pyogenic liver abscess ( pla ) remains a rare disease with a high risk of mortality , up to 19% [ 113 ] . in recent years , diagnosing pla and the underlying cause of the abscess has been made easier by modern imaging modalities . pla management has also changed , with percutaneous drainage and intravenous antibiotics being now considered safe and effective [ 7 , 8 , 12 ] . even though a nonoperative interventional radiology approach has become the first therapeutic choice for pla , surgical treatment is still necessary in some cases , although its proper indications remain unclear . indeed , surgical drainage is associated with increased morbidity and mortality and is often only used as a salvage procedure in cases failed percutaneous treatment [ 10 , 12 ] . the aim of our study was to retrospectively analyze our monocentric french series of pla cases and to reappraise the place of surgery in modern pla management using a recent occidental series . all of the adult patients treated for a pla from 1990 to 2009 in the departments of infectious disease , gastroenterology , and hepatobiliary surgery at the university hospital of caen were retrospectively reviewed . we excluded all abscesses resulting from a fungal or amebic abscess , infected tumor , or infected liver cyst from the study . the clinical presentation , past medical history , and microbiological and radiological parameters were obtained from each patient 's record . this data included age , gender , presenting symptoms , comorbidities , asa score , underlying etiology , presence of diabetes mellitus , bmi , presence of malignancy , imaging studies focused on the size and number of abscesses , microbiological findings , and the abscess components ( fluid , gas , walls ) . the biological parameters examined included hemoglobin and albumin levels , white blood cell count , creatinine level , crp , fibrinogen , total bilirubin level , and liver enzymes . the etiology of the abscesses was classified into four groups : group 1 , biliary ; group 2 , portal ; group 3 , cryptogenic ; group 4 , other ( iatrogenic , arterial ) . the treatments were classified as antibiotics alone for 6 weeks ( group a ) , antibiotics and percutaneous treatment ( percutaneous needle aspiration ( pna ) or drainage ) ( group ap ) , or surgical treatment ( after percutaneous drainage or not ) ( group as ) . failure of antibiotic or percutaneous treatment was defined as persistent infection after 3 to 5 days of the chosen therapy . treating the cause of the abscess cure was defined as resolution of the infectious syndrome and symptoms at 2 months after initiating treatment . the factors associated with failure of medical treatment and mortality were studied to evaluate the indications for early aggressive surgical treatment of patients presenting with such factors . septic shock was defined as a state of combined hypotension , tachycardia , polypnea , oliguria , and altered mental status with a temperature over 38c or under 36c . the continuous numeric data are displayed in tables as means and the categorical data as percentages . the categorical data were compared between groups using either the  
  or fisher 's exact tests . roc curves were used to describe the predictive value of certain biological parameters for mortality . from january 1990 to december 2008 , a total of 103 consecutive patients were treated in the departments of hepatobiliary surgery , gastroenterology , and infectious disease at the university hospital of caen , france . fifty - seven were male , and they had a mean age of 64 years . fifty patients were asa ii , and the most common comorbidities were active smoking ( 22.3% ) and diabetes mellitus ( 17.5% ) . the most common presenting symptoms were hyperthermia ( 93.0% ) and abdominal pain ( 73.0% ) . fourteen patients presented with septic shock , and two patients had an intraperitoneal abscess rupture . the demographic clinical and biological data are reported in table 1 . crp was elevated in all cases , and its level was over 100  mg / l in 90 patients . the microbe responsible could be identified in 71.8% of the cases and was most frequently escherichia coli . table 2 shows an overview of pathogens found in pla patients and correlates the pathogen found with the abscess etiology . most of the abscesses were unique ( 68.3% ) , measured more than 5  cm ( 70.7% ) and were located in the right liver ( 58.2% ) . twenty - nine patients ( 28.1% ) presented with a right pleural effusion on admission . the most common cause of liver abscess was biliary tract disorder ( 45.6% ) , followed by portal origins ( 25.2% ) . despite thorough investigations , the treatment consisted of antibiotics alone in 16.5% of the cases ( group a ) , as compared to 55.4% with antibiotics and percutaneous treatment ( group ap ) . overall 41.7% of the patients underwent surgery for pla treatment ( group as ) ; 28.1% of these cases represented the initial treatment , and 26% were in response to failure of nonsurgical therapy ( table 5 ) . in group a , 17 patients who were successfully treated with antibiotics alone presented with multiple small abscesses ( median size : 3.7  cm ) . 