If you're elderly cat has hyperthyroidism you can probably blame your sofa

Through numerous studies and careful research about the link between the evolution of the disease called feline hyperthyroidism and the introduction of fire retardants into homes, it has been found that there is a distinct link between feline hyperthyroidism and flame retardants.

The primary chemical in flame retardants is polybrominated diphenyl ethers (PBDEs). They are endocrine disruptors. PBDEs were introduced into sofas to help suppress fires but also in all kinds of products including computers. They are/were ubiquitous in the home.

Image: MikeB

And it is worse than that because as one journalist correctly says: PBDEs are "itinerant". This means that they travel around a home because they leach out of the product where they been put by the manufacturer into the home environment. They attached to dust in the environment and therefore they remain in the environment for a long time in the form of dust.

This, as I understand it, makes them particularly hazardous for domestic cats because they lie around the home resting and then they self-groom themselves fastidiously at which point they are likely to ingest some of this dust. The PBDEs then cause cancers in the thyroid gland which leads to hyperthyroidism - an increase in the production of thyroid. This increases the metabolism of the cat which means that despite eating well they lose weight.

You might not know this but hyperthyroidism is also called thyroid cancer as it is almost always associated with a cancer, a benign adenoma (more common) already malignant adenocarcinoma. The cancers have a major effect on the production of thyroid by stimulating production. It is said, by the way, that Himalayan cats and Siamese cats have a lower risk for this problem.

The elderly cat with hyperthyroidism suddenly becomes very active after being very passive together with an increase in their appetite. This sedate older cat spending days in the sun is suddenly flying around the house like a kitten. Despite the increasing appetite and eating more there is weight loss, vomiting and panting.

This illness was not present in domestic cats until the 1970s. The veterinarians scratched their heads when it first arrived because they had no idea what it was. As it was in the 1970s that the manufacturers of numerous different products introduced PBDEs into these products.

And going back as long as 2016, we have a study on the DVM 360 website which clearly states that hyperthyroidism in cats is linked to PBDE exposure.

The opening sentence of the report on their study states: 'Cats with hyperthyroidism had significantly higher serum levels of polybrominated diphenyl ethers (PBDEs) than did euthyroid cats, investigators reported recently in Environmental Science & Technology'. The word "euthyroid" means normal thyroid function. Scientists do like to use clever words which make the reports more confusing.

This report confirms an older report linking feline hyperthyroidism to the same chemicals. The problem, and this is a big problem as I see it, although PBDE have been banned in numerous countries in numerous products the ban has not been universal and as mentioned these chemicals are likely to be in many homes even today years after they were first introduced.

The prevalence of feline hyperthyroidism in older cats is at about 10-25%. I don't know exactly how prevalent it is but at least one in 10 older cats have the disease which is a big number. If there are about 10 million elderly cats in America which there might be at a rough guess, this means that 1 million of them at least have hyperthyroidism. This is a big number and it should not be accepted. It confirms to me that there PBDEs remain in homes in 2023.

One study from Japan as I understand it concluded that some domestic cats develop hyperthyroidism from the wet food products that they eat which is based upon fish contaminated by PBDEs. Specifically, they say that the cats were exposed to these chemicals through food products containing 'fish flavours'.

I suppose the point to make is that cat owners should not accept feline hyperthyroidism as an inherited disease. It is a disease from the environment in which they live and that environment is human-made. Feline hyperthyroidism is a human created disease and it affects millions of cats across the world. We should be uneasy with that and a lot more needs to be done to resolve the matter.

The cure for this disease is quite difficult. It may include surgery or drugs or radioactive iodine as I understand it. These are all difficult procedures it seems to me. I don't see enough being done to prevent the disease occurring.

For example, does America import products from countries where they have not banned PBDEs? I don't know but it is unlikely. Big countries like India have not banned PBDEs to anywhere near the extent that they are banned in America or Europe.

