Syndrome of inappropriate antidiuretic hormone secretion: Revisiting a classical endocrine disorder

Syndrome of inappropriate antidiuretic hormone secretion as an adverse reaction of ciprofloxacin: a case report and literature review

Antidiuretic hormone (ADH) is secreted by the posterior pituitary gland. Unsuppressed release of ADH leads to hyponatremia. This condition is referred to as syndrome of inappropriate antidiuretic hormone secretion (SIADH). Hereby, a case report is presented on ciprofloxacin-induced SIADH. A 67-year-old male patient was examined in the emergency room with symptoms of lethargy, headache, lack of attention, and a generally depressed mood lasting for three days. One week prior, empirical antimicrobial therapy involving ciprofloxacin for prostatitis was initiated. Laboratory analysis showed no relevant abnormalities except for hyponatremia (Na = 129 mmol/L). Chronic hyponatremia, thyroid dysfunction, and adrenal dysfunction were ruled out. Serum osmolality was 263 mOsmol/kg, urine osmolality was 206 mOsmol/kg, and urine sodium was 39 mmol/L. Given that all criteria for SIADH were met, ciprofloxacin was discontinued, and fluid restriction was advised. Four days later, the patient's serum sodium concentrations nearly normalized (Na = 135 mmol/L), and all symptoms resolved. The Naranjo Scale yielded a score of 8, supporting the likelihood of a probable adverse reaction to ciprofloxacin. This case is presented to raise awareness among clinicians about the potential of ciprofloxacin to cause even mild hyponatremia.

Atypical Clostridium difficile Infection in a Pregnant Patient: A Case Study on Non-Diarrheal Presentation and Syndrome of Inappropriate Antidiuretic Hormone (SIADH) Complication

Clostridium difficile (C. difficile) is a Gram-positive, spore-producing bacterium that often leads to pseudomembranous colitis, typically manifesting as watery diarrhea. The risk factors for C. difficile infection (CDI) include exposure to broad-spectrum antibiotics, immunocompromised states, advanced age, usage of proton pump inhibitors (PPI), and comorbid conditions such as chronic kidney disease (CKD). This report details a case involving a 23-year-old pregnant woman who presented with symptoms of abdominal pain and constipation. She was diagnosed with a urinary tract infection (UTI) and treated with ceftriaxone. During her hospitalization, she was administered opioid pain relievers and underwent an intensive bowel regimen. Despite these measures, her constipation and abdominal discomfort persisted, and magnetic resonance imaging (MRI) of the abdomen revealed significant dilatation of the large bowel. The patient, discovered to have hyponatremia, underwent further evaluation. This revealed elevated urine osmolality and decreased blood plasma osmolality, indicative of a syndrome of inappropriate antidiuretic hormone secretion (SIADH). The patient received treatment with hypertonic saline. Later in her hospital stay, she tested positive for CDI through stool analysis and was treated with oral vancomycin. This case underscores the importance of considering CDI as a differential diagnosis in cases of ileus, abdominal pain, and constipation, especially in patients with notable risk factors for CDI. It highlights that the presence of diarrhea or watery bowel movements is not a necessary symptom for CDI testing.

Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) Complicated by Generalized Tonic-Clonic Seizures After a Course of Antibiotics: A Case Report

Nitrofurantoin and cephalexin are commonly used antibiotics for treating urinary tract infections. Hyponatremia secondary to syndrome of inappropriate antidiuretic hormone secretion (SIADH) has been reported as a rare side effect of nitrofurantoin but has never been a reported side effect of cephalexin. We report a case of a 48-year-old female who developed severe hyponatremia complicated by generalized tonic-clonic seizures after a course of antibiotics (nitrofurantoin followed by cephalexin) used for treating a urinary tract infection. She presented to the emergency department with a one-week history of dizziness, nausea, fatigue, and listlessness. She also had a two-week history of persistent urinary frequency despite completing a course of nitrofurantoin followed by a course of cephalexin. While in the emergency department waiting room, she had two episodes of generalized tonic-clonic seizures. Immediate post-ictal blood test results revealed severe hyponatremia and lactic acidosis. Results were consistent with severe SIADH and she was subsequently managed with hypertonic saline and fluid restriction. She was discharged after 48 hours of admission when her serum sodium levels normalized. Though we believe that nitrofurantoin was the culprit drug, we still asked the patient to avoid future use of both nitrofurantoin and cephalexin. Healthcare providers need to be aware of antibiotic-induced SIADH when assessing patients with hyponatremia.

