Hyponatremic dehydration: an analysis of 78 cases

Hyponatremia and malnutrition: a comprehensive review

BACKGROUND

Hyponatremia (serum sodium lower than 135 mmol/L) is the most frequent electrolyte alteration diagnosed in medical practice. It has deleterious clinical effects, being an independent predictor of mortality. Malnutrition encompasses pathological states caused by both nutrients excess and deficiency, being frequently documented in chronic kidney disease patients. In addition, chronic hyponatremia promotes adiposity loss and sarcopenia, while malnutrition can induce hyponatremia. This pathological interaction is mediated by four main mechanisms: altered electrolyte body composition (low sodium, low potassium, low phosphorus, or high-water body content), systemic inflammation (cytokines increase), hormonal mechanisms (renin-angiotensin-aldosterone system activation, vasopressin release), and anorexia (primary or secondary).

CONCLUSION

Malnutrition can induce hyponatremia through hydro-electrolytic, hormonal, inflammatory, or nutritional behavior changes; while hyponatremia per se can induce malnutrition, so there is a pathophysiological feedback between both conditions.

An inducible intestinal epithelial cell-specific NHE3 knockout mouse model mimicking congenital sodium diarrhea

The sodium–hydrogen exchanger isoform 3 (NHE3, SLC9A3) is abundantly expressed in the gastrointestinal tract and is proposed to play essential roles in Na⁺ and fluid absorption as well as acid–base homeostasis. Mutations in the SLC9A3 gene can cause congenital sodium diarrhea (CSD). However, understanding the precise role of intestinal NHE3 has been severely hampered due to the lack of a suitable animal model. To navigate this problem and better understand the role of intestinal NHE3, we generated a tamoxifen-inducible intestinal epithelial cell-specific NHE3 knockout mouse model (NHE3^IEC-KO). Before tamoxifen administration, the phenotype and blood parameters of NHE3^IEC-KO were unremarkable compared with control mice. After tamoxifen administration, NHE3^IEC-KO mice have undetectable levels of NHE3 in the intestine. NHE3^IEC-KO mice develop watery, alkaline diarrhea in combination with a swollen small intestine, cecum and colon. The persistent diarrhea results in higher fluid intake. After 3 weeks, NHE3^IEC-KO mice show a ~25% mortality rate. The contribution of intestinal NHE3 to acid–base and Na⁺ homeostasis under normal conditions becomes evident in NHE3^IEC-KO mice that have metabolic acidosis, lower blood bicarbonate levels, hyponatremia and hyperkalemia associated with drastically elevated plasma aldosterone levels. These results demonstrate that intestinal NHE3 has a significant contribution to acid–base, Na⁺ and volume homeostasis, and lack of intestinal NHE3 has consequences on intestinal structural integrity. This mouse model mimics and explains the phenotype of individuals with CSD carrying SLC9A3 mutations.

Dehydration and volume depletion: How to handle the misconceptions

Dehydration and volume depletion describe two distinct body fluid deficit disorders with differing pathophysiology, clinical manifestations and treatment approaches. However, the two are often confused or equated with each other. Here, we address a number of commonly encountered misconceptions about body-fluid deficit disorders, analyse their origins and propose approaches to overcome them.

The challenges of managing severe dehydrating diarrhoea in a resource-limited setting

Diarrhoea remains one of the most common causes of childhood deaths worldwide despite the widespread use of oral rehydration solution (ORS). The vast majority of the nearly 2 million diarrhoeal deaths occurring annually in children under five years of age are in south Asia and sub-Saharan Africa. Signs of critical illness in severely dehydrated children are poorly recognised, and although considerable efforts have gone into establishing the management of diarrhoeal disease in general, there is surprisingly little understanding of the aetiology, metabolic processes and risk factors for the very high mortality associated with severe dehydrating diarrhoea (SDD). We suggest that in many resource-poor settings, the degree of fluid requirement as well as the prevalence of electrolyte disturbances are seriously under-recognised and may be contributing significantly to mortality. The heterogeneity of children with SDD renders the generic 'one size fits all' approach to fluid and electrolyte management in these critically ill children inadequate. In this review we will highlight SDD as an important target for research in resource-limited settings, and emphasise the need to re-evaluate the efficacy of prevailing intravenous fluid protocols in well conducted multi-centre interventional trials.

Auditory brainstem potentials in children with protein energy malnutrition

OBJECTIVE

In this study, auditory brainstem potentials (ABPs) were studied in children with protein energy malnutrition (PEM) to determine the effects of PEM on the developing brain in children.

METHODS

A total of 31 children, aged 3-36 months with moderate/severe PEM and 25 healthy children, aged 3-48 months were included in the study. Nutritional status of the children was assessed by the Gomez classification. Recordings of ABPs were performed by using Nihon Kohden Neuropack 2 device.

RESULTS

Of 31 children, 22 (71%) had severe malnutrition, 9 (29%) had moderate malnutrition. Additionally, 8 (26%) and 9 (29%) children had iron deficiency anemia and hypoalbuminemi, respectively. There were significant differences in the mean latencies of the waves I-V on the right and left ears and in the mean interpeak latencies (IPLs) of the waves III-V and I-V on the right ear between the study and control groups (P<0.05). The mean IPLs of I-V on the left side were found to be longer in the moderate PEM group than those of severe PEM group (P<0.05). There was not any difference between the groups of PEM with low serum albumin and PEM with normal serum albumin. While the mean IPLs of I-III on the right side were found longer in the cases of PEM without iron deficiency anemia, the mean latency of wave I on the left side, and the mean IPLs of III-V on the right side were longer in the children with PEM plus iron deficiency anemia (P<0.05).

CONCLUSIONS

Our findings showed that children with moderate/severe PEM had ABPs abnormalities in different degrees, which reflect defects in myelination of auditory brainstem pathways in children with moderate/severe PEM. However, we found contradictory results between abnormalities in ABPs and degree of malnutrition and iron deficiency anemia. We think that more extensive studies should be performed to determine whether or not there was a relationship between these parameters.

Hyponatremia and seizures after bowel preparation: report of three cases

Oral sodium phosphate and sodium picosulfates/magnesium citrate are commonly used to evacuate the colon and rectum before colonoscopy or colorectal surgery. These substances, however, are known to cause electrolyte abnormalities. Seizures caused by electrolyte abnormalities associated with bowel preparation have only rarely been reported. We report the cases of three patients with no prior history of seizures, who had their first seizure associated with hyponatremia following ingestion of sodium phosphate or sodium picosulfates/magnesium citrate combination. Care must be taken with patients with a low seizure threshold and those with possible chronic sodium depletion, such as patients on thiazide diuretics, who are undertaking bowel preparation with oral sodium phosphate or sodium picosulfates/magnesium citrate combination.