Dehydration in dogs can often start from the inside
The small long-haired terrier stood shivering in the middle of my consulting table. His head was held low, and he was staring into the distance with a dull, lifeless expression. His owner, an elderly lady, was worried. 'Jimmy just isn't himself this morning' she told me. 'He's normally a bright, bouncy boy, but look at him today. There's something very wrong.'
Before examining Jimmy, I asked her to tell me the full background to the situation. The so-called 'history' is often the clue to making a veterinary diagnosis: there's little point in examining an animal without first of all asking the owner to tell you as much as possible about what they've observed.
She told me that Jimmy had been perfectly normal the previous evening before she'd gone out. She had known that she wouldn't be back till late, so she had left out a treat for her three dogs: a special bowl of tasty food each. As she left, she noticed that Jimmy devoured his own bowl greedily. The other dogs weren't so hungry, and he began to eat their food too.
She didn't think much of this at the time, other than telling herself Jimmy was getting an extra special dose of treats on this occasion. When she came back later that night, she took the dogs out for a quick walk in the garden and they had all seemed fine. It was just this morning that Jimmy had seemed so miserable.
I then examined Jimmy carefully. Before I even touched him I heard a loud gurgling noise coming from his abdomen. Jimmy looked round at me anxiously.
My examination was normal apart from one important finding: when I pinched the skin over Jimmy's shoulder, the skin didn't flatten as soon as I let go of it. Instead, the pinched skin remained as a wrinkled fold. This is known as 'tenting' (because it looks like a small tent), and it's a classic sign of dehydration.
If the body is deficient in water, every tissue in the body becomes more dried-out, and when the skin is dried-out, it becomes less elastic. If you compare a dried out prune to a plump, fresh plum, it's a similar story. Jimmy had other signs of dehydration: his eyes were sunken into his head, and when I slipped my finger into his mouth, his gums felt dry and sticky.
I took his temperature cautiously: my reasons for doing this became obvious. I had just removed the thermometer from his rear end (noting that his temperature was just below normal), when Jimmy squatted and passed a large pool of diarrhoea onto the table.
I had expected this: Jimmy had given me all the signs that he was a dog who was suffering from a brewing gastroenteritis, and it was just a matter of time until the diarrhoea started. Temperature-taking by the vet is often the final straw for a dog who is suffering from the sense of urgency caused by an upset stomach, and vets get used to dealing with the consequences.
Once the table had been cleaned up and the window opened to clear the air, I explained the situation to Jimmy's owner. I strongly suspected that Jimmy hadn't only scoffed his own special treats the previous evening: he may well have eaten the other dogs' as well. Dogs can cope well with small extras to their normal diet, but when they eat a large quantity of rich food that they are not used to, gastroenteritis is often the result.
'But how does that cause dehydration', Jimmy's owner asked me. 'I've been watching him, and until now, he'd had no sign of an upset stomach since last night.'
I explained that dehydration often starts inside a dog, due to relocation of fluids from one body compartment to another. In Jimmy's case, the brewing gastroenteritis had caused large amounts of fluid to be drawn into the intestines, out of his general circulation. So although he had not visibly lost any fluid, he was dehydrated, and that's why he seemed so unwell.
'If he could talk', I told her, 'Jimmy would be complaining that he had a headache, and that he was feeling completely washed out. That's what dehydration does to humans, and dogs are no different'.
'But why doesn't he just drink water and rehydrate himself', she asked.
I explained that it wasn't as simple as that. While humans can be told to drink special fluids to rehydrate themselves, dogs won't drink on command. And while they can be given some fluid by syringe-feeding , it's not enough when they have serious dehydration. The only answer is to give intra-venous fluids straight into the bloodstream, by setting up a drip.
Jimmy was admitted to our hospital that morning, and soon after he was sitting comfortably in a kennel with a drip flowing into his front leg. We gave him other treatment for gastroenteritis too, with medication to soothe the lining of his irritated bowels. He had a few more accidents throughout the day, but by the evening, his digestive disturbance had settled down, and he was a much happier little dog.
His owner came in to collect him, and he was happy to see her, jumping up to greet her, his tail wagging furiously.
'That's more like my Jimmy' she said delightedly. 'You've got your energy back. Or should I say, you've got your fluid back.'