MANAGEMENT OF ENDOCRINE DISEASE: Hypothyroidism-associated hyponatremia: mechanisms, implications and treatment

[Electrolyte disorders in oncological patients]

Electrolyte disorders (ED) are common in patients with cancer and in most cases, the etiologies do not differ from the general population. They may also be induced by the cancer, its therapy or paraneoplastic syndromes. ED are associated with poor outcomes, increased morbidity and mortality in this population. Hyponatremia is the most common disorder, often multifactorial, iatrogenic or secondary to the syndrome of inappropriate antidiuretic hormone secretion, usually due to small cell lung cancer. More rarely, hyponatremia may reveal adrenal insufficiency. Hypokalemia is generally multifactorial and associated with other ED. Cisplatin and ifosfamide induce proximal tubulopathies with hypokalemia and/or hypophosphatemia. Hypomagnesemia is often iatrogenic, related to cisplatin or cetuximab, but can be prevented by supplementation. Hypercalcemia can impair life quality and be life-threatening in the most severe cases. Hypocalcemia is less common and often of iatrogenic origin. Finally, the tumor lysis syndrome is a diagnostic and therapeutic emergency that affects the prognosis of patients. Its incidence tends to increase in solid oncology, related to the improvement of therapies. Prevention and early diagnosis of ED are essential to optimize the overall management of patients with underlying cancer and cancer therapy. The aim of this review is to synthesize most frequent ED and their management.

Hyponatremia in the emergency department: an overview of diagnostic and therapeutic approach

INTRODUCTION

Hyponatremia, defined as a serum sodium concentration <135 mmol/l, is a frequent electrolyte disorder in patients presenting to an emergency department (ED). In this context, appropriate diagnostic and therapeutic management is rarely performed and challenging due to complex pathophysiologic mechanisms and a variety of underlying diseases.

OBJECTIVE

To implement a feasible pathway of central diagnostic and therapeutic steps in the setting of an ED.

METHODS

We conducted a narrative review of the literature, considering current practice guidelines on diagnosis and treatment of hyponatremia. Underlying pathophysiologic mechanisms and management of adverse treatment effects are outlined. We also report four cases observed in our ED.

RESULTS

Symptoms associated with hyponatremia may appear unspecific and range from mild cognitive deficits to seizures and coma. The severity of hyponatremia-induced neurological manifestation and the risk of poor outcome is mainly driven by the rapidity of serum sodium decrease. Therefore, emergency treatment of hyponatremia should be guided by symptom severity and the assumed onset of hyponatremia development, distinguishing acute (<48 hours) versus chronic hyponatremia (>48 hours).

CONCLUSIONS

Especially in moderately or severely symptomatic patients presenting to an ED, the application of a standard management approach appears to be critical to improve overall outcome. Furthermore, an adequate work-up in the ED enables further diagnostic and therapeutic evaluation during hospitalization.

Beyond Occam's Razor: Concurrent Non-functional Pituitary Macroadenoma and Metastatic Hepatocellular Carcinoma in a Patient With Functional Cure of Hepatitis B

Occam's razor, the principle of parsimony, is frequently employed in medicine to derive a single diagnosis from a patient's myriad symptoms. Conversely, Hickam's dictum, which embraces the principle of plenitude by considering multiple diagnoses for a patient's presentation, is often underutilized or not as widely recognized as Occam's razor. The application of Hickam's dictum is particularly crucial when evaluating nonspecific symptoms such as fatigue, which can manifest in various diseases. This report describes the case of a 72-year-old man with a history of functional cure for hepatitis B who presented with chronic fatigue and hyponatremia. Initially, he was diagnosed with non-functional pituitary macroadenoma and panhypopituitarism. Two months following pituitary surgery, the onset of dyspepsia and the recurrence of fatigue revealed metastatic tumors in the liver, stomach, pancreas, left adrenal gland, and peri-pancreatic lymph nodes. A liver biopsy confirmed the diagnosis of hepatocellular carcinoma. This case highlights the importance of considering multiple, potentially co-existing conditions based on the patient's symptoms and risk factors to complete the thorough diagnoses. Additionally, it emphasizes the need to remain vigilant regarding the risk of liver cancer in patients with a history of chronic hepatitis B infection, irrespective of a functional cure.

Old woman with Sheehan's syndrome suffered severe hyponatremia following percutaneous coronary intervention: a case report and review of literature

Glucocorticoid deficiency can lead to hypoglycemia, hypotension, and electrolyte disorders. Acute glucocorticoid deficiency under stress is very dangerous. Here, we present a case study of an elderly patient diagnosed with Sheehan's syndrome, manifesting secondary adrenal insufficiency and secondary hypothyroidism, managed with daily prednisone and levothyroxine therapy. She was admitted to our hospital due to acute non-ST segment elevation myocardial infarction. The patient developed nausea and limb twitching post-percutaneous coronary intervention, with subsequent diagnosis of hyponatremia. Despite initial intravenous sodium supplementation failed to rectify the condition, and consciousness disturbances ensued. However, administration of 50 mg hydrocortisone alongside 6.25 mg sodium chloride rapidly ameliorated symptoms and elevated blood sodium levels. Glucocorticoid deficiency emerged as the primary etiology of hyponatremia in this context, exacerbated by procedural stress during percutaneous coronary intervention. Contrast agent contributed to blood sodium dilution. Consequently, glucocorticoid supplementation emerges as imperative, emphasizing the necessity of stress-dose administration of glucocorticoid before the procedure. Consideration of shorter intervention durations and reduced contrast agent dosages may mitigate severe hyponatremia risks. Moreover, it is crucial for this patient to receive interdisciplinary endocrinologist management. In addition, Sheehan's syndrome may pose a risk for coronary atherosclerotic disease.

Precision medicine: "Point of Care Ultrasound" (PoCUS) in the diagnostic approach to the patient with hyponatremia

Hyponatremia is a multifactorial disorder defined as a decrease in plasma sodium concentration. Its differential diagnosis requires an adequate evaluation of the extracellular volume (ECV). However, ECV determination, simply based on the clinical history, vital signs, physical examination, and laboratory findings can leads to misdiagnosis and inappropriate treatment. The use of Point-of-Care Ultrasound (POCUS), through the combination of Lung Ultrasound (LUS), Venous Excess UltraSound (VExUS) and Focused Cardiac Ultrasound (FoCUS), allows a much more accurate holistic assessment of the patient's ECV status in combination with the other parameters.

