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Management of intersphincteric abscesses.

OBJECTIVE: Intersphincteric abscesses are relatively rare, and in some cases of upward extensions in the supralevator plane, can be difficult to manage. The aim of this study was to analyse the type of treatment used in these abscesses. METHODS: Twenty-one intersphincteric abscesses treated by endoanal drainage in our colorectal unit between 1992 and 2004 were reviewed from our database; location and extension of the abscess, type of treatment and recurrence rates and the use of endoanal ultrasound were studied. RESULTS: Ninety per cent of patients were male; 10 had a previous history of surgery for perianal abscess and suppuration (48%); 16 (76%) had a posterior location and five were anterolateral. Twelve patients had low intersphincteric abscesses and were treated by laying open the abscess and dividing the internal sphincter. Nine were found to have high extensions into the intermuscular planes and were treated by staged procedures: a temporary transanal mushroom catheter was used in seven patients. Endoanal ultrasound was used initially in seven patients (33.3%) and for the evaluation of definitive treatment in 11 (52%). CONCLUSIONS: Low intersphincteric abscesses should be treated by de-roofing of the abscess and division of the internal sphincter up to a level of the dentate line. High intersphincteric abscesses are relatively frequent and mostly require staged surgery with a temporary mushroom (de Pezzer) catheter. Accurate anatomical ultrasound localization and proper drainage become important to avoid recurrences or extrasphincteric fistulas.

Abscess↗

The importance of immunoglobulin-breakdown supporting the growth of bacteria in oral abscesses.

Oral bacteria play an important rôle in the causation of oro-facial abscesses. However, they can also be involved in brain, liver and lung abscesses. To persist, it is essential that these bacteria can grow on those sites. The main source of nutrients for growth in abscesses is likely to be tissue exudate, which is rich in serum-derived proteins, and relatively poor in free amino acids and carbohydrates. Degradation of intact proteins seems a crucial step in providing the peptides necessary for energy generation. The aim of this study was to investigate the capacity of microorganisms from asscesses to degrade serum proteins, in particular immunoglobulins. To this end, samples were taken by aspiration from 16 odontogenic abscesses. It was found that pus from abscesses differed strongly in the concentration of viable bacterial cells. The ability of the abscess microflora to degrade serum proteins was investigated after growth of the sample in heat-inactivated human serum. The microflora from abscesses with a high concentration (n = 10) of bacteria strongly degraded immunoglobulins, whereas breakdown of immunoglobulins was virtually absent after growth of the microflora from low-bacterial concentration (n = 6) abscesses. Bacteriological analyses revealed the presence of at least one proteinase-producing species, like Porphyromonas, black-pigmented Prevotella species, or Actinomyces meyeri, in abscesses with a high density of bacteria, but not in those with low bacterial density. The results indicate that the capacity to degrade intact proteins, in particular immunoglobulins, is a major determinant of bacterial growth in abscesses.

Adult↗

Comparison of 99m technetium hexamethylpropylene-amine oxime labelled leucocyte with 111-indium tropolonate labelled granulocyte scanning and ultrasound in the diagnosis of intra-abdominal abscess.

Fifty patients with suspected intra-abdominal abscess were investigated prospectively with ultrasound and with 99mTc-hexamethylpropylene-amine oxime (HMPAO) isotope labelled mixed leucocytes, using 111-In tropolonate granulocyte scanning as the reference standard. Twenty five patients had inflammatory bowel disease (three were postoperative): 21 of these had Crohn's disease and four had ulcerative colitis. The remainder comprised nine with postoperative fever and 16 with fever and abdominal pain. An abscess was diagnosed when focal activity on serial 111-In tropolonate and 99m-Tc-HMPOA images at one, three, and 24 hours resulted in activity at least equal to liver activity at 24 hours. Thirteen abscesses were diagnosed using each type of white cell scanning, resulting in 100% sensitivity for 99m-Tc-HMPAO compared with 111-In tropolonate. Bowel inflammation was easily distinguished from abscess on serial images. Eight of these 13 abscesses were detected by ultrasound. Altogether 17 abscesses were found. Ultrasound detected 12, including four liver abscesses which were not purulent and had not been detected by white cell scanning. Ultrasound had a sensitivity of 71% (12 of 17) and a specificity of 87% (33 of 38) using all confirmed abscesses as the reference standard. White cell scanning showed a sensitivity of 76% (13 of 17: as a result of the four non-purulent liver abscesses) and a specificity of 100%. 99m-Tc-HMPAO scanning is as accurate as 111-In tropolonate scanning, and has several advantages including simplicity, availability, superior image quality, and reduced radiation dose. Both methods are more sensitive and specific than ultrasound for intra-abdominal abscess detection but ultrasound is advisable if a neutrophil infiltrate is not suspected.

