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.

Chlorpromazine-Induced Severe Hyponatremia in 66 Years Old Patient

Hyponatremia is a common clinical problem in older people. The aging process is usually accompanied by various maladaptations to stress in different organs and physiologic functions. Medications are often the cause of hyponatremia such as thiazide diuretics, antidepressants, antiepileptic and antipsychotics. Antipsychotics can lead to severe hyponatremia by the mechanism of the development of the syndrome of inappropriate antidiuretic hormone secretion (SIADH). We report a patient who presented with severe hyponatremia due to Chlorpromazine and improved after receiving corrective hyponatremia.

Chloride and Potassium Assessment Is a Helpful Tool for Differential Diagnosis of Thiazide-Associated Hyponatremia

CONTEXT

Differential diagnosis of thiazide-associated hyponatremia (TAH) is challenging. Patients can either have volume depletion or a syndrome of inappropriate antidiuresis (SIAD)-like presentation.

OBJECTIVE

To evaluate the impact of the simplified apparent strong ion difference in serum (aSID; sodium + potassium - chloride) as well as the urine chloride and potassium score (ChU; chloride - potassium in urine) in the differential diagnosis of TAH, in addition to assessment of fractional uric acid excretion (FUA).

METHODS

Post hoc analysis of prospectively collected data from June 2011 to August 2013 from 98 hospitalized patients with TAH < 125 mmol/L enrolled at University Hospital Basel and University Medical Clinic Aarau, Switzerland. Patients were categorized according to treatment response in volume-depleted TAH requiring volume substitution or SIAD-like TAH requiring fluid restriction. We computed sensitivity analyses with ROC curves for positive predictive value (PPV) and negative predictive value (NPV) of aSID, ChU, and FUA in differential diagnosis of TAH.

RESULTS

An aSID > 42 mmol/L had a PPV of 79.1% in identifying patients with volume-depleted TAH, whereas a value < 39 mmol/L excluded it with a NPV of 76.5%. In patients for whom aSID was inconclusive, a ChU < 15 mmol/L had a PPV of 100% and a NPV of 83.3%, whereas FUA < 12% had a PPV of 85.7% and a NPV of 64.3% in identifying patients with volume-depleted TAH.

CONCLUSION

In patients with TAH, assessment of aSID, potassium, and chloride in urine can help identifying patients with volume-depleted TAH requiring fluid substitution vs patients with SIAD-like TAH requiring fluid restriction.

A case of linezolid-induced SIADH in elderly and a review of the literature

INTRODUCTION

Linezolid is a synthetic oxazolidinone antimicrobial drug with a broad spectrum and a unique mechanism of inhibiting resistant pathogenic strains, and it was approved by the Food and Drug Administration (FDA) in April 2000. Several different systemic side effects were reported after the use of this medication. In this article, we report a case in which a syndrome of inappropriate antidiuretic hormone (SIADH) was developed after linezolid treatment was started.

CASE PRESENTATION

We present the case of a 79-year-old woman who developed severe hyponatremia during linezolid treatment (0.6 g i.v. q12 h) after undergoing hemiarthroplasty for left femoral neck fracture. The patient's baseline serum sodium upon admission (138 mmol/L) decreased to 118 mmol/L, urine sodium was 102 mmol/L, plasma osmolality was 248 mOsm/kg and urine osmolarity was 310 mOsm/kg at day 4, thus a diagnosis of SIADH was made. The patient was not taking any other medication known to cause SIADH, and she did not present a comorbidity that could explain her condition. Her serum sodium increased to 135 and 137 mmol/L, respectively, 11 and 12 days after cessation of linezolid, strongly suggesting that SIADH was the cause in this case.

CONCLUSIONS

This is the fourth case of linezolid-induced SIADH. A thorough workup was essential for the diagnosis to correctly differentiate between SIADH and other causes of hyponatremia, which helped us properly conducting follow-up treatments. SIADH is a rare but serious side effect of linezolid, and practicing physicians should be aware of this complication. It is necessary to periodically monitor the serum sodium.

Management of SIADH-related hyponatremia due to psychotropic medications - An expert consensus from the Association of Medicine and Psychiatry

OBJECTIVE

Hyponatremia is the most common electrolyte imbalance encountered in clinical practice and is associated with negative healthcare outcomes and cost. SIADH is thought to account for one third of all hyponatremia cases and is typically an insidious process. Psychotropic medications are commonly implicated in the etiology of drug induced SIADH. There is limited guidance for clinicians on management of psychotropic-induced SIADH.