[Consensus recommendations on the diagnosis and treatment of hyponatremia from the Austrian Society for Nephrology 2024]

Hyponatremia is a disorder of water homeostasis. Water balance is maintained by the collaboration of renal function and cerebral structures, which regulate thirst mechanisms and secretion of the antidiuretic hormone. Measurement of serum-osmolality, urine osmolality and urine-sodium concentration help to diagnose the different reasons for hyponatremia. Hyponatremia induces cerebral edema and might lead to severe neurological symptoms, which need acute therapy. Also, mild forms of hyponatremia should be treated causally, or at least symptomatically. An inadequate fast increase of the serum sodium level should be avoided, because it raises the risk of cerebral osmotic demyelination. Basic pathophysiological knowledge is necessary to identify the different reasons for hyponatremia which need different therapeutic procedures.

Salt-losing nephropathy associated with severe hypothyroidism

Here, we present a case of an older man presenting with worsening confusion. Laboratory tests showed serum sodium of 120 mmol/L with severe hypothyroidism and renal salt wasting that improved with treatment of hypothyroidism, normalising the serum sodium.

Hypothyroidism-Etiologies, Evaluation, and Emergency Care

Thyroid hormone affects every human organ system and is a vital component of metabolism. Common and easily treatable, hypothyroidism does not usually require emergency management. However, myxedema coma is the decompensated form of hypothyroidism and can be life threatening if not treated expediently.

An enigma of hypothyroidism and hyponatremia coexistence: a nationwide population-based retrospective study

INTRODUCTION

Hypothyroidism is a rare and possible cause of hyponatremia. However, the clinical epidemiology and risk of mortality (ROM) when they coexist still remain elusive.

OBJECTIVES

We assessed the epidemiology and ROM among index patients with coexisting hypothyroidism and hyponatremia via a national population database.

PATIENTS AND METHODS

This retrospective cohort study utilized Taiwan's National Health Insurance program database. Distributions of definite sociodemographic factors were analyzed. The annual incidence among the overall group and sex-subgroups was investigated. In addition, potential factors influencing the ROM were also evaluated.

RESULTS

Of 4,549,226 patients from 1998 to 2015, a total of 3,140 index patients with concurrent hypothyroidism and hyponatremia were analyzed. The incidence rate increased tenfold from 1998 to 2015; average annual incidence rate was 174. Among the total participants, 57.1% were women; mean age was 72.6 ± 14.7 years and 88.8% were aged > 55 years. Although average length of stay (LOS) was 13.1 ± 15.4 days, the mortality group had significantly longer LOS than that in the survival group (12.9 days vs 22.2 days). Old age, catastrophic illness, cardiac dysrhythmia, and low hospital hierarchy were independent predictors of hospital mortality. The optimal LOS cutoff value for ROM prediction was 16 days. Index patients with LOS > 16 days increased ROM by 2.3-fold.

CONCLUSIONS

Coexistent hypothyroidism and hyponatremia is rare, although the incidence increased gradually. Factors influencing the ROM, such as old age, underlying catastrophic status, cardiac dysrhythmia, hospital hierarchy, and LOS should be considered in clinical care.

Clinical applications of smart wearable sensors

Smart wearable sensors are electronic devices worn on the body that collect, process, and transmit various physiological data. Compared to traditional devices, their advantages in terms of portability and comfort have made them increasingly important in the medical field. This review takes a unique clinical physician's standpoint, diverging from conventional sensor-type-based classifications, and provides a comprehensive overview of the diverse clinical applications of wearable sensors in recent years. In this review, we categorize these applications according to different diseases, encompassing skin diseases and injuries, cardiovascular diseases, abnormal human motion, as well as endocrine and metabolic disorders. Additionally, we discuss the challenges and perspectives hindering the development of sensors for clinical use, emphasizing the critical need for interdisciplinary collaboration between medical and engineering professionals. Overall, this review would serve as an important reference for the future direction of sensor devices in clinical use.

Severe recurrent hyponatremia in a 72-year-old patient with undiagnosed partially empty Sella syndrome-a case report

Hyponatremia is one of the most common electrolyte abnormalities encountered in medical practice and is caused by multiple conditions. SIADH is the most common cause of hyponatremia, however, careful workup must be performed on all patients as mere supplementation may cause recurrent hyponatremia and serious side effects. Adrenal insufficiency is a principal culprit that mimics the clinical picture of SIADH and tends to worsen when treated in the line of SIADH. In addition, individuals may have various comorbidities, such as hypothyroidism in our case, which can also cause hyponatremia, making it difficult to determine precise etiology. We present a case of a 72-year-old man with recurrent hyponatremia, who was subsequently diagnosed as partially empty sella syndrome. Given the temporal relationship between the use of corticosteroids and the improvement of his symptoms, low cortisol and ACTH levels, adrenal insufficiency was most likely the cause of the hyponatremia in our patient.

Incidence trends and risk factors for hyponatremia in epilepsy patients: A large-scale real-world data study

OBJECTIVE

This study aimed to evaluate the annual incidence and risk factors of hyponatremia in pediatric, adult, and older adult patients with epilepsy.

METHODS

We enrolled 26,179 patients: 8598 pediatric patients (aged 0-15 years), 16,476 adults (aged 16-64 years), and 1105 older adults (aged ≥65 years). Patients were included if their serum sodium levels were measured between January 2006 and December 2020. Moderate-severe hyponatremia was defined as a serum sodium level of less than 130 mEq/L.

RESULTS

From 2006 to 2020, 677 patients (2.6%) developed moderate-severe hyponatremia. The incidence of hyponatremia per 1000 person-years was 3.1 in the pediatric group, 19.8 in the adult group, and 50.4 in the older adult group. The incidence increased markedly from 36.8 in 2007 to 58.5 in 2020 in the older adult group but remained unchanged in the adult group and tended to decrease in the pediatric group. In the multiple logistic regression model, use of carbamazepine, valproate, phenytoin, phenobarbital, benzodiazepines, and antipsychotics was found to be a significant risk factor for hyponatremia. In adult patients, carbamazepine, benzodiazepine, and antipsychotics induced hyponatremia in a dose-dependent manner. Concomitant use of zonisamide reduced the risk of hyponatremia.

