Serum sodium abnormalities in children

The Emergency Department Approach to Newborn and Childhood Metabolic Crisis

For most emergency medicine physicians, the phrases "newborn workup" and "metabolic disease" are, at best, uncomfortable. This article, however, provides a simple approach to the recognition,evaluation, and treatment of infants with all manners of metabolic issues, including hypoglycemia, inborn errors of metabolism, jaundice, and electrolyte abnormalities. The disorders are grouped based on symptomatology, and have simple guidelines for work-up and management, with an emergency department practitioner perspective in mind.

Hyponatremic seizures secondary to oral water intoxication in infancy: association with commercial bottled drinking water

In recent years, hyponatremic seizures resulting from water intoxication have been reported in the United States with an increasing frequency that some have likened to an epidemic. Infants of parents living in poverty and uninformed of the risks of feeding fluids other than infant formula to their babies are particularly at risk. Young infants with vomiting and diarrhea are especially prone to developing hyponatremia if fed fluids lacking sufficient sodium, but even those who are otherwise well may develop symptomatic hyponatremia as a result of being fed excess solute-free water. Most often tap water, either in the form of supplemental feedings or overly dilute formula, has been given in excessive amounts over relatively short periods of time. Less frequently, water in other forms such as juice, soda, or tea has been implicated. This report includes the cases of two infants treated at our institution for hyponatremic seizures and water intoxication after being fed with the same bottled drinking water product marketed for use in infants. The medical records of all infants </=1 year of age admitted to our institution over 10 years with the diagnosis of hyponatremic seizures were also reviewed.

Continuous infusion of vasopressin in comatose children with neurogenic diabetes insipidus

Three comatose children with neurogenic diabetes insipidus were treated with intravenous infusion of vasopressin. The infusion of vasopressin was started at a dose of 1.3 to 2.7 mU/kg/h as soon as diabetes insipidus was diagnosed. The effect (urine flow < 2 ml/kg/h with increased specific gravity) was noted in 1 to 6 hours. The infusion rate of vasopressin was adjusted according to urine flow rate which was usually kept around 65 ml/100 kcal metabolized/day. Hypernatremia was corrected 17 to 53 hours after the initiation of infusion of vasopressin. The levels of sodium stayed between 127 and 151 mmol/l during a period of 2.5 to 22 days until the patients' death due to the termination of respiratory support or cardiac decompensation. A continuous infusion of vasopressin offered the advantage of rapid onset and termination of effect and therefore could be easily titrated. It seems a rational therapy for comatose children with neurogenic diabetes insipidus.

Clinical settings and vasopressin function in hyponatraemic children

Hyponatraemia is one of the most common electrolyte abnormalities in hospitalised children. In a prospective study we tested whether hyponatraemia is associated with sustained release of the antidiuretic hormone arginine vasopressin (AVP). Out of 27 children with persistent hyponatremia (serum sodium < 130 mmol/l), 25 had measurable plasma concentrations of AVP [median and quartiles 5.0 pg/ml (1.5-8.3)]. Volume contraction as consequence of sodium loss caused hyponatraemia in 16 patients. Hyponatraemia in the presence of extracellular volume expansion and reduced effective arterial blood volume occurred in 5 patients. Only 3 patients had normovolaemic hyponatraemia (so-called syndrome of inappropriate antidiuretic hormone secretion) and 3 suffered from chronic renal failure. It is concluded that plasma AVP concentration is measurable in most children with hyponatraemia. Non-osmotic stimulation of AVP release and lack of suppression of this hormone is an important pathogenetic mechanism of hyponatraemia in children.

Hyponatremia: pathophysiology and treatment, a pediatric perspective

Hyponatremia is the most commonly observed electrolyte abnormality in hospitalized children. The most serious consequences of hyponatremia and its treatment involve the central nervous system (CNS). Important factors determining the development of clinical symptomatology include: the rate of fall in serum sodium, and the severity and duration of hyponatremia. Acute hyponatremia is associated with increased brain water resulting in varying grades of encephalopathy whereas the osmoregulatory mechanism allows normalization of CNS water content in chronic hyponatremia. It is recommended that the therapy for hyponatremia be initiated on the basis of the presence or absence of symptoms. An increase of 4-6 mmol/l in serum sodium over 10-15 min is recommended in symptomatic patients. Rapid correction of chronic hyponatremia may result in osmotic dehydration syndrome and therefore should be avoided.

