Syndrome of inappropriate antidiuretic hormone secretion (SIADH) in children undergoing high-dose chemotherapy and autologous peripheral blood stem cell transplantation

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.

Severe Hyponatremia in a Single-Center Series of 84 Homogenously Treated Children With Acute Lymphoblastic Leukemia

Electrolyte abnormalities are hallmark metabolic disturbances during the treatment of acute lymphoblastic leukemia (ALL). Hyponatremia is an ominous laboratory sign in the setting of neoplasia. We analyzed the incidence, risk factors, associations, specific interventions and outcomes of severe hyponatremia in a single-center series of children with ALL. The incidence of severe hyponatremia, defined as serum sodium levels below 130 mmol/L on at least 2 of 3 consecutive days, was 11.9%. History of hyponatremia episode is associated with neurologic complications (P=0.023) and the presence of overt central nervous system leukemia (CNS3) at diagnosis (P=0.005). Most observed hyponatremia episodes resolved relatively quickly, rarely requiring specific treatment. All but 1 hyponatremia episodes occurred in the induction or reinduction phases, but none before the administration of cytotoxic drugs, pointing to the role of therapy complications rather than leukemia per se. Most patients received vincristine shortly before hyponatremia onset, and vincristine has been previously strongly implicated in hyponatremia. We also suggest a role for imatinib. Although every patient with severe hyponatremia requires swift and thorough diagnostics a serious sequelae in the setting of pediatric ALL is rare. Hyponatremia association with neurotoxicity likely points to vincristine hypersensitivity in the subgroup of patients with both complications.

Syndrome of inappropriate antidiuretic hormone secretion induced by a single dose of oral cyclophosphamide

OBJECTIVE

To report a case of syndrome of inappropriate antidiuretic hormone secretion (SIADH) induced by a single oral dose of cyclophosphamide.

CASE SUMMARY

A 69-year-old woman was treated with oral CTD (cyclophosphamide/thalidomide/dexamethasone) chemotherapy for multiple myeloma. Two days after the first dose (including cyclophosphamide 500 mg), the patient developed vomiting, drowsiness, and headache. Medication history included sertraline, started in 2005. On admission, laboratory values were serum sodium 113 mEq/L, serum osmolality 240 mOsm/kg, urinary osmolality 701 mOsm/kg, urinary sodium 91 mEq/L, and serum creatinine 0.71 mg/dL. Thyroid and adrenal function were normal. SIADH was diagnosed. Cyclophosphamide and sertraline were stopped and fluid restriction was commenced. The patient was discharged on day 9 following chemotherapy with serum sodium 132 mEq/L. Sertraline was restarted. Four days later she developed vomiting with serum sodium 119 mEq/L. Fluid restriction, which the woman had not performed, was reinstituted and she was discharged on day 17. Two further cycles of chemotherapy were subsequently given without cyclophosphamide and serum sodium remained within normal limits.

DISCUSSION

Cyclophosphamide-induced severe hyponatremia and SIADH have been documented in patients receiving treatment for a wide range of malignant and autoimmune disorders. All cases have involved intravenous therapy, with doses ranging from single pulse doses of 500 mg to 3000 mg/m(2). Selective serotonin reuptake inhibitors are a common cause of SIADH. Because sertraline was instituted in 2005 and reinstituted without incident, it was eliminated as a contributing factor. Malignancy, tumor lysis syndrome, other medications, hydration to prevent hemorrhagic cystitis, and renal impairment were also ruled out. The Naranjo probability scale indicated a probable association between SIADH and cyclophosphamide administration.

CONCLUSIONS

To our knowledge, our report represents the first case of SIADH due to a single oral dose of cyclophosphamide. Clinicians should be aware of this rare adverse event, as it can have life-threatening consequences.

Iatrogenic hyponatremia in hospitalized children: Can it be avoided?

Iatrogenic hyponatremia in hospitalized children is a common problem. It is usually caused by the administration of free water, either orally or through the prescription of hypotonic intravenous fluids. It can result in cerebral edema and death, and is most commonly reported in healthy children undergoing minor surgery. The current teachings and practical guidelines for maintenance fluid infusions are based on caloric expenditure data in healthy children that were derived and published more than 50 years ago. A re-evaluation of these data and more recent recognition that hospitalized children are vulnerable to hyponatremia, with its resulting morbidity and mortality rates, suggest that changes in paediatricians' approach to fluid administration are necessary. There is no single fluid therapy that is optimal for all hospitalized children. A thorough assessment of the type of fluid, volume of fluid and electrolyte requirements based on individual patient requirements, plus rigorous monitoring, is required in any child receiving intravenous fluids. The present article reviews how hyponatremia occurs and makes recommendations for minimizing the risk of iatrogenic hyponatremia.

