Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH): Optimal Management

Hyponatremia After Colonoscopy Bowel Preparation: Challenges in Managing Syndrome of Inappropriate Antidiuretic Hormone Without Established Guidelines

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a condition that leads to free water retention and solute excretion, predisposing patients to hyponatremia. We present the case of a 79-year-old female with a history of SIADH well-controlled with fluid restriction and sodium chloride tablets who presented with hyponatremia after bowel preparation. Her medication regimen was not adjusted before she took the bowel preparation. Her SIADH diagnosis was unknown when she presented but was exemplified by her sodium levels dropping while on a normal saline drip on her third day in the hospital. She was able to successfully take the bowel preparation without hyponatremia after oral urea was added to her regimen. There are currently no clinical guidelines for SIADH patients receiving bowel preparation for colonoscopies and no case reports describing this situation. We discuss the pathophysiology behind the patient's fluctuating sodium levels when on various maintenance fluids and when on fluid restriction. This case concludes that it is imperative to either increase solute intake or increase free water excretion for SIADH patients receiving bowel preparation to prevent potentially deadly hyponatremia.

Human Data on Pharmacokinetic Interactions of Cannabinoids: A Narrative Review

Concomitant use of cannabinoids with other drugs may result in pharmacokinetic drug-drug interactions, mainly due to the mechanism involving Phase I and Phase II enzymes and/or efflux transporters. Cannabinoids are not only substrates but also inhibitors or inducers of some of these enzymes and/or transporters. This narrative review aims to provide the available information reported in the literature regarding human data on the pharmacokinetic interactions of cannabinoids with other medications. A search on Pubmed/Medline, Google Scholar, and Cochrane Library was performed. Some studies were identified with Google search. Additional articles of interest were obtained through cross-referencing of published literature. All original research papers discussing interactions between cannabinoids, used for medical or recreational/adult-use purposes, and other medications in humans were included. Thirty-two studies with medicinal or recreational/adult-use cannabis were identified (seventeen case reports/series, thirteen clinical trials, and two retrospective analyses). In three of these studies, a bidirectional pharmacokinetic drug-drug interaction was reported. In the rest of the studies, cannabinoids were the perpetrators, as in most of them, concentrations of cannabinoids were not measured. In light of the widespread use of prescribed and non-prescribed cannabinoids with other medications, pharmacokinetic interactions are likely to occur. Physicians should be aware of these potential interactions and closely monitor drug levels and/or responses. The existing literature regarding pharmacokinetic interactions is limited, and for some drugs, studies have relatively small cohorts or are only case reports. Therefore, there is a need for high-quality pharmacological studies on cannabinoid-drug interactions.

Pituitary Apoplexy-associated Cerebral Salt Wasting Syndrome: A Case Report and Literature Review

PURPOSE

This is a case report of a patient experiencing hyponatremia who was ultimately diagnosed with pituitary apoplexy-associated cerebral salt wasting syndrome (CSWS).

METHODS

Laboratory tests, clinical evaluations, and magnetic resonance imaging were performed by specialists.

FINDINGS

The patient presented with severe headache, thirst, and polyuria. Results of laboratory tests indicated hyponatremia, decreased plasma osmolality, and elevated urine osmolality. Fluid restriction worsened the situation, and normal saline treatment helped return serum sodium and chloride levels to normal. Pituitary apoplexy-associated CSWS was finally considered.

IMPLICATIONS

Pituitary apoplexy is a rare but reasonable etiology for CSWS with hyponatremia. Saline therapy is usually effective.

A rare case of concomitant Lambert-Eaton myasthenic syndrome and syndrome of inappropriate antidiuretic hormone secretion in a patient with small cell lung carcinoma

Small cell lung carcinoma (SCLC) is a neuroendocrine carcinoma with a poor prognosis and is a common cause of paraneoplastic syndromes. Paraneoplastic syndromes are characterized by neurological and endocrinological problems in patients with malignancy and are often associated with difficulty in induction of chemotherapy. Here we report the case of a patient with SCLC concomitant with two paraneoplastic syndromes, syndrome of inappropriate antidiuretic hormone secretion (SIADH) and Lambert-Eaton myasthenic syndrome (LEMS), who was treated with a platinum-doublet chemotherapy regimen. A 66-year-old male patient presented with a 1-month history of progressive proximal muscle weakness, ataxia gait and 5 kg of body weight loss. The laboratory tests revealed hyponatremia due to SIADH and the existence of antibodies against P/Q-type voltage-gated calcium channels. The nerve conduction study showed a low amplitude of compound muscle action potential (0.38 mv), a 34% decrement on 3-Hz stimulation, and a 1939% increment after maximum voluntary contraction in 10 seconds (7.75 mv). The endobronchial ultrasound transbronchial needle aspiration biopsy revealed the pathological findings of SCLC. A 2-cycle chemotherapy regimen of irinotecan plus cisplatin resulted in temporary tumor shrinkage that lasted 2 months, but the improvement of proximal muscle weakness and hyponatremia were maintained over the tumor re-progression period after chemotherapy. Although paraneoplastic syndromes accelerate the decrease in performance status, chemotherapy for SCLC may improve symptoms related to paraneoplastic syndromes and could be considered in similar cases.

Relapsing Syndrome of Inappropriate Antidiuretic Hormone Production Responding to Tolvaptan Treatment in a Patient With a Micronodular Formation of the Posterior Pituitary Gland

The syndrome of inappropriate ADH-secretion (SIADH) is a common cause of low sodium levels with diverse aetiology. Here, we report a case of a 41 years old male patient diagnosed with SIADH and a good response to Tolvaptan therapy. Of interest, as a potential unique cause, magnetic resonance imaging revealed a micronodular structure in the posterior pituitary, while no other common cause of SIADH could be identified. Hence, to the best of our knowledge, this is the first case of a Tolvaptan-responsive SIADH associated with a pituitary micronodular structure.

Risk of Hyponatremia after Tramadol/Acetaminophen Single-Pill Combination Therapy: A Real-World Study Based on the OMOP-CDM Database

BACKGROUND AND OBJECTIVE

Tramadol has been reported to cause hyponatremia but the evidence is conflicting. The risk of hyponatremia resulting from combination oral tramadol/acetaminophen (TA) therapy is thus unknown. This study examined whether, compared with acetaminophen (AA), TA use is associated with an increased risk of hyponatremia.

METHODS

Hospital data compatible with the Observational Medical Outcomes Partnership-Common Data Model (OMOP-CDM; version 5.3) for 30,999 patients taking TA or AA from 2011 through 2020 were analyzed. New-onset hyponatremia was defined as a serum sodium level < 135 mEq/L within 10 days after drug initiation. The incidence rate ratio was calculated based on crude and 1:1 propensity-score-matched models. Subgroup analyses compared patients taking TA extended-release (TA-ER) and TA immediate-release (TA-IR) formulations.

RESULTS

Among the 30,999 patients, 12,122 (39.1%) were aged > 65 years and 16,654 (53.7%) were male. Hyponatremia within 10 days developed in 1613 (8.4%) of the 19,149 patients in the TA group; the incidence rate was higher than in the AA group (4.2%; 493 out of 11,850 cases). In the propensity-score-matched model, the incidence rate of hyponatremia in the TA group was 6.8 per 1000 person-days (PD), which was 1.57-fold (1.31, 1.89) higher than that in the AA group (4.3 per 1000 PD). In both the crude and propensity-score-matched models, the incidence rate of hyponatremia was significantly higher in the TA-ER than TA-IR subgroup.

CONCLUSION

In this real-world study, hyponatremia was more frequently observed in the TA than AA group, and in the TA-ER than TA-IR subgroup. Therefore, it is imperative to prescribe tramadol cautiously and closely monitor electrolyte levels.