METHODS

After an extensive review of the existing literature, clinical-educators from the Association of Medicine and Psychiatry developed expert consensus recommendations for management of psychotropic-induced SIADH. A risk score was proposed based on risk factors for SIADH to guide clinical decision-making.

RESULTS

SSRIs, SNRIs, antipsychotics, carbamazepine, and oxcarbazepine have moderate to high level of evidence demonstrating their association with SIADH. Evaluation for an avoidance of medications that cause hyponatremia is particularly important. Substitution with medication that is less likely to cause SIADH should be considered when appropriate. We propose an algorithmic approach to monitoring hyponatremia with SIADH and corresponding treatment depending on symptom severity.

CONCLUSIONS

The proposed algorithm can help clinicians in determining whether psychotropic medication should be stopped, reduced or substituted where SIADH is suspected with recommendations for sodium (Na+) monitoring. These recommendations preserve a role for clinical judgment in the management of hyponatremia with consideration of the risks and benefits, which may be particularly relevant for complex patients that present with medical and psychiatric comorbidities. Further studies are needed to determine whether baseline and serial Na+ monitoring reduces morbidity and mortality.

Symptomatic hyponatremia induced by low-dose cyclophosphamide in patient with systemic lupus erythematosus: A case report

RATIONALE

Cyclophosphamide (CY) is an alkylating agent used widely to treat cancer and autoimmune diseases. Hyponatremia is a common adverse effect of high-dose and moderate-dose of intravenous CY, but is rare in patients treated with low-dose (<15 mg/kg).

PATIENT CONCERNS

A 52-year-old woman with new-onset systemic lupus erythematosus (SLE) was treated with low-dose cyclophosphamide (8 mg/kg, CY), but showed sudden headaches, disorientation and weakness. Laboratory examinations revealed severe isovolumic hyponatremia along with low-serum osmolality and high urine osmolality.

DIAGNOSIS

The acute hyponatremia was consistent with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and was an adverse event of low-dose CY, with no evidence of endocrine, cancer, pulmonary, or cerebral abnormalities relevant to the SIADH.

INTERVENTION

The hyponatremia was resolved after the supplementation of NaCl solution.

OUTCOMES

The hyponatremia was resolved without any complications.

LESSONS

Hyponatremia induced by low-dose CY should be recognized as an underlying life-threatening complication in clinical practice.

Acute Hyponatremia Resulting from Duloxetine-induced Syndrome of Inappropriate Antidiuretic Hormone Secretion

A 77-year-old woman who had taken a single oral dose of duloxetine subsequently developed a headache and nausea. On the first day, her serum sodium level was 135 mEq/L. She became confused on the third day. Her serum sodium level was 119 mEq/L and her antidiuretic hormone level was 1.9 IU. We diagnosed her with acute hyponatremia from duloxetine-induced syndrome of inappropriate antidiuretic hormone secretion (SIADH). This case suggests that we must not rule out SIADH on the basis of normal serum sodium levels when a patient who has started serotonin-norepinephrine reuptake inhibitor (SNRI) treatment presents with symptoms similar to hyponatremia.

Duloxetine and Angiotensin II Receptor Blocker Combination Potentially Induce Severe Hyponatremia in an Elderly Woman

We encountered a case of syndrome of inappropriate antidiuretic hormone secretion (SIADH) caused by duloxetine, serotonin and norepinephrine reuptake inhibitor (SNRI). A 74-year-old woman complaining of severe lethargy was transferred to our emergency department. Her serum sodium level was 109 mEq/L. Plasma hypo-osmolality with urine normo-osmolality was observed, indicating SIADH. Her essential hypertension had long been treated with telmisartan, and she had just started duloxetine 20 mg/day for chronic musculoskeletal pain 4 days prior to admission. On prescribing duloxetine in the primary care setting, clinicians should be aware of the possibility of duloxetine-induced hyponatremia, particularly in combination with telmisartan.

