Syndrome of inappropriate secretion of arginine vasopressin in patients with cancer of the head and neck

Squamous cell carcinoma metastatic to the lymph nodes of the parapharyngeal space: case series and systematic review

Objective

Parapharyngeal space (PPS) is a rare and unusual site of head and neck squamous cell carcinoma (SCC) metastases. Treatment strategy for PPS metastases is still not well defined. This research aims to investigate the clinical implications and oncological outcomes of SCC metastases in PPS.

Material and methods

A systematic review was conducted according to PRISMA criteria. The authors considered only articles reporting the history and treatment of patients with PPS SCC metastases. A retrospective chart review was conducted in two tertiary referral academic centers collecting data of patients with diagnosis of PPS SCC metastases between 2010 and 2023 to study their outcome based on clinical presentation and treatment strategy.

Results

The retrospective chart review showed that the oropharynx was the most frequent primary tumour site. The advanced stage at the time of diagnosis was related to poorer survival and higher recurrence rates. A significant difference in 2-year overall survival in the subgroup of patients who experienced PPS metastases within the primary treatment and those who experienced PPS metastases as regional recurrence (66.7 vs 30.8%) was observed. Similar low survival rates were reported in the literature review with a mean overall and disease-free survival of 19.8 and 8.6 months, respectively.

Conclusions

PPS metastases are associated with a dismal prognosis, especially when diagnosed as regional recurrence after primary treatment, due to patients' poor general conditions and difficulty of treatment.

A Case Series of Uncommon Sodium Disorders in Common Clinical Scenarios

Dysnatremias or sodium disorders (either hyponatremia or hypernatremia) are the most common electrolyte problems in clinical medicine. They pose diagnostic and therapeutic challenges and have high mortality. Even mild changes in sodium levels from normal are associated with worse outcomes and considerable morbidity and mortality. We present a series of four patients with either hypo- or hypernatremia in different clinical scenarios requiring immediate treatment with close monitoring to avoid overcorrection. This case series shows that uncommon or unusual sodium disorders can happen in an otherwise usual situation.

Hyponatraemia and the syndrome of inappropriate antidiuresis (SIAD) in cancer

Hyponatraemia is a common electrolyte abnormality seen in a wide range of oncological and haematological malignancies and confers poor performance status, prolonged hospital admission and reduced overall survival, in patients with cancer. Syndrome of inappropriate antidiuresis (SIAD) is the commonest cause of hyponatraemia in malignancy and is characterised by clinical euvolaemia, low plasma osmolality and concentrated urine, with normal renal, adrenal and thyroid function. Causes of SIAD include ectopic production of vasopressin (AVP) from an underlying tumour, cancer treatments, nausea and pain. Cortisol deficiency is an important differential in the assessment of hyponatraemia, as it has an identical biochemical pattern to SIAD and is easily treatable. This is particularly relevant with the increasing use of immune checkpoint inhibitors, which can cause hypophysitis and adrenalitis, leading to cortisol deficiency. Guidelines on the management of acute, symptomatic hyponatraemia recommend 100 mL bolus of 3% saline with careful monitoring of the serum sodium to prevent overcorrection. In cases of chronic hyponatraemia, fluid restriction is recommended as first-line treatment; however, this is frequently not feasible in patients with cancer and has been shown to have limited efficacy. Vasopressin-2 receptor antagonists (vaptans) may be preferable, as they effectively increase sodium levels in SIAD and do not require fluid restriction. Active management of hyponatraemia is increasingly recognised as an important component of oncological management; correction of hyponatraemia is associated with shorter hospital stay and prolonged survival. The awareness of the impact of hyponatraemia and the positive benefits of active restoration of normonatraemia remain challenging in oncology.

Hyponatremia in patients with cancer

PURPOSE OF REVIEW

Hyponatremia is seen commonly in patients with cancer and is associated with increased mortality and morbidity. Understanding the proper diagnosis and therapy of cancer-associated hyponatremia is critical to ensure improved outcomes.

RECENT FINDINGS

The most common cancers associated with hyponatremia are the various forms of lung cancer with incidences approaching 25-45%. The most common causes of hyponatremia in cancer patients are the syndrome of inappropriate antidiuretic hormone secretion [syndrome of inappropriate antidiuretic hormone (ADH)] and volume depletion. Proper diagnosis rests on clinical information supplemented by laboratory studies and is critical to ensure appropriate therapy. In recent years, the development of drugs that specifically antagonize the vasopressin type 2 receptor in the distal tubule have offered targeted and highly effective therapies for syndrome of inappropriate ADH.

SUMMARY

Hyponatremia in cancer patients generally indicates advanced or severe disease but proper therapy that targets the underlying process can improve outcomes.

Paraneoplastic Syndromes Associated with Laryngeal Cancer

OBJECTIVES

Paraneoplastic syndromes occur rarely in association with laryngeal cancer. When present, the syndrome may be the first sign of the malignancy. The aim of the present study was to review and report on all published cases in the international literature.

METHODS

A search of PubMed was conducted for "paraneoplastic syndromes in laryngeal cancer" without any restrictions on language or publication year. The full texts of all relevant articles were reviewed and all cases of paraneoplastic syndromes associated with any type of laryngeal cancer were extracted and analyzed.

RESULTS

We identified 59 cases of paraneoplastic syndromes related to laryngeal cancer in the literature published from 1963 until recently. There were 46 squamous cell carcinomas and 10 neuroendocrine carcinomas. Twenty-two of the paraneoplastic syndromes involved the endocrine system, 21 were dermatologic or cutaneous, 8 neurologic, 5 osteoarticular or rheumatologic, 1 ocular, 1 muscular, and 1 hematologic. Treatment strategies included surgery, radiotherapy, chemotherapy, and often multimodal therapy, depending on the histology and stage of the laryngeal cancer.

CONCLUSIONS

Because of their rarity, paraneoplastic syndromes associated with laryngeal cancer are difficult to diagnose. By presenting and systematically reviewing all published cases in the international literature, the present review may help clinicians to recognize them and to suspect the diagnosis of laryngeal cancer at an earlier stage than otherwise might be possible.

