels of T3, T4, and TSH were measured. Hematoxylin and Eosin staining of thyroid and hippocampal sections was performed. Additionally, toluidine blue staining and immunohistochemical staining for PCNA, GFAP, and synaptophysin were applied to hippocampus sections. Both morphometric measurements and statistical analysis were performed.ResultsComparison of thyroxine-treated group with hypothyroidism and recovery groups revealed a significant reduction in TSH level and an increase in T3 and T4 levels, as well as improved histological architecture in both the thyroid and hippocampal sections. Hippocampal sections revealed a significant decrease in the mean area percent of GFAP, a significant increase in the mean number of PCNA-positive cells in the subgranular zone (SGZ); a niche for the adult neural stem cells (NSCs) in the hippocampus; and a significant increase in the mean area percent as well as the mean optical density of synaptophysin.ConclusionHippocampal degeneration is induced by hypothyroidism and can be restored by thyroxine replacement therapy, probably through neuronal cell preservation, synaptogenesis, and stimulation of neurogenesis in SGZ. On the other hand, spontaneous recovery from this degeneration was inadequate.

Thyroxine Replacement Therapy during Ramadan Fasting: Physicians' and Patients' Perceptions and Practices

Abstract Objective Thyroxine (T4) therapy is taken on an empty stomach and no food is taken for a short period. During Ramadan fasting (RF), Muslim patients may face difficulties taking levothyroxine as recommended. Materials and Methods We performed a mixed methods study of an online survey of 218 physicians to explore their perceptions and practices. Also, we interviewed a sample of 172 hypothyroid patients to establish their practices and source of information. Their median age was 46 (17–90) years; they had hypothyroidism for a median of 5 years and took a median thyroxine dose of 100 µg daily. Furthermore, we attempted to explore the effects of RF on available thyroid function tests. Results Consultants were 58.4%, and the most represented specialty was endocrinology, 46.1%. Regarding the impact of RF on T4 therapy, 52.3% thought the RF was not clinically relevant in most patients on T4 replacement. However, 27.5% thought RF affects T4 replacement therapy in a clinically relevant manner. About 77.1% of respondents reported giving advice routinely to all patients on T4 replacement during RF. One hundred sixty-four respondents were split between recommending taking the medications with Iftar, Suhour, or other times. Most respondents (73.9%) do not repeat measurements of thyroid hormone levels after Ramadan unless needed during their scheduled clinic visit. On the other hand, 50.3% of the patients confirmed that their physician advised them to take their thyroxine during Ramadan, whereas 40.4% could not recall receiving any advice. About 59.9% of the patients took thyroxine with Iftar, 23.8% with Suhour, and 16.3% at different times. In those patients where thyroid function tests were available before and after RF, serum thyroid-stimulating hormone and serum-free T4 did not show a specific pattern in the group as a whole and with subgroups. Conclusion There is variation in the advice that hypothyroid patients receive on taking thyroxine during Ramadan and in their practices. Further studies are needed to determine the best timing for thyroxine replacement.

Lithium as an alternative option in thionamide-resistant Graves’ disease

Conventional treatments for Graves’ disease include thionamides, radioactive iodine therapy (RAI), and thyroidectomy. Occasionally, patients may develop resistance to thionamides and may require additional treatment. We present the case of an adolescent girl with thionamide-resistant Graves’ disease who was successfully treated with lithium and subsequent RAI after stabilizing her thyroid hormone levels. Following RAI, the patient developed hypothyroidism, and thyroxine replacement therapy was initiated. This case highlights the potential of lithium as a safe and effective alternative for controlling hyperthyroidism in Graves’ disease and its role in preparing patients for more definitive treatment.