Syndrome de sécrétion inappropriée d’hormone antidiurétique secondaire à la rispéridone et la carbamazépine: à propos d’un cas

Le syndrome de sécrétion inappropriée de l'hormone antidiurétique (SIADH) représenterait environ 50% de tous les cas diagnostiqués d'hyponatrémie. Seule une faible proportion de SIADH serait d'origine médicamenteuse. Nous rapportons le cas d'une patiente suivie pour un trouble schizo-affectif qui a développé le SIADH après avoir commencé un traitement à base de la rispéridone et la carbamazépine. Les résultats des tests biochimiques suggéraient un SIADH secondaire à l'utilisation de la rispéridone et la carbamazépine. La patiente a été traitée avec succès par l'arrêt des deux médicaments et une restriction hydrique. Après correction de la natrémie la décision thérapeutique était de mettre la patiente sous clozapine. Elle est actuellement sous 400mg avec des taux de natrémie stables. Les psychiatres doivent être conscients du risque d'hyponatrémie sévère associé aux médicaments psychotropes. Il est donc primordial de surveiller les électrolytes, en particulier le sodium, chez les patients prenant des antipsychotiques et des anticonvulsivants.

Management of hyponatremia: causes, clinical aspects, differential diagnosis and treatment

INTRODUCTION

Hyponatremia is the most frequent electrolyte disorder in hospitalised patients. Acute and severe hyponatremia may be a life-threatening situation. However, also mild and chronic hyponatremia may negatively affect the health status (i.e. gait disturbances, attention deficits, falls and fractures, and bone loss) and may increase the risk of death. Therefore, it is of paramount importance for clinicians to have an in-depth knowledge on this topic, in order to appropriately manage patients affected by hyponatremia.

AREAS COVERED

This review will cover different areas related to this electrolyte disorder. Because many pathologic conditions may be associated with hyponatremia, thorough investigations have to be performed in order to establish the underlying etiology. To establish the cause of hyponatremia is of great importance, because an appropriate therapeutic strategy is strictly dependent on a correct diagnosis. A description of the different available therapeutic approaches for the correction of hyponatremia, including vaptans, will follow.

EXPERT COMMENTARY

Undoubtedly, the studies that have been published in recent years and the introduction of vaptans in clinical practice have contributed to increase the awareness on hyponatremia among clinicians. Nevertheless, additional studies are needed in order to clarify some partially uncovered areas.

Rapid-onset hyponatremia and delirium following duloxetine treatment for postherpetic neuralgia: Case report and literature review

RATIONALE

Hyponatremia following duloxetine treatment has been reported in patients with major depressive disorder, fibromyalgia, diabetic neuropathy, or sciatic pain. The manifestations of duloxetine-induced hyponatremia are varying in different individuals. The overall prognosis for this type of hyponatremia is favorable if properly managed.

PATIENT CONCERNS AND DIAGNOSES

Herein, we reported rapid-onset hyponatremia and delirium in an older patient after 2 doses of duloxetine, which was used to control his postherpetic neuralgia. Laboratory examinations revealed a rapid decline in serum sodium level and indicated the possibility of syndrome of inappropriate antidiuretic hormone (SIADH).

INTERVENTIONS

Discontinuation of duloxetine, restriction of water intake, and intravenous supplement of normal saline were adopted to manage the hyponatremia.

OUTCOMES

Serum concentration of sodium gradually normalized following aforementioned strategies.

LESSONS

Special attention to the electrolyte abnormality is recommended in old patients undergoing duloxetine treatment.

Syndrome of Inappropriate Antidiuretic Hormone Secretion Associated with Hepatic Arterial Infusion of Vinblastine in Three Patients with Breast Cancer

We report the occurrence of the syndrome of inappropriate antidiuretic hormone secretion in 3 patients with breast carcinoma metastatic to the liver who received hepatic arterial infusion of vinblastine at lower doses than those previously associated with this effect. Leukopenia was severe in all patients, who additionally experienced hypokalemia with excessive kaliuresis. The etiology of the observed hypokalemia is unclear. We suspect that vinblastine may induce renal tubular dysfunction. These toxicities appear dose-related.

