Congenital extrahepatic portosystemic deviation of gastric vein with azygos in a bitch

Background: Portosystemic shunt (PSS), an alteration commonly found in toy dogs, is caused by an anastomosis between the systemic and portal circulation, interfering with the metabolism of several toxins. It can be of congenital or acquired origin and is classified as intra- or extrahepatic. Clinical signs include the gastrointestinal tract, nervous system, and urinary system according to the fraction of the shunt. It is diagnosed by several imaging tests and exploratory laparotomy. Therapy involves drug therapy and/or surgical correction of the anomalous vessels. Thus, the aim is to present an unusual case of extrahepatic cPSS originating from the left gastric vein and insertion into the azygos vein. Case: A 2-year-old female toy poodle, spayed, weighing 2.7 kg was treated with a history of recurrent cystitis and neurological signs such as focal seizures, ataxia, tremors, blindness, lethargy, head pressing, and compulsive gait. Complementary tests revealed normochromic microcytic anemia, neutrophilia-induced leukocytosis, monocytosis, and lymphopenia. Biochemical analysis revealed hypoproteinemia due to hypoglobulinemia, an increase in alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and gamma-glutamyl transferase, and a decrease in urea. In the urinalysis, ammonium biurate crystals were detected, and Doppler ultrasound revealed microhepathy and the presence of an anomalous gastrosplenic vein inserted into the azygos vein, a finding compatible with the congenital extrahepatic PSS. Abdominal tomography confirmed vascular deviation with a sinuous path originating from the left gastric and splenic veins, inserting into the azygos vein, measuring approximately 5.95 cm in length. Cranial tomography revealed changes consistent with hepatic encephalopathy. Drug therapy was performed with hydration, liver chow, lactulose, probiotics, metronidazole, S-adenosyl-L-methionine, and ursodeoxycholic acid, and after 15 days, surgery was performed to place a 3.5 mm ameroid constrictor ring for gradual occlusion of the anomalous vessel. The animal recovered well, and a control abdominal ultrasound was repeated 30 days after the procedure, noting that the constrictor had not yet fully occluded the deviation. Doppler imaging revealed a favorable evolution with an increase in the diameter of the portal vein in the hepatopetal direction. The patient was followed-up for a year and had a normal and healthy life. Discussion: Extrahepatic PSS is frequently diagnosed in purebred and toy dogs, commonly occurring between the portal vein and one of its tributaries, with a lower frequency of anomalous vessels between the azygos veins, as in the present report. The patient's age and clinical signs were compatible with the disease, in addition to ammonia biurate crystals and hematological and biochemical alterations. The neurological clinical signs observed were compatible with hepatic encephalopathy secondary to congenital PSS. The imaging examinations facilitated the identification of the extrahepatic vascular anomaly, with the tomography being more accurate and helping in proper surgical planning. Clinical treatment should be performed for presurgical stabilization, and occlusion can be performed by placing cellophane bands or an ameroid constrictor, which is the technique of choice for congenital PSS, as it allows for slow constriction to avoid acute portal hypertension, as in this case, emphasizing that anesthesia in animals with portosystemic shunts must be performed with care.

Ultrasonography and portography in the diagnosis of shunt portoazigos in a dog: case report / Ultrassonografia e portografia no diagnóstico de shunt portoázigos em um cão: relato de caso

Portosystemic shunt (PSS) is an anomalous vascular connection between the portal venous system and the systemic circulation. These deviations connect the main portal vein (PV) or some portal branches to the vena cava (VC) or, less commonly, to the azygos vein (AV). The purpose of this case report was to describe the diagnosis of PSS in a dog classified as porto-azygos. This diagnosis is considered uncommon compared to other portosystemic shunts using ultrasonography and portography. The subject was a male dog, Yorkshire, 8 months old, presented neurological signs characterized by head press, ataxia, tremors and episodes of temporary blindness and deafness. Ultrasonographic examination revealed a dilated and curved anomalous vessel with approximately 0.6cm of diameter and turbulent flow seen through pulsed and color Doppler, and segmental dilation of the azygos vein. The portography revealed enhancement by iodinated contrast in the jejunal vein, the portal vein and an anomalous vessel flowing towards the azygos vein in the craniodorsal region of the abdomen. The PSS was surgically corrected with an ameroid constrictor. Ultrasonography and portography were effective at detecting and characterizing the portoazygos shunt despite some limitations.(AU)

Shunt portossistêmico (SPS) é uma comunicação vascular anômala entre o sistema venoso portal e a circulação sistêmica. Esses desvios comunicam a VP ou alguma de suas tributárias à veia cava ou, menos comumente, à veia ázigos (VA). O objetivo do presente estudo foi descrever o diagnóstico, por meio de ultrassonografia e portografia, de um caso de shunt extra-hepático em cão, classificado como portoázigos e considerado incomum quando comparado aos demais tipos de desvio portossistêmico. Um cão, macho, raça Yorkshire, oito meses de idade, chegou ao Hospital Veterinário da Universidade Federal de Minas Gerais apresentando sinais neurológicos, caracterizados por andar apoiando a cabeça na parede, ataxia, tremores, episódios de cegueira e surdez. Ao exame ultrassonográfico, observou-se vaso anômalo calibroso e tortuoso de aproximadamente 0,6cm de diâmetro e fluxo turbulento ao Doppler pulsado e colorido, bem como dilatação segmentar da VA. A portografia revelou realce de contraste iodado em veia jejunal, porta e vaso anômalo (shunt) seguindo em direção à VA em região dorsal do abdômen. Foi realizada a correção cirúrgica do SPS por meio de anel ameroide. A ultrassonografia e a portografia foram eficientes na detecção e caracterização do shunt portoázigos, mesmo que com algumas limitações.(AU)