SIGNIFICANCE

Hyponatremia will become an increasingly important concern in clinical settings because the population of epilepsy patients is aging. Serum sodium levels should be monitored carefully when patients are receiving first-generation antiseizure medications or antipsychotics or combinations of these drugs. Our findings may help to minimize the risk of hyponatremia in epilepsy patients.

A Conspectus of Euvolemic Hyponatremia, Its Various Etiologies, and Treatment Modalities: A Comprehensive Review of the Literature

Hyponatremia is the most prevalent electrolyte imbalance encountered among hospitalized patients, athletes, the elderly, patients with chronic ailments, postoperative patients, and a few asymptomatic individuals. Clinical manifestations of hyponatremia can be diverse, with characteristic neurological symptoms. Depending on in-depth medical history, physical examination (including volume status assessment), laboratory investigation, and drug history, patients can be classified broadly as undergoing hypervolemic, euvolemic, or hypovolemic hyponatremia. However, patients with hypervolemic hyponatremia often present with distinctive signs such as edema or ascites, and the clinical presentation of hypovolemic and euvolemic hyponatremia poses significant challenges for clinicians. The convolution in clinical manifestations of patients is due to the varied etiologies of euvolemic hyponatremia, such as syndrome of inappropriate antidiuretic hormone secretion (SIADH), adrenocortical insufficiency, hypothyroidism, psychogenic polydipsia, different classes of drugs (chemotherapeutics, antipsychotics, antidepressants), endurance exercise events, and reset osmostat syndrome (ROS). The management of hyponatremia depends on the rate of hyponatremia onset, duration, severity of symptoms, levels of serum sodium, and underlying comorbidities. Over the last decade, the clinical understanding of hyponatremia has been scattered due to the introduction of innovative laboratory markers and new drugs. This article will be a conspectus of all the recent advancements in the field of diagnosis, investigations, management, and associations of hyponatremia, along with traditional clinical practices. Subsequently, a holistic overview has been laid out for the clinicians to better understand and identify knowledge deficiencies on this topic.

Disseminated idiopathic lipid keratopathy in a normolipemic cat

OBJECTIVE

To report a case of idiopathic lipid keratopathy in a normolipemic cat.

ANIMAL STUDIED

A 10-year-old neutered female European domestic cat.

RESULTS

A cat was evaluated for bilateral white corneal deposits. Slit-lamp examination revealed multiple, well-defined, round, stromal, cream-colored deposits of different sizes associated with generalized superficial corneal vascularization. Blood lipids were normal, and no history of travel to tropical locations or ocular trauma was present. Topical betamethasone/gentamicin 0.1% suspension q 12 hours did not result in any improvement of clinical appearance after one week. Tomography following the initial therapy revealed dense, hyperreflective deposits with posterior shadowing in the anterior and mid stroma of both corneas. A four-week course of itraconazole 0.01% ophthalmic cream was prescribed q 12 hours with no improvement. Four months after the initial examination, a diagnostic superficial keratectomy and amniotic membrane implantation were performed. Histopathological analysis showed membrane bound vacuoles with infiltration of foamy macrophages suggesting a diagnosis of primary lipidosis. The post-surgical period was unremarkable, and ten days later, the patient was re-examined. Opacification from a corneal leukoma was observed in the excision site with mild fibrotic tissue. Two months post-keratectomy, no further changes were detected in the cornea, and the patient was managed only with topical lubricant.

CONCLUSIONS

To our knowledge, this is the first report of idiopathic corneal lipidosis in a cat and may be considered as a differential diagnosis of corneal disease in felines.

Severe hyponatremia due to trimethoprim-sulfamethoxazole-induced SIADH

Hyponatremia, a serum sodium level of <135 mEq/L, is the most common electrolyte abnormality occurring in 5%–35% of hospitalized patients. It is a predictor of increased morbidity and mortality. Diuretics, psychotropic, and antiepileptic drugs are commonly implicated in drug-induced hyponatremia. Trimethoprim-sulfamethoxazole and spironolactone are two commonly prescribed drugs; unfortunately, most providers are unfamiliar with these two drugs causing hyponatremia. Simultaneous use of trimethoprim-sulfamethoxazole and spironolactone can cause serious drug interactions that increase the risk of hyponatremia, hyperkalemia, and overall mortality. Despite recommendations to avoid using these two drugs concurrently, many healthcare providers continue to prescribe them together. We report a case of an elderly female with severe hyponatremia caused by trimethoprim-sulfamethoxazole superimposed on a chronic but stable mild hyponatremia.

Hypothyroidism Induced Hyponatremia: A Case Report

Thyroid hormones have various effects on the body which include electrolyte and water hemostasis. It is also involved in renal development and physiology. Hyponatremia is a serious electrolyte imbalance that can be associated with the involvement of different body systems and a wide range of deleterious changes. We report a case of a 62-years-old female with the symptoms of severe hyponatremia like altered mental sensorium with a serum sodium level of 110 meq/l. After ruling out other causes, a final diagnosis of hypothyroidism was made. On treating hypothyroidism the symptoms of hyponatremia were resolved. Therefore, thyroid stimulating hormone determination is mandatory during the evaluation of hyponatremia. And, those patients should be treated with fluid restriction and treatment of hypothyroidism.

Adverse Endocrine-Related Effects of Pembrolizumab Precipitating Severe Hyponatremia

Pembrolizumab is an immune-checkpoint inhibitor (ICI), designed as a highly selective anti-programmed death-1 (PD-1) humanized monoclonal antibody, which ultimately inhibits the negative immune regulation due to PD-1 receptor signaling. This inhibition allows for anti-tumor response and reverses T cell suppression. We present a case report of a 53-year-old woman who was treated with pembrolizumab for metastatic melanoma. There have been adverse endocrine-related effects of pembrolizumab, as well as other ICI medications, including hypothyroidism and secondary adrenal insufficiency. Adrenal insufficiency and hypothyroidism can precipitate hyponatremia through different mechanisms. We report a case of a patient developing severe hyponatremia likely precipitated by endocrine-related side effects of pembrolizumab.

