Discrepancy between Clinical and Postmortem Diagnosis of Dogs in a Veterinary Medical Teaching Hospital

Abstract

Background: The postmortem examination offers the opportunity to study the processes involved in disease. Although a portion of veterinary medical professionals and students consider the necropsy as a diagnostic tool of purely academic interest, it can provide valuable assistance in formulating health strategies in order to prevent and control animal diseases. The number of necropsies performed in general is higher in universities where the cost is subsidized. In veterinary medicine, studies intended to assess the frequency of necropsy and the discrepancy between clinical and postmortem diagnosis of dogs are rare. The main purpose of the necropsy is to discover the cause of death of dogs, by defining a possible etiology and pathogenesis in order to reach a diagnosis.

Material, Methods & Results: We used medical records and necropsy records to define the clinical and postmortem diagnosis, respectively. Data relating to deaths was recorded as the number of euthanized dogs and natural deaths in 2014. From the information cause of death, these were categorized as infectious disease, cardiac, gastrointestinal, renal, pulmonary, neurological, metabolic or endocrine disease, neoplastic disease, trauma, or systemic disease. We used the Binomial discrepancy in the comparison of the rates between different years and also to verify the association between discrepancy and the correlation between clinical and postmortem diagnosis of dogs with euthanasia and natural death, with statistical significance (P < 0.05). In 2009, 56.81% (25/44) of cases included in the study had a concordance between the clinical and postmortem diagnosis, while 43.19% (19/44) were discordant. In 2014, it was observed that 71.70% (76/106) of the diagnosis was confirmed with the necropsy, while 28.30% (30/106) were discordant. The disagreement rate was higher in 2009 (P < 0.05) and there was a reduction of 14.89% in the disagreement rate between 2009 and 2014. Regarding the cause of death, infectious diseases, gastrointestinal disease, and heart disease were the categories in which the discrepancy was higher. It was found that in the group of dogs euthanized, the discrepancy rate was lower compared with the group of dogs that had anatural death (P < 0.05).

Discussion: The disagreement rate can be considered high when compared with a veterinary study and similar to those observed in a human study. Decrease in the discrepancy rate in the years, as observed by other authors, that can be attributed to improvements and expansion of diagnostic services of the hospital and better training of veterinarians. The difficulty in determining the etiology of infectious diseases is associated with lack of specific diagnostic tests and the high cost of available tests, which often is not bank rolled by the tutor. Dogs in this study were rarely submitted to diagnostics tests such as electrocardiogram or echocardiogram which explains the high discordance in the diagnosis of heart disease. Distemper is an infectious disease of great importance regarding euthanized animals, especially in cases that progress to central nervous system injuries with extremely poor prognosis and wind up having euthanasia indication. Another common cause of domestic animals euthanasia indication is the occurrence malignant neoplasms, which depends on the progression of the disease and psychological and social conditions of the owner. The results generated herein suggests that infectious, gastrointestinal and cardiac diseases origin tend to have a greater discordance between clinical and postmortem diagnosis, however this rate is decreasing due to improved infrastructure of veterinary centers with better professionals qualification.