Ultrasonography and portography in the diagnosis of shunt portoazigos in a dog: case report / Ultrassonografia e portografia no diagnóstico de shunt portoázigos em um cão: relato de caso

Portosystemic shunt (PSS) is an anomalous vascular connection between the portal venous system and the systemic circulation. These deviations connect the main portal vein (PV) or some portal branches to the vena cava (VC) or, less commonly, to the azygos vein (AV). The purpose of this case report was to describe the diagnosis of PSS in a dog classified as porto-azygos. This diagnosis is considered uncommon compared to other portosystemic shunts using ultrasonography and portography. The subject was a male dog, Yorkshire, 8 months old, presented neurological signs characterized by head press, ataxia, tremors and episodes of temporary blindness and deafness. Ultrasonographic examination revealed a dilated and curved anomalous vessel with approximately 0.6cm of diameter and turbulent flow seen through pulsed and color Doppler, and segmental dilation of the azygos vein. The portography revealed enhancement by iodinated contrast in the jejunal vein, the portal vein and an anomalous vessel flowing towards the azygos vein in the craniodorsal region of the abdomen. The PSS was surgically corrected with an ameroid constrictor. Ultrasonography and portography were effective at detecting and characterizing the portoazygos shunt despite some limitations.(AU)

Shunt portossistêmico (SPS) é uma comunicação vascular anômala entre o sistema venoso portal e a circulação sistêmica. Esses desvios comunicam a VP ou alguma de suas tributárias à veia cava ou, menos comumente, à veia ázigos (VA). O objetivo do presente estudo foi descrever o diagnóstico, por meio de ultrassonografia e portografia, de um caso de shunt extra-hepático em cão, classificado como portoázigos e considerado incomum quando comparado aos demais tipos de desvio portossistêmico. Um cão, macho, raça Yorkshire, oito meses de idade, chegou ao Hospital Veterinário da Universidade Federal de Minas Gerais apresentando sinais neurológicos, caracterizados por andar apoiando a cabeça na parede, ataxia, tremores, episódios de cegueira e surdez. Ao exame ultrassonográfico, observou-se vaso anômalo calibroso e tortuoso de aproximadamente 0,6cm de diâmetro e fluxo turbulento ao Doppler pulsado e colorido, bem como dilatação segmentar da VA. A portografia revelou realce de contraste iodado em veia jejunal, porta e vaso anômalo (shunt) seguindo em direção à VA em região dorsal do abdômen. Foi realizada a correção cirúrgica do SPS por meio de anel ameroide. A ultrassonografia e a portografia foram eficientes na detecção e caracterização do shunt portoázigos, mesmo que com algumas limitações.(AU)

Venous drainage from the tail of the pancreas to the lienal vein and its relationship with the distal splenorenal shunt selectivity / Drenagem venosa da cauda do pâncreas para a veia lienal e sua relação com a seletividade da anastomose esplenorrenal

PURPOSE: To identify the veins draining from the pancreatic tail to the lienal vein and its possible relationship with the loss of the distal splenorenal shunt selectivity. METHODS: Thirty eight human blocks including stomach, duodenum, spleen, colon and pancreas, removed from fresh corpses, were studied with the replenish and corrosion technique, using vinilic resin and posterior corrosion of the organic tissue with commercial hydrochloric acid, in order to study the lienal vein and its tributaries. RESULTS: The number of veins flowing directly to the splenic vein varied from seven to twenty two (14.52 ± 3.53). Pancreatic branches of the pancreatic tail flowing to the segmentary veins of the spleen were found in 25 of the anatomical pieces studied (65.79 percent). These branches varied from one to four, predominating one branch (60 percent) and two branches (24 percent). CONCLUSIONS: In 65.79 percent of the anatomical pieces studied, the veins of the pancreatic tail flowed in segmentary branches of the splenic vein. These branches could be responsible for the loss of distal splenorenal shunt selectivity. The complete disconnection of the pancreatic tail could increase the selectivity in this procedure.(AU)

OBJETIVO: Identificar as veias da cauda do pâncreas afluentes da veia lienal e a possível relação destes ramos com a perda de seletividade da derivação esplenorrenal distal. MÉTODOS: Foram estudadas 38 peças humanas, retiradas de cadáveres, contendo estômago, duodeno, baço, cólon e pâncreas, utilizando-se a técnica de repleção vascular com resina vinílica e posterior corrosão do tecido orgânico com o objetivo de se estudar o molde vascular da veia lienal e seus afluentes. RESULTADOS: O número de veias afluindo diretamente para a veia esplênica variou de sete a vinte dois (MA 14.52±3.53). Ramos pancreáticos da cauda do pâncreas afluindo para as veias segmentares do baço estavam presentes em 25 das peças estudadas (65,79 por cento). Estes ramos variaram de um a quatro, predominando um ramo (60 por cento) e dois ramos (24 por cento). CONCLUSÕES: Em 65,79 por cento das peças veias da cauda do pâncreas desembocavam em ramos segmentares da veia esplênica. Estes ramos poderiam ser responsáveis pela perda de seletividade da derivação esplenorrenal distal e a esqueletização completa da cauda do pâncreas poderia aumentar a seletividade neste procedimento.(AU)