Diabetes insipidus (DI) is a metabolic disorder characterized by excessive, extreme urination, and accompanied by undue thirst. It is either caused by impaired production of a hormone called ADH (anti-diuretic hormone) from the brain (central DI), or an impaired ability of the kidney to respond properly to the ADH (nephrogenic DI).

Central DI can occur if there is damage to the part of the brain that makes the ADH. Trauma or cancer would be potential causes of this kind of damage. Most cases are "idiopathic"; in other words, there is no known cause.

Nephrogenic (originating from the kidneys) DI is a very rare congenital disorder that also occurs for no known reason.

There is no apparent age, gender, or breed predilection for DI. Most cases occur in dogs; cats are rarely affected. As long as dogs with DI have unlimited access to water and are in an environment where excessive urination is not a problem, most dogs do fine and have an excellent life expectancy.

What to Watch For

Severe, excessive urination

Insatiable desire to drink water

Stupor, disorientation, lack of coordination, or seizures if a brain tumor is the primary cause

Diagnosis

Diagnostic tests are needed to rule out other common causes of excessive thirst and urination, including:

Complete medical history and physical examination

Complete blood count

Serum biochemistry panel

Urinalysis

X-rays or ultrasound

Bile acid test

Urine culture

Tests of the adrenal gland

Thyroid hormone test

Modified water deprivation test is the most important test for confirming a diagnosis of diabetes insipidus

Treatment

If therapy is necessary, treatment for diabetes insipidus may include the following:

Desmopressin acetate

Chlorpropamide

Thiazide diuretics

Salt restriction

Home Care and Prevention

Give medications as directed and make absolutely certain the dog has constant access to water.

As most cases of central DI are of unknown cause, that is idiopathic, there is no specific preventative care. Dogs with congenital nephrogenic DI should not be bred in case there is a genetic predisposition to the disorder.