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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
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