Abstract
Suppurative pylephlebitis, that is, infected thrombosis of the portal vein and its branches is a rare condition with a high incidence of mortality and is often difficult to diagnose. We report two cases of suppurative pylephlebitis secondary to acute pancreatitis wherein the whole of the portal vein and its branches were transformed into an abscess cavity. The diagnosis was made after pus was seen coming out while the patient was taken up for portal vein thrombolysis. The pus was drained and the cavity was completely evacuated leading to recovery from this infection. These two cases highlight the fact that suppurative pylephlebitis is rare and extremely difficult to diagnose as it mimics portal vein thrombosis, but a high degree of suspicion in critically ill patients with thrombus-like appearance in portal vein having a uniform and homogeneous portal venous content on magnetic resonance imaging not responding to antibiotic therapy may be considered for aspiration for differentiating from thrombus and management.
Keywords: suppurative pylephlebitis, portal vein abscess, percutaneous drainage, portal vein, drainage
Abbreviations: CT, computed tomography; CECT, contrast-enhanced computed tomography; MRCP, magnetic resonance cholangiopancreatography
Suppurative pylephlebitis is defined as an infected thrombosis of the portal vein and its branches. It is an extremely rare complication of intra-abdominal infections with a high incidence of morbidity and mortality.1 It is often misinterpreted and undiagnosed because of its nonspecific clinical presentation and unfamiliarity with this entity.2 Although pylephlebitis has been reported in the literature, abscess involving the whole of the portal vein and its branches is an extremely rare condition. Ultrasound and contrast-enhanced computed tomography (CECT) scan help to diagnose portal vein thrombosis.3,4 However, they cannot accurately diagnose abscess in the intrahepatic portal vein and its branches. We report two cases of suppurative pylephlebitis where the whole of the portal vein and its branches were transformed into an abscess cavity, which was diagnosed and managed by percutaneous needle aspiration and drainage.
Case 1
A 35-year-old Asian male got admitted to the emergency department with complaints of epigastric pain radiating to the back and intermittent fever for the past 3 days. There was a history of two episodes of alcohol-related pancreatitis in the last 2 years. Laboratory workup revealed an increase in serum amylase level and erythrocyte sedimentation rate (ESR) with normal total leukocyte count and liver function test. Blood culture was negative. HIV serology was negative. There was no history of surgical intervention or endoscopic retrograde cholangiopancreatography (ERCP) in the past. Abdominal ultrasonography showed multiple small microabscesses in the left lobe of the liver with the dilated echogenic portal and splenic vein having few echogenic debris within the lumen and not showing any flow on Doppler ultrasound. It also showed enlarged and hypertrophied hepatic arteries adjacent to it (Figure 1). CECT scan of abdomen confirmed the diagnosis of multiple microabscesses in the left lobe of the liver with portal vein thrombosis extending into the splenic and superior mesenteric vein (Figure 2) with no evidence of mesenteric ischaemia (bowel wall thickening, oedema and dilated bowel loops). In addition to portal vein thrombosis, thrombosis was also involving the middle and left hepatic vein. Computed tomography (CT) also showed mild peripancreatic fat stranding and mild ascites. The modified CT severity index was 4/10. The spleen was seen enlarged in size (14 cm). Based on these findings, a diagnosis of recurrent acute pancreatitis with portal vein thrombosis and the liver abscess was made.
Figure 1.
Ultrasonography with colour doppler showing dilated and echogenic portal vein (white arrow) with no flow in the portal vein and increased flow in the adjacent hypertrophied hepatic artery (black arrow).
Figure 2.
Contrast-enhanced CT (CECT) scan showing dilated and thrombosed portal vein (white arrow) and its extension into a superior mesenteric vein along with multiple small microabscesses in the liver (black arrow).
