© 2015 
Lokes P. I., Doctor of Veterinary Sciences
Kravchenko S. O., Candidate of Veterinary Sciences
Poltava State Agrarian Academy
CHARACTERISTICS OF SELECTED FACTORS
OF SPLENOMEGALY IN DOMESTIC DOGS
Reviewer – Doctor of Veterinary Sciences, Professor B. P. Kyrychko
Results of scientific research for the study of etiological factors, clinical symptoms, laboratory values and changes of ultrasonographic features for splenomegaly in dogs are presented in this work. We established that the etiological factors of splenomegaly is pathologies which is accompanied by blood circulation disorders, haematopoiesis and a pigmentary metabolism. Clinical symptoms of splenomegaly is increasing the size of spleen, as determined by palpation and ultrasonography. The basic provisions for implementing splenomegaly classification in animals with determination of an isolated and systemic form are stated.
Key words: spleen, dogs, splenomegaly, isolated, systemic, ultrasonography.
Statement of the problem. In the modern literature there is no common point of view on function of the spleen in vital activity of the organism. The majority of scientists do not consider spleen as vitally important organ [4, 5, 7, 10]. However, this does not mean that it owns a secondary role. The spleen performs various functions in metabolism, plays a major role in erytrotsytopoesis, through the activities of reticuloendothelium and endocrine effects on the metabolism of hemoglobin, reveals, carries out preparation and utilizes the destruction of abnormal blood corpuscles, regulates erythrocyto-, leukocyto- and trombocytopoiesis in the bone marrow. More over, it retards bacteria and other foreign impurities. Spleen regulates volume of circulating blood due to depositing, and is also involved in lipid metabolism [11].
In addition, special capillary net of the spleen is involved in regulation of portal circulation, that is spleen performs numerous functions through a complex regulatory system that is still insufficiently studied. In recent years new pathologies of the spleen, developed the methods of diagnosis and treatment, were identified. In particular, the most common reaction of the spleen to different pathological processes in the body is splenomegaly [3, 9]. This is an acute or chronic enlargement of the spleen, regardless of the etiological factor. However, publications about the pathology of the spleen in animals are rare and quite fragmented.
So, studying the problem of pathological conditions of the spleen in animals is relevant.
Analysis of major studies and publications which started a solution of the problem. Analyzing the publications about the pathology of the spleen, it should be noted that in national publications only a few investigation on this topic can be found. General information about the spleen in animal shigh light, preferably the topography of organ.  In some works the features of general clinical methods of investigation of the spleen are explained. Thus, in cattle it can`t investigate, in horses is possible only rectal palpation of the posterior part of the edge, the dogs – bimanual palpation of the spleen through the abdominal wall. And only expressed splenomegaly, which may be caused by purulent inflammation, bacterial infections or leukemia may reveal spleen percussion (cattle and horses) or palpation (horses, dogs, cats). One of the extra instrumental methods of research is spleen puncture but unfortunately it is technique which is described only in cattle and horses [6]. In general, the majority of authors indicate significant difficulties in clinical diagnosis of pathological conditions of the spleen, which is often found only postmortem [5, 6, 10]. One of informative and non-invasive instrumental method of studies of the spleen is ultrasonography, which technique is described primarily in foreign [2] and certain national literature [8]. An analysis of the literature shows that clinical research of the spleen in animals is difficult and possible only with splenomegaly. There is limited information about increasing the size and character of ultrasonographic changes of spleen for internal diseases. On the other hand, splenomegaly it is the most widespread reaction of the spleen to various internal diseases. Splenomegaly in animals of various kinds can be caused by blood circulation, accumulation of the pigment bilirubin, hypertrophy, hyperplasia, parasitic diseases, suppuration, cystic lesions, tumors and other pathological conditions on which spleen responds with increasing of its volume [7]. In humane medicine, there are several classifications of splenomegaly, mainly for etiopathogenetic factors. There are two types of  splenomegaly: isolated and system. In veterinary medicine, such a classification is not implemented. Obtained data give us a reason to direct their researches exactly in this direction.
The purpose of research – analysis of etiopathogenetical internal pathology factors in dogs, accompanied by splenomegaly. The main task was to study the manifestations of splenomegaly in various pathological conditions.
Materials and methods. The study was conducted in conditions of therapy department of Poltava State Agrarian Academy in the period from 2009 to 2015. The material for the research served as clinically healthy and sick dogs, which recorded an increase of the spleen. During the implementation of the work we used the research results of 10 clinically healthy and 73 sick animals. Principal diagnosis, if necessary, was confirmed by laboratory tests of the biological substrates and instrumental methods. During the clinical examination of sick animals, diagnosis, pay attention to the information content of palpation of the spleen, and in the case of a positive result – ultrasonography of the abdomen was used. To compare results we investigate clinically healthy dogs. In conducting the ultrasonography SonoScape A6 vet (manufacture China) from 2–6 MHz transducer was used.
Results. In clinically healthy dogs spleen were found in the left side of the abdominal cavity. In healthy animals, it took the form of tape with sharp edges, which are well sonographic visualized. This pathology such as body gaps, distortions of spleenlegs with acute or recurrent course, spleen tumors or cysts, echinococcosis of the spleen, abscesses, congestive spleen, splenic vein thrombosis and splenic artery embolism.
