The management of extreme hypernatraemia secondary to salt poisoning in an infant

Salt Poisoning Due to Inadequate Infant Formula Preparation: A Rare Cause of Hypernatremia and Massive Cerebral Hemorrhage in a Newborn

Salt poisoning is a rare cause of severe hypernatremia in children resulting from the ingestion of toxic amounts of sodium chloride, either from accidental or intentional administration of salted solutions. We present the case of a newborn admitted to a pediatric emergency department for lethargy and reduced oral intake; his laboratory evaluation showed severe hypernatremia ([Na⁺] of 174 mmol/L). The infant developed convulsive status epilepticus during treatment. Neuroimaging showed a tetraventricular hemorrhage, a large right-sided parenchymal hemorrhage with midline shift, and several left hemorrhagic foci. Etiologic evaluation for hypernatremia did not reveal a renal or extrarenal source of water loss nor an intercurrent illness to explain the reduced oral intake. A careful review of how the parents prepared the infant formula revealed an error in dosing the ratio of powder/water, resulting in hyperosmolar infant formula. The infant was diagnosed with salt poisoning as the major cause of hypernatremia. After careful correction of hypernatremia and the use of antiseizure medication, the patient improved and was discharged. The parents were given a careful review of instructions for infant formula preparation. Due to its rarity, a high index of suspicion is mandatory for a correct diagnosis of salt poisoning. Timely and adequate treatment is needed due to the high risk of intracerebral bleeding, seizures, and irreversible neurologic injury. Children, particularly newborns and infants, depend upon adults to ingest water and, thus, have more difficulty in maintaining electrolyte balance. Therefore, it is of utmost importance that parents are educated about childcare, particularly on the importance of careful infant formula preparation.

Regulation of Inflammatory Functions of Macrophages and T Lymphocytes by NFAT5

The transcription factor NFAT5, also known as TonEBP, belongs to the family of Rel homology domain-containing factors, which comprises the NF-κB proteins and the calcineurin-dependent NFAT1 to NFAT4. NFAT5 shares several structural and functional features with other Rel-family factors, for instance it recognizes DNA elements with the same core sequence as those bound by NFAT1 to 4, and like NF-κB it responds to Toll-like receptors (TLR) and activates macrophage responses to microbial products. On the other hand, NFAT5 is quite unique among Rel-family factors as it can be activated by hyperosmotic stress caused by elevated concentrations of extracellular sodium ions. NFAT5 regulates specific genes but also others that are inducible by NF-κB and NFAT1 to 4. The ability of NFAT5 to do so in response to hypertonicity, microbial products, and inflammatory stimuli may extend the capabilities of immune cells to mount effective anti-pathogen responses in diverse microenvironment and signaling conditions. Recent studies identifying osmostress-dependent and -independent functions of NFAT5 have broadened our understanding of how NFAT5 may modulate immune function. In this review we focus on the role of NFAT5 in macrophages and T cells in different contexts, discussing findings from in vivo mouse models of NFAT5 deficiency and reviewing current knowledge on its mechanisms of regulation. Finally, we propose several questions for future research.

Recognition and Management of Pediatric Salt Toxicity

OBJECTIVES

Immediate recognition of salt toxicity and aggressive resuscitative measures are critical in the treatment of this lethal poisoning. Despite heroic measures, pediatric deaths due to salt toxicity still occur from irreversible neurological damage. The objective of this article is to review the relevant literature and offer a therapeutic algorithm for the management of pediatric patients presenting with salt toxicity.

METHODS

A literature search for cases of salt toxicity was conducted. Articles in English that were available electronically through PubMed and Google Scholar were reviewed.

RESULTS

Nineteen cases and case series of salt toxicity were located using our search strategy. Salt poisoning has a distinct pathophysiology compared with hypernatremia, most notable for the lack of formation of idiogenic osmoles.

CONCLUSIONS

The approach to treatment differs between salt toxicity and hypernatremia, focusing on rapid correction of serum osmolality rather than gradual normalization of serum sodium concentrations. Consultation of nephrology and child protection services are strongly recommended in the comprehensive treatment approach.

