The cat is not an animal that usually drinks a lot of water. Being a predator native to the desert, it is used to ingesting practically all it needs at the same time as it eats its prey. But of course, when you start living with humans, you no longer have any need to hunt, since they make sure that your feeder is always full and that you do not lack clean and fresh water in your drinker.
Even so, he usually has a hard time drinking. But sometimes, the furry friend drinks too much . When that happens, we should be concerned, as he might have polydipsia , a condition that often accompanies a serious illness and is almost always linked to another important sign: polyuria , meaning the cat urinates more frequently and in larger quantities.
What is polydipsia (and what is its relationship to polyuria)?
Polydipsia is a symptom that something in your cat's body isn't working properly. When a cat drinks too much water , it could be suffering from thirst. Clinically, a cat is considered to have polydipsia when it ingests more than about 100 ml of water per kilogram of body weight per day if it eats only dry food, or more than about 50 ml/kg/day if it eats only wet food. These values ​​are guidelines, but they give us an idea of ​​when thirst is truly excessive.
Polydipsia is almost always accompanied by polyuria , which is an increase in the amount of urine produced (more than 50 ml of urine per kilogram of body weight per day). It is important to differentiate it from pollakiuria (frequent urination in small amounts, typical of cystitis or lower urinary tract problems) and incontinence (involuntary loss of urine). In polydipsia-polyuria, the cat usually urinates a large volume , the litter box gets dirty more frequently, and the water bowl empties quickly.
Therefore, it is a problem that can appear at any age and in any feline, but those that live in a tense family environment, or where they do not receive proper attention, are especially vulnerable, since a poor general condition or sustained stress can also aggravate many of the diseases that present with polydipsia.
How to tell at home if your cat is drinking more than usual
Often, a cat with polydipsia begins to drink more gradually , so the change can go unnoticed. However, there are several very useful indicators that can alert us:
- The sand tray gets dirtier more than usual and requires us to change it more frequently, because the volume of urine is greater.
- The drinking trough empties quickly even if we haven't changed our cleaning routine or the type of food we eat.
- The cat meows for water Keep fresh water on hand or look for alternative sources (taps, glasses, puddles).
- Urinate more often and even outside their sandbox, sometimes on cold surfaces like the sink or bathtub.
If we want to be more precise, we can easily measure water consumption at home. To do this, we fill the water bowl with a known amount of water (for example, using a measuring jug), let the cat drink for 12-24 hours, and then measure what remains . Subtracting the two amounts will tell us how much the cat has drunk. If several cats live together, this measurement will no longer be as reliable, and the veterinarian will advise us on other ways to assess polydipsia at home.
What are the causes of polydipsia in cats?
There are several causes of this condition, the most common being the following, many of which are shared with polyuria. In most cases, polydipsia is secondary to primary polyuria (the cat urinates a lot due to an illness and, to compensate, drinks more) or is part of a more complex systemic condition.
- Diabetes mellitusIt is characterized by persistently or chronically high concentrations of glucose in the blood. The excess glucose is eliminated through urine, drawing water along with it (osmotic diuresis), causing the cat to urinate and drink more.
- Cushing's syndrome (Hyperadrenocorticism): This is caused by an increase in the hormone cortisol, which raises blood sugar levels and impairs the kidney's response to antidiuretic hormone. This can lead to... secondary polyuria and, consequently, polydipsia.
- Hypoadrenocorticism or Addison's diseaseThis refers to a reduction in the function of the adrenal glands, which then produce very little of the most important hormones, called glucocorticoids or mineralocorticoids. This condition can alter electrolyte balance and the kidney's ability to concentrate urine.
- HyperthyroidismHyperthyroidism is characterized by increased functional activity of the thyroid gland and excessive secretion of thyroid hormones. Cats with hyperthyroidism often have big appetiteThey are more active, can lose weight, and, by increasing metabolism, also increase water consumption and urine production.
- Acute kidney failureKidney failure is a rapid loss of kidney function due to kidney damage. The kidneys stop concentrating urine properly, so the cat urinates more liquid and compensates by drinking more.
- Chronic kidney failureThis occurs when the kidneys are damaged for a prolonged period and cannot filter the blood as they should. It is one of the most frequent causes of polydipsia in adult and senior cats.
- Hypercalcemia: high concentration of calcium in the blood, which can alter the response of the renal tubules to the antidiuretic hormone and produce significant polyuria.
- PyelonephritisKidney inflammation is the inflammation of the kidney and renal pelvis, usually caused by a bacterial infection. This inflammation alters the kidney's structure and can lead to polyuria and polydipsia.
In addition to these classic causes, the veterinarian will also consider other possibilities within the differential diagnosis of feline polyuria-polydipsia, such as:
- Central diabetes insipidus, in which the body produces little antidiuretic hormone (ADH), and nephrogenic diabetes insipidus, in which the kidneys do not respond well to ADH.
- Liver disease significant, which can alter many metabolic processes and the way the kidney handles water.
- Hormonal diseases Less frequent conditions, such as hyperaldosteronism or acromegaly, have also been associated with PU/PD.
- Use of certain drugs such as diuretics or corticosteroids, which can increase urine production and, consequently, thirst.
Therefore, polydipsia in cats is not a disease in itself, but a complex clinical sign that requires a careful search for the underlying cause in order to treat it correctly.
