Diabetes Insipidus

Diabetes insipidus (DI) is a rare endocrine disorder characterized by the inability of the kidneys to reabsorb water, resulting in excessive thirst and urination.

Types of Diabetes Insipidus

• Central Diabetes Insipidus: This type occurs when there is a deficiency of antidiuretic hormone (ADH), also known as vasopressin, which is produced by the hypothalamus and released by the posterior pituitary gland.
• Nephrogenic Diabetes Insipidus: This type occurs when the kidneys are unable to respond to ADH, resulting in an inability to reabsorb water.
• Gestational Diabetes Insipidus: This type occurs during pregnancy and is caused by an enzyme produced by the placenta that breaks down ADH.
• Primary Polydipsia (Psychogenic Diabetes Insipidus): This type is not a true form of DI, but rather a condition characterized by excessive thirst and fluid intake, often due to psychological or psychiatric disorders.

Causes of Diabetes Insipidus

• Trauma to the brain or pituitary gland
• Tumors in the brain or pituitary gland
• Infections, such as meningitis or encephalitis
• Genetic disorders, such as familial central diabetes insipidus
• Kidney disease or damage
• Certain medications, such as lithium or demeclocycline

Symptoms of Diabetes Insipidus

• Excessive thirst (polydipsia)
• Excessive urination (polyuria)
• Frequent nighttime awakenings to urinate (nocturia)
• Fatigue
• Headaches
• Blurred vision
• Dehydration, if left untreated

Diagnosis of Diabetes Insipidus

Diagnosis is typically made through a combination of the following tests:

• Water deprivation test: measures urine concentration and volume after a period of water deprivation
• ADH stimulation test: measures the response to ADH administration
• Blood tests: measure electrolyte levels, blood urea nitrogen (BUN), and creatinine
• Urinalysis: measures urine specific gravity and osmolality
• Imaging studies: such as MRI or CT scans to rule out underlying causes

Treatment of Diabetes Insipidus

Treatment depends on the type and severity of DI:

• Central Diabetes Insipidus: treatment with desmopressin, a synthetic form of ADH, administered intranasally or orally
• Nephrogenic Diabetes Insipidus: treatment with hydrochlorothiazide, a diuretic that helps reduce urine volume, and/or indomethacin, an anti-inflammatory medication that helps increase water reabsorption in the kidneys
• Gestational Diabetes Insipidus: treatment is typically not necessary, as the condition resolves after pregnancy
• Management of underlying causes, such as treating infections or tumors

Complications of Untreated Diabetes Insipidus

If left untreated, DI can lead to:

• Dehydration and electrolyte imbalances
• Kidney damage or failure
• Increased risk of urinary tract infections
• Impaired cognitive function and memory