Acute Oncologic Complications: Clinical-Therapeutic Management in Critical Care and Emergency Departments

Introduction. It is now known that cancer is a major public health problem; on the other hand, it is less known, or rather, often underestimated, that a significant percentage of cancer patients will experience a cancer-related emergency. These conditions, depending on the severity, may require treatment in intensive care or in the emergency departments. In addition, it is not uncommon for a tumor pathology to manifest itself directly, in the first instance, with a related emergency. The emergency unit proves to be a fundamental and central unit in the management of cancer patients. Many cancer cases are diagnosed in the first instance as a result of symptoms that lead the patient's admittance into the emergency room. Materials and Methods. This narrative review aims to analyze the impact of acute oncological cases in the emergency setting and the role of the emergency physician in their management. A search was conducted over the period January 1981-April 2023 using the main scientific platforms, including PubMed, Scopus, Medline, Embase and Google scholar, and 156 papers were analyzed. Results. To probe into the main oncological emergencies and their management in increasingly overcrowded emergency departments, we analyzed the following acute pathologies: neurological emergencies, metabolic and endocrinological emergencies, vascular emergencies, malignant effusions, neutropenic fever and anemia. Discussion/Conclusions. Our analysis found that a redefinition of the emergency department connected with the treatment of oncology patients is necessary, considering not only the treatment of the oncological disease in the strict sense, but also the comorbidities, the oncological emergencies and the palliative care setting. The need to redesign an emergency department that is able to manage acute oncological cases and end of life appears clear, especially when this turns out to be related to severe effects that cannot be managed at home with integrated home care. In conclusion, a redefinition of the paradigm appears mandatory, such as the integration between the various specialists belonging to oncological medicine and the emergency department. Therefore, our work aims to provide what can be a handbook to detect, diagnose and treat oncological emergencies, hoping for patient management in a multidisciplinary perspective, which could also lead to the regular presence of an oncologist in the emergency room.

Bringing GPCR Structural Biology to Medical Applications: Insights from Both V2 Vasopressin and Mu-Opioid Receptors

G-protein coupled receptors (GPCRs) are versatile signaling proteins that regulate key physiological processes in response to a wide variety of extracellular stimuli. The last decade has seen a revolution in the structural biology of clinically important GPCRs. Indeed, the improvement in molecular and biochemical methods to study GPCRs and their transducer complexes, together with advances in cryo-electron microscopy, NMR development, and progress in molecular dynamic simulations, have led to a better understanding of their regulation by ligands of different efficacy and bias. This has also renewed a great interest in GPCR drug discovery, such as finding biased ligands that can either promote or not promote specific regulations. In this review, we focus on two therapeutically relevant GPCR targets, the V2 vasopressin receptor (V2R) and the mu-opioid receptor (µOR), to shed light on the recent structural biology studies and show the impact of this integrative approach on the determination of new potential clinical effective compounds.

The Efficacy of Immunotherapy in Long-Term Survival in Non-Small Cell Lung Cancer (NSCLC) Associated with the Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)

INTRODUCTION

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most common cause of hyponatremia in cancer patients, occurring most frequently in patients with small cell lung cancer. However, this syndrome occurs extremely rarely in patients with non-small cell lung cancer. The results of the clinical trials have revealed that immuno-oncological therapies are effective for long periods of time, providing hope for long survival and with a good quality of life.

CASE PRESENTATION

We present the case of a female patient who was 62 years old at the time of diagnosis in 2016 who underwent surgery for a right pulmonary tumor (pulmonary adenocarcinoma) and subsequently underwent adjuvant chemotherapy. The patient had a left inoperable mediastinohilar relapse in 2018, which was treated using polychemotherapy The patient also had an occurrence of progressive metastasis and a syndrome of inappropriate antidiuretic hormone secretion (SIADH) in 2019 for which immunotherapy was initiated. The patient has continued with immunotherapy until the time this study began to be written (April 2023), the results being the remission of hyponatremia, the clinical benefits and long-term survival.