Approach to the Patient: Hyponatremia and the Syndrome of Inappropriate Antidiuresis (SIAD)

Hyponatremia is the most common electrolyte disturbance seen in clinical practice, affecting up to 30% of acute hospital admissions, and is associated with significant adverse clinical outcomes. Acute or severe symptomatic hyponatremia carries a high risk of neurological morbidity and mortality. In contrast, chronic hyponatremia is associated with significant morbidity including increased risk of falls, osteoporosis, fractures, gait instability, and cognitive decline; prolonged hospital admissions; and etiology-specific increase in mortality. In this Approach to the Patient, we review and compare the current recommendations, guidelines, and literature for diagnosis and treatment options for both acute and chronic hyponatremia, illustrated by 2 case studies. Particular focus is concentrated on the diagnosis and management of the syndrome of inappropriate antidiuresis. An understanding of the pathophysiology of hyponatremia, along with a synthesis of the duration of hyponatremia, biochemical severity, symptomatology, and blood volume status, forms the structure to guide the appropriate and timely management of hyponatremia. We present 2 illustrative cases that represent common presentations with hyponatremia and discuss the approach to management of these and other causes of hyponatremia.

Initial treatment of myxedema coma using oral levothyroxine: a case report from Tanzania

Summary

Myxedema coma is a severe complication of hypothyroidism, commonly affecting women over 60 years of age, causing slow, progressive multi-organ dysfunction, and mental deterioration. Due to improved diagnostics and treatment of hypothyroidism, myxedema coma has become uncommon. However, it is hardly reported in resource-limited settings. We present an elderly female with a history of total thyroidectomy due to multi-nodular goiter. She presented with features of heart failure, excessive weight gain, and cold sensation. Although the patient was on levothyroxine replacement therapy, her laboratory tests were suggestive of overt primary hypothyroidism. During the course of her hospitalization, she developed subcutaneous bleeding with frank hematuria. This led to an altered mental state and hypotension that were suggestive of myxedema coma. Stroke and pulmonary embolism were ruled out as potential differential diagnoses of her current state. She was treated with a high dose of oral levothyroxine followed by 150 μg of oral levothyroxine daily, which resulted in a favorable outcome despite being a fatal emergency. She was also treated with intravenous hydrocortisone and furosemide. Oral thyroid hormone replacement may be an effective option in those resource-limited settings where intravenous thyroid hormone replacement is not available. However, early diagnosis and treatment with an adequate dose of thyroid hormones are crucial to achieve a favorable outcome.

Learning points

Myxedema coma is an uncommon complication of hypothyroidism with a fatal outcome. The diagnosis of myxedema coma is based on clinical suspicion, especially in patients with hypothyroidism and in the presence of precipitating factors. Although diagnostic and scoring criteria based on clinical, laboratory, and imaging features have been proposed, no consensus has been reached. This article shows an alternative treatment option for myxedema coma using oral levothyroxine, which led to a favorable outcome.

Cerebral Salt-Wasting Syndrome in a Patient With Active Pulmonary Tuberculosis

A 37-year-old female with a medical history of recently diagnosed active pulmonary tuberculosis and a new intracranial lesion presented with altered mental status, nausea, and vomiting for two days. An initial physical examination revealed that the patient was euvolemic. Laboratory findings revealed a serum sodium concentration of 105 mEq/L. During her admission, she was initially managed with lactated ringer solution in the emergency department, followed by 3% normal saline in the intensive care unit, and, eventually, on oral sodium chloride and fluid restriction on discharge. Once she was stabilized, she had episodes of dizziness, and concerns were raised about the salt-wasting syndrome.

Clinical Implications, Evaluation, and Management of Hyponatremia in Cirrhosis

Hyponatremia is the most common electrolyte abnormality in patients with decompensated cirrhosis on Liver Transplantation (LT) waiting list. Most of these patients have dilutional or hypervolemic hyponatremia secondary to splanchnic vasodilatation. Excessive secretion of the antidiuretic hormone also plays an important role. Hypervolemic hyponatremia is commonly associated with refractory ascites, spontaneous bacterial peritonitis, and hepatic encephalopathy. Although uncommon, the use of diuretics and laxatives can cause hypovolemic hyponatremia that is characterized by the striking absence of ascites or pedal edema. Clinical features are often nonspecific and depend on the acuity of onset rather than the absolute value of serum sodium. Symptoms may be subtle, including nausea, lethargy, weakness, or anorexia. However, rarely patients may present with confusion, seizures, psychosis, or coma. Treatment includes discontinuation of diuretics, beta-blockers, and albumin infusion. Hypertonic saline (3%) infusion may be used in patients with very low serum sodium (<110 mmol/L) or when patients present with seizures or coma. Short-term use of Vasopressin (V₂) receptor antagonists may also be used to normalize sodium levels prior to LT. However, all these measures may be futile, and LT remains the definite treatment in these patients to improve survival. In this review, we describe the classification, pathogenesis of hyponatremia, and its clinical implications in patients with cirrhosis. Approach to these patients along with management will also be discussed briefly.

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.

Retracing the tracks for SIAD: hyponatraemia due to post-traumatic brain injury hypopituitarism

Hyponatraemia is common in hospital practice, with the syndrome of inappropriate antidiuresis (SIAD) being the most common underlying aetiology. A relatively less frequent but important cause is adrenal insufficiency (AI). We describe the case of a 63-year-old man who presented with symptomatic hyponatraemia and hypoglycaemia associated with abnormal body movements (ballism). The recent commencement of levothyroxine for newly diagnosed hypothyroidism, followed by fluid restriction for presumed SIAD, led to the worsening of a previously undiagnosed AI. His investigations confirmed central AI in association with thyroid and growth hormone deficiencies. The underlying cause of hypopituitarism, in this case, was a traumatic brain injury He responded well to steroid replacement and fluids. This case highlights that SIAD remains a diagnosis of exclusion, and other causes of hyponatraemia, including AI, should always be considered. Second, levothyroxine treatment without steroid replacement can lead to an adrenal crisis in patients with underlying AI.