Endocrine Toxicity of Cancer Immunotherapy Targeting Immune Checkpoints

Immune checkpoints are small molecules expressed by immune cells that play critical roles in maintaining immune homeostasis. Targeting the immune checkpoints cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed death 1 (PD-1) with inhibitory antibodies has demonstrated effective and durable antitumor activity in subgroups of patients with cancer. The US Food and Drug Administration has approved several immune checkpoint inhibitors (ICPis) for the treatment of a broad spectrum of malignancies. Endocrinopathies have emerged as one of the most common immune-related adverse events (irAEs) of ICPi therapy. Hypophysitis, thyroid dysfunction, insulin-deficient diabetes mellitus, and primary adrenal insufficiency have been reported as irAEs due to ICPi therapy. Hypophysitis is particularly associated with anti-CTLA-4 therapy, whereas thyroid dysfunction is particularly associated with anti-PD-1 therapy. Diabetes mellitus and primary adrenal insufficiency are rare endocrine toxicities associated with ICPi therapy but can be life-threatening if not promptly recognized and treated. Notably, combination anti-CTLA-4 and anti-PD-1 therapy is associated with the highest incidence of ICPi-related endocrinopathies. The precise mechanisms underlying these endocrine irAEs remain to be elucidated. Most ICPi-related endocrinopathies occur within 12 weeks after the initiation of ICPi therapy, but several have been reported to develop several months to years after ICPi initiation. Some ICPi-related endocrinopathies may resolve spontaneously, but others, such as central adrenal insufficiency and primary hypothyroidism, appear to be persistent in most cases. The mainstay of management of ICPi-related endocrinopathies is hormone replacement and symptom control. Further studies are needed to determine (i) whether high-dose corticosteroids in the treatment of ICPi-related endocrinopathies preserves endocrine function (especially in hypophysitis), and (ii) whether the development of ICPi-related endocrinopathies correlates with tumor response to ICPi therapy.

Diagnosis of hyponatremia and increased risk of a subsequent cancer diagnosis: results from a nationwide population-based cohort study

BACKGROUND

Hyponatremia has recently been associated with subsequent cancer risk. This population-based nationwide study assessed whether the diagnosis of hyponatremia can predict a cancer diagnosis within most common cancers.

MATERIAL AND METHODS

Using Danish medical registries, we identified 16,220 patients with a first-time diagnosis of hyponatremia, without a cancer diagnosis, from January 2006 through November 2013. We quantified the relative risk of a subsequent cancer diagnosis by standardized incidence ratios (SIRs), comparing observed cancer incidence among patients diagnosed with hyponatremia to that expected, based on national cancer incidence during that period.

RESULTS

During 40,207 person-years of follow-up, we observed 1546 cancer diagnoses compared to 956 expected (SIR: 1.62; 95% confidence interval (CI), 1.54-1.70). The increase in risk of a cancer diagnosis following a hyponatremia diagnosis was most pronounced within 0-6 months of follow-up (SIR 4.16; 95% CI, 3.85-4.48) and in the younger age group; 0-29 years (SIR 8.71; 95% CI, 2.82-20.28), 30-49 years (SIR 3.16; 95% CI, 2.26-4.31), 50-69 years (SIR 2.29; 95% CI, 2.10-2.48) and 70 + years (SIR 1.35; 95% CI, 1.27-1.44). Within six months after a hyponatremia diagnosis, the SIRs increased 10-fold for cancers of the lung (SIR 17.14; 95% CI, 15.15-19.32), brain (SIR 13.52; 95% CI, 8.90-19.66) and liver (SIR 13.26; 95% CI, 7.57-21.53) and increased 5 to 10-fold for cancers of the pancreas (SIR 8.25; 95% CI, 5.72-11.53), esophagus (SIR 6.59; 95% CI, 3.15-12.12), kidney (SIR 6.36; 95% CI, 3.39-10.88), pharynx (SIR 6.15; 95% CI, 1.27-17.97) and non-Hodgkin lymphoma (SIR 6.10; 95% CI, 4.17-8.61). The rate increased across virtually all types of cancers, except melanoma and basal cell carcinomas.

CONCLUSIONS

A diagnosis of hyponatremia may be a marker of occult neoplasms, especially cancers of the lung, brain, liver, pancreas, esophagus, kidney, pharynx and non-Hodgkin lymphoma. Hyponatremia may aid in early detection of cancer.

Idiopathic SIADH in young patients: don't forget the nose

Olfactory neuroblastoma (ONB) is an uncommon neuroendocrine sinonasal cancer associated by many authors to ectopic production of several biologically active substances. We report a case of a 31-year-old male patient who presented with idiopathic syndrome of inappropriate secretion of antidiuretic hormone (SIADH). During diagnostic work-up, a CT scan of the head was performed and an ethmoidal ONB was detected. Endoscopical surgery followed by radiotherapy was carried out. Immediately after surgery natraemia levels normalised. Five years later the patient is disease-free. To our knowledge, 17 cases of SIADH associated to ONB have been published. In nine reports, idiopathic SIADH promptly led to the diagnosis of the sinonasal mass as in our clinical case, however, in many reports, correct diagnosis was accomplished months to years later. In young patients with idiopathic inappropriate antidiuretic hormone secretion, a neuroendocrine malignancy of the sinonasal area must be excluded.

Tolvaptan use in cancer patients with hyponatremia due to the syndrome of inappropriate antidiuretic hormone: a post hoc analysis of the SALT-1 and SALT-2 trials

Hyponatremia is a common electrolyte disorder in cancer patients and has been associated with poor prognosis. A frequent cause of cancer‐related hyponatremia is the syndrome of inappropriate antidiuretic hormone (SIADH). This study was a post hoc subgroup analysis of the SALT‐1 (Study of Ascending Levels of Tolvaptan in Hyponatremia) and SALT‐2 clinical trials. Hyponatremic subjects with SIADH and cancer received the oral selective vasopressin V2‐receptor antagonist tolvaptan (n = 12) or matching placebo (n = 16) once‐daily for 30 days. The initial tolvaptan dose (15 mg) was titrated over 4 days to 30 or 60 mg per day, as needed, according to serum sodium level and tolerability. Baseline serum sodium levels in the SIADH/cancer cohort of the SALT trials was 130 and 128 mEq/L for tolvaptan and placebo, respectively. Mean change from baseline in average daily serum sodium AUC for tolvaptan relative to placebo was 5.0 versus −0.3 mEq/L (P < 0.0001) at day 4, and 6.9 versus 1.0 mEq/L (P < 0.0001) at day 30; the observed treatment effects were similar to those in the overall SIADH population (i.e., with and without cancer) at both time points. Serum sodium normalization was observed in 6/12 and 0/13 subjects at day 4 and 7/8 and 2/6 subjects at day 30 in the tolvaptan and placebo groups, respectively (P < 0.05 for both). Common treatment‐emergent AEs for tolvaptan were consistent with previously reported results. In this post hoc study of the SALT trial population, oral tolvaptan was an effective and safe therapy for the treatment of hyponatremia in subjects with SIADH and cancer.

