Pathomorphological evaluation of hepatobiliary lesions in dogs and cats of Ankara region

The objective of this study was to investigate pathological disorders of the hepatobiliary system in dogs and cats in Ankara using pathomorphological methods, and to determine the types and frequency of the observed lesions. Furthermore, we aimed to evaluate hepatic reparation as a reaction of the liver to injury with different hepatobiliary lesions using immunohistochemical methods. Livers obtained from 56 cats and 74 dogs submitted for post-mortem investigation were examined macroscopically and microscopically. Samples with hepatic fibrosis were stained immunohistochemically with an α-SMA antibody. Lesions were found in 98% of the livers of the examined dogs and cats. The most common histopathological diagnoses were hepatitis (39.28%), hepatocellular lipidosis (16.07%), and cholangitis/cholangiohepatitis (14.28%) in cats. In dogs they were hepatitis (28.38%), passive congestion (25.68%) and proliferative lesions (21.62%). For some hepatobiliary lesions, breed, age and gender predispositions were observed. Immunohistochemically, the α-SMA antibody positively stained parenchymal, portal and septal myofibroblasts. A positive correlation was verified between immunohistochemical α-SMA scores and histochemical fibrosis scores. This is the first study in Turkey documenting both the incidence of hepatobiliary lesions among feline and canine species, and their pathomorphological features. In terms of reparation, the major role of the hepatic myofibroblasts in liver fibrosis was observed. There were variations in the intensity and location of positively stained cells according to the type of lesion. The conclusion of this research indicates the need to pay attention to certain hepatic lesions in dogs and cats, and provides a reference standard for further clinical and histopathological studies.

Right Atrioventricular Valvular Dysplasia in a New Zealand White Rabbit

A sixteen-week-old, male New Zealand White rabbit was euthanized following an acute onset of respiratory distress and cyanosis. On necropsy, the rabbit had marked right atrioventricular eccentric hypertrophy, absence or rudimentary presence of the septal leaflet of the right atrioventricular valve, focally extensive left ventricular infarction, diffuse hepatic chronic passive congestion, and diffuse pulmonary edema. To our knowledge, right atrioventricular valvular hypoplasia, dysplasia, or aplasia has not been previously described in rabbits.

Congestive Hepatopathy

Liver disease resulting from heart failure (HF) has generally been referred as “cardiac hepatopathy”. One of its main forms is congestive hepatopathy (CH), which results from passive venous congestion in the setting of chronic right-sided HF. The current spectrum of CH differs from earlier reports with HF, due to ischemic cardiomyopathy and congenital heart disease having surpassed rheumatic valvular disease. The chronic passive congestion leads to sinusoidal hypertension, centrilobular fibrosis, and ultimately, cirrhosis (“cardiac cirrhosis”) and hepatocellular carcinoma after several decades of ongoing injury. Contrary to primary liver diseases, in CH, inflammation seems to play no role in the progression of liver fibrosis, bridging fibrosis occurs between central veins to produce a “reversed lobulation” pattern and the performance of non-invasive diagnostic tests of liver fibrosis is poor. Although the clinical picture and prognosis is usually dominated by the underlying heart condition, the improved long-term survival of cardiac patients due to advances in medical and surgical treatments are responsible for the increased number of liver complications in this setting. Eventually, liver disease could become as clinically relevant as cardiac disease and further complicate its management.

Unusual caudal vena cava thrombosis in a cow, secondary to Trueperella (Arcanobacterium) pyogenes infection

The caudal vena cava thrombosis, or pulmonary thromboembolism, in cattle is correlated with lactic acidosis, caused by diets rich in grains and highly fermentable, associated or not to septic situations, used in feedlots of beef or high-producing dairy cattle. This paper reports an unusual caudal vena cava thrombosis in a cow, secondary to Trueperella (Arcanobacterium) pyogenes infection, resulting in reduced milk production, anorexia, pale mucous membranes, ruminal atony, sternal decubitus and autoauscultation position. The heart was enlarged at necropsy, presence of clots distributed along the thoracic cavity, adherence between lung and pleura, abscesses, emphysema, petechiae, suffusions and ecchymosis in lungs, thickening of the caudal vena cava wall, hepatomegaly with chronic passive congestion ("nutmeg" aspect), and rumenitis. In lab, the actinomycete Trueperella (Arcanobacterium) pyogenes was isolated from liver and lung samples, probably resulting through dissemination of the bacteria of the rumen content, what reaffirms the opportunistic behavior of this actinomycete.

Gossypol Toxicosis in a Dog Consequent to Ingestion of Cottonseed Bedding

Six dogs died after accidental ingestion of cottonseed bedding. No clinical signs of illness were observed prior to death. A full diagnostic workup was performed on one of these dogs. At necropsy, the lungs were congested and edematous, and the liver was firm, congested, and had a marked reticular pattern. There was also moderate ascites. Histopathologic examination revealed multifocal myocardial degeneration and necrosis, severe pulmonary edema, and chronic passive congestion of the lungs, heart, liver, and kidneys. Transmission electron microscopy of the myocardium revealed disruption of myofibrils, chromatin condensation, and disrupted and swollen mitochondria. The cottonseed bedding contained 1,600 mg/kg of free gossypol, a concentration considered toxic for monogastric animals. The stomach content revealed the presence of gossypol, thus confirming ingestion of cottonseed. Gossypol poisoning in dogs is extremely rare and has not yet been associated with cottonseed bedding. This first documented case of gossypol poisoning in a dog, caused by the ingestion of cottonseed bedding, demonstrates how specific toxicological analysis is crucial in reaching an accurate diagnosis.