DISCUSSION

The main therapeutic option for SIADH in cancer patients is the treatment of the underlying disease, and its correction depends almost exclusively on a good response to oncological therapy. The initiation of immunotherapy at the time of severe hyponatremia occurrence led to its remission as well as the remission of the other two episodes of hyponatremia, which the patient presented throughout the evolution of the disease, demonstrating an obvious causal relationship between SIADH and the favorable response to immunotherapy.

CONCLUSIONS

Each patient must be approached individually, taking into account the various particular aspects. Immunotherapy proves to be the innovative treatment that contributes to increasing the survival of patients with metastatic non-small cell lung cancer and to increasing their quality of life.

Clinical Approach to Euvolemic Hyponatremia

Euvolemic hyponatremia is frequently encountered in hospitalized patients and the syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most common cause in most patients. SIADH diagnosis is confirmed by decreased serum osmolality, inappropriately elevated urine osmolality (>100 mosmol/L), and elevated urine sodium (Na) levels. Patients should be screened for thiazide use and adrenal or thyroid dysfunction should be ruled out before making a diagnosis of SIADH. Clinical mimics of SIADH like cerebral salt wasting and reset osmostat should be considered in some patients. The distinction between acute (<48 hours) versus chronic (>48 hours or without baseline labs) hyponatremia and clinical symptomatology are important to initiate proper therapy. Acute hyponatremia is a medical emergency and osmotic demyelination syndrome (ODS) occurs commonly when rapidly correcting any chronic hyponatremia. Hypertonic (3%) saline should be used in patients with significant neurologic symptoms and maximal correction of serum Na level should be limited to <8 mEq over 24 hours to prevent the ODS. Simultaneous administration of parenteral desmopressin is one of the best ways to prevent overly rapid Na correction in high-risk patients. Free water restriction combined with increased solute intake (e.g., urea) is the most effective therapy to treat patients with SIADH. 0.9% saline acts as a hypertonic solution in patients with hyponatremia and should be avoided in the treatment of SIADH due to rapid fluctuations in serum Na levels. Dual effects of 0.9% saline resulting in rapid correction of serum Na during infusion (inducing ODS) and post-infusion worsening of serum Na levels are described in the article with clinical examples.

Syndrome of Inappropriate Secretion of Antidiuretic Hormone (SIADH) With Severe Hyponatremia As the Initial and Sole Presentation of COVID-19 Infection: A Case Report and Pathophysiologic Insights

Hyponatremia is one of the common electrolyte imbalances among hospitalized patients with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) being a common etiology for hyponatremia. There are multiple pathophysiologic considerations in the differential diagnosis of the etiologic factor for SIADH, including infections such as pneumonia and meningitis, as well as coronavirus disease 2019 (COVID-19) infection. However, SIADH, as the sole initial presentation of the infection of COVID-19, is rarely reported. In this report, we present a case of SIADH as the initial and only presentation of a COVID-19 infection, highlighting the clinical course and treatment strategy while providing the putative pathophysiologic insights into this unusual and potentially serious complication of COVID-19 infection.

Fluid management in hospitalized pediatric patients

The proper use of intravenous fluids has likely been responsible for saving more lives than any other group of substances. Proper use includes prescribing an appropriate electrolyte and carbohydrate solution, at a calculated rate or volume, for the right child, at the right time. Forming intravenous fluid plans for hospitalized children requires an understanding of water and electrolyte physiology in healthy children and how different pathology deviates from the norm. This review highlights fluid management in several disease types, including liver disease, diabetic ketoacidosis, syndrome of inappropriate antidiuretic hormone, diabetes insipidus, kidney disease, and intestinal failure as well as in those with nonphysiologic fluid losses. For each disease, the review discusses specific considerations, evaluations, and management strategies to consider when customizing intravenous fluid plans. Ultimately, all hospitalized children should receive an individualized fluid plan with recurrent evaluations and fluid modifications to provide optimal care.

Preoperative hyponatremia predicts complications in older patients undergoing digestive tract surgery: a propensity score matching analysis

Aim

This study aimed to investigate the association between preoperative hyponatremia and life-threatening postoperative complications (including death) among older patients undergoing digestive tract surgery.

