Gastrointestinal (GI) endoscopy is the use of flexible endoscopic cameras that are guided through the mouth, oesophagus, stomach and the top part of the small intestine. This is known as upper GI endoscopy. Colonoscopy is where the endoscopic cameras are passed up the colon to the junction of where the large intestine joins the small intestine.

Endoscopy and colonoscopy are typically performed in patients with chronic vomiting, weight loss, inappetence or where gastrointestinal abnormalities have been identified on imaging.

They can be very useful in the diagnosis of feline inflammatory bowel disease, intestinal lymphoma, polyps, gastrointestinal ulceration and other types of intestinal cancer.

Both upper GI endoscopy and colonoscopy must be performed under anaesthesia.

Upper GI endoscopy requires patients to be fasted for 12 hours. Colonoscopy requires fasting of the patient for 24 hours. This is to ensure the parts of the GI tract that are being examined are not full of digesta. For patients having colonoscopy, additional enemas maybe performed when the patient is under anaesthesia.

Endoscopy has the advantage of being minimally invasive, however biopsy samples are very small and some regions of the intestinal tract cannot be reached with cameras.  Additionally, some diseases only occur in the deeper layer of the intestines and these can only be diagnosed via surgical biopsies. We will discuss the advantages or disadvantages of each technique with you depending on your cat's combination of findings.

Biopsies obtained during the endoscopy are submitted to an external laboratory for processing and results take 3-5 working days to obtain.

Patients will normally be discharged the same day or the following day, depending on each case.

Your feline clinician will contact you to discuss the findings once the procedure is completed.

Endoscopy is the technique of passing flexible cameras (fiberscopes) into the gastrointestinal tract. It allows visualisation of the inside of the oesophagus, stomach, duodenum and colon. 

This patient had swallowed a thread which is identified within the oesophagus and disappears down to within the stomach.


What is endoscopy?

  • Endoscopy is a medical procedure that allows your feline veterinarian to observe the inside of the gastrointestinal tract without performing major surgery.
  • An endoscope is a long flexible tube with a lens at one end and a video camera at the other. The end with the lens is inserted into the cat and light illuminates the relevant areas and projects it onto the screen. The endoscope can be inserted via the mouth or the anus to assess different regions of the gastrointestinal tract.

What is endoscopy used for?

Endoscopy of the gastrointestinal tract is used for a few different reasons but most commonly,

  • Taking small samples of tissue for diagnostic purposes (biopsy) e.g. when investigating causes of chronic diarrhoea, chronic vomiting or weight loss
  • Locating and sampling tumours 
  • Locating and removing foreign objects 
  • Dilating strictures (scar tissue) in the oesophagus, duodenum, or colon.

Is it painful?

No, endoscopies are generally painless. Compared with the stress experienced by the body in a full surgical procedure, an endoscopy is simple, low risk, and cost effective. Cats also have a very quick recovery time. 

Why might a surgery be a better option?

  • A limitation of endoscopy is that we cannot examine the entire gastrointestinal tract. we can only examine the oesophagus, stomach and duodenum (the upper part of the small intestine) and the ileum and colon. 
  • Some cats only have disease in the parts of the intestine that we cannot access endoscopically. Ultrasound or CT imaging help us to determine whether any abnormalities can be accessed endoscopically or not. 
  • When biopsies are obtained endoscopically, we take a sample from the inner layer of the intestine, however sometimes the changes are deeper in the tissue and surgical biopsies (which can take a sample from all the layers) is the best way to obtain the diagnosis. 
  • We will advise you which option we think would be most suitable. 

What happens on the day of the procedure?

  • Typically your cat is dropped off on the morning of the procedure or they may have been hospitalised overnight (this is more common with colonoscopy as there is more preparation required to empty the intestinal tract).
  • It is important to follow the directions for fasting if your cat has gone home (typically fasting for 12 hours for stomach and upper intestine (upper GI) endoscopy and 24 hours for colonoscopy)
  • Your cat will be anaesthetised. Further preparation of the intestinal tract such as enemas, maybe required if your cat is having a colonoscopy. 
  • The endoscope is then inserted through the mouth or the anus and the intestinal tract is systematically evaluated. Air is pumped into the intestinal tract by the endoscope to allow visualisation (otherwise the intestine collapses over the lens and nothing can be seen).
  • Multiple biopsy samples are obtained (they are very small and disease can be very patchy in location so many samples are taken to increase the odds of diagnosing it).  
  • Any abnormal looking regions or masses will be biopsied, however we also biopsy normal looking tissue, as some diagnoses can only be made based on tissue samples.
  • Once the endoscopy is complete, the endoscope is removed and your cat is recovered from the anaesthetic.

What can I expect with my cat after the endoscopy?

Most cats recover without incident from endoscopy. They are monitored for a few hours afterwards and then in most cases will be able to be discharged later that evening. 

Are complications possible?

Complications are possible but very rare. Sometimes if a cat has a pre-existing ulcer within the intestinal tract, the presence of the endoscope and/or the air that is pumped into the tract can cause perforation of the ulcer. This is a very serious complication but can be treated and luckily is extremely rare. For cats that we think have an ulcer present, we take special precautions to reduce this risk. 

Do I need to do anything special with my cat when they get home?

  • No, it is often best to keep things exactly the same with cats! Although if your cat is an outdoor cat, they should be kept inside for 24 hours following the anaesthetic. 
  • In winter it can be difficult for cats to maintain their body temperature after an anaesthetic so making sure they have somewhere warm is good. 
  • Regarding their food, generally their normal diet will be fine, however if we think your cat should eat something different (e.g. as part of a treatment program) we will discuss this with you. 

When do we get the results?

We will phone you with the initial results as soon as your cat has had their procedure. Biopsy results from the laboratory take an addition 48-72 hours and we will contact you when we have these. 

Endoscopy can only access the inner most layer of the intestine (labelled D1), however sometimes diseases such lymphoma are only in the deeper layers (labelled D2) and in these instances, surgical biopsies would be required to access this location. 

This is the stomach of a cat with gastric lymphoma. It is very thickened and irregular. There is also grass present which he ate because he felt nauseated. Biopsies from this region diagnosed the lymphoma and he received chemotherapy and has been in remission for the last 12 months and feeling great!

Your cat will be monitored closely after their procedure and then are generally discharged the same day.

The appearance of the duodenum on endoscopy. 

Why we recommend regular intestinal wormers for your cats!


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Underwood, QLD, AU, 4119

PhonePh: 1300 228 377

Veterinary Specialist Services