Hyponatremia secondary to reset osmostat

Postoperative Dysnatremia in Pediatric Patients Undergoing Palatoplasty

OBJECTIVE

Identifying predisposing factors to dysnatremia to improve perioperative care after cleft surgery.

DESIGN

Retrospective case series. Patient data were obtained through the electronic medical records of the hospital.

SETTING

Tertiary care university hospital.

PATIENTS

The inclusion criterion was the measurement of an abnormal natremia value, defined as Na >150 or <130 mmol/l after a cleft lip or cleft palate repair procedure. The exclusion criterion was natremia between 131 and 149 mmol/l.

RESULTS

Natremia measurements were available for 215 patients born between 1995 and 2018. Five patients presented with postoperative dysnatremia. Several predisposing factors to dysnatremia have been identified: drugs, infection, administration of intravenous fluids, and postoperative syndrome of inappropriate antidiuretic hormone secretion. Although the hospital environment contributes to dysnatremia development, the fact that only patients undergoing cleft palate repair develop natremia anomalies suggests that this surgery may be itself a risk factor.

CONCLUSION

Children undergoing palatoplasty may be at higher risk to develop postoperative dysnatremia. Early recognition of symptoms and risk factors, postoperative monitoring, and prompt treatment of dysnatremia diminish the risk of neurological complications.

Validity of the Adrogué-Madias Formula for the Management of Acute Dysnatremias in Critically Ill Children: A Prospective Multicenter Analysis

OBJECTIVE

Current conventional formulas do not predict the expected changes in serum sodium after administration of various fluids to correct serum sodium abnormalities. The Adrogué-Madias formula is currently the preferred and widely used fluid prescription for adult patients with dysnatremias, but its therapeutic efficacy has not been validated in pediatric patients.

METHODS

In this prospective study, we used the Adrogué-Madias formula for calculating the appropriate rate of various fluids administration to correct serum sodium abnormalities in 7 critically ill children with acute dysnatremias.

RESULTS

After administration of various intravenous fluids using the Adrogué-Madias formula, the anticipated as well as the achieved sodium concentrations were almost similar.

CONCLUSIONS

This study demonstrates that the use of the Adrogué-Madias quantitative formula allows to calculate the appropriate rate of administration of various fluids. The calculated fluid administration resulted in the subsequent actual laboratory values and clinical changes.

Differentiating syndrome of inappropriate ADH, reset osmostat, cerebral/renal salt wasting using fractional urate excretion

OBJECTIVES

Clinical and laboratory data of reset osmostat (RO) and cerebral/renal salt wasting (C/RSW) mimic syndrome of inappropriate antidiuretic hormone (SIADH) and can pose diagnostic challenges because of significant overlapping between clinical and laboratory findings. Failure to correctly diagnose hyponatremia may result in increased mortality risk, longer hospital stay, and is cost-effective. We aim to illustrate clinical and laboratory similarities and difference among patients with hyponatremic disorders and discuss the diagnostic value of factional uprate excretion (FEurate) to differentiate SIADH from RO and C/RSW.

CASE PRESENTATIONS

We report the use of FEurate in the evaluation of three patients with hyponatremia and elevated urine osmolality in the absence of edema or clinical evidence of dehydration to differentiate SIADH from RO and C/RSW.

CONCLUSIONS

Measurement of FEurate may offset in part the diagnostic confusion imparted by the diagnoses of SIADH, RO, and C/RSW.

Management Challenges in a Child with Chronic Hyponatremia: Use of V2 Receptor Antagonist

Chronic hyponatremia is very rare in children and is often seen in the setting of congestive heart failure or liver failure in adults. Here, we report an 8-year-old child with hypothalamic glioma who presented with severe hyponatremia. Initial management consisted of fluid restriction. This was very difficult for the child to follow and the child developed bizarre drinking habits requiring intervention from child psychiatry. So therapy was initiated with low dose V2 receptor antagonist under close inpatient monitoring. While initial response was reassuring, her sodium levels tended to drift down with longer duration of treatment requiring us to increase the dose frequently. Her response to therapy and her stable clinical situation off therapy suggest that she may have reset osmostat.

Hyponatremia secondary to reset osmostat in a child with a central nervous system midline defect and a chromosomal abnormality

A newborn with a CNS midline defect and persistent hyponatremia was diagnosed with a "reset" osmostat using a 3% hypertonic saline test. The diagnosis was established by measuring urinary arginine vasopressin (UAVP) and plasma osmolality (P(Osmoil)). In this infant a chromosome abnormality with the karyotype 46, X, -X, +der(X) t(X;13) (p22.1;q22) was associated with the midline defect and a reset osmostat.

Epidermal nevus syndrome with hypermelanosis and chronic hyponatremia

Epidermal nevus syndrome is seldom encountered, and its association with hypermelanosis and the chronic syndrome of inappropriate antidiuretic hormone secretion (SIADH) has never been reported. A male neonate who developed intractable seizures and hyponatremia soon after birth is reported. He had alopecic patches on the scalp at birth. Large areas of skin hyperpigmentation, and epidermal nevi developed gradually. The clinical picture of hypotonic hyponatremia, high urine osmolality, elevated urine sodium, and euvolemia was compatible with SIADH. The seizures did not correlate with the hyponatremia, and no other cause for the seizures could be identified. The hyponatremia became chronic and was treated with a direct supply of sodium chloride. The development of the patient was markedly delayed at the last visit when he was 1 year of age. It is suggested that hypermelanosis and chronic SIADH may also be a variant presentation of epidermal nevus syndrome.

Hyponatremia caused by a reset osmostat in a neonate with cleft lip and palate and panhypopituitarism

A neonate with cleft lip and palate and hypopituitarism had persistent hyponatremia despite treatment with hydrocortisone, L-thyroxine, and growth hormone. Serum sodium concentration and urinary osmolality increased and decreased appropriately and concurrently with alterations in sodium and water intake. The ability to regulate serum concentrations of antidiuretic hormone at subnormal serum sodium concentrations indicated a reset osmostat.

Hyponatremia in central partial diabetes insipidus due to postoperative hypothalamic tumor

We report the case of a 4-year-old boy with a postoperative hypothalamic tumor, who exhibited unusual water and electrolyte disturbance. This developed as a late manifestation during the course of central diabetes insipidus (DI), which started when the patient was 2 years old. Clinically, hyponatremia and DI appeared alternately within 1 day. The hyponatremia (lowest value Na+ 115 mmol/I) was associated with afebrile convulsions. Assessment of fluid status revealed that the patient had a reduced capacity for arginine vasopressin(AVP) secretion (partial DI), which was not physiologically regulated and which was not concomitantly sufficient to produce maximally concentrated urine and allow the production of maximally diluted urine. This defective osmoreceptor function in association with the previously existing reduced capacity for AVP release seemed to be responsible for the fluid disturbance in the patient. The administration of nasal 1-desamino-8D-arginine vasopressin (DDAVP) only when urine output was increased, instead of regular administration at a fixed time, prevented both worsening of hyponatremia and development of DI.