Why 3 is Not a Lucky Number for Cats: “Triaditis”
There are some things cats just do differently. It is a truism of veterinary medicine that “cats are not small dogs”; there are some details about how they work that are distinct from the way dogs or people do things.
A recent case I dealt with brought this to mind: I saw an elderly cat who had become both acutely ill, and, as a renowned feline veterinary internist would have put it, was “yeller as a schoolbus”. (Great speaker, Dr. Norsworthy, he is from Texas… I hear that drawl now whenever I look at a yellow kitty!)
Now, lots of conditions in a very senior cat may lead to acute onset of illness; there are not so many that cause such a profound yellowing, or jaundice, of the skin, eyes, and mucous membranes.
The lab tests we did on this kitty pointed to a disease complex that we describe by the shorthand term “Triaditis” – triad meaning three, and -itis meaning inflammation.
Cats have an interesting connection linking their small intestine, liver, and pancreas, that other animals and people do not have.
In everybody else, there is a bile duct going from the liver to the intestine, and a pancreatic duct going from the pancreas to the intestine, and they are separate.
In cats, they have a “Y” shaped duct. The duct from the pancreas, and the bile duct from the liver, join together to make a Common Duct that enters the intestine. That means that if there is any inflammatory process or infection in the small intestine (Part 1 of our Triad) that wants to ascend up a duct and cause problems, it gets a two-for-one deal: access to both the liver (Part 2 of the Triad) and the Pancreas (part 3 of the Triad).
Step 1: “The Perp” aka the Small Intestine
The disease complex starts with inflammation in the small intestine. This can be related to bacterial infection, or it can be a primary inflammation, like IBD (inflammatory bowel disease), no bacteria needed.
- Since we can not tell one from the other without doing a tissue sample of the bowel, we will generally “cover” these patients with broad spectrum antibiotics. Often 2 kinds of antibiotics will be used, to cover a broad scope of the types of bacterial invaders that may be participating.
- If there is a long-standing history of gut issues before this illness flare-up, or if gut issues persist after we get them out of this flare-up, then a tissue sample becomes a really good idea. A little piece of gut tissue can be collected without surgery: a fibre optic scope (endoscope) can be passed down the esophagus of an aneasthetized cat, through the stomach, and into the upper reaches of the small bowel. The stomach and gut linings can then be inspected for inflammation, growths, and ulcers, and pinches of tissue collected for microscopic examination. The microscopic exam can help to tell if there is inflammatory disease (where lots of cells of the White Blood Cell family infiltrate the bowel wall for no apparent reason; think Crohn’s disease in humans), or if there is an infiltrative cancer of the gut. Warning, though: sometimes it can be really hard for the pathologist to draw the line between very active infiltrating white blood cells, and cancer of those same cells. Sometimes response to treatment is all we end up having to go on.
- As for treatment of the intestine problem, we need to get the inflammation to settle down. This can be accomplished with cortisone-type medications, such as prednisolone, or in more severe cases even chemotherapy-type medications such as azathioprine. In either case, these medications are suppressing the immune response. This is great if the immune response is inappropriate, the whole “white blood cells for no good reason” situation; but it is bad news if the immune response is busy waging war against invading bacteria. That brings us back to the antibiotics: if there is any infectious component to what is going on, then we do not want to suppress the immune response without doing something else to knock down bacteria!
“Innocent Bystander” Number 1: The Liver
This organ could be considered the greatest work-horse of the whole body: what doesn’t it do?
- Nutrition is impossible without the liver: all the blood from the veins of the gut passes through the liver on its way back to the heart, and the liver takes up all the good stuff the blood absorbed during digestion. It stores some types, and processes others into forms the rest of the body’s tissues can use.
- The liver is a Factory: it takes a lot of these raw ingredients that pass through it and uses them to synthesize important proteins for the body, such as the blood protein Albumin.
- The liver is the biggest Gland in the body – a lot of the hormones that control and balance the chemical reactions in the rest of the body are made here.
- This is where blood gets cleaned and Detoxified. The waste products made by the body’s own metabolism are either excreted out into the bile, or processed into a form that the kidneys can filter out. Any toxins that have come from ingestion of from the environment are also cleared: they are processed into less-toxic, excretable forms. The liver even “takes the hit” for the rest of the body – often the only evidence we see of an encounter with a toxin is a leakage of liver enzymes into the bloodstream from damaged cells. And liver cells are phenomenal at regeneration, so unless the damage is ongoing and causing scar tissue, the liver is back in fighting form quickly.