Abdominal Abscess↗

Multiple pyogenic brain abscesses: an analysis of 21 patients.

Multiple pyogenic brain abscesses constituted 11.7% (21 patients) of a series of 179 consecutive patients with brain abscess treated from 1976 to 1984. The commonest cause of these abscesses was congenital cyanotic heart disease (38%), followed by middle ear infection (19%). Two thirds of these patients were in the first two decades of life. The clinical presentation was similar to brain abscesses in general, there being no clinical features suggestive of multiple lesions. In 85% the abscesses were supratentorial. Infratentorial abscesses alone or in association with supratentorial abscesses were invariably otogenic in origin. Aspiration of the largest abscesses supplemented with appropriate antibiotics was the treatment of choice in 16 patients; secondary excision of the largest abscesses was required in six patients. Primary excision was performed in three patients when the abscesses were in close proximity to each other. Two patients were managed with antibiotics alone. The overall mortality was 23.8%.

Adolescent↗

Tropical liver abscess.

Forty-one consecutive cases of liver abscesses seen at the National University Hospital, Singapore from 1988 to 1994 were reviewed. Twenty-seven cases (65%) were pyogenic, six (15%) amoebic, two (5%) tuberculous and six (15%) indeterminate. The predominance of pyogenic abscesses is in marked contrast to previous studies from the region a decade ago in which amoebic abscesses were the commonest type. The commonest pathogen causing pyogenic abscess was Klebsiella pneumoniae. Two cases were due to Mycobacterium tuberculosis, and this organism needs to be actively looked for in smears and cultures of aspirated material. As the majority of organisms isolated were resistant to ampicillin, empirical antibiotic treatment for suspected pyogenic abscess should include gentamicin or a cephalosporin. Percutaneous needle aspiration of the abscess was performed for 85% of pyogenic abscesses and surgery was necessary in only two cases because of complications. We found that percutaneous aspiration of liver abscess is helpful to confirm the diagnosis, provides a better bacteriological culture yield, gives a good outcome, and may uncover clinically unsuspected conditions like malignancy and tuberculoma which may mimic the presentation of liver abscesses. We recommend routine cytological examination of aspirated abscess material as well as stains and cultures for acid-fast bacilli.

Adult↗

Pedal abscesses in patients suspected of having pedal osteomyelitis: analysis with MR imaging.

PURPOSE: To document the expected frequency, location, and size of pedal abscesses in patients with advanced foot infection. MATERIALS AND METHODS: Images obtained at contrast material-enhanced magnetic resonance (MR) imaging (at 1.5 T) of 161 feet of 51 women and 107 men (mean age, 58.5 years; 82.3% had diabetes) who underwent bone biopsy after MR imaging for possible osteomyelitis were reviewed by two musculoskeletal radiologists working together. Presence, size, and location of abscesses and presence of adjacent skin ulceration were noted. MR imaging criteria for abscess were the following: presence of fluid collection with isointense or hypointense signal on T1-weighted images, fluid-equivalent signal intensity on T2-weighted images, and peripheral rim enhancement. All patients' charts were reviewed for clinical and surgical information. RESULTS: Thirty-two fluid collections compatible with abscesses were found in 29 (18.4%) of the 158 patients; 26 (90%) of these patients had diabetes (P =.38). Abscess size varied from 1 x 0.5 x 0.4 cm to 3.8 x 3.4 x 2.2 cm (mean = 2.6 x 1.5 x 0.9 cm). Abscesses were located in the forefoot (n = 15), hindfoot (n = 7), toes (n = 3), midfoot (n = 4), or in multiple locations (n = 3). Thirty-one abscesses (97%) occurred near a skin ulcer (distance range, 0-9.1 cm; mean, 1.4 cm). Abscesses were significantly more frequent in patients with osteomyelitis (n = 28, 97%) (P <.001) and in feet that had been treated surgically (n = 16, 33%) (P <.002). CONCLUSION: MR imaging revealed abscesses, predominantly in the forefoot, in 18% of patients suspected of having pedal osteomyelitis. Abscesses are significantly more frequent in patients with osteomyelitis and in feet that have been treated surgically.

