Nephrogenic diabetes insipidus in children (Review)

CANDID Study: Clinical and Molecular Characterization of Congenital Arginine Vasopressin-Resistance and the Use of a Novel Diagnostic Biomarker in Indian Children

OBJECTIVES

To present authors' experience with congenital arginine vasopressin resistance (AVP-R) in children up to 12-y-old at a tertiary care center in Northern India.

METHODS

An ambispective analysis was conducted, focusing on clinical, biochemical, genetic evaluations, treatments, renal and neurological outcomes.

RESULTS

Data from 11 patients (two females) were included, with an average delay of 18 mo between symptom onset and diagnosis. The majority of children presented with failure to thrive (90.9%), polyuria (90.9%), and hyperosmolality (63.6%) at the time of diagnosis. Nearly one-fourth of the cohort experienced acute kidney injury. Random copeptin levels (340.7 ± 59.56 pmol/L) were significantly higher than the diagnostic cutoff suggested in the literature, and molecular diagnosis confirmed AVPR2 mutations in 90% of the cases. The subjects were followed for a median of 2.1 y (range: 1-4.7 y). During this period, there was a median increase of + 0.79 in BMI/weight-for-height SDS and a 30.55% reduction in urine output. However, 63.63% of the children continued to experience failure to thrive. None of the subjects developed renal structural abnormalities or chronic kidney disease (CKD) ≥ stage 2 by the final follow-up. Neurological evaluation revealed attention deficit hyperactivity disorder and gross developmental delay in two children and one child respectively.

CONCLUSIONS

This study provides the first comprehensive analysis of congenital AVP-R in a low-middle-income setting.

Nephrogenic Diabetes Insipidus Affecting Three Males in Two Generations-Case Report and Review of the Literature

Background: Nephrogenic diabetes insipidus (NDI) is defined as the inability of the kidney to concentrate urine owing to the insensitivity of the distal nephron to the antidiuretic hormone, arginine vasopressin. NDI is a heterogeneous rare autosomal dominant or X-linked disease. Objective: We present a family with nephrogenic diabetes affecting three males in two generations. Methods: We report two boys with NDI: a 4-month-old infant who was treated for fever, vomiting, and failure to thrive, and his 10-year-old uncle (the mother's brother), who was admitted concurrently for consuming 11 L of fluid per day. According to family history, the mother's sibling passed away at the age of two from severe hypernatremic dehydration. Results: The infant's clinical and laboratory evaluation revealed a 7.8 mL/kg/h urine output, hypernatremic hyperchloremic alkalosis, extremely low urine density (1002), and elevated copeptin level. In contrast, the uncle's clinical and laboratory evaluation revealed marked polyuria, low urine density, and elevated copeptin, all of which were suggestive of diabetes insipidus. After starting hydrochlorothiazide treatment (2 mg/kg/body), the infant's urine production reduced (2.85 mL/kg/h); however, severe hypokalemia and alkalosis followed. Spironolactone, an aldosterone antagonist, were added, with good therapeutic response. Hydrochlorothiazide was administered to the uncle, and his daily fluid intake decreased to 3-4 L. Given the family history, Sanger sequencing for the AVPR2 variant was performed on the boys and the infant's mother. Analysis showed hemizygous likely pathogenic variant c.335G>A p. (Cys112Tyr) in the 2 boys and heterozygous (carrier) status of the mother. Within the same family, we observed phenotypic heterogeneity: one child died at the age of two, another lived well into ten years without therapy, and a four month-old baby could have had a poor outcome without specific treatment. Conclusions: NDI is a rare and possibly fatal genetic disorder with heterogeneous manifestations. In families with a history of NDI, molecular genetic testing is crucial for family planning.

The natural history of untreated X-linked nephrogenic diabetes insipidus with mutation in the vasopressin V2 receptor gene

Nephrogenic diabetes insipidus (NDI) results from the kidneys' inability to concentrate urine. We describe a 6-month-old male with a history of poor weight gain who presented with an incidental finding of hypernatremia (155 mEq/L) during an episode of acute gastroenteritis. The arginine vasopressin (AVP) test, along with molecular analysis revealing the M272R mutation in the AVP receptor 2 (AVPR2) gene, confirmed the diagnosis of congenital NDI. Interestingly, this mutation was also identified in the patient's maternal grandfather, who had never been diagnosed or treated for NDI despite a history of polydipsia, polyuria, and evidence of chronic kidney disease (CKD), severe bilateral hydronephrosis, hypertension, and severe bladder dysfunction. Early intervention with hydrochlorothiazide in the infant resulted in a significant reduction in urinary output and improved growth. The untreated grandfather's case highlights the potential severity of untreated NDI and the benefits of timely therapeutic intervention. This report contributes to the limited long-term data on congenital NDI, emphasizing the critical role of early detection and consistent management in preventing severe complications such as CKD, hydronephrosis, and bladder dysfunction. Regular follow-up, including renal ultrasound and monitoring of renal function, is essential for effectively managing NDI and improving patient outcomes.