Patient procoagulant workup (Protein C, Protein S, antithrombin III, homocysteine, factor V Leiden, Prothrombin G20210A & JAK2 gene mutation) was negative. Ultrasound-guided fine-needle aspiration cytology of the liver abscess showed no evidence of any granuloma or malignancy. Culture, gram staining and amoebic serology were also negative. Aspirate from pus did not show the presence of any trophozoites of entamoeba histolytica on the wet saline mount. The patient was initially treated with i.v. antibiotics (piperazillin/tazobactam and metronidazole injections) and anticoagulants (clexane injection) for 7 days. Follow-up CECT scan after 6 days showed the same findings, that is, persistent portal vein thrombosis and multiple microabscesses in the liver. Considering the persistent portal vein thrombosis, portal vein thrombolysis was planned. The portal vein was assessed using a 22-gauge Chiba needle and while placing an angiographic catheter frank pus was seen coming out and thereafter approximately 100 ml of pus was aspirated, which was sent for gram staining and culture. The guidewire could not be advanced into the superior mesenteric vein because of a sharp cut-off, simultaneously no blood was noted within the portal system. Portography was performed, which outlined the portal vein and its branches (Figure 3). Gentamicin and metronidazole injection was instilled into the portal vein (cavity). The culture of pus did not show any bacterial or fungal growth and gram staining was also negative.
Figure 3.
Direct transhepatic portography obtained with the use of 22 G Chiba needle shows contrast opacification of abscess cavity with complete obstruction of the portal vein near the confluence (arrow) along with nonopacification of superior mesenteric vein and splenic vein.
Follow-up abdominal ultrasonography after 5 days showed a significant reduction in the size of the cavity within the portal vein with the presence of few collaterals. Microabscesses in the left lobe of the liver had partially regressed in size and number. The patient's condition gradually improved and became afebrile. At the time of discharge, the portal vein was reduced in calibre with the formation of adjacent venous collaterals.
Case 2
A 60-year-old Asian male got admitted to the emergency department with complaints of epigastric pain, fever and loss of appetite for the last 15 days and was shifted to the intensive care unit. He was admitted to another hospital and was being treated for alcohol-related pancreatitis for the last 10 days before being referred to our hospital. Laboratory workup showed increased serum amylase and lipase level. There was an increase in total leukocyte count and serum C-reactive protein with increased serum bilirubin and increased transaminases. Blood culture was negative. There was no history of surgical intervention in the past. Abdominal ultrasonography revealed few small microabscesses in the right lobe of the liver with dilated and echogenic portal and splenic vein and no colour flow on Doppler ultrasound. On CECT scan, there was the presence of few microabscesses in the right lobe of the liver with portal vein thrombosis extending into the splenic and superior mesenteric vein with no evidence of mesenteric ischaemia. The rest of the abdominopelvic organs and bowel loops appeared unremarkable. There was also the presence of portal vein wall enhancement with few hyperdense contents along with few portal vein collaterals. CECT also revealed pancreatic necrosis (<30%) with mild to moderate peripancreatic fat stranding, walled-off collection in the lesser sac and perihepatic region and mild ascites. The modified CT severity index was 8/10.
He was initially started on i.v. antibiotics (gentamicin, piperacillin and metronidazole) and i.v. anticoagulants (clexane injection) for 7 days. On the fifth day of admission, a pigtail catheter was placed in the walled-off collection (lesser sac and perihepatic region). Despite drainage of collection, fever persisted with raised total leukocyte count. Subsequently, on the 13th day of admission, the patient was planned for portal venous thrombolysis; however, after puncturing the portal vein, pus was seen coming out and a 7-Fr external drainage catheter was placed into the main portal vein and 50 ml of purulent material was aspirated. No return of the blood was seen from the drain after the complete emptying of the portal vein. Portography revealed contrast outlining the normal portal venous branches and there was a cut-off at the level superior mesenteric vein/splenic vein confluence. Pus sample taken from the portal vein showed gram-negative staining. Escherichia coli was detected in the aspirate by a bacterial culture study. The patient became afebrile on day 5 of drainage. The total leukocyte count, C-reactive protein and levels of transaminase had decreased.