- The liver makes and excretes bile, which gathers in the gall bladder and then squirts down the bile duct into the gut. This counts as part of the liver’s waste-clearing function: the stuff that bile is made of is a breakdown product of blood hemoglobin, recycled into something useful, plus the bile duct is the pipe down which the liver “flushes” chemicals it wants to allow to be pooped out of the body. But even more significant than the waste aspect is the role that bile plays in Digestion: bile is what allows the body to make use of fats for nutrition. Without the emulsifying effect of bile, fats would just pass right on through.
So, when inflammation ascends from the gut up the bile duct, it can mess up a LOT of functions. So what do we do about it?
- Same as with the gut, we need to control Inflammation. Usually this will be with the cortisone-type medication, prednisolone.
- We can also support the cells themselves – help to protect them from further cell membrane damage, and give them a key ingredient for many of their functions (glutathione). Supplements can include sAME (which stands for – are you ready for this?- s-adenosylmethionine – we often refer to this by pronouncing it “Sammy”), and the herb Milk Thistle.
“Innocent Bystander” Number 2: The Pancreas
The pancreas has two big jobs:
- It has little islands of cells in it, called, surprisingly enough, Islets, that produce insulin for getting blood sugar out of the blood stream into the cells where it can be used for fuel.
- The main bulk of the organ is an enzyme factory. And if you don’t have enzymes, you don’t have digestion. The enzymes are synthesized, and then get a protective cap stuck on them before being secreted out of the cells and down the pancreatic duct. Once they are in the intestine, an enzyme produced there, called Trypsin, cuts the cap off and activates the enzymes for duty.
- Now here’s the problem: when there is inflammation damaging the cells, they leak. And they leak out the enzymes before they have the protective cap on. Which means these enzymes start to DIGEST THE CAT. Not hard to imagine that this HURTS.
So, what do we do?
- Once again, our good friend Inflammation control, usually courtesy of the cortisone-type drug prednisolone.
- We really, really need to control the pain. Pain messes up so many of the body’s functions, and its attempts to repair itself. Plus, if there is pain, there will not be any eating or drinking. A good medication for serious pain in cats is buperonorphine.
And of course, we need to look after the body that houses all these troublesome organs (!) by providing supportive care. There is no point medicating certain tissues while we allow others to become damaged by neglect. This means:
- Fluids. Dehydration is the enemy! Being dehydrated makes you feel like you have the flu: achy, headachy, run down. Which means not feeling up to eating or drinking, which means getting more dehydrated… vicious cycle! If the dehydration is bad enough, the heart has a hard time getting blood and nutrients out to all the tissues. Kidneys are especially sensitive to damage from dehydration. And we need to have enough fluid to flush through the filter-system of the kidneys to remove wastes, including the bilirubin that gives the “yeller-as-a-schoolbus” tint in the first place.
- Fluids can be given through an IV (best option for maximum delivery), or as big blebs under the skin to get absorbed gradually.
- Nutrition, nutrition, nutrition! You can not rebuild tissues without building materials. And when the main digestive organs are messed up (small intestine, liver and pancreas – as in all of the above) then your ability to break down and absorb foods SUCKS. This means you need both.
- Highly digestible food, with a very high nutrient density so a little goes a long way.
- Food delivery – these kitties feel too awful to eat on their own! So at least at the start, you need to hand-feed or syringe-feed them. Feeling as awful as they do, they may not appreciate your efforts to get food down their gullets – feeding can become a battle! In some cases, an indwelling feeding tube passing in through a hole in the side of the throat may be the answer. Sounds awful, but going in the side of the throat gets past the gag reflex that comes from passing the tube down the nose. And passing it in through the mouth to leave in place is not an option – those teeth are NOT going to leave it alone. The throat-tube is called a Pharyngoesophageal Gastric tube, or PEG tube. The tube is bandaged up so its end sticks out by their shoulders. Several times a day, you hook up a syringe to the tube and pass a slurry of food right into the stomach – much easier on the cat than fighting!
So, those are the steps. The outcome depends on how bad the inflammation is, and how much the organs are damaged.
My patient did really well with her medicines, fluids under the skin, and dedicated nursing care from her people. Her yellow got less and less, and gradually she started to eat on her own again. She is back on her somewhat-aged paws now!