What is Diabetes Insipidus?

DI has nothing to do with blood sugar or "Diabetes Mellitus." It is a problem with water balance. The body cannot concentrate urine, leading to massive urine output and extreme thirst.

Types:

• Central DI: The pituitary doesn't make enough ADH (antidiuretic hormone, also called vasopressin).
• Nephrogenic DI: The kidneys don't respond to ADH.

Symptoms:

• Polyuria: Urinating 5-20 liters a day (normal is 1-2 liters). Waking up multiple times at night to urinate.
• Polydipsia: Extreme thirst. Constantly drinking water.
• Dehydration: If you can't drink enough to keep up.

Diagnosis:

• Water Deprivation Test: You stop drinking water under supervision. In DI, urine stays dilute. Then, you're given synthetic ADH (desmopressin). If urine concentrates, it's Central DI. If not, it's Nephrogenic DI.

Causes:

• Central DI: Pituitary surgery, brain injury, tumors, or idiopathic.
• Nephrogenic DI: Lithium (medication), genetic, or chronic kidney disease.

Treatment:

• Central DI: Desmopressin (DDAVP) nasal spray or pill. It replaces ADH.
• Nephrogenic DI: Stop offending drugs (like Lithium if possible). Thiazide diuretics (paradoxically help). Low-salt diet.