[Syndrome of inappropriate secretion of antidiuretic hormone in multiple myeloma patients treated with bortezomib, lenalidomide, and dexamethasone combination therapy]

Hyponatremia occurs while receiving bortezomib-containing combination therapy in multiple myeloma (MM) ; however, the mechanism of hyponatremia remains unclear. A 65-year-old female with MM was treated with bortezomib, lenalidomide, and dexamethasone. Fourteen days after chemotherapy initiation, she developed hyponatremia (serum sodium, 127 mEq/l, compared with 136 mEq/l before chemotherapy) with plasma hypo-osmolality and urine hyper-osmolality. She exhibited neither dehydration nor adrenal insufficiency. Her serum arginine vasopressin peptide (AVP) level was 1.5 pg/ml. She was diagnosed with syndrome of inappropriate secretion of antidiuretic hormone (SIADH), wherein causative roles of inflammatory cytokines were strongly suggested in the development because (1) SIADH was triggered by the cessation of the dexamethasone treatment and (2) hyponatremia was successfully treated with prednisolone, which was administered for the complication of drug eruption. Perhaps, bortezomib-induced immune reactions could be involved in a subset of hyponatremia during bortezomib-containing antimyeloma chemotherapy.

[The syndrome of inappropriate diuretic hormone secretion (SIADH) ending lethal during the use of paliperidon and lamotrigine]

Hyponatremia, as a result of the syndrome of inappropriate antidiuretic hormone secretion (SIADH), is well known with the use of nearly all antipsychotics and mood stabilizers. The first symptoms are atypical and are not always mentioned by the patient. However, not recognising the syndrome in due time can be lethal. We describe a 35-year-old woman who died due to lack of recognition of SIADH. The patient, who had a bipolar disorder and was for a long time on a paliperidone depot, developed complaints of nausea, vomiting and thirst after lamotrigine was prescribed. A few days after increasing the dose, she died; no evidence was found of suicide. The SIADH was probably triggered by the use of lamotrigine and paliperidone. Paying sufficient attention to the symptoms that may cause this syndrome, as well as their early recognition, could save lives.

Single-tubule RNA-Seq uncovers signaling mechanisms that defend against hyponatremia in SIADH

In the syndrome of inappropriate antidiuretic hormone secretion (SIADH), hyponatremia is limited by onset of vasopressin-escape caused by loss of the water channel aquaporin-2 in the renal collecting duct despite high circulating vasopressin. Here, we use the methods of systems biology in a well-established rat model of SIADH to identify signaling pathways activated at the onset of vasopressin-escape. Using single-tubule RNA-Seq, full transcriptomes were determined in microdissected cortical collecting ducts of vasopressin-treated rats at 1, 2, and 4 days after initiation of oral water loading in comparison to time-control rats without water loading. The time-dependent mRNA abundance changes were mapped to gene sets associated with curated canonical signaling pathways and revealed evidence of perturbation of transforming growth factor β signaling and epithelial-to-mesenchymal transition on Day 1 of water loading simultaneous with the initial fall in Aqp2 gene expression. On Day 2 of water loading, transcriptomic changes mapped to Notch signaling and the transition from G0 into the cell cycle but arrest at the G2/M stage. There was no evidence of cell proliferation or altered principal or intercalated cell numbers. Exposure of vasopressin-treated cultured mpkCCD cells to transforming growth factor β resulted in a virtually complete loss of aquaporin-2. Thus, there is a partial epithelial-to-mesenchymal transition during vasopressin escape with a subsequent shift from quiescence into the cell cycle with eventual arrest and loss of aquaporin-2.

Escitalopram Induced SIADH in an Elderly Female: A Case Study

Hyponatraemia is a well-established and potentially, a life-threatening adverse effect of selective serotonin receptor uptake inhibitors (SSRI). However, its occurrence secondary to syndrome of inappropriate antidiuretic hormone secretion (SIADH) with escitalopram, has been reported extremely sporadically. The reporting of such rare, but life-threatening adverse effects of escitalopram assumes immense significance in light of the fact that SSRIs presently form the mainstay of treatment of depressive disorders. Here, we report a case where a 58 year old diabetic lady, when initiated on escitalopram for dysthymia developed severe hyponatraemia within 2 weeks. Further, we discuss other relevant cases that have been reported in the past with an eye on the management of SIADH and hyponatraemia.