Paraneoplastic Syndromes in Patients with Cancer of the Larynx and Hypopharynx

Paraneoplastic syndromes may be the first sign of a malignancy. They are systemic, nonmetastatic manifestations associated with a variety of malignant neoplasms and occurring in a minority of cancer patients. These associations of symptoms and signs are not directly related to the site or local manifestations of a malignant tumor or its metastases, but their recognition may facilitate the detection of malignancies or recurrences. Paraneoplastic syndromes are categorized into 6 types: Dermatologic or cutaneous, endocrine, hematologic, neurologic, osteoarticular or rheumatologic, and ocular. Different oncotypes have rarely been associated with paraneoplastic syndromes in patients with cancer of the larynx and hypopharynx. The world literature has been reviewed.

A copeptin-based classification of the osmoregulatory defects in the syndrome of inappropriate antidiuresis

The syndrome of inappropriate antidiuretic hormone secretion (SIADH), also referred to as syndrome of inappropriate antidiuresis (SIAD), is the most common cause of hyponatremia characterized by extracellular hypotonicity and impaired urine dilution in the absence of any recognizable nonosmotic stimuli for the antidiuretic hormone arginine vasopressin (AVP). Hyponatremia in SIADH is primarily the result of excessive water retention caused by a combination of inappropriate antidiuresis and persistent fluid intake in the presence of impaired osmoregulated inhibition of thirst. It is sometimes aggravated by a sodium deficiency caused by a decreased intake or a secondary natriuresis in response to elevated extracellular volume. Inappropriate antidiuresis usually results from endogenous production of AVP that can be either ectopic (from a malignancy) or eutopic (from the hypothalamus/neurohypophysis). Regardless of its origin, different types of osmotic dysregulation of AVP have been reported with possibly fundamental deviations in treatment need and efficacy. A recent quantitative analysis of 50 patients with SIADH, which underwent serial measurements of copeptin during hypertonic saline infusion, revealed five distinct types of osmoregulatory defect ("type A to E") without affiliation to specific underlying diseases. In addition to apparently impaired osmoregulated inhibition of AVP release in the majority of patients, 12% of patients showed an AVP-independent mechanism of inappropriate antidiuresis, whilst 20% of them presented a reverse relation between hormone release and serum osmolality, presumably related to interrupted nonosmotic inhibitory pathways. The interference of these different types of SIAD with clinical presentation and therapy response will be a relevant subject for future research.

Hyponatremia is a predictor of hospital length and cost of stay and outcome in cancer patients

PURPOSE

Hyponatremia is the most common electrolyte disorder in hospitalized patients, and it might be an indicator of poor prognosis and might have negative effects on hospitalization length and quality of life in non-malignant as well as in malignant diseases. The aim of this study is to determine the impact of hyponatremia on the length and on the cost of hospitalization as well as on outcome in cancer patients.

METHODS

The present study includes 105 consecutive cancer patients hospitalized at our institution from June 2013 to December 2013. Data regarding age, sex, staging, histology, chemotherapy, and serum sodium levels at admission, during hospitalization, and at discharge were recorded and statistically analyzed. Impact of hyponatremia on length and cost of hospitalization and on outcome was evaluated.

RESULTS

A significant difference in overall survival since the date of admission was observed between eunatremic and hyponatremic patients (p = 0.0255). A statistically significant correlation was also found between the length of stay and the detection of hyponatremia. At multivariate analysis, hyponatremia at admission, severity of hyponatremia, and stage of disease resulted independent prognostic factors. Furthermore, a patient with moderate or severe hyponatremia cost, in rate terms, 128 and 299 % more than a normonatremic patient, respectively.

CONCLUSIONS

The occurrence of hyponatremia at the admission or during the hospitalization may represent a significant factor influencing the outcome and the length of hospitalization. Acting effective and timely on the normalization of sodium levels might have a positive effect on prognosis in this setting of patients, as well as on the length of stay in hospital, thus potentially resulting in savings.

Hyponatraemia is a predictor of clinical outcome for malignant pleural mesothelioma

PURPOSE

Hyponatraemia is one of the most common tumour-related electrolyte disorders. Several clinical, histological and serum factors have been found to influence prognosis, but, to date, there are no studies focusing on the prognostic role of hyponatraemia in mesothelioma. The aim of this study was to assess the prognostic role of hyponatraemia in malignant pleural mesothelioma.

METHODS

We analysed 62 consecutive patients with histologically or cytologically proven advanced malignant pleural mesothelioma undergoing chemotherapy at our institution between January 2003 and September 2013.

RESULTS

All patients received a first-line pemetrexed-based chemotherapy. A second-line chemotherapy was administered to 29 patients. The onset of hyponatraemia (serum sodium <135 mEq/L) during the treatment was significantly related to a worsened median overall survival (7.93 vs 13.48 months; p = 0.0069). The occurrence of hyponatraemia during first-line chemotherapy (cutoff 135 and 130 mEq/L) was significantly associated to a shorter median progression-free survival (p = 0.0214). Results were also similar in the subgroup receiving a second-line treatment. At the multivariate analysis, including haemoglobin and sodium level at the beginning of first-line chemotherapy, age, gender, smoking habit, job exposure and performance status, only hyponatraemia was found to be an independent factor (p = 0.029). Hyponatraemia was also found to be a predictive factor for both first-line chemotherapy, being related to poorer response to pemetrexed-based chemotherapy (p = 0.047) and second-line chemotherapy (p = 0.044).