Severe hypernatremia by excessive bamboo salt ingestion in healthy young woman

Severe hypernatremia is an important electrolyte disorder that has serious effects. The patient had no medical history. A. 20-year-old ingested bamboo salt for digestion and weight reduction according to the folk remedies posted on an internet website. She presented with vomiting and diarrhea over ten times per day. Her initial serum sodium concentration was 174mEq/L. Her symptoms improved rapidly with hypotonic saline infusion. She recovered completely without any sequelae in three days. Severe hypernatremia in a normal young adult with clear consciousness and normal renal function has not been reported in Korea yet. So we report a case of severe hypernatremia by excessive bamboo salt ingestion in healthy young woman.

Severe hypernatremia and hyperchloremia in an elderly patient with IgG-kappa-type multiple myeloma

A 77-year-old male was admitted to hospital after suffering a pelvic bone fracture in a road traffic accident and was incidentally found to have IgG-kappa-type multiple myeloma with hypercalcemia. The patient was also noted to be hypokalemic and had low HCO₃⁻, with possible damage to the distal tubules in the kidneys. When the treatment was begun with bortezomib/dexamethasone/elcatonin and sodium bicarbonate (NaHCO₃) in normal saline (equivalent to a daily sodium dose of 200 millimoles per liter [mmol/L]), the patient was in a state of poor oral fluid intake. The patient developed hypernatremia and hyperchloremia, with a peak serum sodium and chloride levels of 183 mmol/L and 153 mmol/L, respectively, at the sixth day after the start of treatment. Following the switch of the intravenous infusions from normal saline to soldem 1 and soldem 3 solutions, these high-electrolyte levels gradually returned to normal over the next 7 days. Although the patient showed disturbed consciousness (Japan Coma Scale = JCS-I-3) during the period of electrolyte abnormality, he eventually fully recovered without sequelae. In this patient, we successfully managed the severe hypernatremia/hyperchloremia, caused by the combined effects of intravenous saline burden in a state of poor oral fluid intake, during the treatment for IgG-kappa type multiple myeloma.

Severe hypernatremia in a hospitalized child: munchausen by proxy

An 8-week-old infant presented to a referring institution with profuse diarrhea and infectious enteritis for 1 week. He was initially treated for suspected Salmonella spp. sepsis and meningitis, because the organism was found in the stool, but the child's illness progressed, manifested by paroxysmal profuse diarrhea and increased urine output. After several weeks, he suffered a sagittal venous thrombosis and intracranial hemorrhage. Subsequently the child was transferred to a tertiary center for intestinal evaluation. The patient's diarrhea and excessive diuresis resolved, and his sodium normalized soon after transfer. Four days later, however, after his mother arrived, he immediately developed severe hypernatremia (serum sodium concentration [Na(+)] = 214 mEq/L), with resumption of diarrhea and excessive diuresis. A gastric aspirate during the crisis demonstrated an extremely high sodium content, [Na(+)] = 1416 mEq/L, consistent with salt intoxication. Surveillance of the mother revealed that she manipulated the indwelling nasogastric tube; confronted, she admitted to salt administration. This case describes one of the ways that Munchausen syndrome by proxy can manifest with profound neurologic sequelae, and highlights the need for close observation and swift intervention when sufficient cause is present.

The transcription factor NFAT5 is required for cyclin expression and cell cycle progression in cells exposed to hypertonic stress

Background

Hypertonicity can perturb cellular functions, induce DNA damage-like responses and inhibit proliferation. The transcription factor NFAT5 induces osmoprotective gene products that allow cells to adapt to sustained hypertonic conditions. Although it is known that NFAT5-deficient lymphocytes and renal medullary cells have reduced proliferative capacity and viability under hypertonic stress, less is understood about the contribution of this factor to DNA damage responses and cell cycle regulation.

