Equine hyperadrenocorticism: A report of 4 natural cases


C. K. KOUTINAS (X.K. ΚΟΥΤΙΝΑΣ)
M. N. SARIDOMICHELAKIS (Μ.Ν. ΣΑΡΙΔΟΜΙΧΕΛΑΚΗΣ)
M. E. MYLONAKIS (Μ.Ε. ΜΥΛΩΝΑΚΗΣ)
K. HAMHOUGIAS (Κ. ΧΑΜΧΟΥΓΙΑΣ)
A. FYTIANOU (Α. ΦΥΤΙΑΝΟΥ)
N. DIAKAKIS (Ν. ΔΙΑΚΑΚΗΣ)
A. F. KOUTINAS (Α.Φ. ΚΟΥΤΙΝΑΣ)
Abstract

Hyperadrenocorticism, the most common equine endocrinopathy, is the result of hyperplasia or a functional adenoma of the pars intermedia (intermediate lobe) of the pituitary gland. The study population included a 20-year old Irish hunting gelding (case 1), a 13-year old English Thoroughbred stud horse (case 2), an 18-year old intact male donkey (case 3) and a 22-year old mare belonging to a mixed breed (case 4). From a historical and clinical standpoint, the most common clinical signs were hypertrichosis (4/4), progressive loss of body weight (3/4), polyuria-polydipsia (3/4), laminitis (3/4), depression-lethargy (2/4), sway-back (lordosis) (2/4), pot-belly (2/4), bulging of the supraorbital region due to the excessive deposition of adipose tissue (2/4), hyperhidrosis (2/4) and delayed wound healing (2/4). The results of the routine laboratory testing showed lymphopenia (4/4), anemia (2/4), mature neutrophilia (1/4), monocytosis (1/4), hypertriglyceridemia (4/4), increased ALP activity (3/4), hypocalcemia (3/4) and hypoalbuminemia (2/4). Also, case 2 developed type III diabetes mellitus as a consequence of the disease. The diagnosis of hyperadrenocorticism, that was initially based on the classical clinical signs, noticed in all 4 animals, was further confirmed in 3 of them (cases 1, 3, 4) with the overnight dexamethasone suppression test. Oral bromocryptine (dopamine agonist), that was subsequently prescribed in two horses (cases 1, 4) resulted in a remarkable clinical improvement, first noticed in both animals approximately two months after the beginning of the treatment.

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