Abscess↗

Percutaneous management of pyogenic hepatic abscesses.

Twelve patients (9 men, 3 women) with a mean age of 65 (54-78) years, with pyogenic hepatic abscesses were managed by percutaneous drainage between 1979 and 1987. Biliary origin was most common (4 patients), followed by hepatic abscesses as a late postoperative complication (seen in 3 patients) and hepatic abscesses occurring in association with acute appendicitis (2 patients). The origin was unknown in 3 patients. Diagnosis was reached by computed tomography or ultrasonography with a diagnostic delay of in mean 11 days. Seventeen abscesses were found among the 12 patients. The median abscess size (maximal diameter) was 7 (1-12) cm. Nine patients were treated with percutaneous drainage with an indwelling catheter within the abscess cavity for up to 3 weeks, while 3 patients were managed with percutaneous puncture and aspiration alone. The most commonly isolated organism from the drained hepatic abscess was E. coli. The course following percutaneous treatment was uneventful, without mortality and recurrence of the hepatic abscess during follow-up. One patient required surgical drainage of an additional hepatic abscess. Percutaneous drainage of hepatic abscesses, independent of origin, thus seems as a safe and reliable method, which should be considered as the treatment of choice if facilities and knowledge of percutaneous management are provided.

Aged↗

[99mTc-ceftizoxime scintigraphy in normal rats and abscess induced rats].

UNLABELLED: This study aimed to investigate the biodistribution of the 99mTc-ceftizoxime in normal rats and in rats bearing septic and sterile induced abscess. MATERIAL AND METHODS: Three groups of rats were studied. a) Six normal rats b) 15 rats with E. coli induced abscess and c) 15 rats with sterile zymosan induced abscess. Septic abscess was induced with 2 x 10(8) colony forming units of E. coli and sterile one with 0.1 mL of 5% sterile Zymosan. 24 h after the abscess induction, 12 MBq of 99mTc-CFT were injected iv. and whole body images were collected at 30 min, 1, 2, 4 and 6 h p.i. Areas of interest were drawn and lesion/background index was calculated. The 6 normal rats were scanned at the same times, killed at 6 h p.i and kidney, liver, spleen, lung, heart and muscle activity were measured. Each organ was weighed, cut and its activity measured. Parallelly, the biological activity of the labeled antibiotic and its binding to the E. coli and S. aureus bacteria were analyzed. RESULTS: High biliary excretion was seen in all rats. Organ measurement showed the maximal uptake in kidney and very low uptake in muscles. Mean +/- s.d abscess/background ratio at 30 min, 1, 2, 4 and 6 h were 2.60 +/- 0.36, 2.67 +/- 0.66, 2.6 0 +/- 0.58, 2.78 +/- 0.84, 3.24 +/- 1.00 for septic abscess and 2.37 +/- 0.39, 2.10 +/- 0.38, 1.97 +/- 0.34, 1.82 +/- 0.25, 1.65 +/- 0.23 for aseptic abscess. The 99mTc-CFT uptake was significantly higher in the septic abscess than in sterile one (p < 0.05). The 99mTc-CFT uptake in the septic abscess remains stable or increases until along the 6 h. The 99mTc-CFT uptake in the aseptic abscess decreases along the time. CONCLUSIONS: The scintigraphy with 99mTc-CFT seems able to differentiate sterile inflammation from infection. High biliary excretion limits its application in abdomen. Main application could be diagnosis of osteoarticular infection.

