A 7-year-old male castrated mixed breed dog was presented because of acute haemorrhagic vomiting and watery haemorrhagic diarrhoea. According to clinical signs, nonspecific clinicopathological abnormalities, normal electrolytes and a rapid improvement with fluid therapy, haemorrhagic gastroenteritis (HGE) was suspected. One month later the dog was represented with weakness and electrolyte changes characteristic for typical hypoadrenocorticism (hyperkalaemia and hyponatraemia) were found. The tentative diagnosis was confirmed using an ACTH stimulation test. This case report highlights that dogs with hypoadrenocorticism may be presented with acute haemorrhagic diarrhoea. Electrolyte changes characteristic for hypoadrenocorticism may not be present in case of gastrointestinal potassium loss because of vomiting and diarrhoea. To rule out hypoadrenocorticism, a basal cortisol measurement should be performed in every dog with acute haemorrhagic diarrhoea of unknown cause.
Keywords: Addison‘s disease; HGE; haemorrhagic gastroenteritis.