Accepted Answer

Hi there XXXXXXXXX,

 

Thank you for your question regarding your 9 year old Lab mix who has been drinking excessive amounts of water and urinating frequently as a result. There are quite a number of conditions that can cause this symptom in the dog and it is usually also tied along with excessive urination as is the case with your girl. We call this syndrome PU/PD in the Veterinary world - or polyuria (excess urination) and polydypsia (excess thirst). There are quite a number of different diseases associated with PU/PD and most of them are much more likely in a middle aged to older dog such as your Lab mix. The main Veterinary list of diseases associated with PU/PD are listed below:

 

"Diabetes insipidus: Central (decreased production of vasopressin (ADH)) or nephrogenic (decreased ADH receptors or decreased sensitivity to ADH in the renal tubules) diabetes insipidus causes PU/PD.

Hyperadrenocorticism results in excessive amounts of cortisol that can block the effect of ADH on renal tubules.

Hypoadrenocorticism causes loss of sodium, the major medullary solute. Hyperkalemia may interfere with ADH function.

Escherichia coli infections, as seen with some pyometras, often produce endotoxins believed to interfere with ADH activity.

Psychogenic polydipsia increases fluid load promoting diuresis. It may result in renal medullary solute washout. Polydipsia as the primary cause of PU/PD is not as common as polyuria. Psychogenic polydipsia can be induced by stress. Damage to the hypothalamus may overstimulate the thirst center. Certain foods (salty, spicy) encourage excessive intake of fluids.

Hepatic failure can produce PU/PD via poorly understood mechanisms. Theories include an increase in glucocorticoids, mineralocorticoids, or renin. Another theory is that there is decreased ammonia conversion to urea, a major medullary solute.

Hypokalemia interferes with renal tubular function and ADH sensitivity. It can be caused by chronic renal disease, excessive use of furosemide, and nutritional deficiency.

Hyperthyroidism promotes diuresis by increasing sensitivity to catecholamines, increasing renal medullary blood flow and medullary washout. Hyperthyroidism is uncommon in the dog, but common in the cat.

Hypercalcemia associated with malignancy, cholecalciferol toxicity, or hypoadrenocorticism can cause renal damage or interfere with ADH function.

The use of diuretics, certain drugs, and intravenous fluid therapy promote diuresis.

Pheochromocytomas are catecholamine producing tumors that produce PD/PU by increasing renal medullary blood flow and medullary solute washout.

Polycythemia may produce PD/PU by causing a decrease in ADH production."

 

As you can see there is a large list and you need to work through these with your Vet. It really would be a good idea to get your dog to the Vet for a full check up as well as blood and urine tests to help ascertain the true cause of the PU/PD. Please talk to your Vet about the excessive thirst your dog has at the moment. If I can be of any further assistance to you, please be sure to reply won't you. Best of luck with your lab mix girl and please keep me updated with your progress.

 

Thank you and now please click ACCEPT.

Kind Regards,

XX X X Edwards

Expert:	Dr M D Edwards
Pos. Feedback:	99.7 %
Accepts:
Answered:	3/22/2009

Dog Veterinarian

Veterinarian - BVSc (DVM equivalent) - Webmaster & Head Veterinarian for www. onlinepetdr.com