Post-cytokine-release Salt Wasting as Inverse Tumor Lysis Syndrome in a Non-cerebral Natural Killer-cell Neoplasm

The pathogenesis of cerebral/renal salt-wasting syndrome remains unknown. We herein present a case of salt-wasting syndrome with a natural killer-cell neoplasm without cerebral invasion. A 78-year-old man with hemophagocytic syndrome received two cycles of chemotherapy that did not induce tumor lysis syndrome, but repeatedly caused polyuria and natriuresis. The expression of tumor necrosis factor-α in the neoplasm led us to hypothesize that an oncolysis-induced cytokine storm may have caused renal tubular damage and salt wasting. Our theory may explain the pathogenic mechanism of cerebral/renal salt-wasting syndrome associated with other entities, including cerebral disorders, owing to the elevation of cytokine levels after subarachnoid hemorrhage.

Citalopram-Associated SIADH

OBJECTIVE:

To report a case of the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) associated with use of citalopram in an elderly male patient and to review the English-language literature for any previous reports of SIADH or hyponatremia caused by citalopram.

CASE SUMMARY:

An 87-year-old Filipino man was admitted to the hospital reporting malaise, confusion, dizziness, and falls approximately 3 weeks following an increase in his citalopram dosage from 10 to 20 mg/d. On physical examination, the patient was euvolemic and had no evidence of malignancy, cardiac, renal, or hepatic disease. Pertinent laboratory test results revealed hyponatremia, serum hypoosmolality, urine hyperosmolality, and elevated urine sodium concentration, leading to a diagnosis of SIADH. Citalopram was discontinued and fluid restrictions were instituted. The patient was discharged after his serum sodium increased from 122 to 128 mEq/L and he reported increased strength and decreased confusion. Five days after discharge, the patient denied experiencing any new falls, weakness, confusion, or lethargy. His serum sodium measured that day was 131 mEq/L; 2 months later, it was 135 mEq/L.

DISCUSSION:

We report the seventh case of citalopram-induced hyponatremia published in the English language and the second in a man. Review of the cases demonstrated that the onset of citalopram-induced hyponatremia or SIADH ranged from 6 to 20 days. Potential risk factors for SIADH due to citalopram included advanced age, female gender, concomitant use of medications known to cause SIADH or hyponatremia, and, possibly, higher citalopram doses.

CONCLUSIONS:

Elderly patients receiving citalopram should be monitored for signs and symptoms of SIADH, especially in the first few weeks of therapy, in the presence of risk factors, and during dose escalation.

[Onset of Syndrome of Inappropriate Secretion of Antidiuretic Hormone in a Gastric Cancer Patient on SOX Treatment]

A 78-year-old man with advanced gastric cancer was treated with S-1 and oxaliplatin chemotherapy. He developed hiccups and nausea, and was diagnosed with hyponatremia (serum Na: 120 mEq/L) on day 6 of the first treatment course. Because of his increased urinary Na excretion and relatively high ADH values, he was subsequently diagnosed with chemotherapy-induced syndrome of inappropriate secretion of antidiuretic hormone. The patient recovered after an infusion of hypertonic saline. Although S-1 was restarted, hyponatremia did not recur. We suspected adverse drug reactions to ACE inhibitors and K-sparing diuretics in our case of hyponatremia.

[A Case of Severe Hyponatremia Caused by Renal Salt Wasting Syndrome in Oropharyngeal Cancer]

Hyponatremia is one of the electrolyte abnormalities frequently encountered in cancer therapy. Cisplatin is a well-known drug which can raise various adverse events, including hyponatremia. A male with advanced oropharyngeal cancer is presented in the present report, who was treated with radiotherapy with concurrent administration of cisplatin and who underwent a total of three episodes of severe hyponatremia in the course of therapy. The first two attacks of hyponatremia following cisplatin administration were accompanied by dehydration and excessive urination, and the patient recovered in one week with rehydration and salt supplementation. Excessive loss of salt in urine confirmed that these events were caused by renal salt wasting syndrome after cisplatin administration. On the other hand, the third attack was due to the syndrome of inappropriate antidiuretic hormone secretion after surgery for a bone fracture. Estimation of the extracellular fluid volume and salt intake/output balance is always believed to be necessary for the diagnosis and proper management of severe hyponatremia after chemotherapy-based treatment with cisplatin.

