Hepatic Portal Venous Gas: the Abcs of Management

REVIEW ARTICLE Hepatic Portal Venous Gas The ABCs of Management Aaron L. Nelson, MD, PhD; Timothy M. Millington, MD; Dushyant Sahani, MD; Raymond T. Chung, MD; Christian Bauer, MD; Martin Hertl, MD; Andrew L. Warshaw, MD; Claudius Conrad, MD, PhD, PhD Objective: To review the use of computed tomogra- Data Synthesis: Early studies of HPVG were based on phy (CT) and radiography in managing hepatic portal plain abdominal radiography and a literature survey in 1978 venous gas (HPVG) at a university-affiliated tertiary found an associated mortality rate of 75%, primarily due care center and in the literature. Hepatic portal venous to ischemic bowel disease. Modern abdominal CT has re- gas is frequently associated with acute mesenteric sulted in the detection of HPVG in more benign condi- ischemia, accounting for most of the HPVG-associated tions, and a second literature survey in 2001 found a total mortality. While early studies were necessarily depen- mortality of only 39%. While the pathophysiology of HPVG dent on plain abdominal radiography, modern high- is, as yet, unclear, changing abdominal imaging technol- resolution CT has revealed a host of benign conditions ogy has altered the significance of this radiologic finding. in which HPVG has been reported that do not require Hepatic portal venous gas therefore predicts high risk of mortality (Ͼ50%) if detected by plain radiography or by emergent surgery. CT in a patient with additional evidence of necrotic bowel. If detected by CT in patients after surgical or endoscopic Data Sources: Patient records from our institution over manipulation, the clinician is advised that there is no evi- the last 10 years and relevant studies from BioMed Cen- dence of increased risk. If HPVG is detected by CT in pa- tral, CENTRAL, PubMed, and PubMed Central. In ad- tients with active peptic ulcer disease, intestinal obstruc- dition, references cited in selected works were also used tion and/or dilatation, or mucosal diseases such as Crohn as source data. disease or ulcerative colitis, caution is warranted, as risk of death may approach 20% to 30%. Study Selection: Patient records were selected if the CT or radiograph findings matched the term hepatic por- Conclusion: The finding of HPVG alone cannot be an tal venous gas. Studies were selected based on the search indication for emergency exploration, and we have de- terms hepatic portal venous gas or portal venous gas. veloped an evidence-based algorithm to guide the clinician in management of patients with HPVG. Data Extraction: Quantitative and qualitative data were quoted directly from cited work. Arch Surg. 2009;144(6):575-581 EPATIC PORTAL VENOUS of imminent death and the correspond- gas (HPVG) was first de- ing maxim that HPVG demands scribed in abdominal laparotomy. plain radiographs in 1955 Hepatic portal venous gas is a rare by Wolfe and Evans1 in 6 radiologic finding, with only 182 cases Hneonates who died secondary to necrotic documented in the literature by 2001.6 Author Affiliations: Tufts bowels, followed by reports of HPVG in Retrospective reviews of computed tomo- University School of Medicine graphic (CT) scans identified 17 cases in (Dr Nelson) and Departments 14 000 at 1 academic medical center7 and of Surgery (Drs Millington, See Invited Critique 11 in 19 000 at another.8 Hepatic portal Hertl, Warshaw, and Conrad), at end of article venous gas is defined radiologically as Radiology (Dr Sahani), and tubular areas of decreased attenuation in Medicine, Gastrointestinal Unit 5 adults who died2,3 and the first reported the liver periphery.9 This definition was (Dr Chung), Massachusetts survivor in 1965.4 Liebman and col- derived from the work of Sisk,10 who General Hospital, Boston, and 5 Section of Gastroenterology, leagues analyzed all cases of HPVG re- injected radiologic contrast into the por- Medizinische Klinik Innenstadt, ported in the literature by 1978 and found tal vein and detected it in the liver University of Munich, Munich, an oft-cited mortality rate of 75%, thereby periphery, within 2 cm of the capsule. Germany (Dr Bauer). codifying the link between HPVG and risk Proof of the localization of HPVG to the (REPRINTED) ARCH SURG/ VOL 144 (NO. 6), JUNE 2009 WWW.ARCHSURG.COM 575 ©2009 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/30/2021 moving through the hepatic portal system in real time in patients with HPVG.18 REPORT OF CASES CASE 1 A 63-year-old woman presented to the emergency de- partment complaining of constipation and bilious vomiting. She denied bowel movements over the preceding 7 days and had developed escalating, diffuse abdominal pain, bloating, and vomiting. During a prior episode of abdominal discomfort months earlier, CT examination