Syndrome of Inappropriate Antidiuretic Hormone Secretion and Trimethoprim-Related Hyponatremia Following Transurethral Bladder Wall Biopsy

Postoperative hyponatremia is common. It results from the physiological antidiuretic hormone (ADH) response to surgery and associated exacerbating factors. Common exacerbating factors include medications, excessive fluid administration, and syndrome of inappropriate antidiuretic hormone (SIADH) secretion. High-dose trimethoprim can cause transient salt-losing nephropathy, resulting in SIADH-like hyponatremia associated with hypovolemia, hyperkalemia, and metabolic acidosis. We present a patient who developed symptoms of vomiting, loss of appetite, fatigue, and abdominal discomfort six days after having a transurethral bladder wall biopsy. He had also started a course of trimethoprim two days prior to the onset of the symptoms. Initial investigations demonstrated severe hyponatremia, concentrated urine, and compensated metabolic acidosis. These results suggested postoperative SIADH possibly exacerbated by trimethoprim-related hyponatremia. Cautious IV normal sodium chloride infusion resulted in a rapid recovery. While raising the awareness of postoperative hyponatremia, this case also highlights the difficulty distinguishing between SIADH and trimethoprim-related hyponatremia.

Severe hyponatremia in children: a review of the literature through instructive cases

Hyponatriemia is the most common electrolyte disorder in the paediatric population. Symptoms are related to the time in which hyponatriemia has developed. The acute presentation could be dramatic, with neurological symptoms like headache, seizure, impaired mental status and even coma. It is essential for the physician to be aware of the possible causes of hyponatremia in the child in order to start a prompt treatment.

A study to understand the pattern of hyponatremia in patients using selective serotonin reuptake inhibitors and serotonin dopamine antagonists

INTRODUCTION

Hyponatremia can be a common but often overlooked side effects of psychotropics drugs. Most patients with drug-induced hyponatremia are asymptomatic and diagnosis is made incidentally following routine blood tests.

OBJECTIVES

The aim of the study was to understand the pattern of hyponatremia in patients using selective serotonin reuptake inhibitors (SSRI) and serotonin dopamine antagonists (SDA).

MATERIALS AND METHODS

All inpatients and outpatients who were diagnosed with International Classification of Diseases-10 psychiatric disorders and undergoing treatment with SSRI, SDA, or combination of both for the same, were included in the study after simple random sampling, subject to inclusion and exclusion criteria.

STATISTICAL ANALYSIS USED

Categorical variables were observed as numbers and percentages. Continuous variables were evaluated as mean ± standard deviation. A Chi-square test was done to find the association between categorical variables. SPSS (IBM) version 21 was used for data analysis.

RESULTS

In 150 patients, we found hyponatremia in 17 patients (11.33%). About 66-75 age group patients had maximum found cases of hyponatremia (66.66%). About 20.31% of females found hyponatremia. Among SSRIs, 16% of individuals had hyponatremia whereas among SDA it was 6%. Patients who were taking both SSRIs and SDA total prevalence of hyponatremia was 12%.

CONCLUSIONS

Older age groups and females had higher chances of hyponatremia while taking SSRIs and SDAs. Among SSRIs, escitalopram had maximum percentage of hyponatremia, whereas fluvoxamine had minimum. Among SDAs, risperidone had maximum percentage, whereas quetiapine had minimum percentage of hyponatremia. Patients who were taking both fluoxetine + olanzapine or fluoxetine + risperidone had higher percentage of hyponatremia.