CONCLUSION

Our results show that hyponatraemia might be considered a negative prognostic parameter in malignant pleural mesothelioma patients. To our knowledge, this is the first study to evaluate the association of hyponatraemia with the outcome of malignant pleural mesothelioma patients.

Disorders of sodium and water balance

Dysnatremias occur simultaneously with disorders in water balance. The first priority is to correct dehydration; once the patient is euvolemic, the sodium level can be reassessed. In unstable patients with hyponatremia, the clinician should rapidly administer hypertonic saline. In unstable patients with hypernatremia, the clinician should administer isotonic intravenous fluid. In stable patients with either hyponatremia or hypernatremia, the clinician should aim for correction over 24 to 48 hours, with the maximal change in serum sodium between 8 to 12 mEq/L over the first 24 hours. This rate of correction decreases the chances of cerebral edema or osmotic demyelination syndrome.

Combined small cell carcinoma of the sinonasal tract associated with syndrome of inappropriate secretion of antidiuretic hormone: A case report

Combined small cell carcinoma (SmCC) and squamous cell carcinoma (SqCC) is a rare malignant neoplasm in the head and neck. This study presents the first reported case of combined SmCC and SqCC originating from the sinonasal tract accompanied by syndrome of inappropriate secretion of antidiuretic hormone (SIADH). An 80-year-old female presented with a four-week history of right nasal discharge, nasal obstruction and left neck swelling. Imaging studies revealed a tumorous lesion in the maxillary sinus encroaching upon the right nasal cavity and left cervical lymph node (LN) swelling. An incisional biopsy carried out from the right maxillary sinus and LNs resulted in a diagnosis of combined SmCC with SqCC, staged as T4aN2cM0. Clinical examination revealed a sustained increase of antidiuretic hormone, hyponatremia with urinary sodium increase, and serum hypo-osmosis, resulting in SIADH. Water restriction to <1,000 ml/day was effective in improving sodium and osmotic imbalance. Curative treatment for the tumor was not prescribed due to the poor condition of the patient. Palliative treatment was administered and the patient succumbed to cachexia five months after histological diagnosis. The presence of SIADH may have marked implications for the treatment and prognosis of this disease.

The impact of low serum sodium on treatment outcome of targeted therapy in metastatic renal cell carcinoma: results from the International Metastatic Renal Cell Cancer Database Consortium

BACKGROUND

Hyponatremia has been associated with poor survival in many solid tumors and more recently found to be of prognostic and predictive value in metastatic renal cell cancer (mRCC) patients treated with immunotherapy.

OBJECTIVE

To investigate the influence of baseline hyponatremia in mRCC patients treated with targeted therapy in the International Metastatic Renal Cell Carcinoma Database Consortium.

DESIGN, SETTING, AND PARTICIPANTS

Data on 1661 patients treated with first-line vascular endothelial growth factor (VEGF) or mammalian target of rapamycin (mTOR) targeted therapy for mRCC were available from 18 cancer centers to study the impact of hyponatremia (serum sodium level <135 mmol/l) on clinical outcomes.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary objective was overall survival (OS) and secondary end points included time to treatment failure (TTF) and the disease control rate (DCR). The chi-square test was used to compare the DCR in patients with and without hyponatremia. OS and TTF were estimated with the Kaplan-Meier method and differences between groups were examined by the log-rank test. Multivariable logistic regression (for DCR) and Cox regression (for OS and TTF) were undertaken adjusted for prognostic risk factors.

RESULTS AND LIMITATIONS

Median OS after treatment initiation was 18.5 mo (95% confidence interval [CI], 17.5-19.8 mo), with 552 (33.2%) of patients remaining alive on a median follow-up of 22.1 mo. Median baseline serum sodium was 138 mmol/l (range: 122-159 mmol/l), and hyponatremia was found in 14.6% of patients. On univariate analysis, hyponatremia was associated with shorter OS (7.0 vs 20.9 mo), shorter TTF (2.9 vs 7.4 mo), and lower DCR rate (54.9% vs 78.8%) (p<0.0001 for all comparisons). In multivariate analysis, these effects remain significant (hazard ratios: 1.51 [95% CI, 1.26-1.80] for OS, and 1.57 [95% CI, 1.34-1.83] for TTF; odds ratio: 0.50 [95% CI, 34-0.72] for DCR; adjusted p<0.001). Results were similar if sodium was analyzed as a continuous variable (adjusted p<0.0001 for OS, TTF, and DCR).

CONCLUSIONS

This is the largest multi-institutional report to show that hyponatremia is independently associated with a worse outcome in mRCC patients treated with VEGF- and mTOR-targeted agents.

Iatrogenic water intoxication in two cats

OBJECTIVE

To describe 2 cats that developed acute iatrogenic water intoxication, one associated with a continuous infusion of water provided via an esophagostomy tube and one following SC administration of 5% dextrose in water (D5W).

CASE OR SERIES SUMMARY

A 10-year-old cat with squamous cell carcinoma was hospitalized for treatment of dehydration. Rehydration was provided with water via an esophagostomy tube at 5.7 mL/kg/h. After 30 hours of therapy, the cat was found dull and weak. Serum sodium was markedly decreased at 116 mmol/L (116 mEq/L). Supplemental water was stopped, and IV furosemide and mannitol were provided to eliminate free water. Hypertonic saline (1.5%) was administered IV to rapidly restore the sodium concentration. The serum sodium concentration corrected over 17 hours, and the cat was discharged without neurological complications. The second cat had previously received 300 mL D5W subcutaneously and represented 8 hours later with lethargy and paresis with a serum sodium level of 126 mmol/L (126 mEq/L). Intravenous fluid therapy was provided using 0.9% NaCl. Over the following day, the cat's mentation and paresis resolved and sodium concentrations normalized.

NEW OR UNIQUE INFORMATION PROVIDED

These 2 cases describe a presumed uncommon iatrogenic complication of severe hyponatremia due to water provided either via an esophagostomy tube or subcutaneously. While oral rehydration is often considered ideal, it may result in signs of water intoxication if not carefully monitored; additionally, D5W is never considered an acceptable fluid choice as a SC bolus. If promptly recognized, acute hyponatremia may be corrected rapidly with no lasting consequences.