Differentiated thyroid carcinoma recurrence: patterns and participating factors

Background Surgery for recurrent differentiated thyroid carcinoma is technically difficult, is demanding, and carries a higher risk for complications than de novo cases, so understanding the precipitating factors and patterns of recurrence will help in practicing maneuvers that can help in decreasing the recurrence. In this study, we examined these factors and patterns of recurrence. Patients and method A total of 40 patients with recurrence after differentiated thyroid carcinoma surgery were subjected to redooperations after clinical evaluation and all needed preoperative investigations. Preoperative and operative data and postoperative surgical and pathological outcomes were collected and analyzed. Results Our results revealed that the size of the primary tumor had a negative or inverse significant relationship with time passed till occurrence of recurrence or relapse (P=0.044). However, postoperative radioactive iodine therapy, postoperative thyroxine replacement therapy, unifocal tumors, and total thyroidectomy in primary procedure all were associated with a wider range of recurrence time with a higher mean±SD but did not reach a statistically significant level. Central compartment lymph nodes are the most affected group (95%) followed by level IV nodes, which had a 100% correlation with central group, and all lateral groups summed 82.5%. Conclusion The primary tumor size has a significant inverse relationship with time till occurrence of relapse. However, other factors did not reach a statistically significant level. Central compartment lymph nodes, which are very difficult for safe dissection in recurrent cases, are the most affected group, confirming being the first echelon nodes followed by level IV nodes. Therefore, prophylactic routine meticulous central dissection in the primary cases is advised for being much easier and safer.

Abstract 14091: Severe Hypothyroidism Revealing Hidden Tracts

Discussion: Atrioventricular reciprocating tachycardia (AVRT) is a type of Supraventricular tachycardia (SVT) caused by an accessory pathway can result in symptomatic and also life-threatening arrhythmias. Supraventricular tachycardias are less commonly seen in hypothyroidism than hyperthyroidism. We present a case of a 41 year old gentleman who presented with chest pain and SVT was found to have severe hypothyroidism with pre-excitation pattern on his EKG. Case: 41-year-old Caucasian gentleman with history of untreated Hashimoto’s thyroiditis presented with palpitations and acute onset left-sided chest pain. His symptoms were aggravated with movement and improved with rest. When EMS found him, his vitals were significant for tachycardia with a heart rate (HR) of 200 beats per minute (bpm). EKG showed supraventricular tachycardia. Vagal maneuvers were attempted followed by adenosine. This resulted in conversion to sinus rhythm and improvement in HR to 88 bpm. His chest pain completely resolved. He was then brought to the emergency room where he had normal vitals. Examination revealed thyroid gland was palpable and noted to be diffusely enlarged. Laboratory data was significant for an elevated thyroid-stimulating hormone (TSH) of 373 mIU/ml and undetectable free thyroxine (fT4) levels. His creatinine kinase (CK) was high at 16260, and troponin was elevated at 0.220 ng/ml (reference:<0.04 ng/ml). TPO antibodies were >600 IU/ml. EKG demonstrated sinus rhythm with pre-excitation and incomplete left bundle-branch block. He had normal chest x-ray. An echocardiogram showed an ejection fraction of 55% with mild LV diastolic dysfunction. He later underwent a stress myocardial perfusion scan which showed no definite evidence of inducible ischemia. Follow up: He was started on thyroxine replacement therapy. He is due for an EP study to evaluate for an accessory pathway causing pre-excitation with repolarization pattern on his ECG. Conclusion: This case suggests that severe hypothyroidism can also cause supraventricular tachycardias (SVT) by metabolic and conduction derangements revealing concealed bypass tracts in patients with accessory pathways. In most cases these arrhythmias are reversible once the underlying thyroid disorder is treated.

Bidirectional Relationship Between Tuberculosis and Hypothyroidism: An 18-Year Nationwide Population-Based Longitudinal Cohort Study.