In Europe Directive 2003/11/EC, which amends Directive 76/769/EEC on the marketing and use of certain dangerous substances and preparations, bans the sale of two commercial mixtures of PBDEs, known as PentaBDE and OctaBDE, in concentrations higher than 0.1% by mass. That does to seem to be comprehensive to me. Governments are reluctant to restrict businesses as they are heavily lobbied.

Domestic cat calcium levels low. A reason.

When a domestic cat is suffering from a deficiency in calcium i.e. their blood-calcium concentration is low, it may well be due to inadvertent damage to the parathyroid glands during a thyroidectomy operation. This is an operation to remove the thyroid gland because the cat is suffering from hyperthyroidism. A dramatic fall in blood-calcium concentrations can be life-threatening. Cats who have been through the thyroidectomy operation should be hospitalised for a few days after surgery so the blood-calcium concentrations can be monitored.

Thin, elderly cat suffering from hyperthyroidism. Picture: PoC.

Hyperthyroidism is fairly common in older cats and is caused by an increase in the production of thyroid hormones from enlarged thyroid glands in the cat's neck. Most often it is caused by a benign tumour hence the operation. It should be noted that second hand cigarette smoke may be a contributory factor in developing this disease. Surgery is an option to remove the cancerous gland. If both thyroid glands are removed the cat will need supplemental thyroid for the remainder of their life.

Alternative options are radioactive iodine to destroy the cancerous tissue or an oral medication called methimazole. This drug lowers hormone production. It is given daily. The administration of this drug can it seems be difficult but the manufacturers are making it more palatable. Perhaps they have done this because my information comes from a book written in 2008.

If hyperthyroidism is caught early before the heart and kidneys are damaged it is a treatable disease. However, if these organs are damaged they will need treatment after the thyroidectomy. A thyroidectomy is a straightforward operation with an excellent success rate but beware the parathyroid glands!

Diagnosis for hyperthyroidism is carried out by a vet examining the cat's neck area for enlarged glands and they check the heart rate and blood pressure. The cat's general health is also evaluated because hyperthyroidism is often associated with other conditions and it can predispose a cat to other conditions. Therefore they need to be checked for associated conditions.

P.S. Other potential reasons for low blood calcium in cats might be kidney or liver failure, parathyroid tumour, hypoparathyroidism or poor nutrition during pregnancy to name some examples. I'm not a veterinarian so I won't go on.

Sources: Dr Bruce Fogle, Drs Eldredge, Carlson, Carlson and Giffin.

Most common domestic cat diseases treated under pet insurance policies in America

The most common domestic cat diseases treated under pet insurance policies in America in 2018 were reported as: undiagnosed diarrhoea and vomiting, urinary tract diseases, kidney diseases, gastrointestinal conditions, hyperthyroidism, diabetes, periodontitis and general oral health problems. This information comes from five different pet insurance companies: Trupanion, ASPCA, Pets Best, Nationwide and Embrace. 

You can see a trend there or at least I can. Urinary tract problems including kidney disease are a major issue in domestic cats and also it seems are diseases of the gastrointestinal tract. These would appear to be related to diet because what goes in has to be digested and waste is expelled. Both ends of the food processing channel are affected.

Photo: Pixabay.

I have this feeling that there is something hidden is going on in homes in the West which is affecting the health of domestic cats. The high incidents of kidney disease is unacceptable. And I don't think anything is being done about it. I'm referring to food and the chemicals in the home such as fire retardants and carpet chemicals. These are volatile chemicals which give off fumes and these fumes linger in the atmosphere inside the home. I wonder whether the air quality inside homes is sufficiently good for domestic gas. If it isn't it can't be good for people either but cats are nearer the surfaces.

Cats lie on sofas. If that sofa has a fire retardant inside it then the cat is more likely to absorb these chemicals. The same goes for carpet chemicals. These are examples. And as for cat food, I think we know now that the cheap dry cat food is simply not good enough. A lot of people rely on it because it is cheap and convenient. They allow their cat to graze at any time day or night. Arguably this is overly convenient.

