Severe hyponatremia following radioactive iodine therapy in patients with differentiated thyroid cancer

Biomodified Extracellular Vesicles Remodel the Intestinal Microenvironment to Overcome Radiation Enteritis

Ionizing radiation (IR) is associated with the occurrence of enteritis, and protecting the whole intestine from radiation-induced gut injury remains an unmet clinical need. Circulating extracellular vesicles (EVs) are proven to be vital factors in the establishment of tissue and cell microenvironments. In this study, we aimed to investigate a radioprotective strategy mediated by small EVs (exosomes) in the context of irradiation-induced intestinal injury. We found that exosomes derived from donor mice exposed to total body irradiation (TBI) could protect recipient mice against TBI-induced lethality and alleviate radiation-induced gastrointestinal (GI) tract toxicity. To enhance the protective effect of EVs, profilings of mouse and human exosomal microRNAs (miRNAs) were performed to identify the functional molecule in exosomes. We found that miRNA-142-5p was highly expressed in exosomes from both donor mice exposed to TBI and patients after radiotherapy (RT). Moreover, miR-142 protected intestinal epithelial cells from irradiation-induced apoptosis and death and mediated EV protection against radiation enteritis by ameliorating the intestinal microenvironment. Then, biomodification of EVs was accomplished via enhancing miR-142 expression and intestinal specificity of exosomes, and thus improved EV-mediated protection from radiation enteritis. Our findings provide an effective approach for protecting against GI syndrome in people exposed to irradiation.

Is there a causal relationship between hypothyroidism and hyponatremia?

Hyponatremia is one of the most common lab abnormalities seen in clinical practice. It has become widely accepted that hypothyroidism is a cause of euvolemic hyponatremia. The primary mechanism is thought to be due to impaired free water excretion and changes in sodium handling in the kidney. However, the clinical studies are conflicting and do not definitively confirm the association between hypothyroidism and hyponatremia. Therefore, if severe hyponatremia occurs in a patient without myxedema coma, other potential etiologies should be sought.

Impact of low iodine diets on ablation success in differentiated thyroid cancer: A mixed-methods systematic review and meta-analysis

BACKGROUND

Debate remains regarding whether to recommend a low iodine diet (LID) before radioactive-iodine treatment and its duration and stringency. This mixed-methods review aimed to determine if iodine status affects treatment success, the most effective diet to reduce iodine status, and how LID impacts wellbeing.

METHODS

Five electronic databases were searched until February 2021. An effectiveness synthesis (quantitative studies) and views synthesis (qualitative, survey, and experience-based evidence) were conducted individually and then integrated. Quality assessment was undertaken.

RESULTS

Fifty-six quantitative and three qualitative studies were identified. There was greater ablation success for those with an iodine status of <50 mcg/L (or mcg/gCr) compared with ≥250 (odds ratio [OR] = 2.63, 95% confidence interval [CI], 1.18-5.86, n = 283, GRADE certainty of evidence very low). One study compared <50 mcg/L (or mcg/gCr) to 100-199 and showed similar rates of ablation success (OR = 1.59, 95% CI, 0.48-6.15, n = 113; moderate risk of bias). People following a stricter LID before ablation had similar rates of success to a less-strict diet (OR = 0.67, 95% CI, 0.26-1.73, n = 256, GRADE certainty of evidence very low). A stricter LID reduced iodine status more than a less strict (SMD = -0.40, 95% CI, -0.56 to -0.24, n = 816), and reduction was seen after 1 and 2 weeks. The main challenges were a negative impact on psychological health, over restriction, confusion, and difficulty for sub-groups.

CONCLUSIONS

Although a LID of 1-2 weeks reduces iodine status, it remains unclear whether iodine status affects treatment success as only a few low-quality studies have examined this. LIDs are challenging for patients. Higher-quality studies are needed to confirm whether a LID is necessary.

Low-Iodine Diet of 4 Days Is Sufficient Preparation for 131I Therapy in Differentiated Thyroid Cancer Patients

CONTEXT

No consensus exists about the optimal duration of the low-iodine diet (LID) in the preparation of 131I therapy in differentiated thyroid cancer (DTC) patients.