Methodology/Principal Findings

We have generated conditional knockout mice to obtain NFAT5^−/− T lymphocytes, which we used as a model of proliferating cells to study NFAT5-dependent responses. We show that hypertonicity triggered an early, NFAT5-independent, genotoxic stress-like response with induction of p53, p21 and GADD45, downregulation of cyclins, and cell cycle arrest. This was followed by an NFAT5-dependent adaptive phase in wild-type cells, which induced an osmoprotective gene expression program, downregulated stress markers, resumed cyclin expression and proliferation, and displayed enhanced NFAT5 transcriptional activity in S and G2/M. In contrast, NFAT5^−/− cells failed to induce osmoprotective genes and exhibited poorer viability. Although surviving NFAT5^−/− cells downregulated genotoxic stress markers, they underwent cell cycle arrest in G1/S and G2/M, which was associated with reduced expression of cyclins E1, A2 and B1. We also show that pathologic hypertonicity levels, as occurring in plasma of patients and animal models of osmoregulatory disorders, inhibited the induction of cyclins and aurora B kinase in response to T cell receptor stimulation in fresh NFAT5^−/− lymphocytes.

Conclusions/Significance

We conclude that NFAT5 facilitates cell proliferation under hypertonic conditions by inducing an osmoadaptive response that enables cells to express fundamental regulators needed for cell cycle progression.

Analysis of the transcriptional activity of endogenous NFAT5 in primary cells using transgenic NFAT-luciferase reporter mice

Background

The transcription factor NFAT5/TonEBP regulates the response of mammalian cells to hypertonicity. However, little is known about the physiopathologic tonicity thresholds that trigger its transcriptional activity in primary cells. Wilkins et al. recently developed a transgenic mouse carrying a luciferase reporter (9xNFAT-Luc) driven by a cluster of NFAT sites, that was activated by calcineurin-dependent NFATc proteins. Since the NFAT site of this reporter was very similar to an optimal NFAT5 site, we tested whether this reporter could detect the activation of NFAT5 in transgenic cells.

Results

The 9xNFAT-Luc reporter was activated by hypertonicity in an NFAT5-dependent manner in different types of non-transformed transgenic cells: lymphocytes, macrophages and fibroblasts. Activation of this reporter by the phorbol ester PMA plus ionomycin was independent of NFAT5 and mediated by NFATc proteins. Transcriptional activation of NFAT5 in T lymphocytes was detected at hypertonic conditions of 360–380 mOsm/kg (isotonic conditions being 300 mOsm/kg) and strongly induced at 400 mOsm/kg. Such levels have been recorded in plasma in patients with osmoregulatory disorders and in mice deficient in aquaporins and vasopressin receptor. The hypertonicity threshold required to activate NFAT5 was higher in bone marrow-derived macrophages (430 mOsm/kg) and embryonic fibroblasts (480 mOsm/kg). Activation of the 9xNFAT-Luc reporter by hypertonicity in lymphocytes was insensitive to the ERK inhibitor PD98059, partially inhibited by the PI3-kinase inhibitor wortmannin (0.5 μM) and the PKA inhibitor H89, and substantially downregulated by p38 inhibitors (SB203580 and SB202190) and by inhibition of PI3-kinase-related kinases with 25 μM LY294002. Sensitivity of the reporter to FK506 varied among cell types and was greater in primary T cells than in fibroblasts and macrophages.

Conclusion

Our results indicate that NFAT5 is a sensitive responder to pathologic increases in extracellular tonicity in T lymphocytes. Activation of NFAT5 by hypertonicity in lymphocytes was mediated by a combination of signaling pathways that differed from those required in other cell types. We propose that the 9xNFAT-Luc transgenic mouse model might be useful to study the physiopathological regulation of both NFAT5 and NFATc factors in primary cells.

Fatal Hypernatremia from Saltwater Used as an Emetic

An adolescent boy returned home from a party and told his parents he may have taken some pills while there. He was given saltwater to drink, in an effort to induce emesis. He vomited numerous times, then seized. Hypernatremia (195 mmol/L) was diagnosed at the community hospital, and he was transferred to a pediatric intensive care facility. He suffered numerous complications and died from cerebral herniation. This case is presented to remind physicians of the dangers of this obsolete therapy.