Hypervitaminosis D
- May be of dietary or iatrogenic origin (has narrow safety margin)
- Key features are hypercalcaemia with metastatic calcification of soft tissues
- Acute poisoning
- In dogs and cats often from rodenticides containing cholecalciferol
- Grossly:
- Gastrointestinal haemorrhage
- Foci of myocardial discoloration
- Microscopically:
- Mucosal haemorrhage
- Necrosis of crypts
- Focal myocardial necrosis
- Mineralisation of intestinal mucosa, blood vessel walls, lungs and kidneys
- Chronic poisoning
- Grossly:
- Intense osteoclastic activity -> active resorption of bone, especially trabecular
- Microscopically:
- Excessive production of osteoid - appears both eosinophilic and basophilic in different places
- Marrow cavity may be obliterated
- Mineralisation of soft tissues, especially blood vessel walls
- Due to inhibition of Parathyroid Hormone (PTH)|PTH and increase of calcitonin
- Grossly: