Diabetes insipidus is a disease that results from the body's inability to directly reabsorb water in the kidneys. A person with diabetes insipidus makes large volumes of urine and is often dehydrated and thirsty as a result. Electrolyte imbalance is commonly associated with diabetes insipidus since various electrolytes, normally reabsorbed together with water, are also lost in the urine.
Causes
Antidiuretic hormone (ADH) is the primary hormone involved in the direct reabsorption of water in the kidneys; it is produced in the brain. Any condition that interrupts the brain's ability to make and release ADH, including surgery, brain tumor, head trauma and brain infections such as meningitis and encephalitis, can cause diabetes insipidus. Lack of response by the kidneys to ADH as a result of damage by drugs, including lithium and tetracycline, can also cause diabetes insipidus.
Symptoms
Most symptoms of diabetes insipidus are related to electrolyte imbalance and dehydration. In diabetes insipidus, there is excess loss of electrolytes, which include potassium and calcium. Fatigue, muscle pains and headaches are symptoms that occur in relation to electrolyte imbalance. Dehydration results in increased heart rate, low blood pressure, weight loss, fever and dry mouth.
Associated Complications
Hypernatremia is the most common electrolyte imbalance associated with diabetes insipidus. Hypernatremia, in this case, is a combined effect of excess water loss and increased sodium reabsorption in the kidneys. Excess water loss results in low blood volume; when blood volume is low, the body attempts to correct the problem by increasing the reabsorption of sodium in the kidneys.
Treatment and Management
To treat diabetes insipidus, it is important to identify what organ is the source of the problem. When the problem is caused by the brain's inability to produce ADH, treatment involves the administration of desmopressin -- a drug that acts like ADH in the body. Desmopressin decreases urine formation and, therefore, increases blood volume and helps in correcting electrolyte imbalance. Hydrochlorothiazide is used as treatment when the kidneys are unresponsive to ADH; hydrochlorothiazide improves the kidneys sensitivity to ADH.
