A piece of wood which caused a serious health scare
A young Boxer dog, called Yuki, suffered from a severe bout of gastroenteritis. She vomited every day, for three days in a row. I treated her with the usual supportive treatment, and within a few days, she had made a full recovery.
It was a week later that a new, peculiar, problem started. A small, firm, semi-spherical swelling appeared on her left flank, just behind her rib cage. It felt hard, as if a solid rubber ball had started to grow beneath her skin. Over a couple of days, the swelling grew much bigger, until it was around 15cm diameter, almost as big as half a melon. The skin looked normal over the swelling, but it was uncomfortable, and Yuki didn't like it if I squeezed it.
There were a number of possible causes. Boxers are prone to certain types of cancer, and this was the main worry. If this was the case, she would need major surgery to remove the lump. It was critically important to find out exactly what was causing the swelling, so I started a process of investigation.
The first step was to take an x-ray picture of the area, to try to work out how deep the lump went into her body, and to see if there were any clues about its origin from the x-ray images. The x-rays confirmed that it was made up of just soft tissue (i.e. no bones or other more solid components) and it was localised to the area beneath the skin and outside her abdomen. It was not growing into her chest, nor anywhere else.
The second step was to take a biopsy of the lump: this is the only way to make a definitive diagnosis about what's causing it. If the report told us that it was made up of cancer cells, it would be serious, unwelcome news, but at least we would know what we were dealing with, and we could plan accordingly.
The biopsy result ended up being good news: the lump was definitely not cancer. Instead, the cells were "inflammatory cells", which meant that it was the result of the immune system reacting to something. The question still remained: what was it that the body was reacting to? What was the root cause of the swelling?
There were two possibilities: first, it could be some sort of strange infection, or second, it could be a so-called "foreign body". A foreign body is an object from outside the body that sometimes tracks in beneath the skin. Examples include thorns and grass seeds. When this happens, the immune system reacts by trying to expel the object from the animal's body. Foreign bodies tend to be seen in the feet (after dogs stand on objects) or around the head (sometimes when a dog is chewing a piece of wood, a splinter penetrates the lining of the mouth).
In Yuki's case, a foreign body seemed unlikely: how on earth could an object get under the skin of her abdomen? I treated her for the other possibility - an infection - to start with. She was given a course of antibiotics, and within a couple of days, the lump had begun to shrink down. After a week, it had almost vanished. If an infection had been the entire cause of the swelling, this would be the end of the saga. However it's common for infection to gather around a foreign body, in which case antibiotics make the swelling shrink initially, but when the course is finished, the swelling gets bigger again. There was an anxious few days after the antibiotics stopped: what would happen next?
I was not hugely surprised when the lump swelled up again: this confirmed, that yes, there probably was a foreign body in there. But the big question was: how could I find it and remove it? In theory, surgery is the answer, but in practice, it can be like looking for a needle in a haystack. A tiny foreign body can be very difficult to locate. The safest answer was to get an MRI scan done: this would give me a three dimensional image of the lump, and it would show up objects - like pieces of wood - that do not show up on xrays.
Yuki was scheduled for her MRI scan, but while we were waiting for this to happen, something dramatic happened. Her owner noticed something hard beginning to protrude from the side of the lump, and then the skin of the surface of the lump burst open, and there was something small protruding from it. She bravely grasped this and tugged: and it turned out to be a small piece of wicker-type wood, measuring just 2cm long.
Now the pieces of the puzzle could be fitted together. Yuki had chewed a wicker basket, and she must have swallowed bits of wood, causing the initial episode of vomiting. Her stomach must have contracted hard against a sharp piece of the wood during a vomiting session, and this had then penetrated her stomach wall, moving into her abdomen.
And that's where her clever immune system had come into play: her body had naturally "pushed" the piece of wood towards the outside world. As it moved towards the outer surface of the skin on her left flank, a firm swelling of inflammatory tissue had grown around it, causing the lump which had been worrying us. Eventually, the immune system had succeeded: it had pushed the wood right out of the body.
Yuki didn't need any further treatment: her immune system had managed to carry out a complete cure. The lump vanished, and this time, it was gone forever.