Cat drinks a lot and urinates a lot

Your cat drinks a lot of water and pees a lot? Good that you noticed! Because these two symptoms are alarm signals for some of the most common diseases in cats (z.B. for chronic renal insufficiency or diabetes). So whenever you have the impression that your cat is drinking or urinating more than before, you should get to the bottom of the cause!


If the water bowl gets empty faster than before or suddenly there are more or bigger lumps in the litter box, it is usually time for a visit to the vet. Because behind this there are often two symptoms, which veterinarians call Polyuria and polydipsia (abbreviated: PU/PD) denote.

It says Polydipsia (Greek for "much thirst") for a pathologically increased thirst and increased fluid intake. A cat affected by polyuria so drink a lot of water.

Polyuria (Greek for "a lot of urine"), on the other hand, refers to a pathologically increased urine production and an excessive urination. Affected cats pee more often and more (recognizable by many large lumps in the litter box). Overall, the daily amount of urine is thus larger than normal.

Because cats that drink a lot also have to pee more – and vice versa, cats that urinate a lot are also more thirsty – the two symptoms almost always come together symptoms almost always come together in front of.

Therefore, it is practically impossible to determine at first sight whether the real problem of a cat is "drinking a lot" (polydipsia) or "peeing a lot" (polyuria). Veterinarians therefore speak of "symptom complex polyuria/polydipsia".

Because the affected cats have to pee so often, it can also be that the cat has a next to the litter box (z.B. on carpets or in bed) makes. This uncleanliness is not a behavioral problem, but a consequence of the symptoms polyuria/polydipsia.

Attention, risk of confusion!

Polyuria/Polydipsia can easily be confused with other symptoms. This is the case, for example, with Pollakisuria also frequent peeing – but only small amounts of urine are passed at a time (sometimes only a few drops). The total amount of urine excreted throughout the day is not increased. In addition, the affected cats often show pain when urinating.

The PU/PD can z.B. but also with a Urinary incontinence be confused. In this case, the cat unintentionally loses urine – which can give the impression that he often or. pees a lot. However, the total amount of urine is not increased with incontinence. In addition, the cat does not drink more water than before.

It is very important to know which symptom is present in a cat. Depending on the condition, other diseases and problems may be the cause. Sometimes, however, it can be difficult to tell what symptom is behind the cat’s "peeing a lot". That is why we have a test created to help you identify the "right" symptom:

(The test opens in a new tab, so you still stay on this page.)

How much water and urine is normal for cats?

It is not easy to determine what is normal and what is abnormally increased. Although there are generally accepted maximum values, but unfortunately not all animals follow the textbook. That is individual maximum values of the respective animals may be lower. So it can be that a cat drinks less than the maximum amount, but its water intake is nevertheless already increased pathologically.

So the rule is: if your cat a cat that drinks or pees much more than before, this could already be an indication of a disease. If the drinking quantity of your cat against it above the given maximum this is a clear sign that something is wrong and that polyuria/polydipsia is present.

But also here applies – no rule without exception! In situations where the body has increased need for fluids has (z.B. in high heat, in fever, in stress situations) the "healthy" drinking amount can be higher. The same is true for conditions in which much fluid is lost goes, as z.B. in case of vomiting or diarrhea. Even with a Change from wet food to dry food can lead to an increase in the amount of fluid drunk, without any underlying disease

In general normal Drinking amount a cat that eats canned food, i.d.R. less than 20 ml per kilogram of body weight per day is. The generally accepted upper limit of a "healthy" water intake is at maximum 80-100 ml per kilogram of body weight per day (for a 4 kg-heavy cat, this means max. 400 ml per day).

The normal, "healthy" amount of urine output of a cat is a maximum of 50 ml per kilogram of body weight per day (so for a 4 kg cat max. 200 ml per day).

How does the increased thirst and urine production occur??

Fluid regulation in healthy cats

The fluid content of the blood is very closely controlled and regulated by the body – because a lack of fluid can have serious consequences and even lead to death. For this purpose in the body of the cat are several "Measuring stations". There, the fluid content of the blood and the concentrations of certain salts (electrolytes) in the blood are constantly checked.

