Diabetes insipidus (DI) is an uncommon form of diabetes that causes an imbalance of fluids in the body leading to excrete large amounts of urine and to increased thirst. The amount of urine produced can be nearly 20 liters per day in some cases, which is much more than the typical one to two liters of urine for normal adults.
Diabetes insipidus occurs when your body cannot properly balance the body's fluid levels. When your fluid regulation system is working normally, your kidneys help maintain this balance. The kidneys remove fluids from your bloodstream which is stored in your bladder as urine, until you urinate. An anti-diuretic hormone (ADH), or vasopressin, helps control the speed of fluid excretion. ADH is made in the hypothalamus (a part of the brain) and stored in the pituitary gland. According to the Mayo Clinic, the causes vary depending on the type of diabetes insipidus one has:
Central diabetes insipidus (CDI). Damage to the pituitary gland or hypothalamus from surgery, a tumor, a head injury, or an illness can cause central diabetes insipidus by affecting the usual production, storage, and release of ADH. Sometimes CDI is simply caused by genetics. Symptoms of CDI may develop over time or suddenly and may affect individuals of any age and gender. CDI is characterized by excessive thirst (polydipsia) and excessive urination (polyuria), even at night (nocturia). The severity and progression of CDI varies with some individuals having a severe form of the disorder (complete CDI) with nearly nil ADH activity while others may have a mild form of the disorder (partial CDI) with miniscule ADH activity. CDI affects males and females in equal numbers and can occur at any age but is more common between the ages of 10 and 20 years. The inherited form of CDI is extremely rare with fewer than 100 cases reported in the medical literature. Overall, CDI is estimated to occur in 1 out of every 25,000 individuals.
Nephrogenic diabetes insipidus (NDI). Nephrogenic diabetes insipidus occurs when there is a defect in the kidney tubules — the structures in your kidneys that cause water to be excreted or reabsorbed. This defect makes your kidneys unable to properly respond to ADH. The defect may be due to an inherited /genetic disorder or a chronic kidney disorder. Certain drugs, such as lithium or antiviral medications such as foscarnet/Foscavir (an anti-viral medicine), also can cause nephrogenic diabetes insipidus. The two primary symptoms of NDI are chronic excessive thirst (polydipsia) and excessive urine production (polyuria), or excessive urination at night (nocturia). Some infants may develop vomiting, retching, unexplained fevers, lethargy, irritability, constipation, diarrhea, and poor feeding.