Abscess↗

Needle aspiration of neck abscesses in children.

Needle aspiration of neck abscesses with CT-scan guidance was studied in 17 children with 18 abscesses from 1986 to 1991. Clinical and radiologic findings were analyzed according to treatment outcome. A majority of abscesses (55.6%) resolved after treatment with one to two attempts at needle aspiration and parenteral antibiotics. Unilocular abscesses were more likely than multilocular abscesses to resolve with needle aspiration. In general, abscesses in younger children who presented with smaller neck masses on physical examination and smaller abscess cavities on CT scan resolved with needle aspiration. The data support the use of needle aspiration as an effective initial treatment for pediatric neck abscesses. CT scan was found beneficial in documenting the abscesses and in guiding treatment. A treatment protocol is suggested for the use of needle aspiration in the management of neck abscesses in children.

Abscess↗

Immunohistochemical and pathological study of Mycoplasma bovis-associated lung abscesses in calves.

Out of 45 cases of fatal chronic pneumonia in calves examined for Mycoplasma bovis infection from February to July 1994, 11 cases with pulmonary abscesses that were culture positive for M. bovis were encountered. The cases were studied in detail using a recently developed monoclonal antibody-based immunoperoxidase technique. Mycoplasma bovis organisms were detected in specific locations at all stages of abscessation observed. In bronchioles or terminal airways within which abscesses developed, M. bovis was located at the epithelial surface and in close association with infiltrating neutrophils and macrophages. Abscessed airways that had lost the epithelium were encapsulated and were seen as coagulative necrotic foci that stained intensely for M. bovis, especially at the periphery. Some foci stained weakly and such might have been resolving lesions. Mycoplasma bovis was also demonstrated at sites of mild mononuclear cell infiltration in the livers and kidneys of 2 calves. The mycoplasma was detected within bile ducts in the liver and in the tubular epithelium of the kidney. Abscesses not staining for M. bovis, presumably caused by other pathogens, were seen concurrently with M. bovis-associated abscesses in some lungs. Thirteen other M. bovis-positive cases showed no abscesses, possibly indicating heterogeneity among M. bovis strains. Three other cases with abscesses were negative for M. bovis by culture and immunoperoxidase staining. The monoclonal antibody-based immunohistochemical technique is efficient for specific detection of M. bovis in cases of enzootic pneumonia of calves with or without abscessation. Mycoplasma bovis is implicated in the pathogenesis of lung abscesses in some calves.

Animals↗

Percutaneous needle aspiration of multiple pyogenic abscesses of the liver: 13-year single-center experience.

OBJECTIVE: The aim of this study was to report 13 years of experience in the management of multiple pyogenic liver abscesses with only percutaneous needle aspiration of the abscess cavities under sonographic guidance. MATERIALS AND METHODS: From December 1991 to October 2004, 39 consecutively registered patients (29 men and 10 women; age range, 37-82 years; mean age, 64 years) with 118 pyogenic liver abscesses were treated with sonographically guided percutaneous needle aspiration at our institution. The number of pyogenic liver abscesses per patient ranged from two to 15 (mean, 3.0). RESULTS: Eighty-seven percutaneous needle aspirations were performed on 39 patients with 118 pyogenic liver abscesses (range, 1-4 aspirations per patient; mean, 2.2 aspirations per patient). Because they were close to another aspirated abscess in the right lobe of the liver, 31 (26.3%) of 118 abscesses were aspirated without removal of the needle from the liver. Thirty-six (92.3%) of 39 patients were treated with a single aspiration of an abscess in a single session. The other three patients needed two aspiration sessions. No patient needed imaging-guided percutaneous catheter drainage or open surgical drainage. Complete reconstitution of liver parenchyma occurred within a maximum of 80 days. No abscesses recurred during the follow-up period, which ranged from 7 to 42 months (mean, 18 months). CONCLUSION: Percutaneous needle aspiration of multiple pyogenic abscesses under sonographic guidance is a safe, effective, and low-cost procedure. In our experience, percutaneous needle aspiration was acceptable to patients. Our data suggest that a trial of percutaneous needle aspiration should always be undertaken before catheter drainage or surgery.