Once the output from the drain became negligible, it was removed. Initially, the patient improved but later developed hospital-acquired pneumonia, then the patient was shifted to ICU again and intubated on the 26th day of hospital admission. Owing to personal constraints, the patient left against medical advice on the 28th day of hospital admission. Hence a further follow-up was not available.
Discussion
Pylephlebitis is an extremely rare and serious complication of intra-abdominal infection, inflammation such as diverticulitis,5 appendicitis,6 pancreatitis,2,7 inflammatory bowel disease8 and also due to previous abdominal surgery.3 Despite the modern antibiotic era, it has a high incidence of morbidity and mortality rate.1 Pylephlebitis is mostly undetected and undiagnosed because of its unfamiliarity and lack of specific clinical and imaging features.2,7
Portal vein and splenic vein thrombosis are well-known complications of pancreatitis, but pylephlebitis is rarely associated with it.3 Pylephlebitis and associated portal vein abscess is an extremely rare complication of pancreatitis. In both of these cases, the entire portal vein and its branches were transformed into an abscess cavity as a complication of recurrent acute pancreatitis and necrotizing pancreatitis, respectively. Diagnosis is often missed because of similar clinical presentation with pancreatitis, both of them presenting as acute abdominal pain and fever.7 Patients with pylephlebitis have positive blood culture in 50% of cases, whereas raised leukocyte count and abnormal liver function tests are seen in 25% of cases.4,9 Bacteriodes fragilis and E. coli are the most common organisms seen in blood culture.10 In the first case, blood culture, liver function tests and total leukocyte count were normal and made diagnosis difficult. However, in the second case, there was an increase in total leukocyte count, increased serum C-reactive protein and increased serum bilirubin and transaminases.
CECT scan and ultrasonography are helpful in the diagnosis of the portal vein thrombosis but cannot accurately detect portal vein abscess within it.7,11 Based on the findings of these two cases, some features may be indicative of portal vein abscess and include: (1) dilated portal vein with uniformly thick enhancing wall, (2) portal venous content showing a uniform and homogenous signal intensity (with or without fluid–fluid level) on magnetic resonance imaging. However, if imaging remains elusive, percutaneous needle aspiration can confirm and differentiate between a thrombus and an abscess.
Percutaneous needle aspiration and drainage of portal vein abscess are rarely reported in the literature. To the best of our knowledge, only six cases of percutaneous drainage for pylephlebitis have been reported in the literature.2, 3, 4,7,9,11 Four cases were due to pancreatitis,2,4,7,9 one due to cholangitis4 and one due to previous abdominal surgery.3 In all six cases reported in the literature, an external drainage catheter was placed in the portal vein for 10–12 days. There was no requirement of further surgical intervention for pylephlebitis and no vascular complications were noted in any of the cases.3,4,7,9,11 All six patients had significant resolution of symptoms after percutaneous drainage like in the present cases. In the first case, we did a single-time aspiration of the abscess from the portal vein and injected antibiotics (gentamicin and metronidazole) in the abscess cavity. In the second case, a percutaneous drainage catheter was placed with the portal venous system for seven days. In all the above cases and both our cases, percutaneous needle aspiration and drainage was safely performed without any complications.2, 3, 4,7,9,11 In the contrary, a high incidence of morbidity and mortality are reported secondary to surgical interventions.12,13
In conclusion, the above two cases emphasize the importance of recognizing suppurative pylephlebitis in patients with intra-abdominal infections and imaging suggestive of portal vein thrombosis. Percutaneous needle aspiration may help in differentiating it from the bland thrombus of the portal vein as well as management of this rare condition.
CRediT authorship contribution statement
V.S. Shyam: acquired, analysed and interpreted the data, Writing – original draft. Shaleen Rana: Conceptualization, Methodology. Ashok Choudhury: Writing – review & editing. Amar Mukund: Conceptualization, data analysis, Writing – review & editing, final approval for submission.
Conflicts of interest
The authors have none to declare.
Funding
None.
References
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