Common Electrolyte and Metabolic Abnormalities Among Thyroid Patients

The prevalence of thyroid diseases is high in the general population and causes serious abnormalities and disorders that can affect the quality of life. Many complications can result from poor or inappropriate management of the disease, leading to serious cardiovascular and metabolic complications. In the present review study, we aim to discuss the effect of thyroid diseases on metabolic and electrolyte abnormalities and the potential correlation with some common disorders. Evidence from previous studies has demonstrated that thyroid dysfunctions hugely affect the metabolism of glucose in the bodies of the affected patients, which can lead to the development of both type 1 and 2 diabetes mellitus (DM). Hyperthyroidism can lead to the development of impaired glucose tolerance and secondary diabetes mellitus. These include an increased glycogenolysis and gluconeogenesis process, increased intestinal absorption of glucose, and secondary ketogenesis and lipolysis, which will subsequently affect the functions of the insulin-secreting cells of the pancreas. Evidence showed that thyroid diseases are associated with the development of obesity and metabolic syndrome, and the management for these modalities should involve prior management of underlying thyroid diseases. Efforts should be made to adequately manage these cases with concomitant approaches to achieve the best clinical outcomes.

Syndrome of inappropriate antidiuretic hormone secretion in a patient with pituitary apoplexy

Pituitary apoplexy (PA) is an endocrine emergency presenting with headache, visual and hormonal disturbances. Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is rare after PA. A 64-year-old woman presented with acute frontal headache and nausea with normal neurological examination. Labs included normal sodium and creatinine. Echo showed new-onset congestive heart failure (CHF) and MRI of the brain revealed PA. She had normal cortisol levels and low thyroid stimulating hormone with normal thyroxine (T₄) levels. During her hospitalisation, patient developed hyponatraemia. Initially, this was attributed to CHF and she was treated with tolvaptan with normalisation of sodium. One week later, she was readmitted with diarrhoea and hyponatraemia. She was euvolaemic on examination indicating compensated CHF. Despite fluid challenge, patient had no improvement of sodium levels. The diagnosis of SIADH was made. Clinicians should suspect SIADH in patients with hyponatraemia in the setting of PA with normal T₄ and cortisol levels.

A narrative review of progress in diagnosis and treatment of small cell lung cancer patients with hyponatremia

Small cell lung cancer (SCLC) is one of the malignant cancers of lung tumors, and hyponatremia, defined as serum sodium concentration (Na⁺) lower than 135 mmol/L, is the most common complication of solid tumors, with an incidence of up to 18.9% and a negative impact on quality of life in SCLC. As a prognostic index of SCLC, timely monitoring and correcting of hyponatremia is of great clinical significance for prolonging the survival period of patients. In the explore of new drugs for small cell lung cancer, it is necessary to include hyponatremia as an evaluation index in clinical studies. As the occurrence of hyponatremia is sometimes unavoidable owing to SCLC specific neurological characteristics, early monitoring to detect the presence of hyponatremia and timely correction are helpful to improve the prognosis of patients. There are many predisposing factors for hyponatremia, including heterotopia of antidiuretic hormone (ADH), use of platinum-based chemotherapy drugs, and intracranial metastasis, among others. Patients with small cell lung cancer are usually asymptomatic in the early stage, while it is of great significance to find a suitable clinical index to judge whether it is a malignant inducement or not. In the clinical setting, due to different electrolyte levels and therapeutic scheduling for the primary disease, an individualized plan is often made, mainly comprising water restriction, infusion, and medications. This review includes related clinical studies and describes the common symptoms and predisposing factors of hyponatremia in patients with SCLC, and their impact on quality of life and prognosis.

Hyponatremia in Patients with Hematologic Diseases

Hyponatremia is the most common electrolyte disorder in clinical practice and is associated with increased morbidity and mortality. It is frequently encountered in hematologic patients with either benign or malignant diseases. Several underlying mechanisms, such as hypovolemia, infections, toxins, renal, endocrine, cardiac, and liver disorders, as well as the use of certain drugs appear to be involved in the development or the persistence of hyponatremia. This review describes the pathophysiology of hyponatremia and discusses thoroughly the contributing factors and mechanisms that may be encountered specifically in patients with hematologic disorders. The involvement of the syndrome of inappropriate antidiuretic hormone (SIADH) secretion and renal salt wasting syndrome (RSWS) in the development of hyponatremia in such patients, as well as their differential diagnosis and management, are also presented. Furthermore, the distinction between true hyponatremia and pseudohyponatremia is explained. Finally, a practical algorithm for the evaluation of hyponatremia in hematologic patients, as well as the principles of hyponatremia management, are included in this review.

Anticancer Medications and Sodium Dysmetabolism

Therapeutic advances have revolutionised cancer treatment over the last two decades, but despite improved survival and outcomes, adverse effects to anticancer therapy such as dyselectrolytaemias do occur and need to be managed appropriately. This review explores essential aspects of sodium homeostasis in cancer with a focus on alterations arising from anticancer medications. Sodium and water balance are tightly regulated by close interplay of stimuli arising from hypothalamic osmoreceptors, arterial and atrial baroreceptors and the renal juxtaglomerular apparatus. This delicate balance can be disrupted by cancer itself, as well as the medications used to treat it. Some of the conventional chemotherapeutics, such as alkylating agents and platinum-based drugs, can cause hyponatraemia and, on rare occasions, hypernatraemia. Other conventional agents such as vinca alkaloids, as well as newer targeted cancer therapies including small molecule inhibitors and monoclonal antibodies, can cause hyponatraemia, usually as a result of inappropriate antidiuretic hormone secretion. Hyponatraemia can also sometimes occur secondarily to drug-induced hypocortisolism or salt-wasting syndromes. Another atypical but distinct mechanism for hyponatraemia is via pituitary dysfunction induced by immune checkpoint inhibitors. Hypernatraemia is uncommon and occasionally ensues as a result of drug-induced nephrogenic diabetes insipidus. Identification of the aetiology and appropriate management of these conditions, in addition to averting treatment-related problems, can be lifesaving in critical situations.

