Monday, July 20, 2015

Why dogs should avoid the hor d'oeuvres: the tale of a migrating toothpick

Devils on horseback
These, I am told, are "devils on horseback". A plate like this, left unattended, can easily turn into "devils inside a dog".
Reading a decent case report is like reading a great detective story, with the added bonus of learning something you might use in practice.

In this month’s issue of the Australian Veterinary Practitioner there is a case report, modestly entitled “Toothpick as a perforating splenic foreign body in a dog: ultrasonography diagnosis and surgical treatment”. Some of you might have tuned out half way through the title, but this little tale contains some very important lessons for dogs and those who live with them – as well as their vets.

Let me paint the picture for you. A five-year-old, 8.5kg male dachshund, kept indoors with another dachsy, is a much loved companion. The owner dotes on the dogs and I would imagine these dogs are the kind who are ever-present when one is preparing meals or hor d’oeuvres for special occasions.

But this poor dog develops diarrhoea, which continues for about two months. There is occasional vomiting and abdominal pain. It’s one of those cases where they have good days and bad days, the signs are occasionally subtle, sometimes more dramatic, but nothing to write home about.

The regular vet, concerned there might be something more sinister going on (perhaps pancreatitis) refers the dog for an abdominal ultrasound. The dog has peritonitis – an inflamed abdomen containing free fluid, which was sampled and contained bacteria and inflammatory cells. Ultrasound is very good for detecting fluid, but when there is a lot of fluid it can mask some things that would otherwise be visible.

No diagnostic test is 100 per cent perfect, none guarantees a definitive diagnosis and far too often in a veterinary context we’re reluctant to repeat a test, instead moving up the diagnostic ladder. Fortunately, after some fluid was drained, the ultrasound was repeated. The culprit, previously hidden by a volume of fluid, was immediately visible: a toothpick sitting in the spleen.

How does a toothpick get into a spleen? One of two ways. One either falls on that toothpick with such force that it is rammed through the skin and lodges into the organ, although you’d imagine there would be an obvious wound or tract. OR one swallows the offending toothpick which, with its pointy tips, simply perforates the stomach and goes a-wandering around the abdomen until it lodges somewhere else.

Pointy foreign bodies can migrate, I found this kebab tip in a skin abscess in a dog that had nibbled on a kebab several months prior. 
Once the toothpick was sited, the owner vaguely recalled a possible window during which the dog might have ingested the toothpick – around two months ago. That explains the chronic signs.

Foreign bodies – particularly those that don’t obstruct the gastrointestinal tract – can be very tricky to diagnose. They can cause intermittent, waxing and waning clinical signs. Bloodwork may be unremarkable. Wood and plant material, including toothpicks, don’t show up very well on radiographs.

There are several morals to the story.
  1. Be very wary when using toothpicks or those sharp wooden kebab skewers anywhere in the vicinity of a canine (and remember that dogs don’t mind going through the trash after you have a party, and toothpicks are the sort of thing that perforate garbage bags so are easily sited and removed by dogs).
  2. If you detect evidence of inflammation in the thorax or abdomen, consider a migrating foreign body as a possibility.
  3. Ultrasound is an important diagnostic step for identifying the cause of abdominal pain, but it might have to be repeated.

Fortunately for this patient the diagnosis was the tricky bit. Once that was achieved the surgery was (relatively speaking) a piece of cake. The toothpick was easily located and very gently extracted from the spleen by simply pulling it out. There was no major haemorrhage and certainly no need to remove the spleen. The abdomen was lavaged (washed with sterile saline) and he made a complete recovery.

Reference


Silva DM, Pavelski M, Govoni VM, de Oliveira ST and Froes TR (2015) Toothpick as a perforating splenic foreign body in a dog: ultrasonography diagnosis and surgical treatment. Australian Veterinary Practitioner 45(2):91-93.