8 days with a mean duration of treatment of 44 , 64 days . of these patients , two patients died , one of sepsis and one of the volution of an underlying cancer . in group the successful initial percutaneous treatment cases involved 26 patients who underwent percutaneous drainage , 7 who underwent percutaneous needle aspiration only , and 6 who required drainage after having had a pna . the plas were unique in 72.5% of the cases , with a mean size of 8.7  cm . the pathogen was identified in 77.5% of the patients , and antibiotic treatment was administered for a total of 50 days . the mean hospital stay was 25.8 days , and 65% of the patients had recovered at 2 months . the plas were mostly unique ( 68.3% ) ; the mean size was 4.5  cm , which is slightly larger than the plas successfully treated by antibiotics alone . fourteen ( 32.5% ) group as patients required surgery after failure of percutaneous treatment . their abscesses were unique in 57% of the cases and measured more than 8  cm . a total of 35% of the abscesses were of biliary origin , and 35% were of portal origin . surgery resolved all symptoms and helped find the cause of the abscess in one - third of the patients . eighty - three percent of the abscesses were unique , with a mean size of 9,14 centimeters . of the patients needing surgery , 79% underwent simple drainage of the abscess cavity with large abdominal drains . hepatectomy was necessary in 21% of the patients ; 2 underwent major liver resections , and the majority only required minor liver resection , mainly segmentectomies . the causes of the abscesses were treated in 80% of the cases . in total , 64.6% of the patients required a surgical procedure to treat the cause , which was performed after resolving the pla in 27.5% of the patients . forty - two patients underwent surgical treatment of the pla cause during the same hospital stay ; this treatment consisted of 21 cholecystectomies , 8 colectomies , 4 appendectomies , 3 choledocojejunostomy resections , 1 gastrectomy , and 1 nephrectomy . in the univariate analyses , the only significant factor associated with the surgical pla treatment was bmi ( 26.8 versus 24.2 ; p = 0.03 ) . diabetes mellitus and septic shock were more likely to be associated with surgery , but neither reached significance ( p = 0.08 for both ) . the factors associated with failed medical treatment and requiring surgical therapy were gas - forming pla ( p = 0.006 ) and severe sepsis or septic shock ( table 6 ) . four men and 5 women , with a mean age of 72 years , died during the study period . five patients died of causes directly related to the pla , and 4 died of thromboembolic complications or of cancer evolution . in the univariate analyses , the factors associated with mortality were a high asa score ( p = 0.02 ) , neoplastic pla origin ( p = 0.047 ) , and right pleural effusion ( p = 0.018 ) . according to the  
  test , the roc curves constructed for the albumin level and the hemoglobin level ( chosen as a sign of severity of the sepsis ) showed that an albumin below 21 g / l predicted mortality with a sensitivity of 60% and a specificity of 80% . a hemoglobin level below 9,5  g / dl predicted mortality with a low sensitivity ( 40% ) but a high specificity ( 90% ) . the series reported in the literature after 1988 have mainly been from asian countries , with the largest series ( 483 patients ) being reported by chou et al . in 1997 . our series of 103 pla patients found epidemiology that was similar to that of the other series ( table 7 ) , with a slight male predominance . a pla diagnosis was associated with certain clinical and imaging features , with fever and abdominal pain being the most common ( table 7 ) . in our series , the microbiological isolates found in cultures were different from those reported in asian studies ; the most common isolates were e. coli and streptococcus spp . , whereas klebsiella pneumoniae is often the second - most common pla pathogen isolated in asian series [ 1 , 8 , 1012 , 1416 ] . was by