Adult↗

Magnetic resonance imaging in the evaluation of abscesses.

Ten patients with percutaneous biopsy or surgically proven abscesses were evaluated with magnetic resonance imaging (MRI) to describe the appearance of abscesses, define the capability of MRI to localize abscesses, and compare the capabilities of MRI and CT for the diagnosis and determination of the extent of an abscess. Comparative CT scans were available in six cases. The most common MRI finding was an abnormal area of low signal intensity, either homogeneous or heterogeneous, on the short repetition rate (500 msec TR) images with a relative increase in signal intensity on the longer repetition rate (1500 or 2000 msec TR) images. MRI demonstrated a more clear delineation of the extent of inflammatory changes than did CT, and MRI demonstrated the abscess as a collection distinct from surrounding structures on at least one repetition rate. Intravenous contrast medium was unnecessary with MRI to evaluate vasculature or to define the capsule around an abscess. With CT, unless an abscess contained air or was of low attenuation, it often blended with the surrounding structures and was difficult to differentiate from them. Surgical clips in the postoperative patient with an abscess did not degrade the MR images as often occurred with CT. This study describes the MRI appearance of abscess and indicates a potential value of the use of MRI to evaluate abscess outside the central nervous system and spine.

Abdomen↗

CT of amebic liver abscess.

CT findings in 23 patients with amebic liver abscess were analyzed retrospectively. A solitary abscess was present in 17 patients. Five patients had two to five lesions. One patient, a male homosexual, had 15 abscesses. Of the 46 abscesses, 74% occurred in the right lobe. The lesions were generally round or oval. One-half of the abscesses were 2-6 cm in diameter; 11% measured 13-16 cm. An enhancing wall was present in most cases. An incomplete rim of edema was seen in eight abscesses. The margin of the abscess was smooth in 63% and nodular in 37%. Internal septations were noted in 30%. Four patients had focal intrahepatic biliary dilatation peripheral to an abscess. One patient had intraabscess hemorrhage. Extrahepatic abnormalities were present in 18 patients; right pleural effusion (nine), perihepatic fluid collection (five), gastric or colonic involvement (eight), and retroperitoneal extension (one). Gas within an abscess was due to hepatobronchial fistula in one patient and hepatocolic fistula in another. Amebic abscess should be included in the differential diagnosis when CT shows one or more cystic or complex masses in the liver, especially when there is evidence of extrahepatic extension.

Adolescent↗

Therapeutic percutaneous aspiration of hepatic abscesses: effectiveness in 25 patients.

OBJECTIVE: The objective of this study was to evaluate the effectiveness of sonographically guided needle aspiration and systemic antibiotic therapy for the treatment of hepatic abscesses. SUBJECTS AND METHODS: From June 1989 to September 1991, sonographically guided needle aspiration and systemic antibiotics were used to treat 25 consecutive patients with 25 hepatic abscesses. Among 36 patients with hepatic abscesses who were admitted to the hospital during that time, six had antibiotic therapy only; of these, three had microabscesses, two had abscesses less than 3.0 cm in diameter, and one refused needle aspiration. Four patients had surgical external drainage (three had cholelithiasis in addition to hepatic abscesses, and one did not respond to needle aspiration). Two patients treated in 1989 had drainage via an indwelling catheter, which was the preferred method at that time. The remaining 24 patients and one patient who had needle aspiration followed by surgical drainage made up the study group. Seventeen of the hepatic abscesses were caused by pyogenic organisms, six by amoeba, and two by unknown organisms. Eighteen abscesses (72%) were aspirated once, four (16%) were aspirated twice in 8 days, two (8%) were aspirated three times in 14 days, and one (4%) was aspirated four times in 10 days. Persistent fever, pain and tenderness in the right upper quadrant, and leukocytosis were the indications for multiple aspirations. Follow-up sonography was performed to evaluate the outcome of treatment. RESULTS: In 16 cases (64%), the abscesses disappeared within a mean of 84 days. In eight cases (32%) with only partial follow-up, the patients were asymptomatic at the time of discharge and the abscesses were markedly smaller on the last follow-up sonograms (mean, 43 days). One patient (4%) did not respond to aspiration and had surgical drainage. The length of hospitalization varied from 5 to 42 days (mean, 22 days). In patients who became afebrile during the treatment, the fever had lasted from 0 to 10 days (mean, 3 days). Only one patient had a complication of the procedure, a pleural effusion that was treated conservatively. CONCLUSION: Our results show that sonographically guided needle aspiration combined with antibiotic therapy is effective as the initial treatment for hepatic abscesses.

