Aspects of Medical Veterinarian Perception About Incidence and Clinical Characteristics of Hyperadrenocorticism in Dogs
M.S. Giacon; M.M. Jericó
Hyperadrenocorticism (HAC) is a set of clinical and chemical abnormalities that results from chronic exposure to high glucocorticoids concentrations in the organism (Feldman & Nelson 2004). Dogs afflicted by HAC present many clinical alterations, secondary to the deep effect on the carbohydrates metabolism, as well as proteins and lipids. Therefore, it's very important that the veterinarian establishes the correct diagnosis and treatment of this disease, seen to be one of the most important endocrinopathies in Veterinary Medicine. The main objective of this study was to evaluate the aspects of the veterinarian perception about the incidence as well as characteristics and conduct for the illness, through research accomplished in clinics in the city of Sao Paulo.
Materials and Methods
During the period from May to August 2008, were interviewed, using a questionnaire form, fifty professionals working in 37 clinics situated in the city of Sao Paulo--SP. The interviews were done personally, through nineteen questions about the illness incidence, main complaints by owners, main symptoms observed, diagnosis tests, treatment of choice, complications, owner's participation and necessity of specialist's indication. The data obtained were tabulated and analyzed, demonstrating the profile of veterinarian's performance about the disease as well as their perception of the illness incidence in the city.
According to the information by the interviewed group, the total general attendance is around 8.000 dogs, with a median of 200 general attendances by clinic, observing one case of hyperadrenocorticism for each 400 new attendances. The most affected breeds as state by the group are poodle (forty, 63%); dachshund (seven, 11%); pinscher (five, 8%), mixed breeds (three, 5%), beagle (two, 3%), terrier (two, 3%), and Yorkshire, Maltese, schnauzer and shi tzu with one representative each (2% each one).
Six veterinarians (10%) did not know the answer. According to the opinion of the interviewed, the most affected sex is female (59%). Concerning the reproductive condition, 24 veterinarians (48%) answered that it did not play a major role if the dog is castrated or entire. 21 (42%) answered that HAC attack more entire dogs; five veterinarians (10%) declared that HAC occurs mainly in castrated dogs. Regarding age, the ones from five to ten years old were most cited by the group (41, 82%), followed by dogs with more than ten years old (six, 12%), and from one to five years (three, 6%).
According to interviewed veterinarians, the main complaint by the owner are dermatological alterations (33; 66%); followed by polydipsia (27; 54%); polyuria (22; 42%); distended abdomen (sixteen; 34%); polyphagia (thirteen; 24%); gain of weight (eleven; 22%), and difficulty of locomotion (one; 2%). The main symptoms presented in anamnesis are hair falls (39, 78%); polydipsia (36, 72%); polyuria (33, 66%); gain of weight (30; 60%), polyphagia (26; 52%); wounded skin (26; 52%); pruritus (eleven; 22%), respiratory distress (six, 12%), loss of weight (five, 10%), distended abdomen (two; 4%) and lameness, anestrus, apathy and thin skin with 2%, each, in conformity with the group.
