Owners may become aware that their dog has suddenly begun to drink lots of water. The medical term for this condition is polydipsia. Excessive thirst in dogs may be the clue to many disorders, some only transitory, others of a more serious, chronic nature.
Dry feeding: A change of feeding may alter the dog’s drinking pattern. Wet food contains a lot of moisture, so dogs do not need to drink much at all.
A change from wet to dry feeding requires the absorption of far more water from the bowel. This is because moisture is extracted during the cooking process to ensure a long shelf life.
Salty foods: Some foods contain much more salt than others and stimulate an increased thirst. Salt alters the balance of fluids in the body. This acts as a vacuum of sorts.
If the salt content of the fluid surrounding cells is higher than inside the cells, more fluid is pulled from the cells, leading to a condition called hypernatremia. The brain then sends a warning of low body fluids and it is this that triggers the thirst response.
Diarrhea: Diarrhea has a high water content, so a temporary attack of diarrhea will be associated with an increased water intake. The two most frequent causes of diarrhea are a poorly balanced diet and worms.
It is a mistake to keep up the bread and milk type of food when the puppies have been weaned. Changing diet too quickly can cause shock to the digestive tract or irritate the stomach lining and lead to diarrhea. High-fat diets will also have a similar effect.
Infections: The first sign of a bacterial, viral or fungal infection is normally a fever or increased body temperature. This causes the heart to work harder and for excess heat to be lost as sweat via the paws and nose. Due to this extra moisture loss from the body, the dog will instinctively look to drink more water in an attempt to replace the lost fluids.
A simple course of antibiotics to treat the infection will also stop excessive drinking. As the infection is treated, the body temperature will drop and the dog will no longer lose the body’s water content via sweating.
Medications: Some medications cause the dog to drink more than usual. Corticosteroids, used to treat skin conditions or arthritis, have a marked effect when given in fairly high doses at the commencement of treatment.
Several other medications cause a dog to increase their water intake. Medication for heart failure, seizures and allergies all have this same common side effect. A veterinarian will always advise that extra water is available during the course of treatment.
Inflamed throat: Dogs with an inflamed throat or with tonsillitis will lap small quantities of water frequently while refusing solid food.
Water is easier and less painful to swallow and the cool temperature will help soothe them. The same is true if the inflammation is in the stomach. Cool water helps to relieve some of the discomforts.
Constipation: Dogs with long-standing constipation seem only interested in drinking copious amounts of water. Dogs are intelligent creatures and if they are struggling to pass bowel movements, they will instinctively drink more water.
Diabetes: Diabetes is a disorder of the carbohydrate metabolism of the dog caused by a deficiency of the hormone insulin.
Insulin is secreted by specialized cells in the pancreas. The function of insulin in the body is to convert excess glucose to carbohydrates which are stored in the liver for the future needs of the animal.
In a diabetic dog or cat, the daily energy requirements must be gained from the immediate intake of sugars. Any energy requirement not able to be met from the daily food supply must be supplied by the breakdown of fats.
The process is not as efficient as the normal breaking down of stored carbohydrates and over a long time not only does the dog lose weight despite an increased appetite, but the waste products of fat breakdown can cause certain toxic effects in the animal’s body.
Free glucose is excreted by the dog’s kidney cells and this requires much greater amounts of water.
Kidney disease: Kidney cells remove the waste products of metabolism and excrete them via the urine. Any impairment in their function is usually detected by the presence of protein in the urine.
As more kidney cells are affected the dog compensates for this lack of efficiency by drinking more water to flush the impurities with an increased flow of fluid. Eventually, an animal with nephritis will lose weight, but unlike the diabetic animal whose appetite is excessive, it gradually demands less and less food.
It is important to seek veterinary advice where there is a noticeable increase in water intake over a protracted period. Both nephritis and diabetes can be controlled if treatment and dietary changes are begun before the disease process has progressed too far.
Cushing’s disease: Cushing’s Disease is a condition caused by overactive adrenal glands. It’s usually due to a tumor on the gland itself or a brain tumor sending too many signals and causing the adrenal gland to produce much more than normal.
Certain steroid medications can cause Cushing’s disease if the dog takes the steroids long-term. The adrenal glands produce cortisol, which is a hormone required for several bodily functions to occur. An increase above the normal level causes several symptoms including increased urination and excessive thirst.
Body heat: A dog may experience an increase in body heat. This is common in places with hot summer months or if the dog has done more exercise than normal. In this instance, excessive drinking is not a concern and is simply the dog’s natural response to cool themselves.