2017 - 86 (4)

Title: 
Pheochromocytoma in a horse with polymorphic ventricular tachycardia
Author(s): 
A. DUFOURNI, D. DE CLERCQ, L. VERA, B. BROUX, L. LEFERE, L. BOSSELER, H. VERSNAEYEN, G. VAN LOON
Abstract: 

A twenty-four-year-old mare, which had been examined seven years earlier for mitral valveregurgitation and mild left sided cardiomegaly, was presented with tachycardia, profuse sweatingand muscle fasciculations. Blood examination revealed an increased packed cell volume, metabolicacidosis, hypocalcemia, hyperglycemia and increased cardiac troponin I concentration.ECG revealed ventricular premature beats and monomorphic ventricular tachycardia followedby polymorphic ventricular tachycardia with R-on-T phenomenon. The horse was treated immediatelywith hypertonic solution followed by isotonic solution and calcium, but the general conditiondeteriorated within forty-five minutes after arrival. The horse was euthanized due to poorprognosis. On necropsy, a pheochromocytoma of the left adrenal gland was found. Although thishorse had undergone a cardiovascular examination seven and one year prior to the onset of theclinical signs, no indications for a neoplastic process or symptoms of a pheochromocytoma werefound at that time. Early diagnosis of pheochromocytoma is based on catecholamine mediatedcardiovascular effects, blood examination, blood pressure measurement, rectal palpation andrectal ultrasound of the adrenal gland. Based on a retrospective analysis of echocardiographicimages and measurements, no predisposing factors were found. In this article, the importance ofincluding pheochromocytoma as a differential diagnosis is highlighted, especially in older horseswith acute polymorphic ventricular tachycardia, sweating, muscle tremors and signs of acuteabdominal pain.

Full text: 
pp 241-249