Henry Ford Hospital Medical Journal

Volume 19 | Number 3 Article 5

9-1971 Critical Factors in the Management of Liver Abscesses Melvin A. Block

Hubert M. Allen

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Recommended Citation Block, Melvin A. and Allen, Hubert M. (1971) "Critical Factors in the Management of Liver Abscesses," Henry Ford Hospital Medical Journal : Vol. 19 : No. 3 , 149-160. Available at: https://scholarlycommons.henryford.com/hfhmedjournal/vol19/iss3/5

This Article is brought to you for free and open access by Henry Ford Health System Scholarly Commons. It has been accepted for inclusion in Henry Ford Hospital Medical Journal by an authorized editor of Henry Ford Health System Scholarly Commons. Henry Ford Hosp. Med. Journal Vol. 19, No. 3, 1971

Critical Factors in the Management of Liver Abscesses

Melvin A. Block, M.D.* and Hubert M. Allen, M.D.*

Newer diagnostic techniques, including radioisotope liver scans, bacteriologic culture procedures for anaerobes, serologic tests for amebiasis, ultrasonic echograms, and hepatic arteriography, permit more specific identification and localization of hepatic abscesses. Large pyogenic abscesses are of particular Importance to surgeons; are frequently caused by anaerobic organisms; and require early, direct, adequate, and sufficiently prolonged surgical drainage. The clinician should be alert also to recognition and management of the primary lesion responsible for the hepatic abscess, associated abscesses elsewhere, and the possible presence of an underlying liver neoplasm.

The critical factors in the manage­ ful in considering etiology and man­ ment of liver abscesses relate to early agement (Table 1). The pyogenic va­ diagnosis, precise localization for ef­ riety of apparent hematogenous origin, fective surgical drainage, identification from a primary infection elsewhere in of the etiologic organisms, follow-up the body, is of greatest importance to care after specific therapy to ensure the surgeon and wiU be given major complete resolution, and recognition consideration in this report. This pyo­ and proper treatment of primary or genic variety has predominated in our associated diseases. Although not com­ experience, from 1962 through 1969, mon, hepatic abscesses are life- with 21 patients having large hepatic endangering. Advances in recent years abscesses. have facilitated greatly the successful management of curable liver abscesses. Large Pyogenic Liver Abscesses

Classification of Liver Abscesses Large pyogenic liver abscesses de­ velop usually as a complication of in­ Separating of hepatic abscesses into traperitoneal infection, including that four major categories is clinically use- associated with abdominal operations. These abscesses have been difficult to * Department of General Surgery. recognize, are usually fatal if not

149 Block and Allen

scesses, has contributed to the current TABLE I low mortality from these lesions Clinical classification of hepatic abscesses. (Table III).^-* 1. Pyogenic, fiematogenous origin Usually single, large (over 2 cm.) Occasionally multiple or multiiocular Jaundice uncommon TABLE III 2. Amebic Usually large, single Reduction during recent years of mortality from large Jaundice uncommon pyogenic hepatic abscesses, unrelated to obstruction 3. Associated witfi obstruction to extrahepatic biliary ducts of extrahepatic . Pyogenic etiology Period of Time Number of Patients Usually multiple, small (under 2 cm.) Total Operated Associated with acute cholangitis throughout liver No. Mortality No. IVlortality Jaundice common 4. Miscellaneous, pyogenic 1923 - 1961 40 28 (70%) 18 6 (33%) Associated with acute , by direct extension 1962 - 1969 21 2 (10%) 19 1 ( 5%) Associated with primary or metastatic malignancy Associated with hepatic trauma

drained, and continue to occur with Clinical Features: Although a major­ an incidence equaling or exceeding ity of patients will notice mild to that in the past. Factors responsible moderate degrees of discomfort in the for the previous high mortality from upper right abdomen or right lower these pyogenic abscesses are listed in chest and evidence of moderate liver Table H.^- - The availability of hepatic enlargement, the manifestations of radioisotope scanning and arterio­ large pyogenic abscesses are otherwise graphy now permit early identification nonspecific and consist of intermittent and localization of the abscesses for , chills, and with weight effective surgical drainage. Also, hepa­ loss. A few patients develop systems of tic echograms can differentiate between right diaphragmatic irritation. solid and abscess masses in the liver. The development of readily available Diagnostic Laboratory Findings: bacteriologic techniques to provide Elevation of the right diaphragm dem­ recognition of anaerobic organisms, onstrated by a chest x-ray provides the significant etiologic agents in liver ab- best clue for the presence of a liver TABLE II abscess. Since the majority of abscesses