OBJECTIVE

This work aimed to investigate if a LID of 4 days is enough to achieve adequate iodine depletion in preparation for 131I therapy. In addition, the nutritional status of the LID was evaluated.

METHODS

In this prospective study, 65 DTC patients treated at 2 university medical centers were included between 2018 and 2021. The patients collected 24-hour urine on days 4 and 7 of the LID and kept a food diary before and during the LID. The primary outcome was the difference between the 24-hour urinary iodine excretion (UIE) on both days.

RESULTS

The median 24-hour UIE on days 4 and 7 of the LID were not significantly different (36.1 mcg [interquartile range, 25.4-51.2 mcg] and 36.5 mcg [interquartile range, 23.9-47.7 mcg], respectively, P = .43). On day 4 of the LID, 72.1% of the DTC patients were adequately prepared (24-hour UIE < 50 mcg), and 82.0% of the DTC patients on day 7 (P = .18). Compared to the self-reported regular diet, DTC patients showed a significantly (P < .01) lower percentage of nutrient intake (calories, protein, calcium, iodine, and water) during the LID.

CONCLUSION

The 24-hour UIE on day 4 of the LID did not differ from day 7, and therefore shortening the LID from 7 to 4 days seems justified to prepare DTC patients for 131I therapy in areas with sufficient iodine intake and may be beneficial to maintain a sufficient nutritional intake during DTC treatment.

Analysis of the incidence and influencing factors of hyponatremia before 131I treatment of differentiated thyroid carcinoma

BACKGROUND

Hyponatremia is a common clinical electrolyte disorder. However, the association between hyponatremia and acute hypothyroidism is unclear. Acute hypothyroidism is usually seen in patients who undergo preparation for radioactive iodine therapy.

AIM

To analyze the incidence and influencing factors of hyponatremia in a condition of iatrogenic acute hypothyroidism in patients with differentiated thyroid cancer (DTC) before ¹³¹I treatment.

METHODS

The study group consisted of 903 DTC patients who received ¹³¹I treatment. The clinical data before and after surgery, as well as on the day of ¹³¹I treatment were analyzed. According to the blood sodium level before ¹³¹I treatment, patients were divided into the non-hyponatremia group and hyponatremia group. Correlations between serum sodium levels before ¹³¹I treatment and baseline data were analyzed. Univariate analysis and binary logistic regression were performed to identify the influencing factors of hyponatremia.

RESULTS

A total of 903 patients with DTC, including 283 (31.3%) males and 620 (68.7%) females, with an average age of 43.8 ± 12.7 years, were included in this study. The serum sodium levels before surgery and ¹³¹I treatment were 141.3 ± 2.3 and 140.5 ± 2.1 mmol/L, respectively (P = 0.001). However, the serum sodium levels in males and females before ¹³¹I treatment were lower than those before surgery. Patients aged more than 60 years and less than 60 years also showed decreased serum sodium levels before ¹³¹I treatment. In addition, the estimated glomerular filtration rate (eGFR) in males and females decreased before ¹³¹I treatment compared with those before surgery (P = 0.001). Moreover, eGFR in patients over 60 years and under 60 years decreased before ¹³¹I treatment, when compared with that before surgery. There were no significant differences in serum potassium, calcium, albumin, hemoglobin, and blood glucose in patients before surgery and ¹³¹I treatment (P > 0.05). Among the 903 patients, 23 (2.5%) were diagnosed with hyponatremia before ¹³¹I treatment, including 21 cases (91.3%) of mild hyponatremia and 2 cases (8.7%) of moderate hyponatremia. Clinical data showed that patients with mild hyponatremia had no specific clinical manifestations, while moderate hyponatremia cases were mainly characterized by fatigue and dizziness, which were similar to neurological symptoms caused by hypothyroidism and were difficult to distinguish. Correlation analysis showed a correlation between serum sodium before ¹³¹I treatment and the preoperative level (r = 0.395, P = 0.001). There was no significant correlation between blood sodium and thyroid-stimulating hormone (TSH) levels and urine iodine before ¹³¹I treatment (r = 0.045, P = 0.174; r = 0.013, P = 0.697). Univariate analysis showed that there were significant differences in age, sex, history of diuretic use, distant metastasis, preoperative blood sodium, blood urea nitrogen (BUN), eGFR, TSH and urinary iodine between the two groups (all P < 0.05). Logistic regression analysis showed that factors such as history of diuretic use, distant metastases, preoperative sodium and BUN were all influencing factors of hyponatremia. The Hosmer and Lemeshow test (c2 = 2.841, P = 0.944) suggested a high fit of the model. Omnibus tests of model coefficients indicated the overall significance of the model in this fitted model (P < 0.05). Preoperative serum sodium was a significant factor associated with pre-¹³¹I therapy hyponatremia (OR = 0.763; 95%CI: 0.627-0.928; P = 0.007).