RENAL FUNCTION AND PLASMA RENIN ACTIVITY AS POTENTIAL FACTORS CAUSING HYPERKALEMIA IN PATIENTS WITH THYROID CARCINOMA UNDERGOING THYROID HORMONE WITHDRAWAL FOR RADIOACTIVE IODINE THERAPY

Objective: Hypothyroidism is not commonly considered a cause of hyperkalemia. We previously reported that hyperkalemia was observed mainly in elderly patients treated with renin-angiotensin-aldosterone system (RAS) inhibitors when levothyroxine treatment was withdrawn for the thyroidectomized patients with thyroid carcinoma to undergo radioactive iodine treatment. Here, we investigated whether acute hypothyroidism causes hyperkalemia in patients who were not treated with RAS inhibitors. We also investigated factors influencing potassium metabolism in hypothyroid patients. Methods: We conducted a single-center, prospective cohort study of 46 Japanese patients with thyroid carcinoma undergoing levothyroxine withdrawal prior to radioiodine therapy. All patients were normokalemic before levothyroxine withdrawal. Blood samples were analyzed 3 times: before, and at 3 and 4 weeks after levothyroxine withdrawal. We investigated factors that may be associated with the elevation of serum potassium levels from a euthyroid state to a hypothyroid state. Results: None of the patients developed symptomatic hyperkalemia. The mean serum potassium level was significantly higher at 4 weeks after levothyroxine withdrawal compared to baseline. The serum sodium levels, the estimated glomerular filtration rate (eGFR), and the plasma renin activity (PRA) decreased significantly as hypothyroidism advanced. In contrast, the plasma levels of adrenocorticotropic hormone, cortisol, aldosterone, and antidiuretic hormone were not changed, while serum thyroid hormone decreased. At 4 weeks after their levothyroxine withdrawal, the patients' serum potassium values were significantly correlated with the eGFR and the PRA. Conclusion: Acute hypothyroidism can cause a significant increase in the serum potassium level, which may be associated with a decreased eGFR and decreased circulating RAS. Abbreviations: ACTH = adrenocorticotropic hormone; ADH = antidiuretic hormone; ATPase = adenosine triphosphatase; eGFR = estimated glomerular filtration rate; HbA1c = glycated hemoglobin; K⁺ = potassium; Na⁺ = sodium; PRA = plasma renin activity; RAS = renin-angiotensin-aldosterone system; T4 = thyroxine; TSH = thyroid-stimulating hormone.

The Association of Obesity with Autoimmune Thyroiditis and Thyroid Function-Possible Mechanisms of Bilateral Interaction

A growing number of patients suffer from autoimmune diseases, including autoimmune thyroid disease. There has simultaneously been a significant increase in the prevalence of obesity worldwide. It is still an open question whether adiposity can directly influence activation of inflammatory processes affecting the thyroid in genetically predisposed individuals. Adipokines, biologically active substances derived from the adipocytes, belong to a heterogenic group of compounds involved in numerous physiological functions, including the maintenance of metabolism, hormonal balance, and immune response. Notably, the presence of obesity worsens the course of selected autoimmune diseases and impairs response to treatment. Moreover, the excess of body fat may result in the progression of autoimmune diseases. Nutritional status, body weight, and energy expenditure may influence thyroid hormone secretion. Interestingly, thyroid hormones might influence the activity of adipose tissue as metabolic alterations related to fat tissue are observed under pathological conditions in which there are deficits or overproduction of thyroid hormones. Functioning TSH receptors are expressed on adipocytes. Thermogenesis may presumably be stimulated by TSH binding to its receptor on brown adipocytes. There could be a bilateral interaction between the thyroid and adipose. Obesity may influence the onset and course of autoimmune disease.

Effect of Optimal Thyroid Replacement Therapy on Chronic Hyponatremia with Focused Review of the Evidence, Mechanisms, and Clinical Implications

We present an unusual case of hyponatremia in an ambulatory hypothyroid patient and review related published literature on PubMed including, original articles, reviews and case reports that describe or refute the association and mechanism for the development of hyponatremia in hypothyroidism.

A 50-year-old female presented in ambulatory clinic with complaints of bilateral hand swelling, fatigue, dizziness, and unsteadiness while walking. Laboratory investigations revealed that she had hypothyroidism and hyponatremia. Thyroid hormone replacement therapy resulted in resolution of hypothyroidism symptoms as well as hyponatremia. A comprehensive search of related literature regarding the development of chronic hyponatremia in hypothyroidism revealed two schools of thought, which we have summarized in this report.

Based on our observations, we conclude that due to overlap in symptoms of hyponatremia and neurological manifestations of hypothyroidism, it is imperative to screen hypothyroid patients for underlying hyponatremia and treat accordingly in order to prevent long-term complications of chronic hyponatremia. Hyponatremia secondary to hypothyroidism resolves with appropriate thyroid hormone replacement therapy, which shows convincing evidence of an association between the two entities.

Prevalence of hypothyroidism in patients with hyponatremia: A retrospective cross-sectional study

Objective

Hypothyroidism has been suggested to be an uncommon cause of hyponatremia. However, little is known about the prevalence of hypothyroidism in patients with different levels of hyponatremia. The objective of this study was to investigate the prevalence of hypothyroidism among patients with hyponatremia of varying severity while taking into consideration potential confounders associated with thyroid function.

Methods

All data on thyrotropin (TSH), free thyroxine (T4), and serum sodium (Na) levels were retrospectively collected from medical records at two Japanese tertiary hospitals. The main outcome measure was overt hypothyroidism, defined as TSH > 10.0 μIU/mL and free T4 < 1.01 ng/dL.

Results

Of 71,817 patients, 964 patients (1.3%) had overt hypothyroidism. The prevalence of overt hypothyroidism in each category of hyponatremia (Na ≥136, 130–135, and ≤129 mEq/L) was 1.2% (787/65,051), 2.4% (124/5,254) and 3.5% (53/1,512), respectively. A significant increase in prevalence was observed as the severity of hyponatremia increased (P < 0.001 for trend). Multivariate logistic regression with adjustment for age, sex, kidney function, and serum albumin level showed that the odds ratios for overt hypothyroidism increased with increasing severity of hyponatremia when compared with Na ≥ 136 mEq/L (130–135 mEq/L: 1.43, 95% confidence interval [CI], 1.15 to 1.78, P = 0.001; ≤129 mEq/L: 1.87, 95% CI, 1.32 to 2.63, P < 0.001; P< 0.001 for trend).