Some antituberculosis agents may cause hypothyroidism, and thyroid hormones play a vital role in Mycobacterium tuberculosis infection. However, the relationship between tuberculosis (TB) and hypothyroidism has not been clearly established. Therefore, this retrospective, longitudinal cohort study aimed to investigate the association between these two diseases using the 2000–2017 data from the Taiwan's National Health Insurance Research Database. The hypothyroidism and TB cohorts were matched with the control group in a 1:4 ratio. Adjusted hazard ratios (aHRs) were assessed using Cox proportional hazards regression analysis in each cohort. In total, 3,976 individuals with hypothyroidism and 35 120 individuals with TB were included in this study. The risk of developing TB in patients with hypothyroidism was 2.91 times higher than that in those without hypothyroidism (95% confidence interval [CI], 1.50–3.65). The subgroup of thyroxine replacement therapy (TRT) had a 2.40 times higher risk (95% CI, 1.26–3.01), whereas the subgroup of non-TRT had a 3.62 times higher risk of developing TB than those without hypothyroidism (95% CI, 2.19–4.84). On the other hand, the risk of developing hypothyroidism in patients with TB was 2.01 times higher than that in those without TB (95% CI, 1.41–2.38). Our findings provide evidence that TB and hypothyroidism are interrelated. Thus, clinicians and public health authorities should monitor the association between these two diseases to reduce the relevant disease burden.

Prognostic value of hypothyroidism in patients undergoing intensity-modulated radiation therapy for nasopharyngeal carcinoma.

The purpose of this study was to investigate the effect of hypothyroidism and thyroxine replacement therapy on the prognosis of nasopharyngeal carcinoma (NPC) patients. The clinical data of 284 NPC patients, who received intensity-modulated radiation therapy (IMRT) between January 2011 and December 2016, were retrospectively analyzed. Hypothyroidism occurred in 38% of patients. Patients with hypothyroidism had significantly better disease-free survival (DFS) (p=0.002) and relapse-free survival (RFS) (p=0.008). Multivariate analysis showed that hypothyroidism was a positive independent prognostic factor (DFS and RFS). Among the patients with hypothyroidism, thyroxine replacement therapy did not yield inferior survival (DFS, RFS, all p > 0.05). The NPC patients with complete response are at risk of hypothyroidism, which is attributable to escalating dose. These patients experienced clinical hypothyroidism could be adequately treated with thyroid hormone replacement. Further investigation of the underlying biological mechanism and potential therapeutic implications are required.

Risk of developing pneumonia associated with clinically diagnosed hypothyroidism: a nationwide population-based cohort study.

Hypothyroidism has a detrimental effect on the immune system, which may predispose patients to infection. However, evidence about the risk of developing either community- or hospital-acquired pneumonia in patients with hypothyroidism is scarce. To evaluate the association between hypothyroidism and the risk of developing pneumonia. This was a retrospective population-based cohort study from Taiwan's National Health Insurance Research Database. After 1:1 propensity score matching, 9749 patients (age ≥20 years) newly diagnosed with hypothyroidism between 2001 and 2014 and 9749 patients without hypothyroidism or other thyroid diseases were included in the hypothyroidism and non-hypothyroidism cohorts, respectively, and followed up until 2015. The development of pneumonia was defined as the primary outcome. Cox proportional hazards regression models were used to calculate the hazard ratios (HRs) of developing pneumonia between hypothyroidism and non-hypothyroidism cohorts after adjusting for age, sex and baseline comorbidities. To evaluate whether thyroxine replacement therapy (TRT) modified the risk for pneumonia, we divided patients with hypothyroidism into subgroups: patients who received TRT and those who did not. Hypothyroidism was associated with a higher risk of pneumonia [adjusted HR (aHR) 1.38, 95% confidence interval (CI) 1.29-1.49, P < 0.001]. Patients with hypothyroidism who received TRT had a lower risk of pneumonia than patients who did not (aHR 0.85, 95% CI 0.76-0.93, P = 0.001). Similar results were obtained in the age- and sex-stratified analyses. Clinically diagnosed hypothyroidism was independently associated with the risk of pneumonia. In patients with hypothyroidism, TRT was associated with a lower risk of pneumonia.