CONCLUSION

The incidence of hyponatremia induced by ¹³¹I treatment preparation was not high. Preparation for radioactive iodine therapy was not a risk factor for the development of hyponatremia in thyroid cancer patients.

Intratumoral Heterogeneity in Differentiated Thyroid Tumors: An Intriguing Reappraisal in the Era of Personalized Medicine

Differentiated thyroid tumors (DTTs) are characterized by significant molecular variability in both spatial and temporal intra-tumoral heterogeneity (ITH), that could influence the therapeutic management. ITH phenomenon appears to have a relevant role in tumor growth, aggressive behavior and drug resistance. Accordingly, characteristics and consequences of ITH in DTTs should be better analyzed and understood in order to guide clinical practice, improving survival. Consequently, in the present review, we investigated morphological and molecular ITH of DTTs in benign, borderline neoplasms and in malignant entities, summarizing the most significant data. Molecular testing in DTTs documents a high risk for recurrence of cancer associated with BRAF^V600E, RET/PTC 1/3, ALK and NTRK fusions, while the intermediate risk may be related to BRAF^K601E, H/K/N RAS and PAX8/PPARγ. In addition, it may be suggested that tumor genotype is associated with peculiar phenotype.

Monitoring and Evaluation of Thyroid Function Tests, Serum Electrolytes and Creatinine Levels Before and After 131I Therapy

Background:

Serum electrolytes, Creatinine, and thyroid profile play an important role in 131I treated patients of thyroid disorders.

Objectives:

To determine the effect of radioactive iodine (131I) on renal parameters, serum electrolytes and the correlation among TFT’S, creatinine, and chloride levels before and after I131 treatment in thyroid disorders.

Methods:

The study was performed on 55 patients of thyrotoxicosis with age ranging from 16-65 years (mean age= 41±14years and BMI=24.8±4.46). The significance of the differences between the results of 1st, 2nd, and 3rd-time serum analysis was assessed by paired Student's t-test. Association between parameters was assessed by Spearman correlation analysis.

Results:

40 patients were taking Carbimazole, and 15 were directly recommended for I131 therapy. Strongly significant variations were observed for TFT’S (T3=0.012, T4 =0.017, and TSH=0. 001) during the follow-up treatment. Before taking I131 (Serum analyzed at 1st time), there observed negative correlation of T3(r=-.46, p=0. 002) and TSH (r=-0.31, p=0.02) with creatinine, and positive correlation of TSH(r=0.29,p=0.02) with chloride. BMI was negatively correlated with potassium(r=-0.30, p=0.02). At the 2nd time (after stopping the Carbimazole), no correlation results were observed. Two months after oral administration of 131I, creatinine, and chloride level was significantly increased (p=0.000), (P=0. 03) respectively, but had no correlation with TFT’S.

Conclusion:

Our findings suggest that patients with goiter (diffused or toxic) have association of TFT’S and BMI with serum electrolytes and creatinine, 131I therapy is also associated with the increase in creatinine and chloride levels of patients leading to kidney problems.