Development of Inappropriate Vasopressin Secretion in Association With Lumbar Cerebrospinal Fluid Drainage in an Adult With Traumatic Basilar Skull Fracture

Objective

Hyponatremia associated with cerebrospinal fluid (CSF) drainage is primarily limited to pediatric patients. Only 1 case in an adult, after pituitary surgery, has been described. We present the first adult case, to our knowledge, of lumbar CSF drainage associated with the syndrome of inappropriate antidiuretic hormone (SIADH) in a patient with a traumatic basilar skull fracture.

Methods

Serum and urine samples were evaluated for hyponatremia. Computed tomography and magnetic resonance imaging were performed to evaluate the fractures.

Results

A 31-year-old woman was hospitalized with traumatic facial and skull base fractures and managed conservatively. Four days into her hospital stay, she underwent lumbar CSF drainage for 6 days to treat a CSF leak. On examination, the patient remained hemodynamically stable and euvolemic. Sodium levels decreased from 142 to 136 mmol/L (normal, 135-146 mmol/L) on the day before and after lumbar drain placement, respectively, down to a nadir of 124 mmol/L over 3 subsequent days. Serum osmolality was 260 mOsm/kg (275-295 mOsm/kg); urine osmolality, 482 mOsm/kg; urine Na, 175 mmol/L; and thyroid-stimulating hormone, 4.0 μIU/mL (0.3-4.7 μIU/mL). The patient received treatment with sodium tablets, fluid restriction, and hypertonic saline for a diagnosis of SIADH. Sodium levels normalized from 131 to 136 mmol/L within 16 hours after lumbar drain removal.

Conclusion

This case illustrated a temporal association of SIADH with CSF drainage in an adult. Although this could be coincidental because a basilar skull fracture can lead to SIADH, it raises the possibility that CSF lumbar drainage contributed to the patient’s SIADH.

COVID-19 Pneumonia: An Emerging Cause of Syndrome of Inappropriate Antidiuretic Hormone

Syndrome of inappropriate antidiuretic hormone (SIADH) is the leading cause of hyponatremia. We, herein, report a case of a patient with coronavirus disease-2019 (COVID-19) who developed sudden exertional dyspnea and hypoxia and was found to be hyponatremic. A diagnosis of SIADH was made due to COVID-19 pneumonia. The patient was managed conservatively with a significant improvement during the course of hospitalization and on follow-up.

Equivalent Efficacy and Decreased Rate of Overcorrection in Patients With Syndrome of Inappropriate Secretion of Antidiuretic Hormone Given Very Low-Dose Tolvaptan

Rationale & Objective

Euvolemic hyponatremia often occurs due to the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Vasopressin 2 receptor antagonists may be used to treat SIADH. Several of the major trials used 15 mg of tolvaptan as the lowest effective dose in euvolemic and hypervolemic hyponatremia. However, a recent observational study suggested an elevated risk for serum sodium level overcorrection with 15 mg of tolvaptan in patients with SIADH.

Study Design

A retrospective chart review study comparing outcomes in patients with SIADH treated with 15 versus 7.5 mg of tolvaptan.

Settings & Participants

Patients with SIADH who were treated with a very low dose of tolvaptan (7.5 mg) at a single center compared with patients using a 15-mg dose from patient-level data from the observational study described previously.

Predictors

Tolvaptan dose of 7.5 versus 15 mg daily.

Outcomes

Appropriate response to tolvaptan, defined as an initial increase in serum sodium level > 3 mEq/L, and overcorrection of serum sodium level (>8 mEq/L per day, and >10 mEq/L per day in sensitivity analyses).

Analytical Approach

Descriptive study with additional outcomes compared using t tests and F-tests (Fischer's Exact χ2 Test).