I-131 myth bursting: association of pregnancy/infertility related adverse effects of radioactive iodine I-131 administration

Background: There is very little knowledge on the risks of genetically transmissible diseases after the exposure to radiation. This study aimed to investigate the influence of radioiodine [radioactive iodine therapy (RAI)] on the outcome of pregnancies and the health status of children born to mothers who had received therapeutic doses of I-131 for differentiated thyroid carcinoma or for hyperthyroidism. Methods: Gestational histories of 300 women who were treated with radioactive iodine either for the treatment of hyperthyroidism or for the treatment of thyroid cancer from 2012 to 2017 were retrospectively analyzed. Two Groups were made on the basis of administered doses of radioactive iodine. The first group was further divided into two sub groups. Sub group A consisted of the patients who were treated with radioactive iodine for hyperthyroidism with less than 30 mCi. Sub group B had patients of differentiated thyroid cancer that had been treated with doses above 100 mCi of I-131. Group 2 had patients with primary hypothyroidism and was on thyroxine replacement therapy. Control group consists of healthy young women with no comorbid delivered babies in this time interval. Results: The outcome of the 200 patients were as follows: 97 live births in the group A and 10 miscarriages, while in high dose group, 85 live births and 8 miscarriages were recorded versus 44 live births and 6 miscarriages in the group who were primary hypothyroid. In the control group, there were 50 patients who had 3 miscarriage and 47 healthy babies. Conclusion: Therefore, the present study concluded that radioactive iodine administration does not increased a women risk of infertility or early pregnancy failure.

The effect of ramadan fasting on thyroid function tests: A study of patients on thyroxine replacement therapy

The effect of ramadan fasting on thyroid function tests: A study of patients on thyroxine replacement therapy

The Effect of Induction of Maternal Hypothyroidism on Postnatal Cerebellar Cortex Development in Albino Rat Offspring and the Role of Thyroxin Replacement Therapy Histological, Immunohistochemical and Genetic Study

Background: Maternal thyroid hormones are necessary for the growth of the central nervous system before birth and their shortage can delay cerebellum development.Aim: This study aimed to evaluate the effect of maternal hypothyroidism induction on the development of the cerebellar cortex postnatally in offspring and to compare thyroxin replacement to mothers and postnatally to offspring.Material and Methods: Rat offspring were divided into 3 groups; group I (control), group II (hypothyroid); 15 offspring whose mothers received carbimazole (20 mg/kg/day orally) from the 1st gestational day to the 21st day of lactation. Group III (thyroid hormone replacement) included subgroup IIIa (15 rats) their mothers received carbimazole as group II and Levothyroxine (20 μg/kg/day subcutaneously) from the 10th day of gestation to 21st day of lactation, and subgroup IIIb (15 rats), their mothers received carbimazole as group II and offspring received Levothyroxine (20μg/kg/day subcutaneously) from day 1 postnatally. At the end of 1st, 2nd, and 3rd postnatal weeks, serum Thyroid-stimulating hormone, Free triiodothyronine, and thyroxin were estimated. Cerebellar cortex sections were stained with hematoxylin and eosin, Neurofilament, Myelin basic protein, and Bcl2 immunohistochemical stains. The real-time polymerase chain reaction was done for the reelin gene.Results: Group II showed a significantly reduced Free triiodothyronine, thyroxin, and increased Thyroid-stimulating hormone. Vacuolation in the external granular layer and delayed its disappearance and degeneration of Purkinje cells that increased with age were observed. Reduced myelination, neurofilament content, and Reelin gene expression in the offspring were also detected. Replacement therapy (group III) especially to the mothers (subgroup IIIa) revealed amelioration of these changes.Conclusion: Maternal hypothyroidism impaired development of the offspring cerebellar cortex. However, thyroxin replacement for mothers was more effective than the treatment of offspring. Therefore, treatment of hypothyroid mothers during pregnancy is essential to ensure adequate cerebellar cortex development.

