by Arnold Plotnick MS, DVM, ACVIM, ABVP

Veterinarians are well aware that most ill cats will refuse to eat.  Although some feline disorders cause an increased appetite (e.g. diabetes, hyperthyroidism), the majority of feline illnesses result in partial or total anorexia.  For cats to recover from illness, it is imperative that they receive adequate calories.  For diseases like hepatic lipidosis (“fatty liver disease”), in which nutrition is the primary method of treatment, the cats that survived this illness were those whose owners were tenacious enough to force feed their cat, often against its wishes.  Strong-willed or uncooperative cats were essentially signing their own death warrant.  In the past several years, novel methods of administering nutrition to cats have resulted in increased survival rates for cats with serious disorders that render them unwilling or unable to eat.

The two broad categories of feeding critically ill cats are enteral feeding, in which some portion of the gastrointestinal tract is utilized, and parenteral feeding, in which nutrients are administered in a manner other than using the gastrointestinal tract, most commonly via the bloodstream.

Enteral feeding is generally achieved via feeding tubes.  Nasoesophageal tubes are polyurethane or silicone tubes that are inserted into a nostril.  The end of the tube eventually reaches the deep end of the esophagus.  The tube is anchored in place on the cat’s head using one or two stitches.  An Elizabethan collar is put on the cat to prevent it from using a paw to dislodge the tube.  A liquid diet can be administered through the tube.  Commercially prepared liquid diets (CliniCare or RenalCare) are perfectly designed for these tubes.  General anesthesia or tranquilization is not necessary to place a nasoesophageal tube, allowing enteral nutrition to cats that are an anesthetic risk.  These tubes are a temporary measure; they are rarely kept in place for more than 7 to 10 days, and the tubes are usually removed before the cat is sent home.

Esophagostomy tubes have become a very popular method of administering nutrition to cats requiring more long-term support.  A tube is inserted into the esophagus through an incision in the cat’s neck, and threaded down the esophagus to the very end, just before it reaches the stomach.  These tubes can be kept in place much longer (several weeks), for in-hospital or at-home feeding.  Special liquid diets are generally not necessary – a pureed diet made from commercial pet foods can be used.  These tubes are very useful in cats that are temporarily unable to eat due to disease or trauma to the nose or mouth.  Placement of the tube does require general anesthesia.

Gastrostomy tubes provide nutrition by administering food right into a cat’s stomach.  The tubes can be placed surgically, for example, during an exploratory surgery where the surgeon is obtaining samples for biopsy, or without surgery, i.e. through the skin, using an endoscope.  These tubes can provide nutrition to the cat for months if necessary.  During my internal medicine residency at Colorado State University, I encountered a cat that could not eat due to an irreparable stricture (narrowing) of the esophagus.  This cat was doing well, having been fed pureed cat food at home through a gastrostomy tube that had been in place for over 14 months.

Jejunostomy tubes are small tubes that are placed within the small intestine, usually at the time of surgery, as a way to bypass the mouth, esophagus, and stomach.  They are usually placed in animals with pancreatitis, as these tubes bypass the pancreas, avoiding stimulation and allowing the pancreas to heal.  These are high-maintenance tubes, requiring anesthesia and surgery, followed by a liquid diet that has to be continuously pumped into the tube.

Nutrition that is delivered in ways that avoid the gastrointestinal tract completely is termed parenteral nutrition.  Although it is possible to meet all nutritional requirements in humans via this method, parenteral nutrition, at best, provides only a portion of a veterinary patient’s needs. It is very difficult to meet 100% of a cat’s nutritional requirements intravenously.  Intravenous feeding used to be available only at universities and referral centers, however, recipes that involve combining individual solutions of dextrose, lipid, and amino acids have allowed many veterinary practitioners to offer parenteral nutrition to their critically ill patients.  While most veterinary practitioners cannot prepare the mixture themselves, some human hospitals and independent pharmaceutical companies can compound these mixtures for veterinarians, as long as the veterinarian provides the recipe.    Some veterinary schools and large referral centers will also offer these mixtures to local veterinarians as well.  This is quickly becoming a safe, convenient, and economic method of obtaining an all-in-one mixture for the occasional veterinary patient that desperately needs nutrition but cannot tolerate the anesthesia necessary for tube placement, or will not tolerate a feeding tube for whatever other reason.

Updated 2/9/06