Concerning the physical examination, the main findings as state by interviewed vets are pendulous abdomen (47, 94%); alopecia (38, 76%); hepatomegaly (31, 62%); pyoderma (24, 48%); hyperpigmentation (twenty, 40%) telangiectasia (sixteen, 32%), muscle atrophy (sixteen, 32%), and testicular atrophy (one, 2%). As initial clinical examination for the diagnostic suspicion, hemogram was the most cited among the interviewed ones (38, 76%), followed by dexamethasone suppression test (35, 70%), glycemia (32, 64%), hepatic function (32, 64%), ultrasonography (31, 62%), renal function (29, 60%), and cholesterol and triglyceride (25, 50%). Urinalysis (sixteen, 32%), ACTH stimulation test (six. 12%), abdominal and/or thoracic radiographs (three, 6%) and thyroid function tests (one, 2%) were less cited by the group. Regarding tests for the confirmation of hyperadrenocorticism diagnosis, 90% of the interviewed ones (n = 45) informed to request dexamethasone suppression test; Nine (18%) affirmed to also use ACTH stimulation test and abdominal ultrasonography, each; 8% (n = 4) request cholesterol and triglyceride dosages; 6% (n = 3) hepatic function, and 4% (n = 2) hemogram. Renal function, urinalysis and glycemia were cited by three professionals, representing 2% each. According to the opinion of the interviewed group, 41 (82%) of them observed diabetes mellitus as concomitant illnesses / HAC complications; 33 (66%) had affirmed observe obesity; 20 (40%) pyoderma; eight (16%) urinary tract infection; seven (14%) hypertension and pancreatitis; congestive heart failure and pulmonary thromboembolism were cited by six professionals (12%), each. One veterinarian informed to have observed hypothyroidism. The preferred therapy, as state by 82% of the interviewed ones (n = 41), is mitotane, followed by ketoconazole, with 20% (n = 10). Three (6%) veterinarians answered not to be used to treat HAC; use of trilostane and adrenalectomy were cited by one professional, each. For complementary treatment, doctors (35, 70%) declared to use mainly insulin therapy in diabetic dogs; diet rich in fibers and poor in fat (eighteen, 36%) and use of vasodilatators (nine, 18%); 24% of the interviewed ones (n = 12) had answered not to use complementary treatment. The main collateral effects observed during the therapy in the opinion of the group are vomit (34, 68%), followed by anorexia (24, 48%), intestinal disturbs (17, 34%), prostration (nine, 18%), generalized pains (three, 6%), pruritus (two, 4%), and poor appetite (one, 2%). Six veterinarians (12%) had said not to observe collateral effects, and two doctors (4%) had declared did not follow the treatment. Concerning the conduct for the appearance of collateral effects, 46% (n = 23) had answered that they interrupt the treatment; 42% (n = 21) had used support therapy (e.g., antiemetics and fluid therapy). The use of prednisone was cited by one professional; 26% (n = 13) of the interviewed professionals affirmed to keep the therapy even with the appearance of collateral effects. Two vets (4%) had decrease mitotane's dose, and four interviewed (8%) did not know the answer. Prognostic was considered reserved by 27 (53%) of the interviewed ones, good for sixteen (32%), and bad for seven (14%). One veterinarian did not know the answer. According to the group, 42 (84%) had affirmed there is owner's cooperation during therapy; three (6%) vets declared that owner do not cooperate and two (4%) consider euthanasia. Three veterinarians did not know the answer. Concerning personal opinion in treating the illness, 36 (72%) of the interviewed ones had declared that they do not like to treat it, and fourteen (28%) like. Among 50 professionals, 35 (70%) had informed that they only forward the dog to a specialist when they do not obtain the adequate control of the illness; twelve (24%) always forward and three (6%) never forward.
Discussion and Conclusions
Results showed that, according to the perception of interviewed veterinarians, hyperadrenocorticism represents only 0.3% of the total taken care animals in Sao Paulo, which is considered low when compared with literature data. This study may disclose some incapacity by the professional in recognizing endocrinology cases of high complexity. The main breed afflicted as state by the group is poodle, in accordance with the literature data, due to its significant genetic predisposition, contributing for the biggest prevalence of this illness. In conformity with the interviewed, the sex that most appeared is female, as well as age from five to ten years old, agreeing with the literature. The owner's main complaint had been dermatological alterations as state by the group, despite literature that reports polydipsia and polyuria are the owner's main complaints (Reusch 2005). Maybe this occur because of the non regular growth of hair after shave as well as the presence of thin hair which bothers the owner more then polyuria/polydipsia. However in the segment of the questionnaire where other symptoms were investigated, according to interviewed veterinarians owners describe polydipsia and polyuria in 72% and 66% of cases, respectively, agreeing with the literature and reveling adequate anamnesis by the group researched. Although the pruritus is not a common symptom of