Factors responsible for high mortality of large pyogenic liver are located in the superior aspect of abscesses in the past. the right lobe of the liver, elevation 1. Late or failure to diagnosis of the right diaphragm usually occurs Poor localizing signs, symptoms within several weeks. It was present Unavailable diagnostic techniques Non-recognition at abdominal operation (deep location in liver) in approximately two-thirds of our Complication of additional abscesses elsewhere patients. If the abscess is adjacent to 2. Failure to recognize frequent anaerobic etiology Lack of bacteriologic techniques the right diaphragm, or if the hepatic Erroneous empirical management as amebic abscesses abscess has ruptured into the right sub­ 3. Inadequate surgical drainage Drain site indirect, small phrenic space, variable quantities of Unrecognized multiple or multiiocular abscesses fluid usually appear in the lower right Drainage not sufficiently prolonged 4. Lack of effective and supportive measures pleural space. A large right frequently produces diagnostic

150 Critical Factors in the Management of Liver Abscesses confusion in localizing infection above aggregated albumin ^^^I, each having or below the diaphragm. If there is individual advantages and disadvan­ greater need for diagnostic information tages. Rose bengal ^^"^I has the dis­ than that provided by a liver scan, a advantages of a rapid turnover rate thoracentesis will usually show the and a delayed waiting period for the pleural fluid surrounding the unin­ dye to concentrate, but an advantage in fected lung to be clear rather than permitting an assessment of the extra­ purulent and, therefore, will place the hepatic biliary tract. Colloids have an infection below the elevated dia­ advantage in that the spleen is often phragm. Bacteriologic culture studies visualized with the liver, but the sep­ of the pleural fluid can be of help in aration of the spleen and left lobe of some instances in providing an early the liver may be difficult at times. Both bacteriologic diagnosis, and permitting anterior and lateral scans are essential the institution of proper for diagnosis and in directing surgical therapy prior to drainage of the liver drainage. Technical refinements are abscess. decreasing the time required for the Laboratory studies which provided study and provide improvement in additional help to us include the find­ uniformity and quality of the scans. ings of leucocytosis in at least three- The liver scan is not infaUible and fourths of our patients and a normal has limitations when applied to the serum bilirubin in nearly all patients diagnosis and management of liver with solitary pyogenic abscesses. Al­ abscess. Current techniques are un­ though the leucocyte count was less likely to identify an abscess smaller than 10,000 per cu mm in some pa­ than 2 cm in diameter, and abscesses tients or only slightly greater than this somewhat larger than this may not be figure in others, most patients in our demonstrated when centrally located experience had a persistent high leu­ in the right lobe of the liver. Technical cocytosis. An elevation of total serum factors in accomplishing the procedure bilirubin more than 2 mgm % was as well as experience in interpretation reported in only 3 of 21 of our pa­ of the scans, especially relative to a tients, the highest level being 6.7 mgm variety of congenital variations of gross %. These elevations of serum bilirubin liver configurations which are within were transient. normal limits, influence the accuracy of detection. In the case of an abscess, Radioisotope Photoscan of the the radioisotope liver scan will only Liver: The liver scan has improved demonstrate the presence of a defect greatly the capability for early diag­ but will not differentiate this defect nosis and management of large hepatic from those produced by neoplasms, abscesses. Scintillation scanning of the cysts, and simUar lesions. Ultrasonic liver indicates defects produced by echogram techniques can be of help abscesses in terms of location, size, in making this distinction between and number of lesions. A variety of solid and cystic lesions.° The liver isotopes are available for this study, scan, therefore, must be interpreted on including rose bengal ^•''^I, colloidal the basis of clinical findings; repeated gold ""Au, technetium sulfide Tc99", liver scans should be obtained if the