Adult↗

Percutaneous treatment of liver abscesses: needle aspiration versus catheter drainage.

OBJECTIVE: This study was designed to determine and compare the efficacy of sonographically guided percutaneous needle aspiration and percutaneous catheter drainage in the treatment of liver abscesses. SUBJECTS AND METHODS: In a randomized study, 50 patients (38 males and 12 females; age range, 2-72 years; average age, 35 years) with liver abscesses (amebic, 20; pyogenic, 11; indeterminate, 19) underwent either percutaneous needle aspiration (n = 25) or catheter drainage (n = 25) along with appropriate antimicrobial therapy. In patients assigned to the needle aspiration group, an 18-gauge needle was used to aspirate the abscess cavity. Repeated aspiration was attempted only once in each patient not responding to the first aspiration; nonresponse to the second aspiration was considered failure of treatment, and these patients were given catheter drainage (however, these patients were not included in the catheter drainage group). For catheter drainage, 8- to 12-French catheters were introduced into the abscess cavity using the Seldinger technique. In patients with multiple abscesses (seven in aspiration group and five in catheter group), all the abscesses except those smaller than 3 cm were subjected to percutaneous treatment. Patients were followed up to assess the outcome of the percutaneous treatment, length of hospital stay, and development of any complications. Sonography was performed every third day during hospitalization. After discharge of the patient, periodic clinical and sonographic examinations were done until total resolution of abscesses was achieved. RESULTS: Although percutaneous needle aspiration was successful in only 15 (60%) of the 25 patients after one (n = 11) or two (n = 4) aspirations, catheter drainage was curative in all 25 patients (100%) (p < .05). Among the successfully treated patients, the average time for clinical improvement and the mean hospital stay were similar in the two treatment groups. Although the average time needed for a 50% reduction in the size of the abscess cavity was significantly (p < .05) greater in the aspiration group than in the catheter group (11 days versus 5 days), the average time taken for total resolution of abscess was the same (15 weeks) in both groups. No major complications were encountered. No relapse was documented on clinical and sonographic examination during follow-up, which ranged from 8 to 37 weeks. CONCLUSION: Our results show that percutaneous catheter drainage is more effective than needle aspiration in the treatment of liver abscesses. Needle aspiration, if limited to two attempts, has a high failure rate.

Adolescent↗

Dynamic CT of hepatic abscesses: significance of transient segmental enhancement.