Diagnosis and management of hyponatremia in cancer patients

Hyponatremia, a common electrolyte abnormality in oncology practice, may be a negative prognostic factor in cancer patients based on a systematic analysis of published studies. The largest body of evidence comes from small-cell lung cancer (SCLC), for which hyponatremia was identified as an independent risk factor for poor outcome in six of 13 studies. Hyponatremia in the cancer patient is usually caused by the syndrome of inappropriate antidiuretic hormone (SIADH), which develops more frequently with SCLC than with other malignancies. SIADH may be driven by ectopic production of arginine vasopressin (AVP) by tumors or by effects of anticancer and palliative medications on AVP production or action. Other factors may cause hypovolemic hyponatremia, including diarrhea and vomiting caused by cancer therapy. Hyponatremia may be detected on routine laboratory testing before or during cancer treatment or may be suggested by the presence of mostly neurological symptoms. Treatment depends on several factors, including symptom severity, onset timing, and extracellular volume status. Appropriate diagnosis is important because treatment differs by etiology, and choosing the wrong approach can worsen the electrolyte abnormality. When hyponatremia is caused by SIADH, hypertonic saline is indicated for acute, symptomatic cases, whereas fluid restriction is recommended to achieve a slower rate of correction for chronic asymptomatic hyponatremia. Pharmacological therapy may be necessary when fluid restriction is insufficient. The orally active, selective AVP receptor 2 (V(2))-receptor antagonist tolvaptan provides a mechanism-based option for correcting hyponatremia caused by SIADH or other conditions with inappropriate AVP elevations. By blocking AVP effects in the renal collecting duct, tolvaptan promotes aquaresis, leading to a controlled increase in serum sodium levels.

Syndrome of inappropriate antidiuretic hormone secretion in patients with olfactory neuroblastoma

OBJECTIVE

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) has been reported as a paraneoplastic syndrome in many different types of malignancies. Several case reports of SIADH have been reported in patients with olfactory neuroblastoma (ONB), but the exact incidence is unknown. The purpose of this study was to review our experience with olfactory neuroblastoma and to identify all patients who had a history of SIADH prior to the diagnosis of ONB.

STUDY DESIGN

Case series and chart review.

SETTING

Tertiary care university-affiliated medical center.

SUBJECTS AND METHODS

A total of 21 patients presented to our institution with ONB between 1997 and 2009. All records were reviewed for a history of preoperative hyponatremia or SIADH.

RESULTS

Three patients were identified who had a history of SIADH prior to the diagnosis of ONB. Immunohistochemical staining of the tumor specimens from the 3 patients with SIADH was positive for arginine vasopressin. SIADH resolved in all 3 patients after successful treatment of ONB.

CONCLUSION

Although uncommon, SIADH can be the presenting symptom of ONB and should be considered during the workup for idiopathic SIADH.

Paraneoplastic syndromes in patients with oral cancer

The diagnosis of a paraneoplastic syndrome (PNS) may precede, follow or be concurrent with the diagnosis of a malignant tumor. There is increasing knowledge of association between PNS and head and neck cancers, but the relationship between oral cancer and paraneoplastic disease has not been previously investigated. PNS associated with head and neck cancer can be divided into six main groups: endocrine, cutaneous or dermatologic, hematologic, osteoarticular or rheumatologic, neurologic, and ocular syndromes. We have comprehensively reviewed the literature to evaluate the incidence of occurrence of PNS with oral cancer, and conclude that only endocrine and dermatologic PNS have been associated with oral cancer. Humoral hypercalcemia is the most frequent PNS related to oral cancer, and has a negative prognostic significance. Dermatologic PNS are less common, but when they occur, they may precede the diagnosis of the oral tumor. Awareness of these conditions is important for clinicians who deal with cancer.

Paraneoplastic syndromes in patients with nasopharyngeal cancer

Paraneoplastic syndromes (PNS) represent the clinical manifestation of the remote and indirect effects produced by tumor metabolites or other products. Paraneoplastic effects are not directly mediated by tumor invasion of normal tissue, or by the disruption of normal function of the involved organ, or by distant metastases. More than 260 cases of nasopharyngeal carcinoma (NPC) associated with PNS have been reported in the literature. These syndromes can be divided into six main groups: cutaneous or dermatologic, endocrine, hematologic, osteoarticular or rheumatologic, neurologic, and ocular. The most common dermatologic manifestation is dermatomyositis, while the syndrome of inappropriate secretion of antidiuretic hormone and occasionally Cushing's syndrome due to ectopic ACTH production are the endocrinologic manifestations. Tumor fever and leukemoid reaction, osteoarticular or rheumatic syndromes, including clubbing of the fingers and toes, sensory neuropathy and demyelinating motor polyneuropathy, and rarely optic neuritis represent the most prominent examples of the other groups of syndromes. PNS may occur before the NPC is manifest, or while it is in an occult stage, and thus the possibility of NPC should be considered in patients with these various disorders. While some PNS will respond to direct treatment, most often the PNS subsides in parallel to response of the NPC, and thus may be useful for monitoring tumor response or recurrence.

Severe hyponatremia in a patient with mantle cell lymphoma treated with bortezomib: a case report and review of the literature

BACKGROUND

Hyponatremia is a known complication of cytotoxic treatment. We observed this side effect in a patient treated with bortezomib. This paper gives an overview of the literature on antineoplastic agents that have been associated with hyponatremia.

CASE REPORT

A 77-year-old female patient with mantle cell lymphoma was admitted with rapidly progressive ataxia, slurred speech, and confusion. 43 days earlier, a second-line treatment with the proteasome inhibitor bortezomib had been started. Neurological examination revealed no focal deficits. Laboratory evaluation showed a combined electrolyte disorder with severe hyponatremia (sodium 112 mmol/l).

RESULTS

A syndrome of inappropriate secretion of antidiuretic hormone (SIADH) was diagnosed, and bortezomib was identified as its cause. The drug was consecutively stopped. CT scan showed a complete remission (CR). Since, the patient has remained in a CR without further tumor-specific treatment.