If the fluid content is too low or. the electrolyte concentrations are too high, certain reactions triggered, to restore the correct "fluid level" of the blood.

So on the one hand in the brain of the cat, in the so called "brain". Thirst Center, triggered a feeling of thirst. This causes the cat to drink more. As a result, more fluid enters the intestine through the stomach. There, the fluid is absorbed through the intestinal mucosa and enters the bloodstream, where it increases the fluid content of the blood.

On the other hand, however, the sensors also trigger the release of a certain messenger substance, the so-called. antidiuretic hormone (ADH). This messenger substance tells the kidneys that less water should be excreted with the urine. less urine is produced, but it is more concentrated (recognizable by its dark yellow color). As a result, less fluid is lost and the fluid level of the blood increases.

Disturbed fluid regulation

If your cat drinks and pees a lot for no apparent reason, this is fine tuned fluid regulation disturbed in her.

As already mentioned, a cat that urinates a lot must drink more (otherwise it would dehydrate). And on the other hand, a cat that drinks a lot also has to pee more often. That means, behind the symptom complex "much drinking and much peeing" can be two different main problems stuck.

Primary polydipsia

In case of primary polydipsia increased thirst is the main reason for "drinking a lot and peeing a lot". In this case i.d.R. damage or pathological stimulation of the thirst center in the brain.

Primary polyuria

However, in the vast majority of affected cats, the symptom complex "drinking a lot and peeing a lot" is due to primary polyuria (an increased urine output). The disturbance can lie at different places of the liquid regulation:

  • The kidneys can damaged the cat may be unable to perform its functions adequately. As a result, water and electrolytes are lost unhindered (as in the case of a leaky sieve). This occurs, for example, in the case of chronic renal insufficiency.
  • The recovery of certain soluble substances from the urine (which should actually remain in the body) may be disturbed. For example, in diabetes mellitus, there is a greatly increased concentration of sugar in the blood. This is so high that the kidneys can not keep up with the recovery. The sugar molecules thus enter the urine in large quantities – and in the process draw a great deal of fluid with them, which is also excreted. Something similar can also happen with other substances (z.B. sodium or urea).
  • The disorder can also occur in antidiuretic hormone (ADH) If there is too little of this substance or if its effect on the kidneys is disturbed, there is also excretion of large amounts of fluid.

Causes of polyuria/polydipsia in the cat

The most common cause for the picture "cat drinks a lot and urinates a lot" (polyuria and polydipsia) are

  • chronic renal insufficiency,
  • hyperthyroidism (hyperthyroidism) and
  • diabetes mellitus (diabetes)

Chronic renal insufficiency

Chronic renal insufficiency is one of the most very common disease, in which kidney function is progressively lost over a long period of time (weeks, months or years). Only when large parts of the kidneys have already been destroyed, does the classic symptoms of the disease: the cat drinks a lot and releases large amounts of urine, eats only meagerly or no longer at all, loses weight or. patient even loses weight and is overall in a rather poor general condition. Often the diseased cats also vomit.

hyperthyroidism (hyperthyroidism)

In hyperthyroidism (overactive thyroid gland), this is a pathologically increased production of thyroid hormones. The affected cats can in addition to drinking a lot and urinating a lot u.a. show the following symptoms: an increased, almost insatiable hunger (polyphagia) with simultaneous Weight loss (which can lead up to emaciation), Vomiting, unkempt coat and hairless skin areas (often "patchy"), nervousness to Hyperactivity and sometimes a palpable nodule in the front of the neck (= the pathologically enlarged thyroid gland).

Diabetes mellitus (diabetes)

Diabetes is, together with hyperthyroidism, one of the most common hormonal diseases of cats. Due to a lack of insulin there is a pathological increase of the blood sugar level. In addition to polyuria and polydipsia, most cats also show increased, almost insatiable Hunger (polyphagia) with simultaneous mild Weight loss.

