Clinical features, anaesthetic management and perioperative complications seen in three horses with pheochromocytoma
Authors: Daisy Norgate, A. Foster, B. Dunkel, S. Spiro, K. Veres-Nyéki
Journal: Veterinary Record Case Reports
Summary
# Editorial Summary: Pheochromocytoma in Horses—A Diagnostic and Anaesthetic Challenge Pheochromocytoma, a catecholamine-secreting adrenal tumour, is rarely diagnosed ante-mortem in horses, yet three cases presenting with acute colic between 2013 and 2017 at the Royal Veterinary College suggest it may be underrecognised. All three horses underwent emergency laparotomy under general anaesthesia; whilst one had identifiable haemoperitoneum, the others showed no obvious surgical pathology, yet all deteriorated rapidly with haemodynamic instability and were euthanased within 12 hours. Retrospective analysis revealed consistent biochemical markers—hyperglycaemia, hyperlactataemia, and markedly elevated packed cell volumes (>65% in two cases)—alongside perioperative hypertension and tachycardia that proved refractory to standard management. Recognition of this triad of findings (extreme haemoconcentration, metabolic derangement, and sudden haemodynamic crisis during colic surgery) should prompt consideration of pheochromocytoma and heightened vigilance during anaesthesia, as catecholamine surges triggered by handling or surgical manipulation can precipitate life-threatening cardiovascular events. Farriers and equine practitioners should be aware that acute abdominal pain with marked dehydration disproportionate to clinical signs, combined with unexplained tachycardia and hypertension, warrants thorough pre-operative screening before elective procedures.
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Practical Takeaways
- •Consider pheochromocytoma in colic cases presenting with unexplained haemodynamic instability during anaesthesia, elevated PCV, hyperglycaemia, and hyperlactataemia — early recognition may alter perioperative management strategy
- •Expect significant challenges with blood pressure control perioperatively; prepare for episodes of hypertension and tachycardia that may not respond well to standard interventions
- •These tumours carry a grave prognosis; counsel owners that emergency surgery may not resolve the underlying condition and post-operative survival is poor
Key Findings
- •Three horses with pheochromocytoma presented with colic signs and haemodynamic instability during general anaesthesia, characterized by intermittent hypertension and tachycardia
- •Elevated packed cell volume (>65%) was identified in two cases and high-normal PCV in the haemoperitoneum case
- •Hallmark biochemical findings included hyperglycaemia and hyperlactataemia in all three horses
- •All horses deteriorated within 12 hours of surgery and were euthanased due to intractable pain and haemodynamic instability