CONCLUSION

Hyponatremia may be a side effect of treatment with bortezomib and a number of other antineoplastic agents. Because of limited data available, accurate incidences of this complication are not known.

Paraneoplastic syndromes in patients with primary head and neck cancer

Paraneoplastic syndromes represent the clinical manifestations of the indirect and remote effects produced by tumor metabolites or other products. The clinical spectrum of the various paraneoplastic syndromes related to primary malignancies of the head and neck region is presented. A review of the literature on paraneoplastic syndromes in patients with primary head and neck cancer was carried out. Paraneoplastic syndromes related to primary malignancies of the head and neck region can be categorized as: endocrine, cutaneous or dermatologic, hematologic, neurologic, osteoarticular or rheumatologic, ocular syndromes. Sometimes, paraneoplastic syndromes can be more serious than the consequences of the primary tumor itself and can precede, follow or be concurrent to the diagnosis of a malignancy; moreover, they can dominate the clinical picture and thus lead to errors with respect to the origin and type of the primary tumor. Physicians who deal with cancer-associated syndromes should be able to differentiate the paraneoplastic syndromes from the benign disorders that mimic them. Patients with a suspected paraneoplastic disorder should undergo a complete panel of laboratory studies, in addition to imaging studies and endoscopy. Identification of paraneoplastic syndromes allow the clinician to make an early diagnosis and to provide adequate treatment of tumors, with a favorable oncologic outcome and improved life expectancy for the patient. These syndromes can follow the clinical course of the tumor and thus be useful for monitoring its evolution.

Disorders of water imbalance

Disorders of water imbalance manifest as hyponatremia and hypernatremia. To diagnose these disorders, emergency physicians must maintain a high index of suspicion, especially in the high-risk patient, because clinical presentations may be nonspecific. With severe water imbalance, inappropriate fluid resuscitation in the emergency department may have devastating neurological consequences. The rate of serum sodium concentration correction should be monitored closely to avoid osmotic demyelination syndrome in hyponatremic patients and cerebral edema in hypernatremic patients.

Paraneoplastic syndromes in patients with primary malignancies of the head and neck. Four cases and a review of the literature

Paraneoplastic syndromes rarely affect patients with head and neck cancer. Four patients with different histological types of head and neck cancer are presented in which the primary malignancy was preceded and/or accompanied by a paraneoplastic syndrome. In the first patient erythrodermia preceded the diagnosis of a nasopharyngeal carcinoma. The second patient presented with a B cell lymphoma of the nasopharynx in association with the syndrome of inappropriate secretion of arginine vasopressine (Schwartz-Bartter syndrome). In the third patient paraneoplastic polyarthritis had been diagnosed 5 months before a hypopharyngeal carcinoma was diagnosed. In the last patient the paraneoplastic anti-Hu positive encephalomyelitis was associated with a primary malignancy in the larynx with neck metastases. Diagnostic procedures, treatment and follow-up of these patients are reported and accompanied by a review of the literature.

Sinonasal neuroendocrine carcinoma in association with SIADH

BACKGROUND

Neuroendocrine carcinoma (NEC) is a rare malignancy of the nasal cavity or paranasal sinuses. The syndrome of inappropriate ADH secretion (SIADH) has not been previously reported in association with this cancer.

METHODS

We report a 30-year-old woman with histologically confirmed neuroendocrine carcinoma who also demonstrated SIADH. After successful chemotherapy and radiotherapy treatment for the neoplasm, her SIADH resolved. A literature search found eight cases of olfactory neuroblastoma (ONB) associated with SIADH, four of which resolved after treatment of the malignancy.

RESULTS

Treatment of the underlying malignancy resulted in the immediate resolution of the SIADH.

CONCLUSIONS

We report the first case of SIADH associated with NEC, which resolved after treatment of the cancer. A direct cause and effect between ONB/nasal NEC and SIADH has been established in previous reports.

Syndrome of inappropriate antidiuretic hormone or arginine vasopressin secretion in patients following neck dissection

OBJECTIVES/HYPOTHESIS

The syndrome of inappropriate antidiuretic hormone or arginine vasopressin secretion (SIADH) is a disorder in which release of antidiuretic hormone is independent of plasma osmolarity, resulting in fluid retention and development of dilutional hyponatremia. The incidence of SIADH following neck dissection was found to be 18% to 30% in two separate reports. The incidence of SIADH in a cohort of patients who underwent neck dissection was prospectively studied.

METHODS

Eighty-six patients were included in the study, along with a control group of 19 patients who underwent other neck procedures. Patient gender, age, physical condition (American Society of Anesthesiologists score), type of neck dissection, prior treatment, and smoking history were noted. Blood and urine osmolarity and sodium levels were sampled before surgery and during the first 24 hours after the surgery. These were recorded daily in cases with SIADH until the syndrome resolved.

RESULTS

The incidence of SIADH was only 1.15% in patients before surgery. The syndrome developed in seven patients following neck dissection (8.14%) and in none of the patients in the control group. SIADH resolved within 72 hours at the latest. No association was found with patient gender, age, physical condition, or type or laterality of neck dissection. A statistically significant connection between the syndrome and history of smoking was noted (P <.05), and it was more commonly seen in patients with node-positive necks (P =.1231).

CONCLUSIONS

SIADH following neck dissection may be less common than formerly reported. Previous studies have presented contradicting data concerning the influence of tumor recurrence or prior radiation therapy on its incidence. Our results indicate no such association. A statistically significant connection between smoking and the syndrome was found. No clinical symptoms developed in the patients with SIADH, but it seems prudent to suggest limiting fluid intake in the first postoperative 24 hours for patients following neck dissection.

Syndrome of inappropriate antidiuretic hormone secretion associated with oral squamous cell carcinoma

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is associated with various conditions including malignant disease, particularly small cell lung cancer. It has been reported to occur in 3% of patients with head and neck cancer. Less well known is its association with oral squamous cell carcinoma. This report describes a patient with SIADH associated with recurrent oral squamous cell carcinoma.