Results

Among 18 patients receiving 7.5 mg of tolvaptan, the mean rate of correction was 5.6 ± 3.1 mEq/L per day and 2 (11.1%) patients corrected their serum sodium levels by >8 mEq/L per day, with 1 of these increasing by >12 mEq/L per day. Of those receiving tolvaptan 7.5 mg, 14 had efficacy, with increases ≥ 3 mEq/L; similar results were seen with the 15-mg dose (21 of 28). There was a statistically significant higher chance of overcorrection with the use of 15 versus 7.5 mg of tolvaptan (11 of 28 vs 2 of 18; P = 0.05; and 10 of 28 vs 1 of 18; P = 0.03, for >8 mEq/L per day and >10 mEq/L per day, respectively).

Limitations

Small sample size, retrospective, and nonrandomized.

Conclusions

Tolvaptan, 7.5 mg, daily corrects hyponatremia with similar efficacy and less risk for overcorrection in patients with SIADH versus 15 mg of tolvaptan.

A Rare Case of Syndrome of Inappropriate Anti-diuretic Hormone in Non-small Cell Lung Cancer Presenting as Superior Vena Cava Syndrome

Syndrome of inappropriate anti-diuretic hormone (SIADH) secretion is uncommon in small cell lung cancer (SCLC), but even more rare in cases of non-small cell lung cancer (NSCLC). We report a case of a 59-year-old male who presented with superior vena cava (SVC) syndrome. After further investigation, he was diagnosed with adenocarcinoma of the lung. He delayed his medical care and his condition worsened. He was diagnosed with SIADH as an incidental finding on routine lab draw. Radiotherapy was subsequently initiated, and after one week of treatment, the patient showed marked clinical improvement. In this article, we also review the current indications for radiotherapy in various lung cancers and the management of SIADH.

Influenza A: another cause of SIADH?

The syndrome of inappropriate antidiuretic hormone (SIADH) secretion is a frequent cause of hyponatraemia. It is a dilutional hyponatraemia secondary to impaired urinary dilution in the absence of renal disease or any identifiable non-osmotic stimulus known to induce antidiuretic hormone secretion. SIADH can arise secondary to various respiratory tract infections; however, the association between SIADH and influenza A infection is described in only a few cases in the literature. The authors present a case report of influenza A that may have caused a profound SIADH-related hyponatraemia.

Clinical Profile of Patients Admitted with Hyponatremia in the Medical Intensive Care Unit

Background and Aims

Hyponatremia is the predominant electrolyte abnormality with an incidence rate of approximately 22%. It is the leading cause of morbidity and mortality with scarce data in Indian intensive care settings. The aim of this study is to evaluate the clinical features and etiology of hyponatremia in patients admitted to an Intensive Care Unit (ICU) of a tertiary care hospital.

Materials and Methods

A 1-year prospective cross-sectional observational study was conducted, including 100 adult patients with moderate-to-severe hyponatremia admitted to the Medical ICU. Patients underwent investigations such as serum creatinine, blood urea nitrogen, serum osmolality, serum sodium, urine sodium, and urine osmolality, sputum culture, cerebrospinal fluid analysis, and neuroimaging. Data were analyzed using independent sample t-test, Chi-square test, and Fisher's exact test.

Results

Vomiting (28) followed by confusion (26) was the most common complaint. Syndrome of inappropriate antidiuretic hormone secretion (SIADH) (46) was the most common etiology for hyponatremia, and euvolemic hypoosmolar hyponatremia (50) was the most common type of hyponatremia. Confusion was significantly high in patients with severe hyponatremia as compared to patients with moderate hyponatremia (22 vs. 4, P < 0.001). In majority of the patients (46), SIADH was the main cause of euvolemic type of hyponatremia (P < 0.001). Increased urine sodium levels were observed in patients with SIADH (46), renal dysfunction (12), and drug-induced etiology (8, P < 0.001).

Conclusion

Patients with hyponatremia secondary to an infectious cause should be meticulously screened for tuberculosis. The timely and effective treatment of hyponatremia is determined by the effective understanding of pathophysiology and associated risk factors of hyponatremia.

