It is normal for a cat to drink more water if it is on a dry diet. Cats also drink more when water is lost from the body for example if a cat has diarrhoea and this is a normal physiological response. Increased thirst however can also be a sign of underlying illness especially in older cats and it is important to monitor your cat to see if he is drinking more as if caught early, most of these conditions can be managed to help prolong your cat’s life
Kidney disease – usually due to chronic damage to the kidneys but can be immediate eg with antifreeze poisoning. Often starts with increased thirst followed by a reduced appetite and subsequent weight loss. Blood samples confirm an increase in the kidney enzymes urea, creatinine and phosphorus at varying levels. Your cat is likely to need a diet change to reduce the amount of phosphate given to him in food and provide a smaller amount of high quality protein to reduce the work that the kidneys have to do to cope with waste products. Injections may be given to help prevent weight loss from muscle breakdown and to replace B vitamins that are lost.
Some cats are put on tablets to help increase the blood flow through their kidneys and new products are on the market to help remove phosphates from normal cat food and stop them being absorbed by your cat when he eats. Sometimes cats need to be hospitalised and put on a drip, especially in cases of poisoning.
Hyperthyroidism – due to over activity of one or both thyroid glands in the neck and is very common in cats over 12 years old. Thyroid glands control the metabolic rate so hyperthyroid cats are often overactive, eat and drink a lot but lose weight dramatically. Heart failure occurs as the condition develops as the heart rate is too high and causes strain on the heart muscle. Hyperthyroidism is diagnosed by blood sampling with or without a goitre (swelling of the thyroid gland). Treatment includes tablets, surgical removal of the thyroid glands or radiotherapy.
Diabetes mellitus – due to a decreased production of the hormone insulin by the pancreas or a resistance to is effects around the body. This causes an increse in blood glucose levels and an accumulation of toxic substances called ketones. The glucose level in the blood is so high it leaks through the kidneys into the urine and can be tested for with a urine dip test strip. Treatment involves weight control, mangement of diet and twice daily insulin injections.
Remember, cats can obtain water from various sources including dripping taps, goldfish bowls, toilets, the dog bowl, puddles as well as their own bowl so if you constantly see your cat drinking from different areas it may be worth getting him checked out by your vet incase there is a problem.