Problems of middle age: baldness and a pot belly
IN the past month, I’ve seen two dogs that had the same illness, yet they presented with very different problems.
The first dog was a seven year old Bichon Frise. His owner was worried because hehad become fat and bald.
On close examination, the “fatness” was more accurately described as “a pot belly”. He had begun to waddle around as if he had just eaten a large meal, even when he hadn’t yet eaten.
And his baldness was very obvious: he had lost the fur along his back, especially over his tail head. This had started as thinning of the hair, but over six months, the fur had completely disappeared, so that there were now large bald patches along his back. The dog was in very good general health, eating well and behaving normally.
The big questions were: what was causing the baldness and pot belly, and could he be treated? The only way I could find out was by investigating the illness, starting with blood and urine samples. But more of that later.
The second case was a ten year old West Highland White Terrier. He had a full coat of fur, and no sign of a pot belly. His owner had brought him to me because he had started to piddle in the kitchen every night. Over the previous month, she had been coming down to a flooded floor at breakfast time. He was a very well dog otherwise, with no other signs of illness.
Again, it was impossible to make a diagnosis based on these signs alone: there were many possible causes, and an investigation was needed.
At this point, both of the cases began to run along similar lines, even though they were so different in almost every other way.
I started with a urine sample from each dog. There’s a series of simple tests that can be done on urine, most of which can be done in the clinic. We use dip sticks to check for blood, pH, protein, glucose and other chemicals. We use an instrument called a refractometer to measure the concentration of the urine. And we spin the urine sample down in a centrifuge, to see if it contains any abnormal cells or crystals. In some cases, urine samples need to be sent off to the laboratory for further testing, such as culturing to pinpoint the bacteria involved in a urinary tract infection.
Interestingly, both of these two dogs had exactly the same result on the urine test: their samples were completely normal in every way except that the urine was too diluted. A normal urine sample is reasonably concentrated, reflecting the fact that the job of healthy kidneys is to produce urine containing waste products from the body, but not too much excessive fluid. In a number of diseases, the kidneys lose the ability to concentrate the urine in the normal way, causing it to be weak and over-diluted. The level of concentration can be measured accurately using the refractometer, and both of these dogs had exactly the same level of over-diluted urine.
When I asked the dogs’ owners if they had noticed their pets drinking more water than usual, neither of them had seen this. However, they both agreed that yes, when they thought about it, they had needed to fill the water bowl more often than before. So I had established something significant: as well as having the main signs that the owners had noticed (the pot belly, the baldness, and the kitchen piddling), both dogs had over-diluted urine. But I still hadn’t made a diagnosis of the reason why this was happening.
The second stage of the investigation involved taking blood samples to process in our own in-house laboratory. Like many vet clinics, we have sophisticated automated laboratory equipment that allows us to measure a range of different cells and chemicals in the blood. Results can be obtained within minutes: an immediate diagnosis can often be made, and the speed of the results can be life saving.
Again, with both of these dogs, the results were the same, but they didn’t allow me to make a precise diagnosis. They both had mild elevations of liver enzymes, and raised cholesterol levels. And they both had minor changes in their blood counts.
By now, I had a good idea about what was going on, but to confirm this, I had to send a sample off to a specialist laboratory, to measure variations in the levels of cortisone in their body. The results confirmed what I had suspected: they both had higher than normal levels of cortisone. The diagnosis had finally been made: they were suffering from a common hormonal disease called “hyperadrenocorticism”, colloquially known as “Cushings Disease”.
This is caused by a tiny tumour of hormone-producing tissue, either in the brain or on one of the adrenal glands. The signs of the illness are caused by the high levels of cortisone produced by the tumour, and they vary significantly. Baldness, pot-belly and high thirst are all typical signs, but every dog shows these in differing proportions.
The good news is that both dogs could be treated effectively: a daily tablet selectively destroys the hormone-producing tissue.
I saw both dogs a month later: the first one now had a tucked in tummy, and fur was beginning to sprout on his bald areas. And the second dog had stopped piddling in the kitchen overnight.
Different dogs, the same diagnosis and treatment, and thankfully, both cured.