Anti-Voltage-Gated Potassium Channel Antibody Syndrome: A Rare Cause of Hyponatremia in Intensive Care Unit

Hyponatremia causing seizure is a common cause for admission in the critical care unit. Here, we describe a peculiar case of seizure due to hyponatremia, associated with anti-voltage-gated potassium channel antibody syndrome. This case emphasizes that how a proper workup can unveil unusual but potentially treatable causes of hyponatremia. The hallmark of this syndrome is that neurological symptoms may relapse or progress if the disorder is not recognized in time. This case report emphasizes the point that how a keen observation may decode subtle signs of the grave but potentially treatable pathologies.

Syndrome of Inappropriate Antidiuretic Hormone Secretion in a Patient with Mucosa-associated Lymphoid Tissue Lymphoma

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) may develop in association with several malignancies. However, as an immunohistochemical analysis is not performed in the majority cases, its true cause is often uncertain. We herein report a case of SIADH following chemotherapy due to tumor-derived ADH production in a patient with mucosa-associated lymphoid tissue (MALT) lymphoma. A retrospective immunohistochemical analysis demonstrated ADH expression by lymphoma cells. These findings highlight the importance of using an immunohistochemical analysis to determine ADH production by tumor cells in patients with SIADH. Such analyses play an important role in elucidating the pathogenesis of SIADH and determining the most appropriate treatment.

Paraneoplastic syndromes (PNS) associated with Merkel cell carcinoma (MCC): A case series of 8 patients highlighting different clinical manifestations

BACKGROUND

Paraneoplastic syndromes (PNS) are commonly associated with neuroendocrine cancers, such as small cell lung cancer.

OBJECTIVES

We examined the association of PNS in Merkel cell carcinoma (MCC), a rare neuroendocrine skin cancer.

METHODS

We identified PNS associated with MCC based on chart review of a Seattle-based repository and examined the incidence of MCC-associated hyponatremia in an independent cohort within Kaiser Permanente Northern California.

RESULTS

Eight PNS cases were identified from the Seattle repository. Three distinct PNS types were observed: cerebellar degeneration (1 case), Lambert-Eaton myasthenic syndrome (2 cases), and malignancy-associated hyponatremia (5 cases). Moreover, the incidence of severe hyponatremia (serum sodium <125 mmol/L) coincident with MCC was identified among 4.3% (9 of 211) patients with MCC in the Kaiser Permanente Northern California cohort.

LIMITATIONS

We did not have access to complete medical records on all patients so it was not possible to determine the prevalence of PNS in MCC.

CONCLUSIONS

MCC can be associated with PNS similar to those found in other neuroendocrine cancers. Clinicians should be aware of these presentations as PNS often precede the identification of the underlying malignancy and usually resolve with appropriate treatment of the cancer.

Hyponatremia as the Initial Presentation of Cryptococcal Meningitis After Liver Transplantation

INTRODUCTION

Meningoencephalitis is the most common clinical manifestation of cryptococcal infection, as the organism has a propensity to invade the CNS. Patients often present with elevated intracranial pressure, focal motor deficits, altered mentation and internal hydrocephalus. Syndrome of inappropriate antidiuretic hormone secretion (SIADH) has been reported as a notable cause of euvolemic hyponatremia in immunocompromised patients.

CASE PRESENTATION

A 67-year-old male with liver transplantation due to hepatitis C (HCV) related liver cirrhosis developed severe hyponatremia four months after liver transplantation, which was discovered during routine clinic visit. Patient was referred to the emergency department, treated and discharged with normal serum sodium level. Few days later, he presented with dizziness, confusion, ataxia, abnormal muscle movements and leg pain. Laboratory investigations were consistent with SIADH and revealed a sodium level of 115 mmol/L. Brain MRI showed a leptomeningeal enhancement in the superior cerebellar sulci suspicious for infection. Lumbar puncture was performed and consistent with Cryptococcus neoformans infection; therefore, cryptococcal meningitis was diagnosed. Amphotericin B was started for the patient for six weeks followed by fluconazole for one year. His level of consciousness improved significantly, and his serum sodium level slowly returned to its normal baseline over three weeks after starting amphotericin B.

