Is Your Cat Peeing Outside the Litter Box and Throwing Up? 

Since felines are somewhat mysterious creatures, the range of diseases they could catch is downright perplexing to most cat owners. From all sorts of worms to more dangerous conditions such as FIV, our kitties can get quite sick if we’re not paying much attention to them. But how about a cat peeing outside the litter box and throwing up? 


These two symptoms are so particular that it’s somewhat rare for a cat to experience them both. However, there are a few conditions that are followed by vomiting and failure to reach the litter box in time. Unfortunately, most of them require immediate attention and proper care to avoid complications and premature death.


Cat Peeing Outside the Litter Box and Throwing Up

Cat Peeing Outside the Litter Box and Throwing Up: 3 Common Diseases


  1. Chronic Renal Failure

  2. Hyperthyroidism

  3. Diabetes Mellitus


If we catch our cat peeing outside the litter box and throwing up frequently, there may be a need to go to the vet right away, as its kidneys might be shutting down.


Kidneys in and of themselves are too important in a cat’s life to be ignored. After all, their main job is to regulate blood pressure, remove waste, stimulate the bone marrow to produce more red blood cells, and generate hormones. That said, kidney failure can be either acute or chronic.


When it’s acute renal failure, the onset of the condition is sudden and happens in mere days or weeks. It is often a result of:


  • blockages
  • infection
  • trauma
  • heart failure
  • shock due to loss of blood or dehydration
  • poison ingestions (antifreeze, for instance). 


However, with proper treatment, we may be able to reverse it in time.


On the other hand, chronic renal failure happens as the cat ages. In some cases, blood and urine blockages or infections may not lead to an acute failure but rather weaken the kidneys over the years. Additionally, other diseases, such as cancer and high blood pressure, may play a role here as well.


If the cat has chronic renal failure, its kidneys have probably already lost a part of their function. However, they are still doing much of the work needed and producing urine. The cat will be thirstier than ever before too. The problem is that it will urinate so often that it won’t be able to get to its litter box on time or won’t want to “go” in a dirty one.


Other symptoms include vomiting, lethargy, and muscle loss, which will make the cat lose weight.


Treatment and Diagnosis


Blood and urine tests are a given here, but the vet is likely to ask for an X-ray, a biopsy, or an ultrasound as well. In case the kidneys are failing, the treatment may vary depending on the direct cause. If there are some blockages, the cat will need to have surgery. Other forms of treatment include giving it IV fluids, putting it on a special diet, and treating it with medications at home.


Depending on the severity of the symptoms, you may be able to give the cat other medications as well. Since this is a progressive disease, the point is to keep the feline happy for as long as possible. Therefore, it’s not uncommon to include anti-vomiting drugs, appetite stimulants, vitamins, and other supplements into the treatment. Also, the vet will monitor the progression of the condition over the years to tweak the treatment when needed.


Cat Peeing Outside the Litter Box and Throwing Up



As the most common glandular disease in felines, hyperthyroidism occurs when there is too much thyroxine (thyroid hormone, also known as T4) circulating in the bloodstream. The two most common reasons for the overproduction of the hormone are a benign growth or thyroid gland tumor.


Abnormal growth could lead to other diseases that may endanger the cat’s life. Too high levels of thyroid hormones can mess up the functioning of the cat’s metabolism. Consequently, this could cause irreparable damage to other systems in its body. 


However, if we catch our cat peeing outside the litter box and throwing up, we may not even think that there’s something going on with its thyroid. These are just some of the symptoms that follow the condition.


The cat will be thirstier than ever before and clump up litter quickly, which could make it eliminate outside of it. Additionally, it will vomit because the condition will have a negative effect on its gastrointestinal tract. 


Unfortunately, we cannot know for sure it’s hyperthyroidism based on these. Therefore, other symptoms, such as weight loss despite an increased appetite and behavioral changes (aggression, restlessness, increased vocalization), may help with the diagnosis.


Treatment and Diagnosis


To rule out kidney failure and diabetes, the vet will ask for a chemistry panel, a urinalysis, and a CBC. If those come out clean, they’ll proceed with a thyroid hormone analysis. 


More often than not, this test confirms hyperthyroidism. However, 2–10% of cats with the disease may actually have normal T4 levels. If the condition is mild, the hormone may fluctuate, leading to a false-negative result. On the other hand, it could be suppressed by another disease, such as diabetes, which may happen in older cats.