Massive Ovarian Enlargement with Multiple Cysts Mimicking Ovarian Neoplasm and Primary Hypothyroidism

Background: Cystic enlargement of ovaries may develop due a large number of causesand may need surgical intervention. Moreover, some ovarian cysts arise due to endocrinedisorders &amp; do not require surgery. We report an unusual case of massive enlargement ofovaries with multiple cysts in a girl with severe hypothyroidism. Morphologic features ofcysts on ultrasonography and clinical features of hypothyroidism with elevated TSH levelfacilitates diagnosis of multiple ovarian cysts and hypothyroidism.&#x0D; Case presentation: A 23-year-old unmarried woman presented with abdominal enlargement,pain and moderate anemia. Abdominal ultra sonogram revealed huge enlargement of theovaries with multiple large cysts. She was admitted in a hospital, treated with blood transfusionand laparotomy was decided. She was referred to us in a private clinic. On further evaluation, she had features of hypothyroidism with high TSH level and abdomino-pelvic ultrasoundrevealed enlarged ovaries with multiple large thin-walled cysts and mild ascitis. Conservativemanagement with thyroxin replacement therapy was given and after 3 weeks of thyroxine(T4) therapy, follow-up abdominal ultrasound showed significant reduction in ovarian size.After 4 months of thyroxine therapy, ovarian size normalized, cysts disappeared completelyand there was significant improvement of patient’s condition and she became euthyroid.&#x0D; Conclusion: This case report highlights the rare association between hypothyroidism andmulticystic ovarian enlargement. It is necessary to keep in mind the possibility ofhypothyroidism in the differential diagnosis of adult patients with ovarian enlargement andmultiple cyst formation in order to prevent unnecessary ovarian surgery.&#x0D; Bangladesh J Obstet Gynaecol, 2018; Vol. 33(1) : 78-81

Efficacy of Levothyroxine Therapy on Diastolic Dysfunction in Patients with Subclinical Hypothyroidism

Background: Hypothyroidism is a cause of left ventricular diastolic dysfunction especially in cases with positive history of coronary artery disease. It is suggested that cardiac dysfunction may be improved with thyroxin replacement therapy. However, it is controversial. Hence, in this study the efficacy of levothyroxine therapy on diastolic dysfunction in patients with subclinical hypothyroidism was assessed. Materials and Methods: In this, randomized clinical trial 40 consecutive patients with subclinical hypothyroidism attending to Loghman Hospital in 2018 for the treatment were enrolled. The treatment was 25-50 microgram per day of levothyroxine for one year. During this period, the patients were followed up with visit or phone call with a monthly manner. The echocardiography indices were rechecked after one year beside the thyroid tests by initial lab and operators. Results: The mean BMI was significantly decreased (P=0.001). The T3 and TSH were significantly differed but The T4 had no significant alteration (P>0.05). Among the echocardiographic indices the MV.E, MV.A to MV. E ratio, EF, Eʹ septal, Eʹ lateral had significant increase and the MV.A and PV. Adur had significant reduction. After intervention among 40 patients, there were 17 cases with normal diastolic function. The BMI, MV. A, PV Adur, Eʹ Septal, Eʹ Lateral, and E to Eʹ ratio showed significant correlation. Conclusion: Totally, according to the obtained results, it is concluded that diastolic dysfunction as a common problem in patients with subclinical hypothyroidism may be treated with administration of levothyroxine. In addition, screening for diastolic dysfunction in patients with subclinical hypothyroidism is recommended to decrease the burden of problem.

Hypothyroidism and the Risk of Venous Thromboembolism: A Nationwide Cohort Study.