CONCLUSIONS

Symptomatic hyponatremia secondary to SIADH remains a rare complication of cryptococcal meningitis.

Tyrosine kinase inhibitor-associated syndrome of inappropriate secretion of anti-diuretic hormone

Hyponatremia is a common complication among cancer patients. Certain antineoplastic agents have been associated with syndrome of inappropriate secretion of anti-diuretic hormone-induced hyponatremia. The most common agents associated with secretion of anti-diuretic hormone are vinca alkaloids, platinum compounds, and alkylating agents. We report a case of secretion of anti-diuretic hormone associated with tyrosine kinase inhibitors.

Syndrome of inappropriate antidiuretic hormone secretion and cerebral/renal salt wasting syndrome: similarities and differences

Hyponatremia (sodium levels of <135 mEq/L) is one of the most common electrolyte imbalances in clinical practice, especially in patients with neurologic diseases. Hyponatremia can cause cerebral edema and brain herniation; therefore, prompt diagnosis and proper treatment is important in preventing morbidity and mortality. Among various causes of hyponatremia, diagnosing syndrome of inappropriate antidiuretic hormone secretion (SIADH) and cerebral/renal salt wasting syndrome (C/RSW) is difficult due to many similarities. SIADH is caused by excess of renal water reabsorption through inappropriate antidiuretic hormone secretion, and fluid restriction is the treatment of choice. On the other hand, C/RSW is caused by natriuresis, which is followed by volume depletion and negative sodium balance and replacement of water and sodium is the mainstay of treatment. Determinating volume status in hyponatremic patients is the key point in differential between SIADH and C/RSW. However, in most situations, differential diagnosis of these two diseases is difficult because they overlap in many clinical and laboratory aspects, especially to assess differences in volume status of these patients. Although distinction between the SIADH and C/RSW is difficult, improvement of hypouricemia and an increased fractional excretion of uric acid after the correction of hyponatremia in SIADH, not in C/RSW, may be one of the helpful points in discriminating the two diseases. In this review, we compare these two diseases regarding the pathophysiologic mechanisms, diagnosis, and therapeutic point of view.

Restricted versus Standard Maintenance Fluid Volume in Management of Transient Tachypnea of Newborn: A Clinical Trial

OBJECTIVE

The incidence of Transient Tachypnea of Newborn (TTN) is higher in infants born by cesarean section than with  vaginal delivery. Treatment of transient tachypnea of newborn is supportive. The purpose of this study was to assess the effect of restricted fluid volume intake on the course of respiratory distress in patients with TTN.

METHODS

This is a quasi-experimental clinical trial of 83 neonates diagnosed with TTN admitted to a neonatal intensive care unit in south west Iran. In this study the effect of restriction of maintenance fluid volume in the course of respiratory distress in newborns with transient tachypnea was assessed.

FINDINGS

In the standard fluid volume intake group 18 (42.8%) cases needed nasal continuous positive airway pressure (NCPAP) and one (2.38%) case mechanical ventilation, and in restricted fluid volume intake group 13 (32.5%) cases needed NCPAP and two (5%) cases mechanical ventilation. 54.82% of cases were supported with oxyhood in the standard fluid volume and 62.5% in the restricted fluid volume intake group. Differences in duration of the needed NCPAP and oxygen hood between the two groups were significant. Fluid restriction had no adverse effect on the urine specific gravity or weight loss of the studied newborns.

CONCLUSION

Limited fluid administered to newborns with transient tachypnea of newborn is safe and resulted in shorter duration of respiratory support.

