There are 3 types of canine diabetes. They are diabetes mellitus, diabetes insipidus and canine gestational diabetes. Diabetes mellitus is the most common form, while diabetes insipidus is quite rare in dogs. Diabetes insipidus, also known as water diabetes, can afflict dogs of all ages, sexes or breeds.
Canine Diabetes Insipidus
There are two types of canine diabetes insipidus. Central diabetes insipidus is caused by decreased production of the antidiuretic hormone (ADH) by the pituitary gland. This hormone, also known as vasopressin, regulates the kidneys' ability to absorb water and deficiency of the hormone causes water imbalance in the body. Nephrogenic diabetes insipidus is caused by the kidneys' failure to respond to the ADH produced in the body. The disease impairs the body's ability to maintain water balance and can be serious if left untreated, as it can cause dehydration and even death.
Symptoms of Canine Diabetes Insipidus:
- Diluted and clear urine
- Excessive urination (polyuria)
- Excessive thirst (polydipsia)
- Dehydration
- Disorientation
- Electrolyte imbalance
- Low specific gravity of the urine
- Seizures
- Loss of weight although there is an increase in appetite
- Coma
Causes of Canine Diabetes Insipidus
Canine diabetes insipidus can be idiopathic in nature or caused by congenital defects. Central diabetes insipidus can also be caused by trauma to the brain or a tumor in the brain or pituitary gland. Nephrogenic canine diabetes insipidus can arise due to metabolic disorders, trauma to the kidney, kidney disease or it may be related to the administration of certain drugs.
Diagnosis of Canine Diabetes Insipidus
The vet will perform a physical examination, evaluate the dog's medical history, take urine and blood tests and conduct X-rays during diagnosis. Abdominal ultrasonographies are also performed in some cases. Since the symptoms of diabetes insipidus are similar to those of other diseases such as diabetes mellitus, Cushing's disease, liver disease, kidney disease, hyperadrenocorticism and hyperthyroidism, the vet may also perform a CT scan, a thyroid hormone test and an adrenal gland test to rule out these diseases.
Additional Tests
Diagnosis of polyuria and polydipsia is done by performing tests such as CBC, serum biochemistry panel and urinalysis with bacterial culture. Water deprivation test and response to administration of synthetic vasopressin can help in the diagnosis of diabetes insipidus. The water deprivation test helps the vet diagnose whether the disease is central diabetes insipidus or nephrogenic diabetes insipidus.
Administration of synthetic vasopressin can confirm central diabetes insipidus, because this hormone will cause a decrease in polyuria and polydipsia. There will also be a simultaneous increase in the specific gravity of the urine. If central diabetes insipidus is diagnosed, the vet may suggest neoplasia of the pituitary gland or the hypothalamus, to rule out the presence of a tumor in these areas.
Treatment
Central diabetes insipidus is treated with the administration of desmopressin to replace low amounts of ADH. Conversely, nephrogenic diabetes insipidus is treated with medications designed to increase concentration of the urine such as thiazide diuretics, chlorothiazide or chloropropamide.
Diabetes insipidus is a condition that, although not curable, can be successfully managed if diagnosed and treated in time. Hence, it's imperative that you seek medical help as soon as your pet has symptoms related to this condition.