From the Guidelines
Management of an infant with medullary nephrocalcinosis, significant weight loss, and vomiting requires prompt medical intervention focused on rehydration, electrolyte correction, and addressing the underlying cause, with a consideration for Bartter syndrome as a potential diagnosis, as suggested by the European Rare Kidney Disease Reference Network Working Group for Tubular Disorders 1. The initial treatment should include intravenous fluid resuscitation with isotonic fluids, typically normal saline at 10-20 mL/kg bolus, followed by maintenance fluids with appropriate electrolyte composition. Careful monitoring of serum electrolytes, particularly calcium, phosphorus, sodium, and potassium, is essential, as indicated by the study published in Kidney International 1. Metabolic evaluation should include serum and urine calcium, phosphorus, oxalate, citrate, and creatinine levels to identify the underlying etiology of nephrocalcinosis. Some key points to consider in the management include:
- Rehydration and electrolyte correction
- Metabolic evaluation to identify the underlying cause of nephrocalcinosis
- Consideration of Bartter syndrome as a potential diagnosis, given the symptoms of renal salt wasting, polyuria, rapid weight loss, and signs of dehydration, as well as the presence of medullary nephrocalcinosis, as discussed in the study by Komhoff and Laghmani and Legrand et al. 1
- Potential use of hydrochlorothiazide for hypercalciuria, as indicated in the study published in Kidney International 1
- Nutritional support, potentially requiring specialized formula or fortification, to address the weight loss, as suggested by the international expert consensus statement on the diagnosis and management of congenital nephrogenic diabetes insipidus (arginine vasopressin resistance) 1. The infant should be closely monitored with serial weight measurements, electrolyte checks, and renal ultrasounds to assess progression of nephrocalcinosis, as recommended by the European Rare Kidney Disease Reference Network Working Group for Tubular Disorders 1. This comprehensive approach addresses both the acute symptoms and the underlying renal condition, as nephrocalcinosis in infants can result from various metabolic disorders, medication effects, or prematurity-related factors that require specific targeted therapies once identified, as discussed in the studies published in Kidney International 1.
From the Research
Management Approach for Medullary Nephrocalcinosis
The management approach for an infant with medullary nephrocalcinosis, significant weight loss, and vomiting postnatally involves addressing the underlying cause of the condition.
- The common causes of nephrocalcinosis include renal tubular acidosis, hyperparathyroidism, and medullary sponge kidney, as well as hypercalcaemia or hypercalciuria of any aetiology 2.
- Vitamin D intoxication is also a possible cause of hypercalciuria and nephrocalcinosis, particularly in infants who have received high doses of vitamin D 3, 4.
- Management strategies may include:
- Correction of metabolic acidosis and increased fluid intake 3, 5.
- Reduction of urinary calcium excretion using thiazide diuretics, such as hydrochlorothiazide 5.
- Management of hypercalcemia using injectable calcitonin 4.
- Monitoring for progression of nephrocalcinosis and adjustment of treatment as needed 3, 4.
- It is essential to identify and address the underlying cause of the condition to develop an effective management plan.
- In some cases, nephrocalcinosis may persist despite treatment, and regular follow-up is necessary to monitor the condition 3, 4.