Although cats are less prone to tummy upsets than dogs, they can still start to throw up.
Vomiting is what’s called a “protective reflex” - it happens automatically whether or not they want it to (and I’m sure we can all empathise with that!) to reduce the risk of poisoning - by emptying the stomach and getting rid of whatever it is that the cat’s just eaten. It can be triggered by various drugs and poisons (which activate a special region in the brain called the CTZ, which constantly monitors the blood for anything potentially nasty). Vomiting can also be caused by damage or obstruction to the gut, and by motion (anyone got a cat with travel sickness?).
As a result, there are a HUGE number of possible causes. Some of these are quite minor and will sort themselves out, but others are potentially life threatening.
So, what are the top causes of vomiting in cats?
● Motion Sickness - when the movement the cat sees doesn’t match up with what they feel in their inner ear, it confuses their brains. Their automatic response is to puke - all over your car…! Fortunately, as soon as you stop moving they’ll start to feel better, so this is usually annoying and messy rather than dangerous.
● Hairballs - most common in long-haired cats who groom themselves and then swallow the hair. In the stomach, these hairs ball up and get stuck, so the cat retches to get rid of the hairball.
● Non-Specific Gastroenteritis (“Bad Mouse Syndrome”) - this is the most common cause of vomiting in dogs (because they like to eat rubbish) but it is less common in cats (who are more fastidious). Typically, it’s a result of eating spoiled or gone-off food, so is more common in outdoor and free roaming cats.
● Gut Infection - infection with serious bugs like Feline Panleukopenia Virus or Salmonella can result in severe vomiting.
● Gut Obstructions - anything that stops food moving on down the bowel can result in “overflow” vomiting as food backs up in the intestines. The most common causes are:
○ Constipation (which may also be due to hairballs!).
○ Swallowed toys (usually tapes or ribbons that were shiny and fun to play with, but caused a blockage when swallowed).
○ Tumours in the abdomen which compress the bowel.
● Inflammatory Bowel Disease (IBD) - a group of diseases characterised by inflammation of the gut walls.
● Poisons and Drugs - any drug or poison may trigger the CTZ resulting in vomiting.
● Stomach Ulcers - most commonly due to medicines like painkillers or steroids which can lead to erosions of the stomach lining.
● Metabolic Disorders - anything in the cat’s body that goes wrong can result in abnormal chemical balances in the blood. In many cases these can trigger the CTZ resulting in chronic (or ongoing) vomiting. Common disorders include:
○ Kidney failure.
○ Liver disease.
○ Diabetes mellitus.
○ Hyperthyroidism (overactive thyroid).
Why is vomiting a problem?
When a cat vomits they lose two vital fluids - water and stomach acid (hydrochloric acid, made up of hydrogen and chloride ions). This loss of water results in dehydration (especially if they can’t keep water down). The loss of acid (hydrogen ions) from the body means that the cat’s body becomes increasingly alkalinised, called metabolic alkalosis - and if their blood becomes too alkaline, all sorts of body systems start to shut down. The loss of chloride also causes severe salt imbalances.
If the vomiting is severe and/or long lasting, this can result in shock, collapse, organ failure, heart failure and death.
How is it treated?
In many cases (like “Bad Mouse Syndrome”) symptomatic care is enough - so we’ll advise no solid food for 24 hours to rest the gut, then start a nice bland diet (white fish or chicken, or a commercial intestinal diet). We may also use electrolyte fluids to drink, and perhaps and anti-sickness injection.
However, in more severe cases, or if symptomatic treatment isn’t working, we’ll want to try and work out why they’re throwing up. To do that we’ll do blood tests for metabolic disorders; X-rays and ultrasound scans for blockages; sometimes faeces tests for infections; and endoscopy (looking inside with a flexible telescope) for tumours, ulcers or IBD.
Severe vomiting usually requires intensive nursing care and hospitalisation on a drip to manage the cat’s hydration, blood acidity and blood salt balance. Once the underlying disease is diagnosed, it can be treated appropriately - for example with antibiotics for infections, laxatives for constipation and hairballs, surgery for obstructions and so on.
Although not all causes of vomiting can be cured (for example, kidney failure), they can usually be managed if diagnosed early enough!
If your cat is throwing up, get them checked out by our vets as soon as you can.