discovered a lung mass, and she was diagnosed with stage IIIB non–small cell lung carcinoma, for which she initi- ated treatment days prior. Her vital signs were within nor- mal limits, but her abdomen was tense and rigid. Labo- ratory analysis was notable for leukocytosis. A plain abdominal radiograph demonstrated diffuse gaseous distention of the small and large bowel, and HPVG was vis- ible (Figure 1). A contrast-enhanced abdominal CT con- firmed diffuse gaseous distention of the small bowel and colon with pneumatosis of the colon and portal and mesenteric venous gas. In addition, free peritoneal air was present, consistent with hollow viscus perforation Figure 1. A frontal plain abdominal radiograph obtained in the supine position (Figure 2). Unfortunately, within hours of the CT scan, demonstrates distended loops of bowel and extensive hepatic portal venous gas (arrows). This finding was missed on the initial read of the plain radiograph. the patient died in shock. The primary cause of her gastrointestinal disease was never elucidated. portal sinusoids came from Wiot and Felson,3 who CASE 2 clamped all hepatic vessels during an autopsy, injected barium into the portal circulation, and demonstrated A 56-year-old man presented to the emergency depart- mixture of the gas and contrast. Portal venous gas can be ment complaining of crampy abdominal pain with diar- distinguished from aerobilia, an indication of gallstone rhea, nausea, and vomiting over the preceding 5 days. He ileus, where air is found centrally in the biliary tree,11 described several episodes of melena and admitted to hav- and from pneumoperitoneum, where gas is found out- ing lost 30 lb over preceding months. He denied hemop- side the liver capsule, due to perforation of a hollow tysis, fever, chills, or night sweats. He admitted to fre- viscous.12 quent use of ibuprofen to treat chronic lower back pain. The left lobe of the liver is predisposed to develop Vital signs were stable, and on examination, his abdomen HPVG,8,9 possibly because of peculiarities in hepatic ve- was soft with active bowel sounds and no rebound or guard- nous anatomy. Males and females are equally likely to ing. Rectal examination results were positive for occult develop HPVG.5,6 In approximately 50% of reported cases, blood. Serum lactate level was not elevated. An abdomi- HPVG presents with pneumatosis intestinalis (PI), gas nal CT imaging study was performed, and the results sup- within the intestinal wall.7,13,14 It is generally presumed ported a diagnosis of nonsteroidal anti-inflammatory drug– that PI ascends from the draining venous mesentery and induced gastritis, with a mild pneumatosis of the gastric condenses in the portal venous system15; therefore, PI and wall and HPVG (Figure 3), raising concern of a perfora- HPVG represent progressive steps in a single process.1 tion. Surgical and gastroenterologic services were con- Experimental support for this sequence is scarce, al- sulted, but, given the absence of peritonitis, it was de- though air injected into the submucosa16 or mesenteric cided to treat conservatively. On the fourth hospital day, veins2 of dog intestines was observed in the portal ve- he underwent an upper gastrointestinal tract series, reveal- nous system. ing a 40-mm, nonbleeding, cratered gastric ulcer in the car- Remarkably, in several early works, surgeons dia. The patient was discharged after 2 weeks with signifi- reported air bubbles flowing in the mesenteric veins of cant clinical improvement. patients with preoperative HPVG. In 1 case, the surgeons transilluminated the mesentery and described COMMENT the veins as “resembling the bubbles of gas seen in certain neon light signs.”2(p848) In another, the surgeons noted “intravascular gas seen in all the mesen- RECENT EVIDENCE teric and portal veins” with “a large amount of frothy air bubbles” in a tear in the liver capsule.17 Modern In the half century since HPVG was first described, it has ultrasonography studies have visualized air emboli been reported in many nonfatal conditions, such as Crohn (REPRINTED) ARCH SURG/ VOL 144 (NO. 6), JUNE 2009 WWW.ARCHSURG.COM 576 ©2009 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/30/2021 A A B B Figure 2. Axial (A) and coronal (B) views of contrast-enhanced computed Figure 3. Axial (A) and sagittal (B) computed tomographic images from a tomographic images of the liver with extensive hepatic portal venous gas case with benign portal venous gas in the left lobe of the liver (arrows) with (arrows). Hepatic portal venous gas in a patient with peritonitis is an emphysematous gastritis. Under watchful waiting, the patient did well and ominous finding with a potentially fatal outcome that warrants immediate

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