151 Block and Allen initial study does not demonstrate a quire surgical drainage, this factor can hepatic defect in a patient exhibiting be of real significance if an underlying other features indicative of a hepatic intrahepatic abscess is overlooked at abscess. the time of drainage of a subphrenic Radioisotope scanning identified the abscess. Of the 21 patients seen with liver defect in 19 of our 21 patients hepatic abscesses during the past eight with pyogenic abscesses who were seen years, an associated subphrenic abscess from 1962 through 1969. In one of was concomitantly identified and the failures, the abscess was of border­ drained in two patients. A subphrenic line dimensions, being approximately abscess had been drained ten months 3 cm in diameter. In the other patient, earlier in one additional patient, a the presence of an elevated right dia­ subhepatic abscess drained one year phragm and a liver scan, which was before in another patient, and in a fifth not entirely satisfactory for technical patient a subhepatic abscess required reasons, should have led to repetition drainage at a later date. In still another of the scan. False positive studies were of the patients, an intrahepatic abscess recorded in at least five patients who had apparently drained spontaneously had clinical manifestations suggesting through the right diaphragm to evacu­ the presence of a . The ate itself eventually via the tracheo­ nature of the hepatic defect in these bronchial tree. In our experience the five patients was clarified by the failure defects produced in radiologic studies of aspiration of the liver to confirm the by associated intrahepatic and right presence of an abscess, percutaneous subphrenic abscesses are usually con­ needle biopsies from the region of the fluent. Simultaneous scans of the lungs defect suggested by the liver scan, and and liver may be useful on occasion in operative evaluation of the liver when further elucidating this problem. A abdominal surgery was dictated for discrepancy in the volume of material other reasons. drained from a subphrenic abscess and Selective hepatic arteriography also the size of the defect shown on the liver is of diagnostic value in identifying the scan should alert the surgeon to the presence of a defect in the liver.** In possibility of an associated liver ab­ some cases, the study of vascular pat­ scess. In such instances, aspiration of terns demonstrated in our patients the underlying liver should be done permits the differentiation of neoplasms to detect the presence of the intra­ from abscesses in the liver. Small hepatic abscess and, if positive, ade­ lesions also may be depicted by this quate drainage effected for both the technique. However, hepatic arterio­ intrahepatic and subphrenic abscesses. graphy is associated with potential Overlaying a standard sized liver complications and also has limitations. scan onto a positioning x-ray film, in The differentiation of right sub­ which the level of the diaphragm is phrenic abscesses from intrahepatic evident, assists in the differentiation abscesses may not be provided by of an empyema in the right lower scintillative scanning of the liver. Al­ pleural space and collapse of the lower though this may not appear to be a right lung from a subphrenic or intra­ crucial matter, since both lesions re­ hepatic abscess. Occasionally, an ab-