Case of inappropriate ADH syndrome: Hyponatremia due to polyethylene glycol bowel preparation

Colonoscopic screening has been reported to reduce deaths from colorectal cancer. Adequate bowel preparation is essential for this and safety is an important issue in choosing the methods. Polyethylene glycol (PEG) is regarded as a safe method for cleansing, especially compared with oral sodium phosphate. Here, we present a case of hyponatremia caused by the syndrome of inappropriate antidiuretic hormone (ADH) syndrome after PEG precolonoscopic cleansing resulting in generalized tonic-clonic seizures. A 62-year-old women had ingested PEG for precolonoscopic bowel cleansing. While waiting for the colonoscopy, she developed a stuporous mentality and generalized tonic-clonic seizures, which did not correlate with brain magnetic resonance imaging. Her serum sodium level was 113 mEq per liter and laboratory analyses were consistent with inappropriate ADH syndrome. Her thyroid and adrenal functions were normal. There were no malignancies, infections, respiratory disorders or central nervous disorders and she had no history of taking either diuretics or other medications, which might have caused inappropriate ADH syndrome. She was treated with 3% hypertonic saline and showed a complete neurological recovery as her sodium levels recovered. Follow-up visits showed the patient to have a normal sodium level without neurologic deficits. This case shows that inappropriate ADH syndrome can be caused by PEG preparation, which implies that physicians have to be aware of the possible side effects of this colonic cleansing approach and mindful of the possible ensuing symptoms.

[A case of syndrome of inappropriate antidiuretic hormone secretion in a patient with esophageal carcinoma possibly induced by cisplatin in neoadjuvant chemotherapy]

A 60 -year-old man complained of dysphagia and was admitted to our hospital for adjuvant chemotherapy under a diagnosis of esophageal carcinoma(squamous cell carcinoma[SCC], Stage II ). He was treated with cisplatin(CDDP)and 5- fluorouracil(5-FU). On the fifth day after administration, he experienced mild disorientation, and early morning on the sixth day, he showed impaired consciousness. Laboratory studies revealed a serum sodium level of 111mEq/L and a serum chloride level of 73mEq/L. The findings of computed tomography and magnetic resonance imaging of the head were unremarkable. Other laboratory studies revealed a plasma vasopressin level of 19.2 pg/mL, a plasma osmolality of 219mOsm/kg, a serum creatinine level of 0.61mg/dL, a serum cortisol level of 27.1 mg/dL, a urine osmolality of 665mOsm/kg, and a urine sodium level of 157.1mEq/L. There were no signs of dehydration, and so the patient was diagnosed with syndrome of inappropriate antidiuretic hormone secretion(SIADH). We discontinued chemotherapy and initiated fluid restriction and sodium supplementation. After this treatment, the patient's consciousness progressively improved. On the fifth day of treatment, laboratory studies revealed a serum sodium level of 138mEq/L and a serum chloride level of 98mEq/L, indicating recovery from hyponatremia.

Drug-induced hyponatremia: an updated review

Hyponatremia, defined as serum sodium concentrations <135 mmol/L, is the most frequent electrolyte disturbance observed in both hospitalized and ambulatory patients, and has been associated to relevant negative consequences regarding morbidity and mortality. Drug-induced hyponatremia has been widely observed. However, since it may be clinically symptomatic or asymptomatic, it is frequently an underdiagnosed condition. This review aims to highlight the main drugs involved in the pathophysiology of hyponatremia, which should be considered in the differential diagnosis when approaching a patient with hyponatremia. We discuss their impact and relative importance. In order to prevent undesirable negative consequences we also emphasize the need for awareness of this clinically-relevant adverse effect, and we suggest how clinical management of patients may be approached.

[A case of consciousness disorder induced by the syndrome of inappropriate secretion of antidiuretic hormone following cisplatin and 5-fluorouracil chemotherapy in a patient with esophageal cancer]

We report a case of consciousness disorder following the fourth course of chemotherapy with cisplatin (CDDP) and 5- fluorouracil (5-FU) in a patient with esophageal cancer. A 74-year-old man was admitted to our hospital to receive chemotherapy for esophageal cancer. Six days after chemotherapy, the patient showed impaired consciousness and his serum sodium concentration was found to be 125 mEq/L, but no edema or dehydration was noted. This hyponatremic state was diagnosed as CDDP-induced syndrome of inappropriate secretion of antidiuretic hormone (SIADH) on the basis of serum and urine hypo-osmolality. Accordingly, fluid intake was restricted and sodium supplements were administered, resulting in an appropriate increase in the serum sodium concentration to 132 mEq/L in 4 days.

