Clinical history and questions
Necropsy view of pancreas of a dog: euthanasia by intravenous barbiturate
Close-up necropsy view of the duodenum and associated tissues of a 6 year-old dog that was killed at a local refuge by intravenous barbiturate overdose. There was no relevant history: the animal was simply surplus to the requirements of the donor family and had been deemed unsaleable. It was acquired for an undergraduate practical class.
- Describe the abnormalities.
- What underlying disease process/es could produce these changes?
- Make a differential diagnostic list, in order of probability.
- With your preferred diagnosis in mind, what is the pathogenesis of these macroscopic changes?
- Relate the pathology to the clinical signs.
An interpretation of Diagnostic Exercise No. 7 – Roger Kelly
The duodenum in this view appears normal, apart from a single small haemorrhage near the mesenteric insertion, but the adjacent pancreas shows a striking dark red variegated pattern that outlines the interlobular septa, and this discoloration sometimes progresses into the lobules themselves. The pancreatic serosal surfaces appear normal. The adjacent omentum is focally reddened, but this may be due to contamination with blood from the dissection.
Interpretation (basic underlying disease process/es):
There appears to be no hyperaemia, fibrin or pus deposition, nor any scarring, so inflammation of the pancreas seems less likely than simple haemorrhage. Likewise, there has been no visible new growth, nor are there any anatomical curiosities to suggest a developmental disorder. So, by elimination, the principal disease process is a degenerative process characterised chiefly by haemorrhage into the pancreatic interstitium.
Preferred morphological diagnosis (with differential):
Recent interstitial pancreatic haemorrhage is much more likely than acute haemorrhagic pancreatitis, with a haemorrhagic neoplastic condition (such as metastatic haemangiosarcoma) even less probable.
In the past, when poisoning dogs with strychnine was something of a suburban sport in Brisbane, agonal interstitial haemorrhage of the thymus and pancreas was regarded as a useful gross diagnostic feature, and was held to be due to cataclysmic spiking of blood pressure during convulsions. However, as the supply of strychnine diminished, this haemorrhage continued to turn up unpredictably, usually in otherwise healthy animals killed humanely in refuges. I know of no plausible explanation for it.
This agonal change continues to trick trainees into provisionally diagnosing acute pancreatitis/necrosis, but in these conditions there is invariably some necrotising effect on adjacent fat depots, and there is true hyperaemia of serosal blood vessels, and fine fibrin deposits on serosal membranes are expected.