152 Critical Factors in the Management of Liver Abscesses scess below the diaphragm ruptures xiphoid and the lateral scan to deter­ through the diaphragm and produces mine its anterior-posterior level, the an empyema or an abscess in the lower proper rib for drainage can be selected right lung. In these patients, drainage (Fig 1). We prefer first to aspirate to is needed both below and above the confirm the presence of an abscess and diaphragm. the best level of drainage. Material aspirated from the abscess can be im­ Surgical Drainage: In our experi­ mediately subjected to study for mo­ ence, surgical drainage is required to tile ameba and by gram-stained smears. eradicate large pyogenic liver ab­ Bacteriologic culture studies are also scesses. Open surgical drainage was initiated. Following confirmation of the utilized most in our patients. Pro­ presence of a pyogenic abscess by these longed catheter drainage alone was initial studies, an incision is made im­ used in a few patients with relatively mediately for adequate surgical drain­ small abscesses in the lower right lobe age. The liver often is adherent to the of the liver. Aspiration only, attempted parietal at this point. While in two patients seen in the early years making the incision, apposition of the of this study, was of apparent benefit diaphragm to the bed of the rib can only in one patient. However, this pa­ be ensured by sutures. Following tient had also spontaneously evacuated drainage of the abscess, the cavity of his abscess by rupture through the dia­ the abscess can be gently explored with phragm into the bronchial tree, pro­ the surgeon's finger to be certain that ducing a fistula which eventually afl loculations of a multiiocular abscess closed of itself. The apparent in­ are evacuated. Of the 21 patients with effectiveness of aspiration, even re­ large pyogenic abscesses treated since peated, is possibly related to the 1962, three were multiiocular and lo­ size of these abscesses and the fre­ cated in the right lobe. None in this quency with which anaerobic bacteria series had multiple large abscesses. produce the lesions. Excision of a Drains and gauze packing are placed chronic abscess, 3 cm in diameter and in the abscess cavity. located in the left lobe of the liver, The initial aspiration, or the entire was carried out in a 3-year-old patient drainage procedure, can be performed when the lesion could not be definitely under local anesthesia if desired. If differentiated from a neoplasm at the pus is not obtained by aspiration, a time of operation. percutaneous liver biopsy is performed We prefer to drain abscesses located to determine the nature of the tissue high in the right lobe of the liver in the region of the defect shown on through a lateral approach, usually via the hepatic scintillogram. the bed of an overlying rib from which Abscesses located low in the right a segment is removed. This provides lobe of the liver can be approached the most direct and dependent route laterafly via a rib bed or intercostal for drainage and avoids peritoneal con­ space, as discussed earlier, or by a tamination. By utflizing the anterior subcostal approach. When feasible, an liver scan to show the location of the effort is also made to maintain an abscess as related to the level of the extra-peritoneal route. Abscesses in the

153 Block and Allen low the ribs, an intraperitoneal ap­ abscesses, constituting more than one- proach is needed. Of the 21 patients third of our patients treated since with large hepatic abscesses seen in 1962, result from anaerobic organ­ our institution from 1962 through isms.^ The family Bacteroidaceae are 1969, 12 were located high in the prominent in the group of anaerobes right lobe, 8 in the lower right lobe, producing liver abscesses. This is rea­ and 1 was in the left lobe. sonable since these bacteria increase in frequency in the intestine distal to Bacteriologic Aspects: Inasmuch as the midportion of the pyogenic hepatic abscesses usually rep­ and become the major organism in the resent lesions secondary to an infection stool. These bacteria are fastidious and elsewhere, the bacteriologic etiology of bacteriologic techniques available in the large pyogenic abscesses is deter­ the past have not readily permitted mined by the organisms causing the their recognition. Even with proced­ primary lesion. The majority of these ures in current use, growth of these primary lesions are located in the organisms is slow, usuafly requiring drainage system of the portal vein. a number of days. We believe that A large proportion of pyogenic liver this factor has been a major reason for left lobe require a subcostal approach; the numerous past reports of negative unless the lobe extends inferiorly be- bacteriologic culture for material re-

Figure 1 Use of liver scan in directing lateral approach to aspiration and surgical drainage of abscess located high in right lobe of liver.

