Cats with chronic kidney failure often have a poor appetite, sometimes made worse by feeding prescription kidney diets which may be unpalatable.
General nursing techniques such as feeding warm food by hand may help. In other cases, appetite stimulants such as the anti-histamine cyproheptadine or anabolic steroids may be recommended to stimulate an adequate appetite.
In a minority of cases it may be necessary to fit a feeding tube for long-term nutritional support. Gastrostomy tubes (tubes entering the stomach directly from the outside) can be placed non-invasively via endoscopy (via the throat) or via a laparotomy (via a surgical incision in the wall of the abdomen).
Although an anaesthetic and short period of post-operative hospitalisation is required to place the tube, once in place they can be used for prolonged periods to administer blended food, liquids and medicines to the cat. Depending on the composition of the tube, it will need to be replaced after a few months (2 - 3 months for latex tubes, 6 - 12 months for silicone tubes).
Other medications should be given prior to feeding, except phosphate binders which should be given mixed with the food. Wet food, blended with water to provide a syringable consistency, is warmed to body temperature and injected into the stomach over a period of 10 - 15 minutes.
When administering food via a tube, you should be aware of signs of nausea (e.g. gulping, salivation) which indicate that the meal is being introduced too rapidly or that the stomach was not completely empty prior to feeding.
After feeding, the tube should be flushed with 5 - 10 ml of water. Initially the cat should be fed four to six times a day with equal sized meals and no meal greater than 45 ml/kg (approximate stomach capacity of the cat) in volume. Over time, it is usually possible to reduce the number of feeds a day.
The cat should always be offered food orally before feeding via the tube as appetite can vary and some cats with CRF will intermittently have a good appetite.
If the feeding tube is inadvertently removed, replacement is an urgent emergency in those cats where continued tube support is required, as the entry site heals rapidly. This will prevent easy replacement if not acted upon within a few hours. Some types of tube can be fitted through the existing gastrostomy entry site without the need for an anaesthetic in most cats, and some owners may be able to do this without veterinary assistance.
Occasionally tubes can become blocked with food or medication. Massage of the tube whilst infusing water can help to alleviate this. Coca Cola or cranberry juice can also help to break down blockages. In persistent cases, passing a catheter down the tube may be helpful and some authors advocate the use of meat tenderisers and pancreatic enzyme solutions!