Systemic diseases associated with disorders of water homeostasis

Disorders of AVP secretion and action sometimes present as the first manifestation of a variety of different systemic diseases. It is prudent for the clinician to consider these causes in the differential diagnosis of hypoosmolar hyponatremia, polyuria and polydipsia, since recognizing the underlying disorder may affect treatment decisions, and intervention directed at the primary disorder often can reverse the abnormal water metabolism in these patients. Although much of the pathophysiology of these disorders is not understood completely, great progress has been made toward appreciating the complex and precise system involving thirst, AVP secretion, and renal responsiveness to AVP. Further investigation in this field likely will allow physicians to offer more effective and potent treatments in the future, such as the development of AVP V2 receptor antagonists for the treatment of SIADH [81] and edema-forming states [18, 109].

Immunohistochemical analysis of small cell carcinoma of the head and neck: a report of four patients and a review of sixteen patients in the literature with ectopic hormone production

Small cell carcinoma (SCC) occurs mostly in the lung, and in some patients is accompanied by production of ectopic hormones. Small cell carcinoma of the head and neck is very rare. We report 4 patients with SCC of the head and neck (larynx, tonsil, maxillary sinus, and parotid gland). The patient with SCC of the maxillary sinus demonstrated a high level of plasma serotonin and overexpression of parathyroid hormone; however, he did not show any related symptoms. The patient with SCC of the tonsil showed the syndrome of inappropriate secretion of antidiuretic hormone associated with antidiuretic hormone hyperproduction at the terminal stage. In the literature, 16 patients with SCC of the head and neck with ectopic hormone production have been reported. Antidiuretic hormone and adrenocorticotropic hormone were the hormones that caused clinical symptoms (paraneoplastic syndromes). We believe that the evaluation of hormonal syndromes is valuable for diagnosis and treatment.

Paraneoplastic syndromes in patients with laryngeal and hypopharyngeal cancers

Paraneoplastic syndromes are systemic, nonmetastatic manifestations associated with a variety of malignant neoplasms and occurring in a minority of cancer patients. Paraneoplastic syndromes in association with cancers of the larynx and hypopharynx are considered rare. The world literature is reviewed, dividing paraneoplastic syndromes into 4 main groups, ie, cutaneous (acanthosis nigricans, Bazex's syndrome, Bowen's disease, bullous pemphigoid, dermatomyositis, pruritus, Sweet's syndrome, yellow nail syndrome, and tylosis), endocrine (carcinoid syndrome, adrenocorticotropic hormone syndrome, Schwartz-Bartter syndrome, hypercalcemia), hematologic (Trousseau's syndrome), and neurologic (cerebellar degeneration, Eaton-Lambert myasthenic syndrome). A paraneoplastic syndrome may precede the clinical manifestations of a persistent or recurrent tumor or of asymptomatic metastases, and its onset may even, in a minority of cases, be the presenting sign of a malignancy. Otolaryngologists and head and neck surgeons should have a knowledge of the paraneoplastic syndromes in order to facilitate their detection of malignancies or recurrences.

Syndrome of inappropriate antidiuretic hormone secretion associated with head neck cancers: review of the literature

In a minority of patients with malignant tumors, signs and symptoms develop that cannot be explained on the basis of the mass effect produced by the primary tumor or its metastases, or production of a hormone normally associated with the tissue type that has given rise to the malignant tumor; these peculiar symptom complexes are known as paraneoplastic syndromes, and may be divided into endocrinologic, dermatologic, hematologic, neurologic, and osteoarticular manifestations. In the head and neck region in particular, the syndrome of inappropriate antidiuretic hormone production (SIADH, or Schwartz-Bartter syndrome) is a well-recognized form of paraneoplastic syndrome that may accompany head and neck malignancies. Most of such tumors are squamous carcinomas, with lesser numbers of olfactory neuroblastomas, small cell neuroendocrine carcinomas, adenoid cystic carcinomas, and undifferentiated carcinomas; sarcoma was reported in only a single instance. The lesions associated with the development of SIADH have most often been located in the oral cavity, and less often in the larynx, nasopharynx, hypopharynx, nasal cavity, maxillary sinus, parapharyngeal space, salivary glands, and oropharynx. Key features of SIADH include serum hypo-osmolality; an unexpectedly high urinary specific gravity; an absence of edema or dehydration; normal adrenal, thyroid, and renal function; hyponatremia; and an elevation of plasma vasopressin.

The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) as a consequence of neck dissection

The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) can have multiple causes. Surgical neck dissections may have an association with this syndrome and represent the basis for this study. A retrospective review of 50 patients undergoing neck dissections was performed to evaluate for the development of hyponatraemia as a consequence of SIADH. Based on the results of this review, a prospective study of 20 consecutive patients undergoing 22 neck dissections was performed to determine the incidence of SIADH. A control group of 25 consecutive patients undergoing major non-neck dissection surgery was also studied. SIADH developed in nine of 50 patients (18 per cent) of our retrospective group with a high incidence of development in those who had jugular vein ligation (JVL) (22 per cent), pre-operative radiation therapy (25 per cent) or squamous cell cancers (32 per cent). SIADH developed in six patients undergoing 22 neck dissections (27 per cent) in our prospective group. A high incidence was also noted for those with JVL (42 per cent), pre-operative radiation therapy (67 per cent) or squamous cell cancer (40 per cent). No patients developed symptomatic hyponatraemia. No patients in the prospective control group developed SIADH. Neck dissection surgery is associated with a significant risk for the development of SIADH. Factors such as jugular vein ligation (JVL), pre-operative radiotherapy and squamous cell cancer appear to increase this risk.

Hypercalcemia and electrolyte disturbances in malignancy

Hypercalcemia and electrolyte abnormalities are common problems in patients with malignancy. In this article we discuss the pathophysiology, clinical features, and management of hypercalcemia, which is the most common metabolic abnormality. We also analyze the electrolyte disturbances that occur in association with malignancy, including hyponatremia, hypokalemia, hypomagnesemia, hypophosphatemia, and hyperkalemia. Recognition and treatment of these disturbances are important parts of the management of patients with malignant disease.

