The term polydipsia refers to excessive thirst. We see this as an increase in the amount of water being drank, which in turn usually leads to polyuria, which is means your cat is urinating more often and a larger volume.

 

These changes may be very subtle and slowly progressive or quite obvious.  You may observe an increase in the amount of wet litter in a cat's litter box or even accidents outside the litter box. Some cats may begin drinking from a dripping faucet in the sink or from an open toilet bowl. However, if you want to determine exactly how much your cat is drinking, allow him only one source of water and subtract the amount left in the bowl after 24 hours from the amount you put in originally.  On average, cats take in about 2 ½ cups per day for a 10 pound cat. This includes any water that is taken in from other sources such as from canned food.

 

If you determine that your pet is drinking excessively or just think it’s more than usual, make an appointment with your veterinarian because polyuria and polydipsia (drinking and urinating more) can be an early sign of a serious disease. These can include: kidney failure, diabetes mellitus, hyperthyroidism (overactive thyroid), liver disease, electrolyte abnormalities, pyometra (uterine infection), other less common endocrine disorders and diabetes insipidus. 

 

Several diagnostic tests may be needed to determine the cause of your cat’s polyuria and polydipsia because many different diseases can cause these signs.  Any visit to your vet should begin with a complete medical history and thorough physical examination.  Initial testing may include: measurement of water intake at home, complete blood count (CBC), blood chemistry tests (including electrolytes), urinalysis, urine culture and sensitivity, thyroid hormone (T4) concentration and abdominal x-rays or ultrasound.

 

In older cats, the three most common disease conditions seen in practice that cause polyuria and polydipsia are kidney failure, diabetes mellitus and hyperthyroidism.

 

Diabetes mellitus’ diagnosis is based on high blood glucose concentration and the presence of glucose, and often incompletely broken down fat products called ketones in the urine. This disease is very treatable long term.  Initial treatment depends on the severity and may include hospitalization with intensive fluid and electrolyte therapy in conjunction with administration of short-acting insulin or outpatient management with long-acting insulin.

 

Kidney insufficiency or failure’s diagnosis is based on serum biochemistry tests and urinalysis.  Treatment is based on rehydrating the cat, trying to slow the progression of the kidney disease by dietary modification and treating complications such as hypertension, nausea and urinary tract infection.

 

Hyperthyroidism’s diagnosis is based on measurement of thyroid hormone concentration via bloodwork.  Difficult cases may require specialized blood tests or imaging. Treatment consists of drug therapy or radiation or less commonly surgery.  This disease is also very treatable long term. Treatment with radioactive iodine ("I-131") will require referral to a specialty clinic or teaching institution in your area.

 

Optimal treatment of any persistent medical condition depends on establishing the correct diagnosis. The symptom group polyuria and polydipsia has many different potential causes, and it is important to identify the underlying cause before beginning treatment.  Please visit your veterinarian as soon as you notice any changes because with an early diagnosis you often get a better outcome.