Loss of appetite in a sick cat is a common manifestation, and when this occurs, in many cases, it will be necessary to provide nutritional support until the cat’s appetite has returned.
When do cats need nutritional support?
- Cats who are anorexic or have not eaten enough calories over the previous three days
- Cats who have signs of malnutrition
- Loss of more than 10% body weight or more
- Cats unable to eat on their own because they are too sick, too weak or physically unable to eat
Causes of loss of appetite
Anorexia refers to a loss of appetite and it can be partial, where the cat will still eat, but not enough, or complete, in which the cat is not eating at all. Causes include:
- Pain due to trauma or surgery
- Dental pain
- Infection (viral, bacterial, protozoal)
Signs of malnutrition in cats
Weight loss can be subtle due to a cat’s coat which makes it hard to see even a significant amount of weight loss. I have found two of my cats lost a significant amount of weight under my eyes; it was only when I picked them up that I discovered they had lost weight (to hyperthyroidism and cancer).
Symptoms of malnutrition:
- Poor coat condition
- Muscle wasting (especially along the spine and the hind legs)
- Poor wound healing
- Scaly skin
Effects of malnutrition on the body
There are several serious consequences to lack of nutritional intake in cats. Every cell in the body requires energy from nutrients, and when adequate nutrition is not available, all body systems are affected.
- A cat who is not eating is at risk of developing hepatic lipidosis, a life-threatening condition in which the body starts to use fat (triglycerides) as fuel, which is sent to the liver to be processed into lipoproteins. The cat’s liver is not very good at processing fat, and it begins to accumulate in the liver cells (hepatocytes), which overwhelms and interferes with its ability to function properly.
- Cachexia is the use of muscle tissue to fuel the body in the absence of adequate nutrition. Muscle loss is most noticeable on the hind legs.
- Kidney failure occurs due to a decrease in blood flow to the kidneys. As kidney function drops, toxic waste products build up in the bloodstream.
- Altered ability to metabolise drugs due to fewer protein raw materials.
- Decreased wound healing.
- Increased metabolic rate due to a breakdown of the body’s proteins and fats to use as energy.
- Anemia (low red blood cells), leukopenia (low white blood cells) and thrombocytopenia (low blood platelets).
- Decreased immunocompetence means that cats are at greater risk of infection.
Types of nutritional support
The veterinarian will determine the type of treatment necessary based on the cat’s interest and ability to eat, and if the gastrointestinal tract is functional or not.
There are three basic types of feeding:
- Enteral (feeding tubes)
- Parenteral (intravenous feeding)
If the cat can eat on its own, the first method is to try and coax the cat to eat. This can include offering small amounts of highly palatable warmed up food, hand or syringe feeding, and special diets such as Hills a/d. If these methods don’t work, the veterinarian can prescribe appetite stimulants such as Mirtazapine, Cyproheptadine, or Diazepam.
For cats who cannot be encouraged to eat by hand feeding or appetite stimulants, a tube can be inserted. There are three types of feeding tubes.
High calorie canned food is blended with a small amount of water placed into the feeding tube to provide your cat adequate nourishment until his appetite returns. Treatment may be in-house or at home with a feeding tube.
The meal will consist of a liquid or slurry which is placed into a syringe and inserted into the tube. Warm food to room temperature before administration.
Nasoesophegal (NE tube)
A thin rubber or silicone tube is inserted through the cat’s nostril, down the back of the throat and into the esophagus. Local anesthesia is used when placing a nasoesophegal tube to prevent discomfort during insertion, and in some cats, mild sedation may be necessary. The tube is stitched or glued in place to prevent the cat from dislodging it.
Due to the slim diameter of this tube, a liquid diet is necessary to pass through the tube.
For cats in hospital whose gastrointestinal tract is functioning who are expected to be eating on their own within 5-7 days.
Long term requirement for feeding tube, severe facial trauma, vomiting or esophageal abnormalities.
The e-tube can provide nutritional support for cats at home. The cat can eat and drink without interference. Due to the larger diameter of the esophagostomy tube, a blended diet can be fed as well as oral medications.
The veterinarian places the e-tube into the left side of the neck and directly into the esophagus under heavy sedation or general anesthesia.
Long term nutritional support (weeks/months), and in cats whose gastrointestinal tract is functioning.
Vomiting cats and esophageal abnormalities.
A gastromy is the placement of a feeding tube through an incision in the abdomen and into the stomach which is performed under general anesthesia or an endoscopically guided technique (percutaneous endoscopic gastrostomy or PEG) in which an endoscope is inserted through the mouth and into the stomach, the veterinarian then makes a stab incision through the abdominal wall and pulls the tube into place. The cat will need to wear a protective stocking to prevent dislodging the tube.
The wider diameter of this tube allows for a greater range in diet and blockages are uncommon.
Long term nutritional support (weeks or months), can be used to provide nutritional support for cats at home for cats with oropharyngeal or esophageal disease.
The jejunostomy bypasses the upper gastrointestinal tract (esophagus, stomach, and duodenum). Placement is through the abdominal wall and into the small intestine. The use of a jejunostomy tube is for cats in hospital and not out-patients.
Cats who are unable to tolerate gastric feeding have a normal jejunal, ileal, and colonic function. Small intestinal obstructions, cancer and severe pancreatitis.
Parenteral nutrition (PN)
Parenteral nutrition is intravenous administration of nutrients, bypassing the usual process of eating and digestion. Normally food breaks down in the stomach and small intestine. From there it absorbed in the bowel, which is then carried through the body via the blood. Parenteral nutrition provides a specialised nutrition solution to the body via a catheter.
This kind of therapy is for hospitalised cats, and regular monitoring is necessary to identify and correct mineral and electrolyte imbalances.
For cats who cannot tolerate tube feeding, cats at risk of pulmonary aspiration, severe pancreatitis, hepatic disease, a non-functional gastrointestinal tract, or blocked gastrointestinal tract.
As with any medical procedure, complications are always possible. They can occur during the placement of the tube or after. Common complications can include the following:
- Dislodgement of the tube
- Aspiration pneumonia
- Nausea and vomiting
- Infection at the site of insertion
- Volume overload (parenteral nutrition)
- Fluid and mineral imbalances (parenteral nutrition)