Syndrome of inappropriate secretion of antidiuretic hormone as a leading cause of hyponatremia in children who underwent chemotherapy or stem cell transplantation

BACKGROUND

Hyponatremia is a common metabolic disorder in cancer patients. However, little information is available for patients receiving chemotherapy or stem cell transplantation (SCT). We analyzed the frequency, characteristics, and various causes of hyponatremia including routine use of hypotonic fluids in children following chemotherapy or SCT.

PROCEDURE

We reviewed the clinical and laboratory data of 63 children who received chemotherapy or SCT at the Department of Pediatrics, Hanyang University Medical Center from July 2005 to July 2008.

RESULTS

All 63 patients at admission received routine parenteral fluids of 0.25% or 0.45% NaCl and 82 episodes of hyponatremia were observed in 40 (63.5%) patients. Of these 82 episodes, 50 episodes of hyponatremia developed in 29 children following chemotherapy and 32 episodes in 16 children following SCT. Seventy-six out of 82 episodes (92.7%) of hyponatremia developed in 37 patients receiving hypotonic fluids with NaCl concentrations between 30 and 150 mEq/L. The frequency of SIADH in the SCT setting was more frequent (14/21, 66.6%) than in the chemotherapy setting (18/58, 31.0%) (P = 0.02), even though the leading cause of hyponatremia was SIADH in both settings.

CONCLUSIONS

SIADH is a leading cause of hyponatremia in children following chemotherapy or SCT, and more frequent in SCT settings than in chemotherapy settings. Furthermore, the routine use of hypotonic fluids which could aggravate the development of hyponatremia for these patients should be avoided and then switched to isotonic fluids.

Early Onset of Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) after Allogeneic Haematopoietic Stem Cell Transplantation: Case Report and Review of the Literature

Severe hyponatraemia and syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a rare but fatal complication following stem cell transplantation (SCT). This case report details a patient with early-onset SIADH after allogeneic haematopoietic SCT (allo-HSCT) and reviews the literature on risk factors for the development of this condition. The patient, who had chronic myelogenous leukaemia, developed acute graft-versus-host disease (GVHD) on day 5 after allo-HSCT, which was relieved promptly by steroids. On day 18, he presented with hyponatraemia, which was refractory. Despite intensive restriction of fluid and administration of hypertonic saline, his condition worsened and he died of multiple systemic organ dysfunction. A review of the literature reveals that early-onset SIADH following SCT is insidious, but progresses rapidly. The severity of the disorder is underestimated because of the non-specific clinical features and the lack of effective treatment. Myeloablative conditioning and acute GVHD are two major important predisposing factors in SIADH.

The syndrome of inappropriate secretion of antidiuretic hormone associated with SCT: clinical differences following SCT using cord blood and BM/peripheral blood

Previously, we reported the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) as an underestimated complication associated with SCT. In the present report, we analyzed detailed data on a larger number of patients with SIADH following SCT and found different SIADH clinical features following cord blood SCT (CBSCT) and BMT/PBSCT. The median onset of SIADH following CBSCT and BMT/PBSCT was 19 and 46 days after SCT, respectively, and the median numbers of WBC at the onset of SIADH were 1.0 and 3.1 x 10(9)/l, respectively. Furthermore, severe symptoms such as seizures, somnolence and rigidity of limbs were observed only in patients with CBSCT (8/15 vs 0/10). These differences were statistically significant (P<0.01). Although the precise basis for SIADH following SCT still remains unknown, the different features of SIADH observed following CBSCT and BMT/PBSCT may provide important clues to the disease mechanism following SCT. Additionally, we confirmed our previous results that patients with SIADH showed a higher overall survival and event-free survival rates. However, we first suggested that they had some neurological disorders and that neurological sequelae such as developmental delay and seizures would consequently occur.