Previous studies have shown that hypothyroidism may have an impact on blood coagulation. However, how hypothyroidism and thyroxine replacement therapy (TRT) affect the risk of venous thromboembolism (VTE) remains controversial. This study aimed to examine the associations of hypothyroidism and TRT with VTE risks. This nationwide population-based cohort study was conducted using Taiwan's National Health Insurance Research Database. We enrolled 10,818 hypothyroid patients (the exposed cohort) and 21,636 non-hypothyroid subjects (the unexposed cohort) between 2001 and 2014 after 1:2 exact matching according to age, sex, and index year. Hypothyroid patients were further divided into two groups depending on whether they received TRT or not. Adjusted hazard ratios (aHRs) for VTE were calculated using Fine and Gray competing risk models. The mean follow-up period was 7.5 years. Hypothyroidism was significantly associated with a higher risk of VTE (aHR = 1.83 [95% confidence interval [CI]: 1.44-2.33, p < 0.001]). Among hypothyroid patients, the TRT subgroup had a non-significant trend of lower VTE risk than the non-TRT subgroup (aHR = 0.73 [95% CI: 0.52-1.01, p = 0.058]). The analysis for individual events revealed a significant association between TRT use and a lower risk of pulmonary embolism among hypothyroid patients (aHR = 0.34 [95% CI: 0.13-0.88, p = 0.026]). The data suggest that hypothyroidism was significantly associated with an increased risk of VTE. Among hypothyroid patients, a non-significant trend of lower VTE risk in patients treated with TRT was observed. Further prospective studies or clinical trials are necessary to confirm causality.

Cognitive dysfunction associated with activation of the mTOR signaling pathway after TSH suppression therapy in rats.

Thyroid stimulating hormone (TSH) suppression therapy after thyroid carcinoma surgery could lead to cognitive impairment. But, the possible mechanism of TSH suppression therapy impairs cognitive function is yet unknown. In this study, forty Wistar rats were randomized into the sham operation control (OC), total thyroidectomy (TD), thyroxine replacement therapy (TR), and TSH suppression therapy (TS) groups. We observed that compared to the OC group, escape latency on 1-4 days was significantly prolonged in the TD and TS groups, and the number of rats crossing the virtual platform was significantly reduced in the TD and TS groups. In the TD, TR, and TS groups, the residence time in the target quadrant was significantly decreased, while the activity distance in the target quadrant in the TD group was significantly decreased compared with OC group. In the TD and TS groups, the pyramidal cells in the hippocampal CA1 region showed a disordered arrangement. The cytoplasm was lightly stained, the cells were swollen and round, and spotty liquefaction necrosis could be observed. Compared to the OC group, hippocampal p-mTOR and p-p70s6k levels were significantly decreased in the TD group, while no significant changes were detected in the TR group. Hippocampal p-mTOR and p-p70s6k amounts in the TS group were significantly increased compared with OC group. These results indicated that TSH suppression therapy after total thyroidectomy in rats could impair cognitive function, which might be related to the activation of the mTOR signaling pathway and the damage and necrosis of hippocampal neurons.

Effect of thyroxine on initial catch-up growth in children with hypothyroidism

Background: Hypothyroidism is a common endocrinal cause of growth retardation in children. Following adequate treatment with thyroxine, growth resumes at an accelerated rate which is known as catch-up growth. There are few observational studies from India on the growth parameters following treatment with thyroxine in children with hypothyroidism.Methods: A retrospective study was done in children aged 2-10 years who were newly diagnosed cases of primary hypothyroidism [Total serum Thyroxine (T4) levels &lt;5 µg/dl and serum Thyroid Stimulating Hormone (TSH) levels ˃15 µU/ml] and treated with oral thyroxine to attain euthyroid state. Height measured before starting treatment and at the time of follow up visits was noted, the Height Standard Deviation Scores (HSDS) were calculated. The effect of thyroxine on linear growth was studied.Results: There were 23 children who were diagnosed as having primary hypothyroidism of whom 16(69.6%) were females and 7(30.4%) were males. The mean age of the children studied was 7.3±2.3 years. The mean dose of thyroxine required to maintain euthyroid status was 4.6±2.2 µg/kg/day. Mean duration of follow up was 13.7±2.4 months. The initial HSDS was - 2.31±0.9 which improved to a final value of - 1.7±0.76 (ΔHSDS0.61, p value &lt;0.0001). Mean height velocity was 8.1 cms/year.Conclusions: Following adequate thyroxine replacement therapy catch-up growth occurs and increased growth velocity leads to partial regain of height deficit in the first couple of years of treatment.