OBJECTIVE: The purpose of this study was to evaluate dynamic CT findings of hepatic abscesses, especially segmental hepatic enhancement, and to clarify the cause. MATERIALS AND METHODS: Twenty-four abscesses in eight patients were examined by early (30 sec) and late phase (90 sec) dynamic CT. Patients underwent abscess drainage (n = 1), hepatic resection (n = 2), or antibiotic therapy (n = 5). CT during arterial portography and CT during hepatic arteriography were performed in one patient. We retrospectively observed the frequency and changes of segmental hepatic enhancement on dynamic CT and determined its cause using radiologic and pathologic correlation. RESULTS: Sixteen abscesses (67%) showed transient segmental hepatic enhancement and three abscesses showed only segmental hepatic enhancement in the early phase. Four abscesses in one patient who underwent CT during arterial portography and CT during hepatic arteriography showed a segmental perfusion defect on CT during arterial portography and segmental enhancement on CT during hepatic arteriography. On follow-up dynamic CT performed 10-17 days after the initial CT, segmental hepatic enhancement surrounding hepatic abscesses decreased or disappeared in all abscesses. Pathologic examination of two patients showed marked inflammatory cell infiltration with stenosis of portal venules within the portal tracts surrounding hepatic abscesses without definite inflammation in the liver parenchyma. CONCLUSION: Segmental hepatic enhancement on dynamic CT is frequently associated with hepatic abscesses and may be caused by decreased portal flow resulting from inflammation of the portal tracts.

Aged↗

Liver abscess after percutaneous radiofrequency ablation for hepatocellular carcinomas: frequency and risk factors.

OBJECTIVE: The purpose of this study was to clarify the frequency and risk factors of liver abscess formation after percutaneous radiofrequency ablation in patients with hepatocellular carcinoma. MATERIALS AND METHODS: Over a 4-year period, 603 patients with 831 hepatocellular carcinomas measuring 5 cm or less in maximum diameter who underwent a total of 751 percutaneous radiofrequency ablation procedures were enrolled in this study. We retrospectively reviewed the medical records and analyzed the overall frequency of liver abscess, risk factors for abscess, and clinical features of the patients. The relationships between liver abscess and potential risk factors were analyzed using either generalized estimating equations or multiple logistic regression analysis. RESULTS: Liver abscess developed in 14 tumors of 13 patients after 13 (13/751 [1.7%]) ablation procedures. Generalized estimating equations and multiple logistic regression analysis of various potential risk factors revealed that preexisting biliary abnormality prone to ascending biliary infection (p = 0.0088), tumor with retention of iodized oil from previous transcatheter arterial chemoembolization (p = 0.040), and treatment with an internally cooled electrode system (p = 0.016) were associated with a significant risk of liver abscess formation. No patient died of liver abscess, and all successfully recovered from liver abscess with parenteral antibiotics and percutaneous clearance of pus. CONCLUSION: Although liver abscess formation was infrequent in patients who underwent percutaneous radiofrequency ablation for hepatocellular carcinoma, the patients with significant risk factors-preexisting biliary abnormality prone to ascending biliary infection, tumor with retention of iodized oil, and treatment with an internally cooled electrode system-for liver abscess formation should be closely monitored after treatment.

Anesthesia, Local↗

Role of vascular proliferation on angiographic appearance and encapsulation of experimental traumatic and metastatic brain abscesses.

Experimental traumatic abscesses were produced in rhesus monkeys by intracerebral injection of nutrient agar contaminated with Staphylococcus epidermidis, and metastatic abscesses were induced by intracarotid embolization of silicone cylinders contaminated with Staphylococcus epidermidis. All monkeys underwent preoperative and serial postoperative carotid angiography. Traumatic abscesses produced early capsular blushes and progressive anterior cerebral artery displacements. Metastatic abscesses induced transient midline shifts but no capsular stains. Postmortem studies on the monkeys showed that mean capsular thickness and segmental wall vascularity of the traumatic and metastatic abscesses were significantly different (p less than 0.001), despite equal abscess ages and similar abscess volumes. In comparison to traumatic abscesses, metastatic abscesses demonstrated reduced inflammatory cell infiltration and retarded collagen formation around proliferating capsular vessels. Brain surrounding the metastatic abscesses demonstrated ischemic changes. The results suggest that 1) capsular blushes during cerebral angiography are secondary to vascular proliferation within the capsule and not to compression of surrounding brain, 2) vascular staining reflects capsular thickness, 3) capsular vascularity contributes to collagen formation, 4) encapsulation is dependent upon the integrity of surrounding brain, and 5) adjacent cerebral ischemia may impede inflammatory responses involved in capsule formation.

Animals↗