Preparation for radioactive iodine therapy is not a risk factor for the development of hyponatremia in thyroid cancer patients

The aim of this study was to evaluate whether the preparation for radioactive iodine (RAI) therapy by thyroid hormone withdrawal (THW) or a low-iodine diet (LID) can be risk factors for the development of hyponatremia in patients with differentiated thyroid cancer after thyroidectomy.We retrospectively reviewed the medical records and laboratory findings of 326 patients who underwent preparation for RAI therapy after thyroidectomy from 2012 to 2014. Demographic and clinical variables including the method of thyrotropin stimulation and duration of LID were assessed. Serum sodium was measured twice, before operation and before RAI therapy.Hyponatremia was detected in only 3 patients (0.9%) before operation, but in 15 patients (4.6%) before RAI therapy. None of the patients had severe hyponatremia after preparation for RAI therapy. Pre-RAI therapy serum sodium was correlated with the method of thyrotropin stimulation (TWH vs recombinant human thyroid stimulating hormone, P = 0.014) and duration of LID (r = -0.131, P = 0.018); however, the preparation of RAI therapy, THW and LID, did not affect the development of hyponatremia in logistic regression analysis. Preoperative serum sodium was a significant risk factor for hyponatremia during preparation for RAI therapy.Preparation for RAI therapy by THW or LID is not a risk factor for the development of hyponatremia in patients with thyroid cancer. The development of hyponatremia was neither frequent nor severe during preparation for RAI therapy. Physicians should not be greatly concerned about rare life-threatening hyponatremia during preparation for RAI therapy.

Hyponatremia effect in patients with alcohol dependence on their physical and mental health status

Hyponatremia, i.e. reduction of sodium level in the blood plasma below 135 mmol/L, is one of the most common electrolyte disorders occurring in people addicted to alcohol. Numerous psychopathological symptoms may be significantly associated with its occurrence. Since sodium is one of the main bioelements, which is responsible for proper neuromuscular excitability maintenance and contributes in nerve impulses conduction, sodium balance disorders may be related to a risk to basic life functions. The tested group included 100 alcohol dependent patients (M = 90, F = 10). Sodium was determined using biochemical Indiko Plus analyzer. Analysis of sodium concentration demonstrated that 64% of people with alcohol dependence had low (<135 mmol/L) plasma sodium level, of which: 7% had severe hyponatremia (<120 mmol/L), 13% had moderate hyponatremia (120-130 mmol/L) and 44% had mild hyponatremia (130-135 mmol/L). The analysis showed an occurrence of significant differences in terms of: impulsivity, quality of life, clinical symptoms occurrence, maximum amount of alcohol consumed and general health state. The lower concentration of sodium in blood plasma in alcohol dependent people, the worse psychical and psychological quality of their life.

Low iodine diet in differentiated thyroid cancer: a review

Radioactive iodine (RAI) ablation is a beneficial, adjuvant therapy for the management of differentiated thyroid cancer (DTC) after thyroidectomy. The goal of RAI is to destroy remnant thyroid and microscopic cancerous tissue. Radioactive iodine uptake is enhanced by elevating TSH levels and initiating a low iodine diet (LID) prior to ablation. An ideal LID should preferably not exceed 50 mcg/day of dietary iodine for 1-2 weeks, although the duration may be shortened to a week with a structured patient education programme. A pre-ablation spot urinary iodine concentration (UIC) of <100 mcg/l and/or a urinary iodine to creatinine ratio (UICR) of <100 mcg/gCr would support an adequate LID preparation. Hyponatraemia, most likely due to iatrogenic hypothyroidism, is a potential side effect associated with LID and occurs during and a few days after the LID. Although the overall incidence of hyponatraemia is low, patients at high risk (older age, female sex, use of thiazide diuretics) may benefit from serum sodium monitoring. The existing evidence on the impact of LID on RAI ablation has been largely inconsistent due to retrospective study designs and the lack of an objective measurement of urinary iodine levels. Future large prospective randomized control trials are needed to elucidate and confirm the crucial role of LID in achieving successful RAI ablation and greater disease-free survival in DTC.

Dietary evaluation of a low-iodine diet in Korean thyroid cancer patients preparing for radioactive iodine therapy in an iodine-rich region

BACKGROUND/OBJECTIVES

Despite the importance of a low-iodine diet (LID) for thyroid cancer patients preparing for radioactive iodine (RAI) therapy, few studies have evaluated dietary intake during LID. This study evaluated the amount of dietary iodine intake and its major food sources during a typical diet and during LID periods for thyroid cancer patients preparing for RAI therapy, and examined how the type of nutrition education of LID affects iodine intake.