Often changes Behavior of the diseased cats also: they seem apathetic and do not groom themselves as much. As a result, often develops a dull, shaggy coat. In some cats there is also a reduced jumping ability and lead to weakness of the hind legs. This can even lead to the cats’ heels (hocks) touching the ground when standing and walking.

Other causes of polyuria/polydipsia (PU/PD) in cats include

  • Various drugs
  • glucocorticoids (z.B. cortisone, prednisolone, dexamethasone)
  • diuretics (drugs for dehydration)
  • Anticonvulsants (drugs used to treat epilepsy and seizures)
  • mannitol or glucose solution
  • Poisoning, z.B. with antifreeze (ethylene glycol) or certain plants such as daffodils
    (z.B. as a result of poisoning, in the case of infectious diseases, after an undersupply of oxygen to the kidneys – e.g.B. after anesthesia)
  • Cushing’s syndrome (hyperadrenocorticism, "Cushing’s disease"; in this case there is an overproduction of endogenous cortisone)
  • Hypokalemia (too little potassium in the blood)
  • Hypercalcemia (too much calcium in the blood), z.B. as a result of hyperfunction of the parathyroid gland (Hyperparathyroidism) or in case of tumors (z.B. in lymphomas and anal pouch carcinomas)
  • Large amounts bacterial toxins (from Escherichia coli = E. coli) in the body, z.B. At
  • Kidney pelvis inflammation (pyelonephritis)
  • Uterine suppuration (pyometra)
  • blood poisoning (sepsis)
  • glomerulonephritis (certain type of kidney inflammation in which the so-called. renal corpuscles are affected)
  • After successful removal of a Urethral obstruction (z.B. By urinary stones) (postobstructive diuresis)
  • Low sodium or low protein Feeding
  • Liver disease
  • Liver failure
  • Liver inflammation (hepatitis)
  • Portosystemic shunt (a vascular malformation in which blood no longer flows through the liver and therefore is not detoxified)
  • Acute liver failure
  • diseases of the brain
  • Trauma (injury)
  • inflammation of the brain (encephalitis)
  • Addison’s syndrome (adrenal insufficiency, hypoadrenocorticism, "Addison’s disease")
  • diabetes insipidus (disease in which there is a deficiency or insufficient action of antidiuretic hormone)
  • Psychic conditional (in stressful situations or as a habitual "tic", very rare in cats)

Attention: As mentioned above, cats may have a increased need for fluids have a lot of drinking because of this, z.B. in very hot weather, fever or stressful situations. Even if the cat has much fluid lost goes (like z.B. vomiting or diarrhea) she will drink more than usual.

However, this increased water intake is not pathological, but, on the contrary, a useful mechanism to compensate for the lack of liquid. Cats that drink more for these reasons, however, i.d.R. do not show polyuria, i.e. do not urinate more than usual.

Then you should go to the vet

as quickly as possible you should consult a veterinarian if:

  • The symptoms are very sudden and/or your cat seems very weak, apathetic or "sick"
  • Poisoning cannot be ruled out
  • Other symptoms, such as severe vomiting or diarrhea, occur

If you feel that your cat is drinking and/or urinating more than usual, but is otherwise doing well, you can first try Drinking amount of your cat for 3-5 days to determine. So measure the amount of water you give your cat in the bowl in a measuring cup. After 24 hours, measure how much fluid is left in the bowl. The difference gives the amount of water drunk.

In order for you to assess the amount of drinking as accurately as possible, there are a few points to keep in mind:

  • If you own more than one animal: It is important that the cat in which the amount of drinking is to be determined, only from the measured bowl drinks and otherwise no animal access to this bowl has.
  • The cat should only from water sources drinking in which previously determined the amount of water was. She should not drink from puddles, ponds and other bowls during this time. If necessary, outdoor cats should be kept in the house during this time.

If the daily drinking amount is Upper limit exceeds 80-100 ml of water per kilogram of body weight, there is a high probability that one of the above-mentioned diseases is behind it. In this case necessarily a veterinarian be visited.