154 Critical Factors in the Management of Liver Abscesses moved from liver abscesses. Such nega­ of air, readily dries, and is unlikely to tive culture reports have produced con­ permit isolation of anaerobic organ­ fusion in the clinical management of isms. The specimen should be pre­ liver abscesses. By assuming that such sented immediately to the bacteriolo­ abscesses are amebic in origin, medical gist who is alerted to the clinical therapy has been directed from this problem. The finding of numerous erroneous premise. In our practice, bacteria in a gram-stained smear con­ hepatic abscesses due to anaerobic firms the bacteriologic etiology of the bacteria far outnumber amebic ab­ abscess and rules out an amebic origin, scesses. except for a secondarily infected ame­ In our experience, the Bacteroid­ bic abscess. Failure to obtain growth aceae have important clinical charac­ of the organisms for a few days to teristics other than those associated several weeks, despite the presence of with difficulties in their bacteriologic numerous gram-negative bacilli on the culture. Their isolation as a pure cul­ smear, usually indicates an etiology ture from hepatic abscesses in five of six due to the family Bacteroidaceae. patients firmly supports their etiologic significance. In one of the patients, Post-drainage Care: Treatment fol­ Bacteroides was isolated also from the lowing surgical drainage of hepatic blood. These bacteria produced def­ abscesses relates to supportive meas­ inite although not fulminant toxicity, ures, maintenance of drainage of the and abscesses caused by these organ­ abscess, follow-up radioisotope scin­ isms are potentially fatal. Not only are tillography, a search for abscesses else­ members of the family Bacteroidaceae where when suspected clinically, and difficult to culture, but infections due an investigation for the site of pri­ to these organisms are frequently diffi­ mary infection if not already evident. cult to eradicate. In our experience, Each of these factors must be adapted prolonged administration of proper to the individual patient. antibiotics as well as prolonged open If fever or other evidence of an ab­ surgical drainage are necessary to scess continues or recurs after ade­ eliminate abscesses due to Bacteriod- quate drainage of a hepatic abscess, a aecea, so repeated aspiration is not search should be made for another particularly successful in their man­ abscess elsewhere. Hepatic scintil­ agement." lography is of value in verifying reso­ Management of large pyogenic hep­ lution of the drained abscess and in atic abscesses should be modified in detecting the presence of an additional several additional ways to meet the intrahepatic abscess or the develop­ problems related to the frequency of ment of a subphrenic abscess. Other an anaerobic bacteriologic etiology. common sites for associated abscesses First, the bacteriologist should be pro­ include subhepatic, pulmonary, and vided a large volume of material so cerebral locations, as well as at the that the anaerobic conditions are pre­ site of the primary infection. Of the 21 served for at least some of the organ­ patients treated for hepatic abscesses isms in the specimen. A mere swab since 1962, five required drainage of exposes the bacteria to an abundance abscesses elsewhere as separate pro-

155 Block and Allen cedures. In addition to the three pa­ tract, including the gallbladder. tients requiring drainage of other ab­ In a few patients of our recent scesses previously, two patients later series, the primary lesion has not been were treated for brain abscesses and detected. This faUure may be due to one patient had a pulmonary abscess its smafl size, such as a localized area concomitant with an intrahepatic ab­ of of the sigmoid colon, scess. or because the infection was tempor­ If the primary site of infection has ary, months or even years in the past, not been located and treated already, and not particularly noticeable to the a search for this lesion should be made patient, such as infected internal hem­ postoperatively when the patient's con­ orrhoids. The primary source of in­ dition permits. If the bacteriologic fection can be determined usually from etiology of the hepatic abscess is the patient's history or from diagnostic known, a hint is provided for the studies. A postmortem examination general location of the primary source has provided this information only of the infection. Most primary lesions occasionally. The etiologic bacteria will be located in the peritoneal cavity and probable sources of infection for and related to the . our patients are shown in Table IV. Therefore, radiologic studies are in­ The infection which ultimately leads to dicated of the entire gastrointestinal a pyogenic liver abscess may precede

TABLE IV

Bacteriologic etiology and location of primary infection in 21 patients treated for large pyogenic liver abscesses, 1962 through 1969.

Bacteriologic Etiology Location of Primary Infection No. Patients Anaerobic Bacteroidaceae Unknown 2 '•' 2 * Post-op. gastrectomy Streptococci Pancreatitis Diverticulitis sigmoid Aerobic Enteric bacteria Proteus 'Sigmoid infarction Abd. and liver trauma 'Post-op. abd. nephrectomy E. Coli 'Post-op. gastrectomy and choledochoduod. Unknown Streptococci 'Appendicitis 'Post-op. gastrectomy Cholecystitis Staphylococcus aureus Unknown Cultures reported negative Unknown

' In 10 patients, hepatic abscess followed abdominal operation.