Conclusion

The prevalence of overt hypothyroidism was significantly higher as the severity of hyponatremia progressed, even after adjusting for potential confounders. Hypothyroidism should be differentiated in patients with hyponatremia.

Endocrinopathy-induced euvolemic hyponatremia

Euvolemic hyponatremia results from either the syndrome of inappropriate antidiuretic hormone secretion (SIADH), hypothyroidism, or adrenal insufficiency. Furthermore, the criteria for diagnosis of SIADH entail the exclusion of hypothyroidism and hypoadrenalism. We aim to assess the yield of euvolemic hyponatremia workup focusing on underlying endocrinopathies in a real-world setting. A single-center retrospective study includes all patients diagnosed with euvolemic hyponatremia in a tertiary hospital between 1.1.2007 and 1.1.2013. Demographic, clinical, and laboratory data were collected from medical charts. Euvolemic hyponatremia was detected in 564 patients. Thyroid function was tested in 69% (391/564) and adrenal function was assessed in 29% (164/564) of cases. Endocrinopathy-induced euvolemic hyponatremia was diagnosed in nine (1.6%) patients: three patients were diagnosed with hypothyroidism-induced hyponatremia, three with adrenal insufficiency as an underlying cause, and three with central hypothyroidism and central hypoadrenalism. All nine had medical history and symptoms suggestive of endocrine deficiencies other than the hyponatremia, which resolved within 1-3 days after administration of hormone replacement therapy. Yield of performed workup for hypothyroidism and hypoadrenalism in euvolemic hyponatremia was low. However, in this real-world study, only a limited number of patients underwent a full ascertainment of hypoadrenalism and hypothyroidism, which was diagnosed only in patients with additional findings supportive of these endocrinopathies; a higher rate of undiagnosed endocrinopathies cannot be ruled out. As both hypoadrenalism and hypothyroidism are easily treatable, potentially life-threatening conditions, there are insufficient data to change current recommendation for their universal evaluation in patients with euvolemic hyponatremia.

A case series study of hypopituitarism in older patients with and without gastrointestinal symptoms

OBJECTIVES

Some older individuals who present with gastrointestinal symptoms as their chief complaint were ultimately diagnosed with hypopituitarism instead of gastrointestinal diseases. The aim of this study was to find the characteristics of biochemical indicators in these patients so as to reduce early misdiagnosis.

METHODS

We conducted a retrospective review of 45 patients with hypopituitarism who were at least 60 years of age. Two groups were included: group of hypopituitarism patients with gastrointestinal symptoms (Group G) included 23 patients with gastrointestinal symptoms and group of hypopituitarism patients without gastrointestinal symptoms (Group N) included 22 patients without these symptoms. In Group G, we investigated the prevalence of different gastrointestinal symptoms, the response of these symptoms to treatment, the occurrence of electrolyte disorders, and target gland dysfunction. Then, we compared the electrolyte and target gland function indices between the two groups.

RESULTS

Nausea and vomiting were the most common complaints, accounting for 69.57% of the gastrointestinal symptoms in Group G. Hyponatremia was the most common electrolyte disorder, occurring in 72.86% (n = 18) of patients in Group G. Hypoadrenalism and hypothyroidism were reported by 69.57% and 60.78% of patients, respectively, in Group G. None of the gastrointestinal symptoms were relieved by 4 weeks of treatment with antacid and motility drugs. As mentioned, 18 patients also experienced refractory hyponatremia during early treatment including regular sodium supplements; however, their gastrointestinal symptoms and hyponatremia improved after only a week of treatment for hypopituitarism. Regarding the biochemical indicators, only serum sodium and cortisol in Group G were statistically lower compared with those in Group N (P < .05).

CONCLUSION

Nausea and vomiting were the most common gastrointestinal symptoms in older patients with hypopituitarism, which were associated with lower serum sodium and cortisol. In addition, we hope to share the research to our gastroenterologists that serum sodium and cortisol should be tested when meeting elder patients with unexplained gastrointestinal symptoms.

[Rare Complication of a Common Disease: Thyroid and Epileptic Seizures]

Rare Complication of a Common Disease: Thyroid and Epileptic Seizures Abstract. A myxedema crisis is a life-threatening complication of hypothyroidism (mortality 20-25 %). The diagnosis is made on clinical grounds and thyroid function tests. Treatment with levothyroxine (possibly combined with T3) should be instituted immediately, along with glucocorticoids, until co-existing adrenal insufficiency has been ruled out. Supportive measures and treatment of underlying diseases should be implemented. We are presenting the case of a patient with myxedema crisis complicated by tonic-clonic seizures and severe hyponatremia as first manifestation of primary hypothyroidism.

Hyponatremia in the elderly: challenges and solutions

Decreased serum sodium concentration is a rather frequent electrolyte disorder in the elderly population because of the presence of factors contributing to increased antidiuretic hormone, the frequent prescription of drugs associated with hyponatremia and also because of other mechanisms such as the “tea and toast” syndrome. The aim of this review is to present certain challenges in the evaluation and treatment of hyponatremia in the elderly population and provide practical solutions. Hyponatremia in elderly subjects is mainly caused by drugs (more frequently thiazides and antidepressants), the syndrome of inappropriate antidiuretic hormone secretion (SIAD) or endocrinopathies; however, hyponatremia is multifactorial in a significant proportion of patients. Special attention is needed in the elderly population to exclude endocrinopathies as a cause of hyponatremia before establishing the diagnosis of SIAD, which then requires a stepped diagnostic approach to reveal its underlying cause. The treatment of hyponatremia depends on the type of hyponatremia. Special attention is also needed to correct serum sodium levels at the appropriate rate, especially in chronic hyponatremia, in order to avoid the osmotic demyelination syndrome. In conclusion, both the evaluation and the treatment of hyponatremia pose many challenges in the elderly population.