Findings

Preoperative hyponatremia was associated with an increased risk of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery. Preoperative hyponatremia was also correlated with a higher risk of postoperative infectious complications.

Message

Preoperative hyponatremia can predict the development of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41999-021-00559-4.

Purpose

Whether preoperative hyponatremia increases the risk of postoperative complications in older patients undergoing digestive tract surgery remains unclear. The purpose of the study was to investigate the association between preoperative hyponatremia and life-threatening postoperative complications (including death) among older patients undergoing digestive tract surgery.

Methods

This was a propensity score-matched, retrospective cohort study. We recruited older patients (≥ 65 years of age) who underwent digestive tract surgery in our institution. The propensity score matching (PSM; 1:2) was used to balance a range of covariates between patients with preoperative hyponatremia (serum sodium [Na⁺] levels < 135 mmol/L) and those with normal [Na⁺] levels (135–145 mmol/L). The primary outcome was the occurrence of life-threatening postoperative complications and mortality (i.e., Clavien–Dindo grade IV and V [CD IV and V] complications) during hospital stay. The relationship between preoperative hyponatremia and the development of CD IV and V complications was identified with logistic regression analysis.

Results

A total of 1076 patients were analyzed (mean age 73.9 years; 421 female [39.1%]). Preoperative hyponatremia was identified in 122 patients. After matching, 312 patients were included in the analyses (104 patients with preoperative hyponatremia and 208 patients with normal [Na⁺] levels; mean age, 76.3 years; 130 female [41.7%]). When compared with normal [Na⁺] levels, preoperative hyponatremia was associated with an increased risk of CD IV and V complications (odds ratio [OR] 2.082, 95% confidential interval [CI] 1.041–4.164, P = 0.038). Preoperative hyponatremia was also significantly associated with a higher risk of postoperative infectious complications (OR 2.158, 95% CI 1.138–4.091, P = 0.018).

Conclusion

Preoperative hyponatremia can predict an increased risk of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41999-021-00559-4.

Severe metabolic derangement: a case of concomitant diabetic ketoacidosis and beer potomania

Diabetic ketoacidosis (DKA) and hyponatraemia associated with beer potomania are severe diagnoses warranting intensive care level management. Our patient, a middle-aged man, with a history of chronic alcohol abuse and insulin non-compliance, presents with severe DKA and severe hyponatraemia. Correcting sodium and metabolic derangements in each disorder require significant attention to fluid and electrolyte levels. Combined they prove challenging and require an individualised approach to prevent the overcorrection of sodium. Furthermore, management of these conditions lends to the importance of understanding the pathophysiology behind their hormonal and osmotic basis.

Oncological Emergencies from Pathophysiology and Diagnosis to Treatment: A Narrative Review

Oncological emergencies are defined as any acute possible morbid or life-threatening events in patients with cancer either because of the malignancy or because of their treatment. These events may occur at any time during malignancy, from symptoms present to end-stage disease. The aim of this study is the review of urgent conditions results from cancer or cancer treatment side effects that need to be addressed immediately. In this study, a comprehensive and in-depth narrative review was carried out by searching the databases of PubMed, Scopus, Science Direct, Google Scholar with the keywords of "cancer, emergency, metabolic emergency, neutropenic fever" along with the words, "tumor lysis syndrome, chemotherapeutic emergency, diagnosis, treatment " in last two decades. Patients suffering from cancer mostly face the challenges that we are classified in different categories, including metabolic, hematologic, cardiovascular, neurologic, respiratory, infectious, and chemotherapeutic emergencies. These patients mostly complain of headaches, nausea, pain, and fever. In conclusion, knowledge of oncology emergencies and palliative care as part of a team approach is critical for treating cancer patients. In this light, it is pivotal for physicians to focus on the early detection of oncological emergencies. Moreover, training programs for cancer patients help them to timely recognize and report the oncologic emergency symptoms, leading to avoid deleterious consequences and unnecessary healthcare costs as well as improve the quality of life in these patients.