far the most commonly found ( 40.5% ) microbe . as for diagnosing pla , two biological criteria emerge from this series . this finding is interesting because it is the only highly sensitive indicator and because it was over 100  mg / l in 87% of the cases . leukocytosis , although reported elsewhere as being the most common pla finding , was only present in 74.7% of the cases in our series [ 1 , 5 , 8 , 10 ] . this series confirms that biliary tract diseases are the major cause of pla [ 3 , 8 , 12 , 16 , 18 , 19 ] . portal phlebitis from a bowel infection was the second - most frequent cause , at 25.2% . indeed , only 18.4% of the plas were cryptogenic , as compared to more than 40% in earlier studies [ 8 , 10 , 15 ] . this lower percentage may have been due to the more extensive etiological research that used more precise and sensitive imaging , as has been suggested by cohen et al . , who found that only 10% of abscesses to be cryptogenic . a higher rate of identified pathogens is also helpful in determining the pla etiology . most of our patients ( 55% ) were treated using a combination of antibiotics and percutaneous treatment ( aspiration or drainage ) . this combination is currently the pla treatment of choice because it is a safe and effective option that offers a low - risk approach to these often critically ill patients [ 4 , 10 , 11 , 19 , 2327 ] . however , percutaneous therapy frequently fails , with rates ranging from 15% to 36% ( similar to the 26% rate found in our series ) [ 1 , 11 , 23 , 28 ] . the causes of failed pla treatment include multiple abscesses with multiple loculations [ 1 , 12 ] , large abscesses ( > 5  cm ) containing thick pus with necrotic tissue , issues directly linked to the drainage catheter ( blockage , slippage , and chest empyema due to transpleural drainage ) , and the technical difficulties associated with performing safe drainage . in our experience , there were significantly more gas - forming abscesses ( p = 0.006 ) and patients in septic shock ( p = 0.02 ) among the cases of percutaneous treatment failures . our study represents the first occasion that these two criteria have been linked to failed medical treatment . chou et al .   specifically studied gas - forming abscesses and concluded that they are more severe , often presenting with septic shock and are associated with higher mortality than non  gas - forming abscesses ( 27.7% ) . their treatment algorithm starts with mandatory percutaneous treatment but does not recommend surgery as an initial treatment .   as in other series , we found that plas linked to biliary tract disorders failed to respond to medical therapy more often than other plas . indeed , effective biliary drainage is essential to treating such plas , and pla drainage alone is not enough to achieve a cure [ 2931 ] . as a result of the large variety of medical and interventional treatments , surgery is usually only considered in cases of failed percutaneous treatment ; therefore , the two approaches can be considered complementary and not competitive [ 46 ] . surgery has indications for initial pla treatment and should not be considered only a secondary therapeutic option in cases of failed percutaneous treatment . it is widely accepted that surgery is mandatory in cases where these is abscess rupture into the peritoneal cavity . multiloculated abscesses are often better treated by surgery that completely breaks down of all the loculations [ 12 , 32 ] . surgery is also discussed in other circumstances , depending on the mortality - associated factors involved . some authors agree that surgery should be the first - line therapy in cases of high mortality risk to improve the chances of survival in these critically ill patients [ 12 , 28 ] .   for these reasons , it is important to study the factors linked to mortality . mortality has improved in recent years thanks to more rapid diagnosis , more effective antibiotics , and the development of percutaneous procedures . our series had an overall mortality rate of 8,7% , which is on the low end of the rates reported in the literature ( 046% ) ( table 7 ) . the factors linked to mortality in our series ' univariate analyses were a high asa score ( p = 0.02 ) , a malignant pla origin and the presence of a pleural effusion ( p = 0.018 ) . the pleural effusion is an interesting factor , as has been previously reported , and is probably secondary to the importance of right upper quadrant sepsis . the other factors that have been linked to mortality are severe sepsis and shock , high leukocytosis , low hemoglobin , increased creatinine , elevated blood urea nitrogen and hypoalbuminemia [ 11 , 17 ] . gas - forming abscesses have also been independently associated with mortality [ 6 , 14 , 34 ] . the general condition of the patient is an important factor that affects mortality , although it is difficult to evaluate . patient health indices have been developed in consultation with anesthesiologists , and statistical analyses ( univariate and multivariate ) have reached different conclusions . some teams have reported that an apache score > 15 is significantly associated with mortality [ 5 , 14 , 16 ] , and some authors agree that these patients are better served by surgical exploration [ 1 , 8 ] . similarly , lok et al . found in a recent series that the existence of > 2 comorbid illnesses was associated with mortality in a univariate analysis . , who maintain that patients with high mortality risks based on their apache score should not undergo surgery as a first - line treatment but only percutaneous drainage to attempt to resolve the pla by the least invasive methods possible . their indications for surgery consist of failed medical treatment or pla ruptures into the peritoneal cavity . by contrast , our team and others [ 16 , 35 ] have proposed a more aggressive therapy , especially if the patient is critically ill or has high mortality risk . this position is based on the percentage of failed percutaneous drainage attempts , which was 26% in our series and 27,8% for tan et al . . such a high failure rate for critically ill patients implies delayed effective therapy , which increases the mortality rate [ 10 , 35 ] . we think that an aggressive approach , such as an initial surgical procedure , should be the treatment of choice in patients with poor prognosis or failure of percutaneous drainage , especially given that the mortality rate after surgery , which was high in the 1980s , has decreased as hepatic surgery has improved . indeed , the experience accumulated through these different series helps to distinguish two types of situations leading to surgical pla management . the first set of indications is linked to the risk of failed percutaneous treatment and include gas - forming abscesses , multiloculated abscesses , and septic shock at presentation . the second set of indications is linked to factors associated with high mortality : an elevated asa score , an apache score > 15 , severe sepsis ( leukocytosis , albumin < 21  g / dl , hemoglobin < 9,5 g / l ) , pleural effusion , and a malignant pla origin . in conclusion , even though percutaneous treatment combined with antibiotics is a safe and effective pla treatment , pla remains a surgical concern . we suggest that critically ill patients with severe sepsis associated with gas - forming or multiloculated abscesses on imaging should undergo surgery as a first - line treatment . surgery is particularly appropriate for patients with low albumin and hemoglobin and a high asa score . patients with a right pleural effusion should also be considered at high risk for mortality and therefore likely to benefit from aggressive therapy .
backgrounds . pyogenic liver abscess is a rare disease 
 whose management has shifted toward greater use of percutaneous drainage . 
 surgery still plays a role in treatment , but its indications are not clear . method . 
 we conducted a retrospective study of pyogenic abscess cases admitted to our university hospital between 1999 and 2010 and assessed the factors potentially associated with surgical treatment versus medical treatment alone . 
 results . in total , 103 liver abscess patients were treated at our center . 
 the mortality was 9% . 
 the main symptoms were fever and abdominal pain . 
 all of the patients had crp > 6  g / dl . 
 sixty - nine patients had a unique abscess . 
 seventeen patients were treated with antibiotics alone and 57 with percutaneous drainage and antibiotics . 
 twenty - seven patients who were treated with percutaneous techniques required surgery , and 29 patients initially received it . 
 eventually , 43 patients underwent abscess surgery . 
 the factors associated with failed medical treatment were gas - forming abscess ( p = 0.006 ) and septic shock at the initial presentation ( p = 0.008 ) . 
 conclusion . 
 medical and percutaneous treatment constitute the standard management of liver abscess cases . 
 surgery remains necessary after failure of the initial treatment but should also be considered as an early intervention for cases presenting with gas - forming abscesses and septic shock and when treatment of the underlying cause is immediately required .