Severe metabolic abnormalities after allogeneic hematopoietic cell transplantation

Severe metabolic abnormalities occurring within 100 days after allogeneic hematopoietic cell transplantation (HCT) were investigated in 311 patients. The metabolic abnormalities included hyper- and hypocalcemia, hypophosphatemia, hyper- and hypokalemia, hyper- and hyponatremia, hyper- and hypomagnesemia, hypercholesterolemia, hyper- and hypoglycemia, and hyperuricemia. Severe abnormalities, defined as grades III-V by NCI CTCAE v3.0, occurred in 269 patients (86.5%). Multivariate analysis revealed that patients with moderate-to-severe hepatic veno-occlusive disease had significantly higher risk for the occurrence of severe metabolic abnormalities. Grades III-IV acute graft-versus-host disease was the most frequently associated with individual metabolic abnormalities. Patients with at least one severe metabolic abnormality had significantly higher day 100 nonrelapse mortality (P=0.015) and lower 5-year overall survival (P=0.002) than those without severe abnormalities. The number of metabolic abnormalities also stratified the patients with different clinical outcomes. In conclusion, severe metabolic abnormalities occurring within 100 days after allogeneic HCT were common, and their occurrence was significantly associated with inferior clinical outcomes. These results indicate that metabolic parameters should be monitored in patients undergoing allogeneic HCT and that the occurrence of severe metabolic abnormalities should be considered an important toxicity parameter in prospective clinical trials regarding allogeneic HCT.

Hyponatremia and syndrome of inappropriate antidiuretic hormone secretion complicating stem cell transplantation

Hyponatremia is a common electrolyte disorder in hospitalized patients. Although there are a few case reports of hyponatremia following stem cell transplantation (SCT), no reports concerning the incidence are currently available. We describe the occurrence of hyponatremia and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) following SCT. In a single center analysis of 140 patients, hyponatremia and SIADH were observed in 40 and 11.4% of patients, respectively, following SCT. Risk factors for SIADH included young age, transplantation from an HLA-mismatched or unrelated donor, cord blood transplantation, and graft-versus-host disease prophylaxis with methyl prednisolone. Multivariate analysis revealed that transplantation from an HLA-mismatched donor and performance of SCT in a child below 4 years of age were risk factors for SIADH. For patients who underwent SCT from an HLA-mismatched or unrelated donor, those with SIADH showed a significantly higher overall survival rate (90.9 vs 40.2%) and event-free survival rate (77.8 vs 33.8%) compared to those without SIADH. Overall, our data show that hyponatremia and SIADH are relatively common complications following SCT, especially in children below 4 years of age and after SCT from an HLA-mismatched donor.

Acute hyponatremia related to intravenous fluid administration in hospitalized children: an observational study

OBJECTIVE

To develop hyponatremia (plasma sodium concentration [P(Na)] <136 mmol/L), one needs a source of water input and antidiuretic hormone secretion release to diminish its excretion. The administration of hypotonic maintenance fluids is common practice in hospitalized children. The objective of this study was to identify risk factors for the development of hospital-acquired, acute hyponatremia in a tertiary care hospital using a retrospective analysis.

METHODS

All children who presented to the emergency department in a 3-month period and had at least 1 P(Na) measured (n = 1586) were evaluated. Those who were admitted were followed for the next 48 hours to identify patients with hospital-acquired hyponatremia. An age- and gender-matched case-control (1:3) analysis was performed with patients who did not become hyponatremic.

RESULTS

Hyponatremia (P(Na) <136 mmol/L) was documented in 131 of 1586 patients with > or = 1 P(Na) measurements. Although 96 patients were hyponatremic on presentation, our study group consisted of 40 patients who developed hyponatremia in hospital. The case-control study showed that the patients in the hospital-acquired hyponatremia group received significantly more EFW and had a higher positive water balance. With respect to outcomes, 2 patients had major neurologic sequelae and 1 died.

CONCLUSION

The most important factor for hospital-acquired hyponatremia is the administration of hypotonic fluid. We suggest that hypotonic fluid not be given to children when they have a P(Na) <138 mmol/L.

Evaluation and management of hypo-osmolality in hospitalized patients

Hyponatremia is the most common electrolyte disorder encountered in the clinical setting. Abnormalities of the mechanisms that maintain normal water and sodium metabolism are often present in hospitalized patients, including defects in renal water excretion. All of the current therapeutic approaches in patients with the syndrome of inappropriate antidiuretic hormone secretion and other forms of vasopressin-induced hyponatremia have significant limitations. Studies in animal models and humans have demonstrated that antagonists of the AVP V2 receptor in the kidney are effective in correcting hyponatremia. These new agents have been termed "aquaretics" because of their ability to induce a free water diuresis without the natriuresis or kaliuresis characteristic of diuretic drugs. When approved for clinical use, selective V2, and possibly also combined V1 + V2 receptor antagonists will be helpful in therapy.