Syndrome of inappropriate antidiuretic hormone secretion induced by tacrolimus following allogeneic cord blood transplantation

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is an important electrolyte abnormality that can occur following allogeneic stem cell transplantation. We herein report the case of a 20-year-old man who developed SIADH three weeks after undergoing cord blood transplantation. Tacrolimus administration was suspected to be a cause of the disorder. In addition to restricting water intake and administering hypertonic sodium, the tacrolimus dosage was reduced, resulting in alleviation of SIADH. Therefore, tacrolimus should be recognized as an important, albeit rare, cause of drug-induced SIADH, even in patients with tacrolimus blood concentrations within the normal range. We believe that dose reduction, not discontinuation, is an effective strategy.

[Syndrome of inappropriate secretion of ADH following chemoradiation therapy]

We report a 69-year-old female patient with pulmonary adenocarcinoma complicated by the syndrome of inappropriate secretion of antidiuretic hormone(SIADH)following systemic chemotherapy with cisplatin(CDDP)and vinorelbine(VNR). She was admitted to our hospital for chemo-radiotherapy for advanced lung cancer, and became restless 4 hours after the administration of CDDP and VNR. Symptoms such as restlessness and incontinence were worsening despite the massive infusion that was completed. Laboratory examinations on day 6 after chemotherapy showed severe hyponatremia(107mEq/L)with decreased serum osmolarity(227mOsm/L)and increased urine osmolarity(452mOsm/L). The serum anti-diuretic hormone(ADH)level was elevated to 16. 7 pg/mL despite severe hyponatremia. She was diagnosed with SIADH and was treated with hypertonic saline infusion and fluid restriction. Her restlessness and other psychiatric symptoms were improved. The use of carboplatin and VNR in the subsequent course did not develop SIADH, indicating that the SIADH was induced by CDDP. Although SIADH following CDDP administration is rare, the electrolyte balance should be carefully monitored throughout the clinical course of chemo-radiation therapy, when psychiatric symptoms are found in patients with lung cancer.

Ropinirole does not affect plasma arginine vasopressin levels in patients with advanced Parkinson's disease

OBJECTIVES

Several cases of syndrome of inappropriate antidiuresis induced by anti-Parkinson agents have been reported. Our previous study demonstrated that pergolide and pramipexole stimulated elevation of plasma arginine vasopressin (AVP) levels in some patients with Parkinson's disease (PD), but that levodopa/carbidopa (300/30 mg/day) did not affect plasma AVP levels in treatment-naïve PD patients. On the basis of the binding profile of ropinirole to monoamine receptors, we hypothesized that ropinirole does not stimulate AVP secretion. The aim of this study was to test this hypothesis.

METHODS

Inclusion criteria were patients with probable PD suffering from a wearing-off phenomenon and who had been treated using levodopa/carbidopa with or without entacapone, but not with other classes of anti-Parkinson agents. Patients were excluded if they had at least one condition that could be associated with high AVP levels. Ropinirole was initiated at 0.5 mg 3 times daily, and daily dosages were increased by 1.5 mg/day on a biweekly basis up to 6 mg/day. Plasma AVP levels were determined every two weeks. Effects of escalating ropinirole dosage on plasma AVP levels were evaluated using a one-way analysis of variance for repeated measures, an a priori Dunnett multiple comparison test, and a regression analysis.

RESULTS

Of 16 patients enrolled, 11 patients (four males and seven females) completed the study. There was no statistically significant dose-response relationship between the ropinirole dosage and plasma AVP levels.

CONCLUSION

A minimal therapeutic dosage of ropinirole did not affect plasma AVP levels in patients with PD taking levodopa.

[Syndrome of inappropriate antidiuretic hormone secretion in the course of treatment with venlafaxine--case report]

Treatment with some drugs may induce hyponatraemia secondary to the syndrome of inappropriate antidiuretic hormone secretion (SIADH). This is a report of a 52-year-old man who developed hyponatraemia after starting venlafaxine administration. Serum sodium level returned to the normal range following discontinuation of venlafaxine and application of SIADH--treatment within a few days. The study shows that routine assessment of blood electrolytes is needed in patients treated with drugs affecting vasopresin secretion.

