Very Common
OTHER DIAGNOSES CONSIDERED
Other conditions or ailments that might also need to be ruled out by a vet.
Diagnosis
Conditions or ailments that are the cause of a problem that you see - your observation.
Your vet may diagnose
Diabetes Insipidus, DI
Synonyms: Water Diabetes, Psychogenic Polydipsia/Polyuria, PU/PD
Summary
This is a very rare condition in which there is failure of the kidney's ability to concentrate urine caused by lack of a hormone (Anti-Diuretic Hormone - ADH, or vasopressin).
Loss of kidney concentrating ability happens either because of a lack of Anti-diuretic Hormone (ADH) or by the kidney's insensitivity to ADH. ADH is normally produced in the hypothalamus and stored in the pituitary gland. If these areas of the brain are damaged, then it may not be produced. This is extremely rare in the horse.
ADH normally causes the concentrating parts of the kidney to take up water when the body's hydration reaches a certain level. If ADH is not produced by the body, or the kidney cells cannot react to it normally for some reason, then excessive water is just lost in the urine. Horses with this condition must drink large quantities of water (polydipsia) to keep pace with the losses, and they urinate frequently (polyuria). This condition is not related to other types of diabetes. These conditions just share the name, which relates to the excessive urination seen in both conditions.
ADH cannot be measured readily in the horse. The diagnosis requires ruling out of other conditions that result in the inability to concentrate urine and retain water. This is done using a water deprivation test.
The treatment is injection of ADH (vasopressin). This is generally impractical in the horse and so the prognosis is poor.
Loss of kidney concentrating ability happens either because of a lack of Anti-diuretic Hormone (ADH) or by the kidney's insensitivity to ADH. ADH is normally produced in the hypothalamus and stored in the pituitary gland. If these areas of the brain are damaged, then it may not be produced. This is extremely rare in the horse.
ADH normally causes the concentrating parts of the kidney to take up water when the body's hydration reaches a certain level. If ADH is not produced by the body, or the kidney cells cannot react to it normally for some reason, then excessive water is just lost in the urine. Horses with this condition must drink large quantities of water (polydipsia) to keep pace with the losses, and they urinate frequently (polyuria). This condition is not related to other types of diabetes. These conditions just share the name, which relates to the excessive urination seen in both conditions.
ADH cannot be measured readily in the horse. The diagnosis requires ruling out of other conditions that result in the inability to concentrate urine and retain water. This is done using a water deprivation test.
The treatment is injection of ADH (vasopressin). This is generally impractical in the horse and so the prognosis is poor.
my vet's role
Diagnostics Used
These are tests that might be helpful to make this diagnosis or further characterize the condition.
Treatments May Include
These treatments might be used to help resolve or improve this condition.
PROGNOSIS AND RELEVANT FACTORS
Poor.my role
I might observe
You might make these observations when a horse has this condition.
Very Common
Skills I Might Need
I might need these skills if my horse has this diagnosis.
Questions To Ask Your Vet:
- How did you reach this diagnosis?
- Are the other common diagnoses associated with loss of urine concentrating ability ruled out?
Related References:
Higgins AJ, Snyder JR eds. The Equine Manual. 2nd Ed. Edinburgh: Elsevier Saunders 2006.