Factors that can increase thirst without serious illness
A cat drinking more than usual doesn't always mean it's seriously ill, although it's always best to consult a veterinarian . There are factors that can influence a cat's thirst, either occasionally or moderately:
- Environmental factorsIn hot weather, a cat may drink more water to stay hydrated, especially if it lives in very hot areas or in homes without good ventilation.
- Feed typeA cat that eats only dry food, which is dehydrated food, will need to drink much more water than a cat that eats canned food or a homemade diet rich in moisture.
- Activity levelA very active cat, who runs, plays, or has access to the outdoors, may need more water than one who leads a more sedentary life.
- Lactation: cats that nurse their kittens have increased water requirementssince part of the liquid is used for milk production.
Although these factors may justify a slightly higher consumption, if we notice that the increase in thirst is marked, sustained, or accompanied by weight loss, apathy, changes in hair, or other signs, we must go to the clinic without delay.
How is polydipsia diagnosed in cats?
If we notice our beloved cat has started drinking more water than usual and urinating more frequently, it's very important to take them to the vet as soon as possible. Diagnosing the causes of polyuria/polydipsia can be quite complex , so the veterinarian will follow a specific protocol.
The first thing they will do is a detailed history , that is, ask many questions about the cat's history: from when it started drinking more, changes in food, medications, possible toxins, changes in weight, behavior, etc. They will also ask, if possible, about the approximate amount of water the cat drinks and the amount of urine it produces.
He will then perform a complete physical examination , noting everything he observes (hydration status, mucous membranes, abdominal palpation, kidney size, heart and respiratory rate, temperature, presence of pain, masses, etc.).
Once there, the veterinarian will perform a complete blood and urine test . Measuring urine specific gravity is one of the first key tests to assess whether the kidneys are concentrating urine properly. If the urine is correctly concentrated but glucose is present (glucosuria), problems such as diabetes mellitus or renal tubular disorders will be suspected.
And if you're still not entirely sure, you can opt for these other tests:
- Abdominal ultrasound, to evaluate the size and structure of the kidneys, liver, adrenal glands, and other organs.
- Adrenal function test, such as ACTH stimulation test or tests for hyperadrenocorticism or hypoadrenocorticism.
- Bile acid stimulation test, to assess liver function when liver disease is suspected.
- Measurement of the Glomerular Filtration Rate (GFR), which more accurately indicates how well the kidney is filtering.
In some cases where a definitive diagnosis is not reached after initial and supplementary tests, more specific tests such as the desmopressin test or the water deprivation test can be considered . These tests help differentiate between central diabetes insipidus, nephrogenic diabetes insipidus, and primary polydipsia. These tests should always be performed under strict veterinary supervision, as they carry some risk if the animal has kidney disease or is severely dehydrated.
How is polydipsia treated in cats?
Treatment will depend on the underlying cause . There is no single drug that "cures" polydipsia, as it is only a symptom. Once the veterinarian has a diagnosis, they will tailor the therapy to each individual case.
Immediate treatment may include intravenous saline solution and diuretics if the cause is hypercalcemia or other acute metabolic disturbances. In very controlled situations, the veterinarian may also choose to withhold water from the cat for a short period to observe the effect on urine output, but this should never be attempted at home, as it could cause severe dehydration.
Also, to help the cat return to a normal life, it may be suggested that changes be made to its diet (for example, renal food or specific diets for diabetes), and medications may be recommended to help the kidneys continue functioning or to control hormonal diseases (hyperthyroidism, Cushing's disease, etc.).
In chronic conditions, such as chronic kidney disease, diabetes mellitus, or hyperthyroidism, therapeutic management is often conceptually simple but requires close monitoring to adjust dosages, control side effects, and adapt to each individual's progress. Blood and urine tests, and sometimes ultrasounds, will be repeated over time to assess the response to treatment.
Can polydipsia be prevented in cats?
Polydipsia is a problem that, while it cannot be 100% prevented, we can do some things to ensure the cat's health is not compromised and to detect any changes as soon as possible.
- Feed him wet cat food (cans) without grains or by-productsWith a minimum moisture content of 70%, the cat will ingest almost all the water it needs from its food, just as it did when it lived outdoors. Furthermore, its excellent quality allows for easy digestion, reducing the need to drink large quantities of water to compensate for a very dry diet.
- Always offer clean, fresh waterIt is essential that water is available at various points in the house, away from the sandbox, and that it is frequently renewed to encourage adequate consumption and to better observe if there are sudden changes in intake.
- Take care of it as it deservesAs their caregivers, we must be their companions and friends. We must dedicate time to them, play with them, and give them lots of love every day of their life. This makes it much less likely that they will suffer from stress or anxiety, factors that can worsen many chronic illnesses that involve polydipsia.
- Perform regular veterinary check-upsRegular checkups, especially in middle-aged and older cats, allow detect on time problems such as kidney failure, diabetes or hyperthyroidism, before polydipsia becomes very pronounced.
Observing how much water your cat drinks, how often they urinate, and their daily behavior is a valuable tool for detecting early signs of polyuria/polydipsia and other urinary problems. If you have any concerns, the safest course of action is always to schedule an appointment with your veterinarian so they can assess your cat and, if necessary, begin a comprehensive diagnosis and treatment plan tailored to your feline's needs.
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