From the Guidelines
Diabetes insipidus (DI) should be diagnosed and treated based on its type, with central DI typically managed with desmopressin (DDAVP) and nephrogenic DI treated with thiazide diuretics, low-salt diet, and NSAIDs, as recommended by the most recent expert consensus statement 1.
Diagnosis of Diabetes Insipidus
The diagnosis of DI involves identifying the underlying cause of the disorder, which can be either central or nephrogenic. Central DI is caused by insufficient production of antidiuretic hormone (ADH) by the pituitary gland, while nephrogenic DI is caused by the kidneys' inability to respond to ADH.
- Symptoms of DI include extreme thirst, polyuria (producing large amounts of dilute urine, often 3-20 liters daily), and frequent urination, including at night.
- Proper diagnosis requires water deprivation tests and measurement of plasma osmolality, as well as genetic testing to identify the underlying cause of the disorder 1.
Treatment of Central Diabetes Insipidus
For central DI, desmopressin (DDAVP) is the primary medication, available as:
- Nasal spray (10-40 mcg daily in 1-3 doses)
- Oral tablets (0.1-0.8 mg daily)
- Sublingual tablets
Treatment of Nephrogenic Diabetes Insipidus
For nephrogenic DI, treatment may include:
- Thiazide diuretics like hydrochlorothiazide (25-50 mg daily) to reduce urine volume
- Low-salt diet to minimize renal osmotic load
- NSAIDs to reduce urine volume
- Amiloride to prevent hypokalaemia induced by thiazides 1
Importance of Genetic Testing
Genetic testing is crucial for early diagnosis, precise genetic counselling, and identification of family members at risk 1. It is recommended to perform genetic testing in a laboratory accredited for diagnostic genetic testing using a massively parallel sequencing-based multigene panel that includes at least AQP2, AVPR2, and AVP.
Multidisciplinary Approach
A multidisciplinary team, including a nephrologist, dietitian, psychologist, social worker, and urologist, should be involved in the care of patients with DI to ensure comprehensive management and follow-up 1.
From the FDA Drug Label
Diabetes Insipidus: Desmopressin acetate injection 4 mcg/mL is indicated as antidiuretic replacement therapy in the management of central (cranial) diabetes insipidus and for the management of the temporary polyuria and polydipsia following head trauma or surgery in the pituitary region. The usual dosage range in adults is 0.5 mL (2 mcg) to 1 mL (4 mcg) daily, administered intravenously or subcutaneously, usually in two divided doses.
The diagnosis of Diabetes Insipidus (DI) involves laboratory tests, including:
- Urine volume and osmolality
- Plasma osmolality (in some cases)
The treatment for central (cranial) DI is desmopressin acetate injection, with a usual dosage range of 0.5 mL (2 mcg) to 1 mL (4 mcg) daily, administered intravenously or subcutaneously, usually in two divided doses 2, 2. Key considerations for treatment include:
- Fluid restriction to prevent possible hyponatremia and water intoxication
- Monitoring of urine volume and osmolality to adjust dosage
- Caution in patients with conditions associated with fluid and electrolyte imbalance, such as cystic fibrosis, heart failure, and renal disorders 2.
From the Research
Diagnosis of Diabetes Insipidus (DI)
- Diabetes insipidus is a disorder characterized by a high hypotonic urinary output of more than 50ml per kg body weight per 24 hours, with associated polydipsia of more than 3 liters a day 3
- The diagnosis of DI must be distinguished from primary polydipsia and other causes of hypotonic polyuria 4
- The gold standard for diagnosis is a water deprivation test followed by desmopressin administration 4
- A new surrogate marker of ADH called copeptin may simplify and improve the accuracy in diagnosing DI in the future 4
- Functional tests such as water deprivation or stimulation of copeptin by hyperosmolarity can be proposed to distinguish between different etiologies 5
Treatment of Diabetes Insipidus (DI)
- Treatment of central DI consists of fluid management and drug therapy with the synthetic AVP analogue Desmopressin (DDAVP) 3
- Patients with DI require adequate access to water, and there are nuances on treatment approaches depending on whether a patient is diagnosed with central or nephrogenic DI 4
- The treatment of diabetes insipidus depends on the underlying etiology, and in the case of a central etiology, is based on the administration of desmopressin 5
- Oral dDAVP has replaced nasal dDAVP as a more reliable mode of treatment for chronic central diabetes insipidus 6
- Hyponatraemia is a common side effect of dDAVP treatment, and should be avoided by allowing a regular break from dDAVP to allow a resultant aquaresis 6
- Treatment of nephrogenic diabetes insipidus involves removing the underlying cause, if possible, reducing solute load or therapy with a diuretic agent 7