Syndrome of inappropriate secretion of antidiuretic hormone (SIADH) following carboplatin-paclitaxel administration in a patient with lung cancer

A 60-year-old female underwent right upper lobectomy of the lung and lymph node dissection under a diagnosis of cancer in the upper lobe of the right lung. Pathological examination showed stage IIIA adenocarcinoma with mediastinal lymph node metastasis. One month after the operation, adjuvant chemotherapy with carboplatin (CBDCA) and paclitaxel (PTX) was initiated. Four days after the chemotherapy, hyponatremia progressed, and central nervous system disorder developed. A diagnosis of syndrome of inappropriate secretion of antidiuretic hormone (SIADH) was made. She recovered after fluid intake restriction and electrolyte correction. SIADH was considered to be due to the adverse effects of anticancer drugs. In postoperative adjuvant chemotherapy, attention should be paid to the serum Na level.

Cocaine-associated acute severe hyponatremia

Cocaine is an indirect sympathomimetic agent that acts in the nervous system to block the presynaptic reuptake of serotonin and catecholamines (dopamine, norepinephrine and epinephrine) and to increase their bioavailability at the post-synaptic receptors. The association of cocaine and hyponatremia has not been reported in adults. We describe a case of acute severe hyponatremia that followed smoking cocaine. We propose that cocaine, via its effect on the neurotransmitters, stimulates antidiuretic hormone release and leads to a syndrome of inappropriate antidiuretic hormone secretion.

[Syndrome of inappropriate antidiuretic hormone secretion following adjuvant CDDP and 5-FU administration in a patient with esophageal carcinoma]

A case of hyponatremia following the first course of systemic adjuvant chemotherapy with cisplatin (CDDP) and 5-FU in a previously treated patient with esophageal cancer is reported. A 61-year-old man was admitted to our hospital for adjuvant chemotherapy after transthoracic esophagectomy and 3-field lymphadenectomy for esophageal cancer. Six days following chemotherapy, his serum sodium concentration was found to be 118 mEq/L, without edema or dehydration. This hyponatremic state was diagnosed as the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) induced by CDDP, based on the hypo-osmolality of his serum and urine, and an inappropriate level of plasma vasopressin.

[A case of SIADH developed during neoadjuvant chemotherapy using nedaplatin and 5-fluorouracil in a patient with esophageal cancer]

A 77-year-old male with thoracic esophageal cancer (cT3N3M0, Stage III) received nedaplatin at 80mg/m2 for 1 day and 5-fluorouracil at 800mg/m2 for 5 days as neoadjuvant treatment. On the fifth day of treatment, he lapsed into a coma (Japan Coma Scale 30), and his serum sodium concentration was found to be decreased to 116mEq/L. We concluded hyponatremia due to SIADH (syndrome of inappropriate secretion of antidiuretic hormone) induced by chemotherapy based on the fact that the patient had no finding of dehydration, particular history of related disorders, serum hypoosmolality accompanied by urine hyperosmolality and persistent urinary sodium excretion. We treated him with fluid restriction, sodium supplement and administration of loop diuretic. Then he regained consciousness and appropriate serum sodium level. Thereafter, hyponatremia was corrected without recurrence, and the patient underwent radical esophagectomy safely. He has been in good condition without recurrence of esophageal cancer after surgery.

[A case of drug-induced syndrome of inappropriate secretion of antidiuretic hormone]

The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is characterized by hyponatremia, plasma hypo-osmolality, a urine sodium concentration >30-40 mmol/L, normal acid-base balance, a normal plasma potassium concentration and, frequently, hypouricemia. There are different types of SIADH: idiopathic, iatrogenic, and forms caused by central nervous system or lung disorders, neoplasia and major surgical interventions. Drug-induced SIADH is becoming the most frequent cause of hyponatremia encountered in clinical practice. Here we report the case of a 60-year-old man in a coma (I-II) and with very severe hyponatremia (99 mmol/L) due to SIADH induced by fluphenazine and amitriptyline, which he had been taking since many years as antidepressant drugs. SIADH became very quickly more severe due to the recent administration of cisplatin. There was rapid improvement of the clinical symptoms after withdrawal of the drugs involved and correction of hyponatremia. In conclusion, in rare cases like the present one hyponatremia related to SIADH may be so severe as to represent a true clinical emergency. The administration of drugs known to cause hyponatremia should be avoided, if possible; otherwise, very careful monitoring of the plasma sodium concentration is mandatory to avoid severe neurological complications which may lead to the death of the patient.