In the end, to diagnose the disease, the vet may opt for more specialized testing. Once they confirm it, there are three treatment options in general: 


  • radioactive iodine therapy 
  • surgery (removal of the gland)
  • oral medications (often Methimazole).


Cat Peeing Outside the Litter Box and Throwing Up

Diabetes Mellitus


When a cat is unable to produce enough insulin to support its system, i.e., keep blood sugar and glucose levels in check, it may develop diabetes mellitus. As a known killer among humans, diabetes is another disease that’s a reason behind a cat peeing outside the litter box and throwing up.


Since diabetes itself will make the cat rather thirsty, it will develop a need to urinate more and more, often having to do it outside of the litter box out of sheer convenience at that moment. Vomiting, on the other hand, may not occur right away. If the cat doesn’t receive treatment for diabetes mellitus, it may start losing its appetite and weight, as well as throwing up, leading to dehydration. A severe form of the condition may also cause depression, motor function issues, and later on, coma and death.


Treatment and Diagnosis


To diagnose diabetes, apart from looking into all the symptoms, the vet will have to check the cat’s blood glucose levels. If those aren’t too high, but the signs are still there, they can support their diagnosis with a fructosamine and urine glucose test.


The most common form of treatment is insulin therapy, which ought to be combined with a high protein diet. Since controlling the symptoms is crucial in the case of diabetes, the cat will have to go in for regular check-ups as well. At some point, it may not need insulin anymore, but it has to stay on the same diet to avoid complications. In essence, the disease may go into remission, but the cat won’t be cured.


Cat Peeing Outside the Litter Box and Throwing Up?

About Feline Idiopathic Cystitis and Bladder Blockages


Although many conditions could have a negative effect on the cat’s lower urinary tract, in most cases, the cause is unknown. Thus, a bladder inflammation in cats without a recognizable cause is Feline Idiopathic Cystitis and is more common than you may have thought.


However, even in the case of idiopathic diseases, some underlying issues are wreaking havoc in the cat’s body. Those include stress, and particularly, abnormal stress responses. Other potential causes are neurogenic inflammation and a defective bladder lining.


Now, the issue here is that the cat won’t actually vomit from cystitis. One of its main symptoms is periuria (the cat is peeing outside the litter box), straining to urinate, and blood in the urine. The vomiting starts if the disease isn’t treated on time. Any cat with any form of cystitis could develop a urinary blockage, which may lead to a toxin buildup and death. Some of the most common signs of obstruction are nausea and vomiting, as well as weight loss.


Treatment and Diagnosis


If we catch our cat peeing outside the litter box and throwing up, the vet will have to perform a variety of tests to determine cystitis. Since there isn’t a known cause, the diagnosis includes ruling out any other conditions that come with similar symptoms. Because of that, the vet will analyze urine and the bacterial culture, as well as perform an X-ray. In some cases, they may require an ultrasound to pinpoint the disease.


As far as treatment goes, it should be multimodal. This condition doesn’t really respond to drugs, although the vet may prescribe some. If we rely only on the drugs, it’s likely that the condition will come back. 


Instead, we would have to focus more on the cat’s diet and its environment. We should stick to giving it wet food to increase the production of more dilute urine and boost its water intake overall. Additionally, we must work on stress reduction and lower the cat’s anxiety levels. We could provide more hiding places (cats love their privacy, after all) and introduce pheromone therapy, for example.


Final Thoughts


As you can probably tell, most of the diseases we’ve talked about come with similar symptoms. One of the most common causes of peeing outside the litter box is a bladder infection. However, the disease that mimics the symptoms of that condition is bladder cancer, which can cause vomiting and polyuria (frequent urination) as well.


In the end, you cannot diagnose your own cat by looking for some telltale signs. If you catch your cat peeing outside the litter box and throwing up, get it to the vet fast. It’s best to rule out any potentially lethal conditions. Who knows? It may be just a phase. On the other hand, the reason could be far more sinister and might require medications, surgery, or a complete lifestyle overhaul.


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Michael Grover

About Me I have been a pet owner for most of my life. I am now retired and spend my days writing about problems relating to cats, dogs, and funeral poems. I am passionate to stop animal cruelty in any shape or form. My passion is to help people like you identify behavior problems in cats and dogs. That is what I do. Over the years of my life, I have always kept cats and dogs. About 4 years ago I retired and found I had a lot of time on hands so I started to write all about dog and cat problems. It was suggested to me that I should start up a website and publish my words to help people with their pet problems. I am still writing every day and hope you find my articles useful. Regards Mike Grover

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