VET’S DIARY: On balance, Brook’s on the road to recovery

AS you might expect, there are a number of diseases that we associate with humans that also affect animals, writes Dominic Plumley.

Of course, there are a whole host of infectious organisms that are common to a number of species, mostly fungi or bacteria that are not so host-specific, but the occasional virus as well.

Apart from these, there are plenty of other conditions common to mankind and the animal kingdom.

You probably wouldn’t believe how many times, having diagnosed a particular condition in a dog or cat, the owner pipes up ‘What a coincidence, I suffer from that’ or ‘How funny, mother’s had that for years!’

However, sometimes our pets suffer symptoms that apparently mimic well-known human conditions when actually the disease process is quite different.

One such condition is canine vestibular disease, a form of which is prevalent in old dogs and consequently is commonly diagnosed as a stroke. Actually the mechanisms that cause the two conditions are quite different.

When someone has a stroke, generally a small blood vessel in the brain is blocked by a clot and the surrounding area no longer receives blood to nourish its neurons, some of which may die. Conversely, the vessel may burst causing a small brain haemorrhage, the blood flooding into the surrounding tissue again potentially killing nerve cells.

The human diet is often blamed, with high levels of cholesterol contributing to the general deterioration in artery function, though there are several other factors that play an important role.

Clots and haemorrhages can occur in dogs, but they are less common; though who knows what will happen as we see more and more obese pets?

Like strokes in humans, canine vestibular disease tends to affect older dogs, often coming on very suddenly.

For example, Brook, a wonderful Labrador who is, to put it politely, past her teens, had seemed apparently normal apart from the usual aches and pains associated with her arthritis.

Then one morning her owner noticed that she was very wobbly, her head tilted to one side and her eyes flicking from left to right – a phenomenon called nystagmus. On examination, it was soon apparent that poor Brook had suffered significant disruption of her vestibular function leaving her in a bit of a pickle.

In a nutshell, the vestibular apparatus is the neurological equipment responsible for perceiving the body’s orientation with respect to the earth, determining if it is upside-down, standing up straight or moving, etc.

Located in the middle ear, it signals to the eyes and extremities to allow them to act appropriately and compensate as we move in our environment.

The very sensitive nature of the vestibular apparatus is often apparent in people suffering from ear ache, when the associated inflammation causes them to lose their sense of balance. In fact, ear infections can often be a cause of canine vestibular disease though in older dogs it can occur without an apparent trigger factor.

Brook’s nystagmus was caused because her brain was getting false signals that she was falling to one side. To compensate, she was also tilting her head which actually was only making it harder for her to balance.

The whole experience was obviously making her feel nauseous – effectively sea sick – as she was off her food for the first time in her life.

All of these clinical signs, if seen in an elderly human, would point towards a stroke. In fact, sometimes it helps owners to understand when we describe vestibular disease in the same terms.

The use of modern technology such as MRI scans would enable us to pinpoint the parts of the brain that are damaged, but ultimately the treatment would be much the same. Those dogs that respond to this therapy generally do so within the first 48 hours, giving us a good indication of long-term prognosis.

Thankfully, Brook responded well to treatment and when we caught up with her, apart from a slight head tilt, she was just about back to normal, hopefully on the way to a full recovery.