Routine free thyroxine reference intervals are suboptimal for monitoring children on thyroxine replacement therapy and target intervals need to be assay-specific

Central hypothyroidism is a condition where there is (qualitatively or quantitatively) TSH deficiency, leading to reduced thyroid hormone production. In such patients, serum TSH does not accurately reflect the adequacy of thyroxine replacement, as the log-linear relationship between thyrotropin (TSH) and free thyroxine (FT4) is lost. We aimed to prospectively determine the optimal physiological FT4 treatment range for children treated for primary hypothyroidism, based on their serum TSH concentrations. This information could be used to guide optimal therapy for all children on thyroxine replacement, including those with central hypothyroidism. In total, sixty children (median age: 11 years, range: 11 months to 18 years) were recruited over 21 months. They were prescribed a stable dose of thyroxine for at least 6–8 weeks prior to a thyroid function test that consisted of serum TSH, FT4 and free triiodothyronine (FT3) measurements. The serum sample for the thyroid function tests was collected before ingestion of the daily dose, i.e. the trough concentration, and measured using Beckman Coulter UniCel DxI 800 instrument, Siemens Advia Centaur, Roche Cobas, Abbott Architect, Ortho Clinical Diagnostics Vitros 5600 (Ortho-Clinical Diagnostics, Raritan, NJ) platforms. The FT4 and FT3 reference intervals showed significant inter-method difference. The lower limit of the FT4 reference intervals were generally shifted mildly higher when the TSH concentration of the children were restricted from 0.5–5.0 mIU/L to 0.5–2.5 mIU/L. By contrast, the upper limit of the FT3 and FT4 reference intervals were relatively stable for the different TSH concentrations. Assay-specific target ranges for optimal thyroxine therapy are required until FT4 assay standardisation is realised.

The Effects of Dyslipidemia in Subclinical Hypothyroidism.

BackgroundSubclinical hypothyroidism (SCH) affects 7.5-8.5% of women and 2.8-4.4% of men globally. Usually, both hypothyroidism and hyperthyroidism are related to cardiovascular and cerebrovascular disease development. The relationship between subclinical hypothyroidism and dyslipidemia has been widely investigated, but the findings remain controversial. Recent evidence shows that serum thyroxine (T4) replacement therapy may improve lipid profiles. The objective of the present study is to assess dyslipidemia among patients with SCH in Benghazi, Libya and compare it with controls.MethodsThe study was conducted from August 2018 to November 2018 and included 36 patients with SCH. All the patients were around 30 years of age. We also included sex-matched healthy subjects (controls) selected from three diabetes and endocrinology clinics in Benghazi: Alhaya clinic, Alrazy clinic, and Alnukbah clinic. Clinical information and medical history were obtained through a questionnaire from all SCH patients and normal control subjects. Blood samples were collected and analyzed for thyroid-stimulating hormone (TSH), free thyroxine (FT4), total cholesterol (T-Chol), serum triglycerides (STG), low-density lipoprotein-cholesterol (LDL-C), and high-density lipoprotein-cholesterol (HDL-C).ResultsPatients with SCH showed significantly higher T-Chol, STG, and LDL-C levels, as well as significantly lower levels of HDL-C in comparison to the healthy controls. No significant correlation was found between TSH and T-Chol, STG, HDL-C, and LDL-C; no significant correlation was found between FT4 and HDL-C either. However, a strong negative correlation was found between FT4 and T-Chol, STG, and LDL-C.ConclusionOur study concluded that SCH is associated with dyslipidemia. We strongly recommend biochemical screening for thyroid dysfunction for all patients with dyslipidemia.