 To splenomegaly of systemic type we treated cases in which, besides an enlarged spleen, dysfunction of hematopoiesis, accompanied by anemia and jaundice (mainly hemolytic), leishmaniasis, diseases, which are characterized by hemolytic anemia and hemolytic jaundice, thrombocytopenia, hepatic cirrhosis and so on had been characterized. We found splenomegaly in dogs on some non-contagious, parasitic and infectious diseases (see table).
Diseases accompanied by splenomegaly in dogs
Pathologies	Total of patients	Splenomegaly	
		heads	%	
Offset stomach	8	8	100	
Intussusception	7	7	100	
Hepatitis	18	10	55,6	
Cirrhosis	6	2	33,3	
Cysts of spleen	3	3	100	
Polytrauma	4	3	75,0	
Babesiosis	26	26	100	
Echinococcosis of spleen	1	1	100	
According to data of table, in eight dogs (100 %) splenomegaly developed as a complication of acute expansion and twisting of the stomach. In these animals the spleen was enlarged, irregular shape, leg of spleen formed artery and vein has been distorted, causing violations of hemodynamics. This can be explained by pathophysiological displacement of spleen caudate ventral under pressure of the enlarged stomach, which leads to stretching of lig. gastrolienaleand distortion of spleen vessels and causes venous congestion in this organ. As the spleen is a powerful organ (can hold up to 16 % of blood volume [1]) splenomegaly is developing and spleen occupies most of the abdominal cavity. The results of splenectomy surgery showed that in such cases in the spleen developing irreversible necrotic changes. These cases should be considered as an isolated form of splenomegaly. Intussus ception (seven animals) is accompanied by the development of splenomegaly in 100 % of cases. It is known that this pathology is characterized by partial or complete intestinal obstruction that leads to stagnation of chyme, development of barmy and putrefactive processes – intestinal autointoxication. On the other hand, intestinal obstruction causes poor circulation in the abdomen, with predominant venous congestion, especially in the periportal area. In this case, splenomegaly should be attributed to the group of system and regarded as a compensatory response of spleen directed at redistribution of blood, and caused by intoxication. 
Another diseases which was accompanied by a splenomegaly in dogs was hepatitis, which developed as a result of various etiological factors (alimentary intoxication, metabolic action of infectious agents, etc.). In 55,6 % of cases the spleen was moderately enlarged, the edges had been blunted, but not rounded. Splenomegaly development for hepatitis has several reasons. It is a common gantry blood circulation of liver and spleen, as well as violation of pigment metabolism (bilirubinemia) and anemia that accompanied with the development of hepatitis. Since splenomegaly was not expressed in all animals, sick on hepatitis, obviously, its development depends on the severity of pathological processes in the body, so it should be considered as systematic. Exploring dogs’ sick on acute and chronic forms of babesiosis, we have established the development of splenomegaly in 100 % of cases. Enlarged spleen demonstrated by palpation and confirmed by sonography. Laboratory examination of the blood of these dogs set hemolytic blood changes, hypochromic anemia and poikilocytosis that allows to classify it to the systemic group. In three dogs with sonography we found an isolated anechogenic parenchyma formation in spleen sizes of 26, 34 and 58 mm. Thus, organ edges had been rounded and parenchyma was swollen. However, the clinical picture of the blood of these animals did not differ from that of healthy. Diagnostic laparoscopy revealed non-invasive spleen cysts filled with transparent liquid, the wall of which is formed by several layers of cells and connective tissue of spleen capsule. In one dog revealed echinococcosis of spleen. These cases can be classified as isolated splenomegaly.
Splenomegaly was also found in dogs that came to the clinic after a polytrauma due to car impact (three cases out of four). Ultrasonographic showed hypoechoic centers with different size, irregular shape in the parenchyma of spleen. Two dogs had irregular contours of the capsule. Laparotomy has established ruptures and massive hemorrhages under the capsule and in two animals – in the abdominal cavity. Laboratory blood tests showed normochromic anemia, hypovolemia, lower ESR, that changes characteristic for posthemorrhagic state. It is isolated cases of splenomegaly.
Splenomegaly by cirrhosis of the liver was observed in two out of six animals. Thus, features of ascites were present in three animals. Common laboratory parameters were bilirubinemia features of parenchymal jaundice, hyperchromic anemia, thrombocytopenia, high activity of «liver» transaminases, alkaline phosphatase and indicators of connective tissue. Such cases advisable we include to system splenomegaly.
Consequently, studies indicate that splenomegaly accompanies progress of a number of pathologies of different etiology and pathogenesis. In some cases, enlargement of the spleen is a result, in others – an important pathogenetic link. The classification of various etiologies of splenomegaly in animals gives an opportunity the clinician in time to navigate the complex pathophysiological processes that occur in a sick body.
Conclusion. The spleen is an important hematopoietic, immune organ and plays significance physiological role of which is not fully understood by science. Informational clinical investigation status and functions of spleen is limited, requiring searching for new methods of informative studies of this organ. Splenomegaly is one of the manifestations of spleen response to pathophysiological changes in the body of animal, the study of which deserves attention and requires a significant amount of research. The complexity of causal relationships of spleen pathologies with other organs and body systems requires a search for a rational classification of splenomegaly in veterinary medicine.
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