You add to poor quality dry cat food the extended daytime absence of solme human caregivers and you create a slightly toxic world for the domestic cat which can result in urinary tract health problems such as cystitis, a bacterial infection of the bladder, exacerbated by stress.

If there is a high predominance of gastrointestinal diseases causing vomiting and diarrhoea then surely this points to food. Doesn't it? Shouldn't veterinarians be looking at the quality of food provided to domestic cats? Perhaps they don't want to look at it because they want a huge number of cats coming through their doors vomiting and shitting diarrhoea. I am too cynical. One pet insurance company said that they paid out US$9,650 to treat a cat with a gastrointestinal condition.

They also said that they paid out US$40,000 to treat a cat with kidney disease. Do the insurance companies investigate the cause of these diseases? Do they dig around and try and prevent the diseases happening? Do they have a vested interest in doing nothing about these diseases? Do they work together with veterinarians and pet food manufacturers to try and eliminate them? I know there are lots of questions but can you find the answers? I don't think you can. I know that the pet food manufacturers work with veterinarians and this to my mind creates a conflict of interest.

Two pet insurance companies rated diabetes as their third most common cat illness claim. Arguably, feline diabetes, which I presume refers to type II diabetes or sugar diabetes, might be caused by the high carbohydrate content in dry cat food. Dry cat food has to have a high carbohydrate content in order to make it. It is there simply as a manufacturing necessity. Domestic cats don't need this sort of carbohydrate level in their food. It is unnatural to them and it is causing, it is argued, hypoglycaemic cats and overburdening the pancreas which produces insulin. This upsets the insulin/sugar balance in domestic cats which can lead to type II diabetes. This is the argument of a well-known veterinarian in America called Elizabeth M Hodgkins DVM.

I am harping on about cat food. And I do give my cat dry cat food although it is the highest quality I can find. And I also feed him lots of high quality wet cat food. But I am dissatisfied in general with the quality of cat food. It does not reflect accurately enough the perfect domestic cat diet which is the mouse which is 40% protein, 50% fat and only 3% carbohydrates. The average dry cat food for cats contains 35-50% carbohydrate calories according to the catinfo.org website. Do you see the massive difference and how that could impact a cat's metabolism and ability to cope with it?

Radioactive Iodine As a Treatment for Feline Hyperthyroidism

There are three treatments for feline hyperthyroidism: surgery, medication in the form of pills or via the skin - methimazole (perhaps the most common option), and a third, popular option: to use radioactive iodine to destroy the cancerous tissue.

Hyperthyroidism in cats is almost always associated with cancer.  Sometimes cats respond badly to the prescribed medication.  Surgery I suppose can be dangerous because care must be taken not to damage or remove the parathyroid glands which regulate calcium metabolism.  If these glands are removed, the cat will need supplemental thyroid for the remainder of his life.

Nottingham Vet School Flickr photostream. Published here with their express permission.

It is said that the cost of these three treatments are similar in the long term although a cat owner would probably believe that the medication administered orally would be cheaper but this may not be the case in the long term and is something that needs to be checked with the veterinarian.

Radioactive iodine does or is intended to cure the problem (as opposed to treating symptoms) because it destroys the cause of the hyperthyroidism.  The cost of the treatment in the USA is around $1,300.  To undergo this treatment cats have their hearts checked out by a echocardiogram because hyperthyroidism can damage the heart.  As I understand it, the radioactive iodine is administered by a pill.  Treatment can take about 2 weeks and it appears to be residential treatment meaning that your cat stays at the veterinary hospital during treatment.

The radioactivity that is administered to the cat is shed in the cat's urine and faeces which are checked until it is reduced to a safe level.

Cats treated this way may need supplemental thyroid for the rest of their lives.

Provided this condition is caught early and before the heart or kidney is damaged treatment can be successful.

One sort of cancer which causes hyperthyroidism, a malignant adenocarcinoma, is harder to treat and the prognosis is very poor because the cancer has spread to other parts of the body.