hyperadrenocorticism, it was cited by 22% of the interviewed. It is known that one of the actions of glucocorticoids is its anti-inflammatory effect in the control of several immunomediated illnesses when inhibiting allergenic agent and, consequently, eliminating pruritus, showing that it can have errors of diagnosis by the interviewed veterinarians. Regarding physical examination, abdominal enlargement appears for 94% by the interviewed ones, followed by alopecia and hepatomegaly, reveling good semiologic acuity by them. In relation to the initial examinations, hemogram was the most cited by the group, although it can bring unspecific findings of sick dogs, so it is not the first choice examination. Furthermore, it's known that serum alkaline phosphatase concentration (ALP) increases in about 95% in dogs with HAC, 36% of the interviewed had declared not often to request ALP's dosage, strengthening the idea of possible failed diagnosis. Also, urinalysis was cited by only 32% of the interviewed ones. However, it's known that this examination is one of the most important initial studies in the evaluation of a dog with polyuria/polydipsia syndrome (Feldman & Nelson 2004), demonstrating disinformation by the group. To confirm the hyperadrenocorticism diagnosis, 90% of the interviewed ones answered to request dexamethasone suppression test, being in accordance with literature, which considers this test more sensible for diagnosis of HAC when compared with ACTH stimulation test. However, only 18% of the interviewed affirmed to request ACTH stimulation test, showing a lack of knowledge by ignoring the use of this important test. Diabetes mellitus (DM) was the main concomitant illness complication in the opinion of 82% of interviewed group, despite the North American literature affirms that only 10% of dogs with HAC develop DM. It is known that sterilization, and consequence suppression of progesterone production, decrease the risk of diabetes mellitus in female dogs (Feldman & Nelson, 2004). Moreover, the canine population control by sterilization is well spread out in Europe and U.S.A., in contrast to Brazil, which could justify the high incidence observed of diabetic animals in this study (Cantagallo et al. 2008). In our research, as already cited, only 32% of the interviewed ones had declared to request urinalysis as initial examination, despite other studies had shown that approximately 50% of the dogs with HAC presents urinary tract infections (Forrester & Troy 1999), demonstrating imperfection by the interviewed ones not requesting an important examination to identify a complication of HAC. Although only 14% of the interviewed had cited hypertension as a possible complication of HAC, it is known that great percentage of dogs with HAC is hypertensive (Reusch 2005). It is probable that a few vets interviewed measure the arterial pressure as routine procedure in their patients justifying the low and erroneous number of hypertensive animals in this research. According to the majority of the interviewed veterinarians (82%), the treatment used is mitotane, as this drug is the most known drug in the therapy of HAC.
Furthermore trilostane commercialization in our country still very limited. For complementary treatment, use of vasodilatators was cited by only 18% of the doctors, reinforcing the hypothesis that only few professionals carry through measurement of arterial pressure. Also, concerning diet rich in fibers and poor in fat, only 36% of the interviewed ones had affirmed to use it, indicating that they do not give the right importance for the alimentary handling. Collateral effects more observed during the treatment as state by the interviewed group had been similar as the ones described in literature. However, regarding the conduct for the appearance of these effects, less of the half of the interviewed ones declared to interrupt the treatment. In addition, 26% had affirmed to keep it even with the appearance of collateral effects, and only one professional cited the use of prednisone in the support treatment by occurrence of iatrogenic hypoadrenocorticism crisis. No professional cited neither the realization of ACTH stimulation test nor serum dosage of sodium and potassium, showing clearly a lack of technical knowledge when therapy complications appear. When questioned about their personal position in treating HAC, 72% of the interviewed ones declared that they do not like to treat patients with HAC, which could be a symptom of low experience they have in conducting the diagnosis as well as the treatment of this affection. Furthermore, 70% had informed only forward the animal to a specialist when they do not obtain adequate control of the illness, showing a controversial position by the interviewed ones, since although the great majority affirms that they do not like to treat HAC. Analysis of these results show partial similarity with other studies, concluding that, according to the perception of the interviewed veterinarians in this study, the city of Sao Paulo has low incidence of hyperadrenocorticism, and they also reveal a moderate knowledge over the disease and a significant deficiency in the diagnosis approach, as well as inadequate conduct in treatment.
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