There are two forms of diabetes insipidus (DI):

• Central diabetes insipidus (Central DI)—caused by inadequate antidiuretic hormone (ADH)
• Nephrogenic diabetes insipidus (NDI)—due to renal cells in the kidneys not responding to ADH

ADH controls the amount of water reabsorbed by the kidneys. ADH is made in the hypothalamus of the brain. The pituitary gland , at the base of the brain, stores and releases ADH.

• Central DI (up to 50% of cases, the cause is unknown) may be caused by:
  • A lack of ADH made in the brain due to a genetic defect
  • Damage to the hypothalamus or pituitary glands by surgery, infection, tumor, or head injury
  • Sickle cell disease
• NDI may be caused by:
  • Renal cells in the kidneys not being able to conserve water, which may be due to a genetic defect in some cases
  • Kidney diseases (such as polycystic kidney disease )
  • Medications (such as lithium , amphotericin B , or demeclocycline )—the most common cause of diabetes insipidus

The following factors increase your chance of developing diabetes insipidus:

• Damage to the hypothalamus due to surgery, infection, tumor, or head injury
• Polycystic kidney disease or another kidney disease that may affect the filtration process
• Use of certain medications such as lithium, amphotericin B, or demeclocycline
• High blood levels of calcium
• Low blood levels of potassium

If you have any of these, do not assume it is due to diabetes insipidus. These symptoms may be caused by other health conditions. See your doctor, if you experience any one of them:

• Extreme thirst with preference for cold drinks in central DI
• Muscle weakness
• Headache
• Fever
• Blurred vision
• Low blood pressure
• Rapid pulse
• Frequent urination, especially during the night (nocturia)
• Dehydration

Your doctor will ask about your symptoms and medical history. A physical exam may be done.

Tests may include the following:

• Blood tests
  • Electrolytes
  • ADH levels
  • Blood sugar
• Urinalysis
  • Urine specific gravity and/or osmolality (measures how concentrated or dilute the urine is)
• Water deprivation test
  • Only done under doctor supervision
  • Urine output is measured for a 24-hour period
  • Diabetes insipidus can cause as much as 4-10 liters of urine to be excreted per day
  • Central DI—urine output is suppressed by a dose of vasopressin/ADH
  • NDI—urine output is not suppressed by a dose of vasopressin/ADH
• Magnetic resonance imaging (MRI) of the head—if CDI is suspected

Talk with your doctor about the best plan for you. Treatment options include the following:

• A synthetic form of ADH—this drug could be taken by mouth, inhaled through the nose, or by injection
• Diuretic “water pill” or an antidiabetic medication—in mild cases to boost the ADH effect on the renal cells in the kidney

• A diuretic “water pill” could be used
• If lithium is causing the problem—another diuretic, amiloride, could be used

In both CDI and NDI, symptoms can often be reduced by:

• Decreasing the amount of sodium in the diet
• Medication called thiazide diuretics (diuretics they conserve water loss and decrease urine output in people with diabetes insipidus)