Elevated arginine vasopressin levels in squamous cell cancer of the head and neck

The reported effectiveness of single tumor markers (TMs) associated with squamous cell cancer of the head and neck ranges from 15% to 71%, with most studies reporting sensitivity no higher than 50%. An increased incidence of the syndrome of inappropriate secretion of antidiuretic hormone or arginine vasopressin (SIADH) in patients with head and neck cancer has been reported. Serum arginine vasopressin (AVP) was studied as a possible TM in these patients. Sixty-three patients with squamous cell carcinoma of the head and neck determined as potentially curable were prospectively evaluated before treatment and compared to 17 patients with apparent cure of head and neck squamous cell cancer who served as controls. Serum AVP levels were obtained and determined by radioimmunoassay in the preoperative period and 1 week postoperatively in 15 patients. Thirty-four patients were staged as T4, 26 as T3, and 3 as T2. Twenty-one (33%) of the 63 patients had no neck involvement. Twenty-four (38%) of 63 patients had elevated serum AVP levels corrected for serum osmolarity. Of the 15 patients evaluated before and after surgery, 8 (53%) had elevated serum AVP levels preoperatively. Of these 8 patients, 3 had reduction in AVP levels and 5 had complete normalization after 1 week. The result obtained for serum AVP do not exceed results of other TMs reported. AVP may also not be as specific as other TMs for cancer of the head and neck. Our group with AVP sampled postoperatively is too small for us to draw conclusions, but reduction of its levels after treatment in all patients may be significant. These preliminary results indicate that further evaluation of AVP during the posttreatment course in a larger number of cases, and perhaps with other TMs as well, is warranted.

Syndrome of inappropriate secretion of antidiuretic hormone (SIADH) in malignant disease

The first clinical case of a patient with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) was presented by Schwartz et al. in 1957 (Am J Med 1957; 23: 529-42), describing two patients with lung cancer who developed hyponatraemia associated with continued urinary sodium loss. They postulated that the tumours led to the inappropriate release of antidiuretic hormone (ADH), later discovered to consist of arginine-vasopressin (AVP). This suggestion was later confirmed in several studies. The clinical description of the syndrome has changed little since the original observation, and the cardinal findings of SIADH are as follows: (i) hyponatraemia with corresponding hypo-osmolality of the serum and extracellular fluid, (ii) continued renal excretion of sodium. (iii) absence of clinical evidence of fluid volume depletion, (iv) osmolality of the urine greater than that appropriate for the concomitant osmolality of the plasma, i.e. urine less than maximal diluted, and (v) normal function of kidneys, suprarenal glands and thyroid glands. Measurement of AVP in plasma is not a part of the definition of SIADH. SIADH may be caused by a variety of malignant tumours, but may also be caused by various other conditions, such as disorders involving the central nervous system, intrathoratic disorders such as infections, positive pressure ventilation and conditions with decrease in left atrial pressure. Also, a large number of pharmaceutical agents have been shown to produce SIADH, including a number of cytotoxic drugs such as vincristine, vinblastine, cisplatin, cyclophosphamide, and melphalan. A broad spectrum of malignant tumours has been reported to cause SIADH; however, most of these observations have been in case reports including very few patients. This includes a number of primary brain tumours, haematologic malignancies, intrathoracic non-pulmonary cancers, skin tumours, gastrointestinal cancers, gynaecological cancer, breast-and prostatic cancer, and sarcomas. Larger series of patients have revealed that SIADH occurs in 3% of patients with head and neck cancer (47 cases out of 1696 patients), in 0.7% of patients with non-small-cell lung cancer (three cases out of 427 patients), and in 15% of cases of small-cell lung cancer (214 cases out of 1473 patients). The optimal therapy for SIADH is to treat the underlying malignant disease. If this is not possible, or if the disease has become refractory, other treatment methods are available such as water restriction, demeclocycline therapy, or, in severe cases, infusion of hypertonic saline together with furosemide during careful monitoring.

Thalamic neuron theory: theoretical basis for the role played by the central nervous system (CNS) in the causes and cures of all diseases

The Thalamic Neuron Theory (TNT) postulates that the central nervous system (CNS) is involved in all disease processes, as the CNS not only processes incoming physical and chemical information from the periphery, it also sends out physiological commands to the periphery in order to maintain homeostasis for the entire body. Inherent in its capacity to learn and adapt (i.e. to habituate) is the CNS' ability to learn to be sick (pathological habituation) by looking in certain deranged central neural circuitries, leading to chronic disease states. These pathologically habituated states can be reversed by dehabituation through manipulation or modulation of the abnormal neural circuits by physical means (physical neuromodulation) like acupuncture, or chemical means (chemoneuromodulation) such as Chinese medicine, homeopathy or other modern medical techniques in a repetitious manner to mimic the habituation process. Chemoneuromodulation can also be achieved by delivery of minute amounts of pharmacological agents to specific sites in the periphery such as the acupuncture loci. It is hypothesized that humoral and neurotrophic factors and cytokines could be highly effective neuromodulating agents. TNT assumes the blue print for embryological development is embodied in the phylogenetically ancient part of the brain. This primordial master plan, organized in the form of a homunculus, possibly encased in a small nucleus, retains control over the subsequently evolved parts of the brain so that the entire CNS functions like a composite homunculus which controls the physiological functions of the entire body. TNT further postulates that the master homunculus takes the shape of a curled up embryo with its large head buried close to its pelvic region, with its large feet and hands crossed over to the contralateral sides. Neuronal clusters along a neuronal chain in the homunculus represent acupuncture points in the periphery. The neuronal chain itself represents a meridian and Chi is nothing more than the phenomenon of neurotransmissions. Certain new theoretical concepts such as the principles of Adynamic Stat and Bilaterality are also presented. Many difficult to explain clinical observations in modern medicine, Chinese herbal medicine, acupuncture and homeopathy can now be adequately explained using TNT. Based on this model, new therapeutic techniques can be launched to combat a whole host of intractable diseases.

Paraneoplastic syndromes in patients with head and neck cancer

Paraneoplastic syndromes are distinct physiological disorders of malignancy that occur remote from a tumor site. A review of a number of paraneoplastic syndromes occurring in patients with head and neck cancer has been discussed. These syndromes can produce life-threatening sequelae in the patient with cancer. Understanding these syndromes may provide important clinical information to assist in the early detection of occult malignancy and in reducing the occurrence of tumor-associated morbidity.