156 Critical Factors In the Management of Liver Abscesses recognition of the abscess by many At the time of drainage of any hepatic months or years. Of the 15 patients for abscess, it is wise to explore the wall whom the primary infection could be of the abscess for suspicious defects localized, in 8 it appeared to have been and to biopsy the wafl at such loca­ present 6 months or more prior to rec­ tions. Hepatic trauma can lead to in­ ognition of the hepatic abscess. In 10 trahepatic abscess, even many years of the 21 patients, abdominal surgery after the original injury. had been carried out previously for the Although pyogenic hepatic abscesses primary infection or another lesion. In secondary to extrahepatic bfliary tract the patients developing large pyogenic obstruction are usually multiple, small, liver abscesses following appendicitis, and associated with a diffuse acute there was no evidence for portal pyle­ hepatic cholangitis, they are occasion­ phlebitis. ally large. Surgical therapy for these patients consists of early relief of the extrahepatic bfliary tract obstruction, Pyogenic Liver Infections and use of appropriate antibiotics, and Abscesses—Miscellaneous and supportive care.'-* However, the pres­ Special Cases ence of a large pyogenic hepatic ab­ scess requires, in addition, surgical Although the majority of large pyo­ drainage of this abscess. genic abscesses appear to develop from Pyogenic hepatic abscesses in chfl­ a hematogenous origin, not all have dren differ from those of adults in that this pathogenesis. A few develop from extrahepatic biliary tract obstruction direct extension of infection from is a rare cause and in that a hema­ acute cholecystitis. Although the liver togenous origin is usually from ap­ scan in such patients may show a de­ pendicitis or pneumonia. Dehner and fect larger than attributable to a Kissone noted in children a frequent normal gallbladder indentation, in our association of hepatic abscesses with experience this finding can result from leukemia.i" Staphylococci appeal- to be acute cholecystitis in the absence of the cause more often in children than an associated abscess and, therefore, in adults; our only patient for whom cannot be depended upon to identify staphylococci were cultured from a a pericholecystic abscess. Furthermore, pyogenic hepatic abscess was a 3- carcinoma of the gaflbladder can pro­ year-old child. duce the appearance of a defect in the region of the gaflbladder. Large pyogenic abscesses may be Amebic Hepatic Abscesses associated with primary or metastatic liver malignancy. The clinical history From 1962 through 1969, four pa­ and presence of multiple defects in the tients were treated in our institution hepatic scintiflogram may provide clues for amebic abscesses whfle 21 were to this situation. If this problem is treated for large pyogenic liver ab­ suspected, the operative approach to scesses of apparent hematogenous the Hver and the abscess usually is origin. In each patient, over two liters of through a subcostal incision which material were drained from the hepatic permits evaluation of the entire liver. abscess, resulting in early and perman-

157 Block and Allen

ent recovery. Repeated aspiration of whether patients are treated by surgical the abscess, in conjunction with drainage or by appropriate drugs. emetine and chloroquine therapy, had Surgical drainage then may be needed been carried out in one patient but only for complicated amebic abscesses failed to provide permanent recovery. in patients who are or remain in cri­ Many surgeons with experience with tical condition, in faUure to respond to this lesion have reported that repeated medical therapy particularly by large aspiration provides a safe resolution abscesses, in recurrent and ruptured for amebic liver abscesses and this abscesses, and in secondarily infected may be the preferable technique for abscesses. the surgical management of small to moderate sized abscesses of this Summary and Conclusions etiology. 1. Improved diagnostic techniques, Although amebic hepatic abscesses including radioisotope liver scans and are not common in many regions of serologic tests for amebiasis, now per­ the United States, the lesion is not mit the early diagnosis of large liver rare and must be considered whenever abscesses. Solid tumors may be dif­ evidence of a liver abscess is found in ferentiated by ultrasonic echograms any patient who has been in an area and selective hepatic arteriography. in which amebiasis is endemic. In general, the clinical features of ame­ 2. Liver abscesses may be classi­ bic liver abscesses simulate those of fied into large pyogenic abscesses of large pyogenic abscesses except for a hematogenous origin, amebic abscesses, history suggesting previous acute ame­ pyogenic abscesses due to extrahepatic biasis. Jaundice is unusual in either bfliary tract obstruction, and a mis­ of these varieties of hepatic abscesses. ceflaneous group including those re­ Indirect hemagglutination and im- lated to malignancies in the liver, acute muno-diffusion tests for amebiasis ap­ cholecystitis, and hepatic trauma. pear to be highly specific and sensitive 3. The large pyogenic abscesses are and offer confidence in the laboratory of particular concern to surgeons. diagnosis of this disease." Aspiration Their high mortality in the past has of the liver abscess for diagnosis is not now been greatly reduced. needed when these tests, clinical fea­ tures, and the liver scan all indicate 4. Hepatic radioisotope scanning, the presence of an amebic abscess. although not specific, is of particular Another significant development in value in permitting the identification the management of amebiasis and ame­ of large pyogenic liver abscesses, in bic abscesses is the avaflability of their localization for surgical drainage, newer drugs, including . and in follow-up studies to confirm This drug evidendy provides rapid resolution of the abscess. elimination of toxicity from amebiasis 5. Surgical drainage of large pyo­ and will permit complete eradication genic liver abscesses should be pro­ of amebic hepatic abscesses. The reso­ vided by the most direct and safe route, lution time of amebic liver abscesses is should be adequate, and should be reported to be approximately the same maintained sufficiently long to permit