Undetected hypoparathyroidism: An unusual cause of perioperative morbidity

Routine investigation of serum calcium is not recommended in ASA one and two patients unless abnormalities of calcium metabolism are clinically suspected. The clinical features of hypocalcaemia can often be subtle and may manifest in the presence of associated factors. Hypoparathyroidism, an important cause of hypocalcaemia, often presents as soft tissue calcification (ostosis). Ligamentum flavum ostosis can present with compressive myelopathy requiring laminectomy. We report a case of ligamentum flavum ostosis and subclinical hypocalcaemia due to hypoparathyroidism, who went undetected pre-operatively resulting in significant post-operative morbidity.

Inappropriate antidiuretic hormone secretion due to squamous cell lung cancer

The syndrome of inappropriate secretion of antidiuretic hormone is a disorder of impaired water excretion caused by the inability to suppress secretion of antidiuretic hormone. It has been commonly associated with small cell carcinoma. The association of this syndrome with squamous cell lung carcinoma has rarely been reported, with only 4 cases over the past two decades in the English literature. We describe the case of a 75-year-old Caucasian male who developed the syndrome after a right pneumonectomy for down-staged squamous cell lung cancer previously treated with neoadjuvant platinum-based chemotherapy and radiotherapy.

A case report of syndrome of inappropriate antidiuretic hormone secretion with Castleman's disease and lymphoma

BACKGROUND

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a common cause of hyponatremia in hospitalized patients and is often described in patients with small-cell carcinoma of the lung. In this report, we described both Castleman's disease and lymphoma coexisting in one patient with SIADH.

CASE PRESENTATION

A 70-year-old Chinese woman with a history of diabetes mellitus and insulin therapy had severe hyponatremia and gastrointestinal symptoms. Through a series of examinations, common causes such as pulmonary carcinoma were excluded. An abdominal mass was detected by computed tomography. Although the peripheral lymph node biopsy showed the pathological result as Castleman's disease, the pathology of the abdominal lymph node revealed diffuse large B-cell lymphoma. After chemotherapy, the hyponatremia was treated during a period of follow-up.

CONCLUSION

This patient presented with the rare clinical condition of inappropriate antidiuretic hormone secretion alongside Castleman's disease and lymphoma. Asymptomatic hyponatremia may persist for some time suggesting that clinical physicians should pay attention to the mild cases of hyponatremia. We also hypothesized that Castleman's disease is a condition of pre-lymphoma with both having the ability to cause SIADH. The possibility of lymphoma as well as Castleman's disease triggering the development of SIADH should also be taken into consideration for conducting recurrent biopsies.

Syndrome of inappropriate anti-diuretic hormone in non-small cell lung carcinoma: a case report

Paraneoplastic syndrome (PNS) related to lung cancer is very common. However, the syndrome of inappropriate anti-diuretic hormone secretion (SIADH) is rare in non-small cell lung cancer (NSCLC). We are reporting the case of a 58-year-old female presenting with dyspnea, cough, weight loss, digital clubbing, and one week of haemoptysis. CT showed a mediastinal mass completely encasing her superior vena cava, causing significant narrowing of the trachea and right mainstem bronchus. Bronchoscopy and biopsy identified a non-resectable NSCLC. Palliative radiation therapy was initiated. The day after her first radiation treatment, the patient developed asymptomatic hyponatremia, confirmed to be SIADH by laboratory evaluation. NSCLC-associated SIADH has been reported only thrice over the past two decades and never following radiation therapy with clinical improvement. The patient was discharged home on fluid restriction after her respiratory status improved to continue outpatient radiation and chemotherapy. SIADH in the setting of NSCLC is discussed.

Unusual case of hyponatraemia

Hyponatraemia is the most common electrolyte abnormality, encountered in up to 30% of inpatients. Inappropriate management can have serious implications for patients; including demyelinating disease, coma and death. We have used a case report to identify the common problems, and provide useful strategies in management for which these can be avoided. The aim was to provide a framework which clinicians can adopt, in order to improve clinical practice and provide optimum outcome for the patient.