Impact of etiology, age and gender on onset and severity of hyponatremia in patients with hypopituitarism: retrospective analysis in a specialised endocrine unit

BACKGROUND

Hyponatremia can unmask hypopituitarism and secondary adrenal insufficiency. This is important, since the need to screen for steroid deficiency, in patients with hyponatremia is often neglected.

PATIENTS AND METHODS

In a retrospective study, twenty-five patients (13f/12m, age 58.9 ± 18.6 years) with hyponatremia (119.7 ± 10.5 mmol/L) were identified among 260 in-patients treated for hypopituitarism in our specialized endocrine unit, over the last decade. We analyzed clinical characteristics, etiology, and severity of hypopituitarism in patients who presented with hyponatremia.

RESULTS

Hyponatremia was recorded in 9.6% of our patients with hypopituitarism. In 80.7% it was the key to diagnosis of hypopituitarism. All patients with hyponatremia were steroid deficient with complete hypopituitarism compared to 75% (steroid deficient) and 60% (complete hypopituitarism) of the patients in the cohort. The most common etiology of hypopituitarism was non-functioning pituitary macro adenoma (NFPA) (n = 128, 49.2%). Patients with hyponatremia were divided into two groups, based on the etiology of hypopituitarism: Group 1. with NFPA n = 15 (5F/10M), mean age 71.47 ± 4.8 years, who were significantly older compared to patients with hyponatremia from other rare causes of hypopituitarism in Group 2. n = 10 (8F/2M), mean age 40.2 ± 15.3 years (p < 0.01), such as: congenital hypopituitarism(n = 2), Sheehan's syndrome (n = 2), intracranial aneurysm (n = 2), lymphocytic hypophysitis (n = 1), traumatic brain injury (n = 1), surgery and radiotherapy for astrocytoma (n = 1), pituitary metastasis from bronchial carcinoma (n = 1). Hyponatremia was more severe in Group 2. compared to Group 1. (113.5 ± 10.9 mmol/L vs. 124.3 ± 8.1 mmol/L, p < 0.01). Older age (p = 0.0001) and number of endocrine deficiencies (p < 0.05) were identified as predictive factors for hyponatremia by multivariate analysis in patients with hypopituitarism.

CONCLUSION

Hyponatremia is an important presenting feature of pituitary disease and a strong indicator of life-threatening steroid deficiency. Old age and severity of hypopituitarism are major risk factors for hyponatremia. In older patients NFPA is the most common etiology, while other rare causes of hypopituitarism are more prevalent in younger patients with hyponatremia.

Myxedema Crisis Presenting with Seizures: A Rare Life-Threatening Presentation-A Case Report and Review of the Literature

Myxedema crisis is a life-threatening extreme form of hypothyroidism with a high mortality rate if left untreated. Myxedema crisis is commonly seen in older patients, especially in women, and is associated with signs of hypothyroidism, hypothermia, hyponatraemia, hypercarbia, and hypoxemia. Patients might present with different organ specific symptoms. Seizures are a recognized but rare manifestation of myxedema with a very high mortality rate. Prompt diagnosis and appropriate management may improve the prognosis. Many contributory factors may involve development of seizures in a patient with myxedema. Hyponatraemia is one such cause, which is seen in moderate-severe form in the background of myxedema. We report an elderly male who presented with generalized tonic clonic seizure preceded by memory impairment and drowsiness. He had moderate hyponatraemia and very high thyroid stimulatory hormone levels in association with low free thyroxin levels. Diagnosis of myxedema crisis was made and patient was successfully treated with sodium correction and thyroid hormone replacement.

Hypothyroidism and Hyponatremia: Rather Coincidence Than Causality

BACKGROUND

Hypothyroidism is referred to be a rare but possible cause of hyponatremia. However, there is only poor evidence supporting this association. Since hyponatremia and hypothyroidism are both common conditions themselves, co-occurrence does not have to be causal.

METHODS

To address a potential relationship, a retrospective analysis of data from the Division of Endocrinology of the Medical University of Vienna from April 2004 to February 2016 was performed. A total of 8053 hypothyroid patients (48 ± 18 years of age; 71% female) with thyrotropin >4.0 μIU/mL and available blood tests for free thyroxine and sodium (Na⁺) within maximal ± seven days were included and screened for hyponatremia. Patients' records were searched for concomitant disease and medication when Na⁺ concentration was <135 mmol/L.

RESULTS

Hyponatremia was present in 448/8053 (5.56%) patients. Analysis of medical history revealed potential alternative causes of hyponatremia in 442/448 (98.88%) patients (i.e., side effects of medication, concomitant underlying disease, or other endocrine disorders). This distribution did not differ between patients suffering from clinical or subclinical hypothyroidism. No case of clinically relevant hyponatremia (Na⁺ < 130 mmol/L), present in 111/448 (24.78%) patients could be attributed only to hypothyroidism. There was a very weak but statistically significant trend toward a positive association between thyroid function and serum Na⁺ levels (Na⁺/thyrotropin: R = 0.022, p = 0.046; Na⁺/free thyroxine: R = -0.047, p < 0.001).

CONCLUSION

The results suggest that hypothyroid patients with moderate to severe hyponatremia often have other potential explanations for their low serum Na⁺ concentrations in routine care.

Intracerebral Bleeding and Massive Pericardial Effusion as Presenting Symptoms of Myxedema Crisis

The endocrinological emergency of a fully blown myxedema crisis can present as a multicolored clinical picture. This can obscure the underlying pathology and easily lead to mistakes in clinical diagnosis, work-up, and treatment. We present a case of an unconscious 39-year-old patient with a medical history of weakness, lethargy, and findings of hyponatremia, intracerebral bleeding, and massive pericardial effusion. Finally, myxedema crisis was diagnosed as underlying cause. Replacement therapy of thyroid hormone and conservative management of the intracerebral bleeding resulted in patient's survival without significant neurological impairment. However, diagnostic pericardiocentesis resulted in life-threatening pericardial tamponade. It is of tremendous importance to diagnose myxoedema crisis early to avoid adverse health outcomes.