158 Critical Factors in the Management of Liver Abscesses healing of the abscess cavity. Open 8. Large pyogenic abscesses are as­ surgical drainage is usually required. sociated in a significant number of pa­ tients with subphrenic or subhepatic 6. Material drained from a liver abscesses or abscesses at distant lo­ abscess should be studied immediately cations. by gram-stained smears and for motfle ameba. Both aerobic and anaerobic 9. Large pyogenic liver abscesses are culture studies should be performed. usuafly secondary to lesions elsewhere 7. A great proportion of large pyo­ in the peritoneal cavity, their bacteri­ genic liver abscesses are due to ana- ologic etiology being determined ac­ roebic bacteria, particularly of the cordingly. If the primary infection is family Bacteroidaceae, which are diffi­ not evident at the time of drainage of cult to culture, produce indolent in­ the liver abscess, a search for it shoifld fections, and require prolonged drain­ be made at a later date. age and antibiotic therapy.

REFERENCES

1. Cronin, K.: Pyogenic abscess of liver. Gut 2:53-9, Mar 1961. 2. Ogden, W. W.; Hunter, P. R., and Rives, J. D.: Liver abscess, Postgrad Med 30:11-9, Jul 1961. 3. Block, M. A., et al: Surgery of liver abscesses: Use of new techniques to reduce mortality, Arch Surg 88:602-10, Apr 1964. 4. Block, M. A.: Editorial. Principles in the management of liver abscesses. Amer J Surg 115:587-8, May 1968. 5. Monroe, L. S., et al: The ultrasonic scan in the management of amebic hepatic abscesses. Am J Dig Dis 16:523-8, Jun 1971. 6. Freeman, L. M., et al: Combined diagnostic approach of hepatic scanning and celiac angiography in the investigation of , J Nucl Med 10:628-32, Oct 1969. 7. St. John, F. B.; Pulaski, E. J., and Ferrer, J. M.: Primary abscess of the liver due to anaerobic nonhemolytic streptcoccus, Ann Surg 116:217-22, Aug 1942. 8. Saksena, D. S., et al: Bacteroidaceae: Anaerobic organisms encountered in surgical in­ fections. Surgery 63:261-7, Feb 1968. 9. Hinchey, E. J., and Couper, C. E.: Acute obstructive supporative cholangitis, Amer J Surg 117:62-8, Jan 1969.

159 Block and Allen

10. Dehner, L. P., and Kissane, J. M.: Pyogenic hepatic abscesses in infancy and childhood, J Pediat 74:763-73, May 1969. 11. Juniper, K., Jr.: Editorial. Amebic abscess of the liver, Amer J Dig Dis 14:290-2, Apr 1969. 12. Sheehy, T. W., et al: Resolution time of an amebic liver abscess, 55:26-34, Jul 1968.

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