Ultrasonographic differentiation between portal venous and parenchymal gas may be important for the prognosis of canine and feline hepatic emphysema: 37 cases

Abstract

The aim of this retrospective, cross‐sectional, study was to evaluate clinical findings and outcomes for different ultrasonographic patterns of hepatic emphysema in dogs and cats. Dogs and cats with an ultrasonographic diagnosis of hepatic emphysema and a known outcome, from January 2010 to January 2018, were enrolled. The following data were recorded from medical and ultrasonographic records: ultrasonographic patterns of hepatic emphysema (parenchymal, portal venous, biliary), clinical signs, laboratory findings, and outcomes (favorable, poor). A total of 33 dogs and four cats met the inclusion criteria. Among these, 23 cases were classified as hepatic portal venous gas, 10 as parenchymal emphysema, and four as biliary emphysema. Clinical diagnosis categories were as follows: infection/sepsis (9), gastro‐intestinal disease (9), iatrogenic (9), trauma (5), and liver neoplasia (5). An increase in serum liver enzymes was significantly associated with parenchymal emphysema (P = .03). Other clinical and laboratory findings were not associated with the type of hepatic emphysema. Hepatic portal venous gas was mostly transient in patients with ultrasonographic follow‐up. The overall mortality was 40.5%. A significant difference was found between mortality by portal venous gas (21.7%) and mortality by parenchymal emphysema (90%) (P = .003). In conclusion, the ultrasonographic differentiation of hepatic emphysema between hepatic portal venous gas and parenchymal emphysema may be important for the prognosis of hepatic emphysema. The presence of parenchymal emphysema may be a poor prognostic indicator, while hepatic portal venous gas may be more benign. However, ultrasound findings should be carefully evaluated in the context of clinical findings.

Multiphase multidetector‐row CT reveals different patterns of hepatic portal venous gas and pneumobilia

“…To date, CT characteristics of HPVG are not described in veterinary medicine, whereas imaging features of PB in small animals are limited to the recognition of some gas within the gallbladder or the biliary tree. 19,22,23 Based on the results of the present study, HPVG and PB showed different CT features in small animals. First of all, the location of the gas was similar to that reported in people: the gas was located in the periphery of the liver (reaching almost the hepatic capsule) in case of portal gas, but had a central location in case of gas in the biliary tree.…”

“…23,[27][28][29][30] Nevertheless, the MinIP technique was described in human literature for the detection of intrahepatic gas only in postmortem CT. 31 Differentiating between HPVG and PB is important because of their different clinical significance, and because they recognize different causes (leading to different treatments). As already described both in human and veterinary medicine, 3,4,19 PB was commonly associated with biliary surgery (cholecystoduodenostomy), and the presence of gas in the biliary tree is secondary to a connection between the gastrointestinal tract and the biliary tree. Another cause of PB, also in agreement with previous literature, 19,22,23 was emphysematous cholecystitis.…”

“…19 In that study, HPVG was the most common pattern and pneumobilia (PB) was an uncommon finding, mostly related to biliary surgeries or infections. 19 Although extremely useful and noninvasive, abdominal ultrasound (US) could show some limitations in the detection and in the differentiation of the different localization of the gas in the liver, especially when present in small amount. The presence of few gas bubbles could be missed with US, and due to their similar appearance, the differentiation between portal branches and biliary ducts without Color Doppler could be challenging.…”

“…Recently, ultrasonographic patterns of hepatic gas in the liver parenchyma, portal venous, and biliary structures have been described 19 . In that study, HPVG was the most common pattern and pneumobilia (PB) was an uncommon finding, mostly related to biliary surgeries or infections 19 . Although extremely useful and noninvasive, abdominal ultrasound (US) could show some limitations in the detection and in the differentiation of the different localization of the gas in the liver, especially when present in small amount.…”

“…2,[10][11][12] In veterinary medicine, portal venous gas is a rare condition, described in few cases in dogs and cats. [13][14][15][16][17][18][19] Some of the cases reported in veterinary literature also described the presence of the gas in the portal system at computed tomographic (CT) examination, 14,19 but the CT pattern was not detailed and was not described how to discriminate portal and biliary gas using CT. Recently, ultrasonographic patterns of hepatic gas in the liver parenchyma, portal venous, and biliary structures have been described.…”