SUBJECTS/METHODS

A total of 92 differentiated thyroid cancer patients with total thyroidectomy were enrolled from Seoul National University Hospital. All subjects completed three days of dietary records during usual and low-iodine diets before ¹³¹I administration.

RESULTS

The median iodine intake was 290 µg/day on the usual diet and 63.2 µg/day on the LID. The major food groups during the usual diet were seaweed, salted vegetables, fish, milk, and dairy products and the consumption of these foods decreased significantly during LID. The mean energy intake on the LID was 1,325 kcal, which was 446 kcal lower than on the usual diet (1,771 kcal). By avoiding iodine, the intake of most other nutrients, including sodium, was significantly reduced during LID (P < 0.005). Regarding nutritional education, intensive education was more effective than a simple education at reducing iodine intake.

CONCLUSION

Iodine intake for thyroid cancer patients was significantly reduced during LID and was within the recommended amount. However, the intake of most other nutrients and calories was also reduced. Future studies are needed to develop a practical dietary protocol for a LID in Korean patients.

Special medical conditions associated with catatonia in the internal medicine setting: hyponatremia-inducing psychosis and subsequent catatonia

Diagnosis and treatment of catatonia in the psychiatry consultation service is not infrequent. Usually, the patient either presents to the Emergency Department or develops catatonia on the medical floor. This condition manifests with significant behavioral changes (from mildly decreased speech output to complete mutism) that interfere with the ability to communicate. After structural brain disorders are excluded, one of the diagnoses that always should be considered is catatonia. However, the causes of catatonia are numerous, ranging from psychiatric causes to a plethora of medical illnesses. Therefore, it is not surprising that there are many proposed underlying mechanisms of catatonia and that controversy persists about the etiology of specific cases.There are only 6 reports of hyponatremia-induced catatonia and psychosis in the literature. Here, we present the case of a 30-year-old woman with catatonia and psychosis induced by hyponatremia, and we use this report to exemplify the multitude of biologic causes of catatonia and to propose a new way to look at the neuroanatomical basis of processing, particularly the vertical processing systems we believe are involved in catatonia.

Risk factors for developing hyponatremia in thyroid cancer patients undergoing radioactive iodine therapy

Background

Due to the alarming increase in the incidence of thyroid cancer worldwide, more patients are receiving postoperative radioactive iodine (RAI) therapy and these patients are given a low-iodine diet along with levothyroxine withdrawal to induce a hypothyroid state to maximize the uptake of RAI by thyroid tissues. Recently, the reported cases of patients suffering from life-threatening severe hyponatremia following postoperative RAI therapy have increased. This study aimed to systematically assess risk factors for developing hyponatremia following RAI therapy in post-thyroidectomy patients.

Methods

We reviewed the medical records of all thyroid cancer patients who underwent thyroidectomy and postoperative RAI therapy from July 2009 to February 2012. Demographic and biochemical parameters including serum sodium and thyroid function tests were assessed along with medication history.

Results

A total of 2229 patients (47.0±11.0 years, female 76.3%) were enrolled in the analysis. Three hundred seven patients (13.8%) of all patients developed hyponatremia; 44 patients (2.0%) developed moderate to severe hyponatremia (serum Na⁺≤130 mEq/L) and another 263 (11.8%) patients showed mild hyponatremia (130 mEq/L<serum Na⁺≤135 mEq/L). In univariate analysis, old age, female sex, presence of hypertension, presence of diabetes, use of thiazide diuretics, use of angiotensin receptor blocker or angiotensin-converting enzyme inhibitors, lung metastasis, and hyponatremia and lower estimated glomerular filtration rate at the start of RAI therapy were significantly associated with hyponatremia in patients undergoing RAI therapy after total thyroidectomy. Multivariate analysis showed that old age, female sex, use of thiazide diuretics, and hyponatremia at the initiation of RAI therapy were independent risk factors for the development of hyponatremia.

Conclusion

Our data suggest that age greater than 60 years, female sex, use of thiazide, and hyponatremia at the initiation of RAI therapy are important risk factors for developing hyponatremia following RAI therapy in post-thyroidectomy patients.