Excessive Urination in Cats

According to FelineDiabetes.com, a cat weighing about 10 lbs. should urinate roughly 6 oz. a day or less, drinking about 6.75 oz. of water. Cats have their own habits, but drinking and urinating far beyond these quantities may have underlying medical issues that need attention, especially if the cat starts urinating outside the litter box. Blood analysis is most often used in diagnosis.

  1. Urinary Tract Infection

    • A cat with a urinary tract infection (UTI) may only seem to urinate more because it frequents the litter box without producing much urine. It's painful, and the cat may lick obsessively or urinate on smooth, cool places like the bathtub. The urine may be bloody.
      UTIs have many physical or emotional causes, which a veterinarian should diagnose, because urinary blockage can be fatal. If there's no obstruction like stones, UTIs may be cured with antibiotics. Blockages may require catheterization or surgery. Special diets keep blockages from reforming. Cats prone to UTIs should drink lots of water and urinate more to stay healthy.

    Diabetes

    • Cats develop insulin-dependent diabetes mellitus or diabetes insipitus, which is far less common. With diabetes mellitus, the body doesn't process insulin properly, and the cat secretes sugar in its urine, which causes excessive thirst and urination. It's common in older, overweight male cats, or it may be genetic. Treatments include oral or injectable insulin and a measured high-protein diet. Too much insulin causes a drop in blood sugar (hypoglycemia) that can be life-threatening.
      Diabetes insipidus occurs when the hypothalamus insufficiently produces an anti-diuretic hormone, or the kidneys stop responding to it. Toxins don't concentrate in the urine, so the kidneys need more water. This condition doesn't always require medical treatment if the cat can compensate by drinking plenty of water.

    Kidney Failure

    • Cats with slowly failing kidneys also have diminished capacity to concentrate urine, so they drink more. Kidney failure is detected through abnormally high BUN and creatinine levels in the blood.
      To assist kidney function, subcutaneous fluid is often given to keep the cat sufficiently hydrated, and the extra fluid causes more urination.

    Liver Disease

    • Excessive thirst and urination may also indicate liver disease. One of the liver's many functions is to convert ammonia, which forms when protein is metabolized, into urea.
      Cats develop fatty liver disease by not eating, which overloads the liver when the body starts breaking down fat for energy. Other conditions may be cancer, toxin damage and biliary system inflammation. Veterinarians detect liver disease through high levels of bilirubin and the enzymes ALT and AST.

    Hyperthyroidism

    • Hyperthyroidism, most frequently seen in older cats, also causes excessive drinking and urinating. Often, a noncancerous tumor enlarges the thyroid gland, which then produces too much T3 and T4 hormones. The cat may be treated with medication or radioactive iodine therapy or have the thyroid gland surgically removed.
      Uncorrected, hyperthyroidism can lead to heart disease, and it may camouflage kidney problems. Vets look for elevated T4 to detect this condition.