From the Guidelines
Nephrogenic diabetes insipidus (NDI) should be managed with a low-sodium diet combined with thiazide diuretics, such as hydrochlorothiazide 25-50mg daily, as the mainstay of treatment, according to the most recent expert consensus statement 1.
Treatment Overview
The goal of treatment is to address the underlying cause and manage symptoms, with a focus on reducing urine output and preventing dehydration.
- A low-sodium diet is essential to decrease the renal osmotic load.
- Thiazide diuretics, such as hydrochlorothiazide, can reduce diuresis by up to 50% in the short term, when combined with a low-salt diet 1.
- NSAIDs like indomethacin can be added to enhance water reabsorption.
- For acquired NDI, discontinuing causative medications, such as lithium, is crucial when possible.
- Amiloride is particularly useful for lithium-induced NDI, as it blocks lithium entry into collecting duct cells.
Fluid Intake and Monitoring
- Patients with NDI should have ad libitum access to fluid to prevent dehydration, hypernatraemia, growth failure, and constipation 1.
- Fluid intake should be based on thirst sensation, and patients should be monitored closely for signs of dehydration and electrolyte imbalances.
- Urine volume, serum sodium levels, and improvement in symptoms like thirst and polyuria should be monitored to assess treatment effectiveness.
Emergency Management
- In cases of hypernatraemic dehydration, patients should be treated with water, and salt-containing solutions should be avoided 1.
- Intravenous rehydration with 5% dextrose in water may be necessary in some cases, with close monitoring of weight, fluid balance, and biochemistry.
Follow-up and Surveillance
- Regular follow-up with a specialized center is recommended, with monitoring of weight, height, blood biochemistry, and urine osmolality 1.
- Surveillance imaging, such as ultrasound of the urinary tract, should be performed regularly to detect potential complications, such as hydronephrosis and bladder wall hypertrophy.
From the Research
Definition and Characteristics of Nephrogenic DI
- Nephrogenic diabetes insipidus (NDI) is characterized by the inability to concentrate urine, resulting in polyuria and polydipsia, despite having normal or elevated plasma concentrations of arginine vasopressin (AVP) 2.
- The clinical manifestations of NDI vary according to the degree of dehydration and hyperosmolality, and can be worse when renal water losses cannot be properly compensated by fluid intake 2.
Diagnosis of Nephrogenic DI
- The diagnosis of NDI is important to consider the symptoms of the patient and the diagnostic tests, including the water deprivation test and the baseline plasma copeptin measurement, a stable surrogate biomarker of AVP release 2, 3.
- The water deprivation test followed by desmopressin administration is the gold standard for diagnosis 3.
Treatment of Nephrogenic DI
- The treatment of NDI consists of decreasing the urine output, while allowing appropriate fluid balance, normonatremia, and ensuring an acceptable quality of life 2.
- Therapeutic options include nonpharmacological interventions, such as sufficient water intake and a low-sodium diet, and pharmacological treatment with thiazide diuretics, nonsteroidal anti-inflammatory drugs (NSAIDs), and amiloride, used isolated or in combination 4, 2, 5, 6.
- The hydrochlorothiazide-amiloride regimen is superior to hydrochlorothiazide alone and can be a satisfactory alternative to the hydrochlorothiazide-prostaglandin synthetase inhibitor combination in the treatment of congenital nephrogenic diabetes insipidus 5.
- Treatment with hydrochlorothiazide alone and hydrochlorothiazide and indomethacin combined reduces urine flow in nephrogenic diabetes insipidus by increasing proximal tubular reabsorption of sodium 6.