As described above Upper limit of 100 ml water per kilogram per day however not set in stone. In some cats a water intake of e.g. 60 ml per kilogram per day may already be pathologically increased. So if you have the strong impression that your cat is drinking or peeing a lot (or at least more than before), to be on the safe side you should a visit to the vet plan – or at least a have the cat’s urine sample examined!

Examinations and diagnosis

First, the veterinarian will give you some Questions determine (z.B. since when your cat has been drinking heavily, whether it has been given medication recently, or whether any other symptoms have been observed) and a general clinical examination carry out.

In order to check whether you are correct in your suspicions, your veterinarian will in the next step take a urine sample – preferably collected at home (see section "What you can do yourself") urine sample examine your cat.

In this case, the so-called "urine-specific weight" determined. This value can be used to determine whether the urine is sufficiently concentrated.

If the USG above 1.035, if the urine is sufficiently concentrated and there is no polyuria (exception: false high USG due to glucose in the urine). So either it was a "false alarm" or there is another similar looking problem (z.B. pollakiuria, incontinence, uncleanliness).

If, on the other hand, the urine-specific weight lowers is present (USG< 1.035, the urine is "too thin"), a "real" polyuria is present.

In the case of increased excretion of sugar molecules via the urine, as is typical in diabetes mellitus, the urine-specific weight may be normal, although polyuria is present. Therefore the veterinarian in many cases besides measuring the urine specific weight immediately arrange for further analysis of the urine.

Investigations to determine the cause

If it is clear that polyuria is indeed present, the veterinarian will perform various tests to Cause to find out the reasons for "drinking a lot and peeing a lot.

So he will Urine sample will be examined in more detail (it may be necessary to take some fresh urine sterilely from the bladder for this purpose). He can then determine, for example, whether the affected cat excretes too much sugar with the urine (as in diabetes mellitus).

Most of the time the veterinarian will also blood sample examine. This allows him to check, among other things, the kidney values, the inflammatory cells and various blood salts (such as calcium and potassium) and see whether, for example, a chronic renal insufficiency or a strong inflammation is behind the problem. He may also send a blood sample to a laboratory for a Thyroid hormones to control.

It may also be that your veterinarian has a ultrasound examination of the abdomen will be performed, z.B. to better evaluate the kidneys.

Sometimes, however, it is not so easy to determine the correct diagnosis. That is why your veterinarian may also other tests and examinations will need to perform.

You can do it yourself

As described above in the section "Then you should go to the veterinarian", you can already determine at home the average daily Water intake determine your cat.

However, before the appointment with the veterinarian, you may want to check at home collect urine – urine specific gravity (USG) test provides the highest possible information. At the vet, many cats are so stressed that they release a lot of cortisone (a stress hormone) – and this can lead to a false-low USG. Urine collected at home is the best way to find out if the urine is really too diluted (i.e. if there is polyuria).

Cat litter for obtaining a urine sample

Ideally collect it via 2-3 days in each case the Morning urine (i.e. the first urine of the day) as well as a further urine sample per day. Admittedly: this is not easy.

But also a single urine sample (ideally morning urine) is already very helpful. You can try to stop the urine from flowing when you urinate with a shallow dish or a saucer to collect (this actually works surprisingly well). Alternatively there are also special cat litter made of plastic granules that do not bind the urine, so that it can easily be sucked up with a pipette (z.B. Henry Schein UriGrid pearl litter*, Catrine cat urine collection kit*, Katkor cat litter*, Uro-Tec K).

It is best to fill the collected urine into special urine cups – your vet will certainly be happy to provide you with some. Otherwise also other leak-proof vessels, like z.B. clean, dry jam jars.

You should then label the urine samples with the date and evtl. time labeled and until the appointment with the vet in the Refrigerator store (do not freeze).

By the way, you can also find a detailed guide and tips and tricks on how best to get your cat’s urine here: urine sample from cats – this is how it works!


Nelson, R., Couto, C.: Internal Medicine of Small Animals, 2. German edition. Urban& Fisher, 2010.

tilt, R.: Differential diagnoses internal medicine in dogs and cats. Enke, 2009.

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