Ifosfamide-induced nephrogenic diabetes insipidus and Fanconi syndrome in a patient with femur osteosarcoma

BACKGROUND

Ifosfamide-induced Fanconi syndrome is a relatively infrequent complication that generally occurs in young patients with a high cumulative dose of ifosfamide; and is commonly characterized by glycosuria, proteinuria, electrolyte abnormalities, and a normal anion gap metabolic acidosis.

CASE PRESENTATION

In this study, we present the case of a 16-year-old male patient with of osteosarcoma of the right femur with pulmonary metastasis, who received ifosfamide as part of chemotherapy 1 year and 2 months ago and required hospitalization for cellulitis. During inpatient management, he presented with hypokalemia, hypophosphatemia, polyuria, glycosuria, and proteinuria, by which he was diagnosed with Fanconi syndrome and nephrogenic diabetes insipidus, induced by ifosfamide. Management was focused on the control of the internal environment and use of potassium supplements and potassium-sparing diuretics.

CONCLUSION

Patients receiving ifosfamide should be periodically monitored for kidney function and internal environment to detect any potential complications. It is thus important to carefully observe the cumulative dose of ifosfamide to prevent its associated nephrotoxicity, since its appearance can impoverish the prognosis in patients with neoplasms. Therefore, physicians should always be aware about the possibility of nephrotoxicity development.

Challenging case of hypernatraemia in infancy

A 1-month-old male infant presented unwell with a fever and shock. Blood tests showed hypernatraemia, hyperchloraemia and raised urea and creatinine. Initially, he was treated for dehydration secondary to sepsis. However, high urine output combined with low urine osmolality and high plasma osmolality was suggestive of a disorder of arginine vasopressin (AVP), previously called diabetes insipidus (DI). On further endocrine testing, thyroxine (T4) level was low with an inappropriately normal thyroid-stimulating hormone level with no other anterior pituitary hormone abnormalities, a normal MRI head and ophthalmological assessment. Desmopressin, a synthetic form of AVP, was commenced, however, there was an inadequate response despite dose escalation, leading to a diagnosis of AVP resistance (previously nephrogenic DI) rather than AVP deficiency (previously cranial DI). Copeptin, an AVP precursor peptide and surrogate marker, was significantly elevated. A renal tubulopathy genetic screen demonstrated a likely pathogenic hemizygous variant in the AVP receptor 2 gene, which has previously been associated with X-linked vasopressin resistance. This case demonstrates the challenge of differentiating between AVP deficiency and resistance in infancy and the value of copeptin and genetic testing in confirming diagnosis. We outline an approach to fluid management in AVP disorders.

Congenital nephrogenic diabetes insipidus treated with acetazolamide

Congenital nephrogenic diabetes insipidus (CNDI) is a rare disorder. The condition is characterised by an inability of distal nephron segments to respond to normal or raised concentrations of serum antidiuretic hormone. In this report, we describe the case of a 13-year-old male known with CNDI who experienced a pedestrian vehicle accident leading to coma following a head injury. Intra-operatively, severe hypernatraemia and polyuria were observed. Following an inadequate response to conventional therapy, acetazolamide was prescribed resulting in an immediate response to therapy. To the best of our knowledge, acetazolamide has not been previously documented as a therapeutic option for CNDI. Additional research is necessary before considering the recommendation of acetazolamide for cases of NDI that do not respond adequately to conventional treatments.

Updates in hyponatremia and hypernatremia

PURPOSE OF REVIEW

Hyponatremia and hypernatremia are commonly encountered electrolyte abnormalities that require timely and careful intervention, as they can be associated with significant morbidity and mortality.

RECENT FINDINGS

This review article addresses the etiology, presentation, diagnosis, and management of both hyponatremia and hypernatremia, emphasizing the latest advancements and emerging trends in pediatric care.

SUMMARY

A methodical approach is needed to accurately assess and treat hyponatremia and hypernatremia. Both conditions continue to rely on serum and urine testing, however newer tests such as copeptin and stimulated testing may hold promise to further refine testing in the future.