Disorders of water balance--hyponatraemia and hypernatraemia

Plasma sodium concentration depends on water balance, and is normally maintained in a narrow range by an integrated system involving the precise regulation of water intake via thirst mechanism and control of water output via vasopressin secretion. Anything that interferes with the full expression of either osmoregulatory function exposes the patient to the hazards of abnormal decreases or increases in plasma sodium level. Hyponatraemia is almost always due to a defect in water excretion. Increased intake may contribute to the problem but is rarely, if ever, a sufficient cause. Hypernatraemia is almost always due to deficient water intake; excessive water losses may contribute to the problem, but they are never a sufficient cause. The most dangerous and usually the most blatant clinical effects of the disturbed water balance are those involving the central nervous system. Complex adaptive mechanisms have been developed to mitigate the impact of both hypo- and hypernatraemia on brain cells. However, the same protective changes render the brain more susceptible to severe neuropathology that may arise from inappropriate treatment of these disorders.

Hyponatremia

This article provides a useful clinical classification of hyponatremic states based upon plasma tonicity and extracellular fluid volume. The pathophysiology of hyponatremia induced by hypovolemic, euvolemic, and hypervolemic conditions is discussed. An approach to the treatment of each category of hyponatremia is presented.

The pharmacology and therapeutics of diuretics in the pediatric patient

Selection of appropriate diuretic therapy in children is hampered by a lack of age-specific pharmacokinetic and pharmacodynamic data, especially in premature neonates. Well-designed clinical trials in neonates, infants, and younger children are necessary prerequisites to safer and more efficacious diuretic therapy.

Hyponatremic seizures as a presenting symptom of child abuse

Poisoning is an uncommon manifestation of child abuse. The intentional administration of water to a child as a form of punishment has rarely been reported as the responsible substance among children who have been poisoned. We describe a case of a 5-year-old girl presenting with severe hyponatremia due to acute water intoxication. The patient was brought to the emergency room in status epilepticus. A history was obtained from the child's mother stating that the patient had been playing outside when she collapsed. She had had no known prior illnesses. Laboratory evaluation included a hemoglobin of 10.1 mg%, glucose of 60 mg%, serum sodium of 107 mEq/l, potassium of 3.2 mEq/l and chloride of 71 mEq/l. A CAT scan obtained approximately 1 h after admission revealed generalized cerebral edema. Careful examination of the skin revealed multiple linear ecchymosis of varying ages on the back and thighs and a hand print on the right flank. In addition, the child demonstrated severe failure to thrive with height, weight and bone age compatible with a 2.5-year-old girl. Appropriate therapy for severe hyponatremia was successfully instituted. For the next 12 h she was deeply somnolent, but the following morning was alert and conversant. She stated that she "would be good if she didn't have to drink any more water". The child's mother subsequently admitted that she frequently used water ingestion as a form of punishment. The child stabilized metabolically and demonstrated rapid in-hospital weight gain. She was placed in foster care at discharge and has had no further hyponatremia or seizures.(ABSTRACT TRUNCATED AT 250 WORDS)

Benign intracranial hypertension following severe hyponatremic dehydration in congenital adrenal hyperplasia

A case of salt-losing congenital adrenal hyperplasia with severe hyponatremic dehydration is presented. Clinical signs and symptoms of cerebral edema with elevated intracranial pressure were present. Conventional treatment was started, and after initial concern regarding future head growth and development, there was a good outcome with normal development at 1 year of age. This course is suggestive of benign intracranial hypertension. Possible mechanisms are discussed with a review of the relevant literature.

Hypernatremic dehydration in children with severe psychomotor retardation

Three cases of hypernatremic dehydration in children with severe psychomotor retardation are described. All the children were receiving processed foods that contained extremely high amounts of sodium and were unintentionally deprived of free water. Salt and water intake must be monitored closely in children who can neither communicate thirst nor regulate their diet.