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Original Research |
1 All authors: Interventional Ultrasound in Infectious Diseases Unit, D. Cotugno Hospital, Via Quagliariello 54, 80131 Naples, Italy.
Received June 27, 2005;
accepted after revision October 21, 2005.
Address correspondence to G. Ferraioli.
Abstract
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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.
Keywords: infectious diseases interventional radiology liver liver abscess sonography
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Several reports in the literature show that the mortality rate for multiple pyogenic liver abscesses ranges from 44% to 22.1% [4, 7]. To our knowledge, no data are available on large series of patients with multiple pyogenic liver abscesses managed only with percutaneous needle aspiration under sonographic guidance and with long-term follow-up. This retrospective study was undertaken to report our 13 years of experience in the treatment of 39 patients with 118 multiple pyogenic liver abscesses managed only with percutaneous needle aspiration.
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Clinical Characteristics of Patients at Admission
All patients had a previous diagnosis of multiple liver abscesses, and they
had been treated with antibiotics alone for at least 16 days at other
institutions before being admitted to our hospital (mean length of
antimicrobial therapy, 19.8 days; range, 16-32 days). All patients were
admitted to our hospital because of persistence of fever (temperature range,
37.4-40.5°C; mean temperature, 38.7°C) and sonographic or CT findings
that liver abscesses were increasing in size or number. Clinical findings and
symptoms at admission in the 39 patients with multiple pyogenic liver
abscesses are shown in Table 2.
Total serum bilirubin level ranged from 2.1 to 7.7 mg/dL (mean, 3.4 mg/dL).
Leukocytosis (white blood cell count, 10,000-24,000/µL; mean, 14,500/µL)
was present in 34 (87.2%) of the 39 patients. Coagulation status was assessed
for all patients before percutaneous needle aspiration, and prothrombin time
was always in the normal range (normal value, 11-13 seconds). Platelet count
ranged from 470,000 to 105,000/µL. No patient was being treated with
anticoagulant drugs.
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Predisposing Factors
Predisposing factors for abscess formation are shown in
Table 3. Two of the five
patients with diverticulitis had pylephlebitis, namely, septic
thrombophlebitis of the portal vein. In these cases, color duplex sonography
showed an echogenic thrombus within an expanded portal vein with negative
colorflow findings within the thrombus. The two patients with pyogenic liver
abscess after surgery did not have malignant tumors. Ten patients with
cholangitis had undergone endoscopic sphincterotomy for bile duct stones at
another institution before admission to our hospital. They had had residual
intrahepatic stones that cleared spontaneously before admission. In all 19
patients with cholangitis, no communication between the liver abscesses and
the bile ducts or dilatation of the biliary tree was seen on imaging. Three
patients were immunocompromised because they had cirrhosis of the liver. No
patient in our series had AIDS or underlying malignant disease.
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Methods
This retrospective study was approved by our institutional ethics review
board, which waived the requirement for informed consent. The scheduled
protocol was as follows: All patients would be treated with a single
percutaneous needle aspiration of all abscess cavities in a single session and
then be given broad-spectrum antibiotics until the results of pus cultures and
blood cultures were available. If fever persisted for 3 days after the
procedure and the size of the abscess cavities did not decrease, a second
session would be planned. If the second session were to fail, imaging-guided
percutaneous catheter drainage or open surgical drainage would be
scheduled.
All percutaneous needle aspiration procedures were performed under sonographic guidance. The sonographic systems used during the study period were Aloka SSD 630 with a 3.5-MHz microconvex probe, Esaote Biomedica AU 4/5 equipped with a 3.5-MHz probe, and Aloka SSD-5000 and Aloka Prosound SSD-5500 PHD Extended equipped with a 3.0- to 6.0-MHz convex array broadband probe and a 3.5-MHz microconvex probe. The freehand technique was used because it does not have the limitation of attached needle guides, use of which necessitates that the needle be passed at a specific or fixed angle relative to the transducer. The freehand technique allows changes in the needle path. Local anesthesia was induced with 10 mL of lidocaine hydrochloride 2% (Lidocaina, Molteni). Patients were asked about their pain during the procedure in case they needed conscious sedation. After induction of local anesthesia, continuous real-time sonographic imaging was used to localize the abscess and to guide insertion of the needle. The diameter of the needle was tailored to the diameter of the abscess. A 22-gauge 20-cm needle (Ecojekt modified Chiba needle, Hospital Service, Hakko Shoji) was used for small lesions and up to 18-gauge 20-cm needles for larger lesions. Specifically, a 22- or 20-gauge needle was used for abscesses up to 2 cm in diameter, a 20-gauge needle for abscesses 2-4 cm in diameter, and a 20- or 18-gauge needle for abscesses larger than 4 cm in diameter. At first, deep lesions were punctured to avoid artifacts due to gas bubbles. Whenever possible, an intercostal approach was used for percutaneous needle aspiration. To prevent the spread of infection, needles were changed between aspirations.
In the case of abscesses in the right lobe of the liver, the needle used to drain one punctured abscess cavity was kept in the liver for aspiration of a nearby lesion in the same lobe (Fig. 1A, 1B, 1C, 1D). In these cases, a 20-gauge needle was used for large abscesses because it is more flexible than an 18-gauge needle. To monitor changes in cavity size, the operator performed aspiration while observing the real-time sonographic image of the abscess. The content of each cavity was aspirated as much as possible. Percutaneous needle aspiration was considered successful when the cavity either collapsed or was reduced to one-half its original size. In case of more viscous pus, the cavity was washed with sterile saline solution injected gently to avoid pressure and then reaspirated. Injection of saline solution into the abscess cavity was also aimed at reducing the bacterial load. To avoid excessive pressure and risk of sepsis, the maximum amount of saline solution injected was one-half the volume of pus aspirated. Gentamicin sulfate (160 mg Gentalyn, Schering-Plough) or metronidazole (600 mg Deflamon, Spa) then was injected into the cavity [20]. The duration of each aspiration session was recorded.
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Aerobic, anaerobic, and fungal cultures and sensitivity testing were performed on the aspirated material. Cytologic examinations were performed to exclude secondarily infected necrotic tumors. Microscopic examinations of pus smears were performed to find protoscoleces or hooklets of Echinococcus granulosus and for Entamoeba histolytica. Echinococcosis was ruled out with clinical and imaging findings and a negative test result for specific echinococcal antibodies in the serum by enzyme immunosorbent assay performed before percutaneous needle aspiration. While the results of pus culture were awaited, systemic broad-spectrum antibiotics were administered. After culture results were obtained, the antibiotic most effective against the most active organism was given. In patients with negative culture results but with purulent material at visual inspection and a cytologic diagnosis of abscess, broadspectrum antibiotic therapy was continued. The patients were discharged from the hospital when fever and clinical signs disappeared and the dimensions of the abscess were reduced to at least one third of the size on initial sonographic examination.
Follow-Up
Follow-up consisted of sonographic and clinical examinations of all
patients every 3 days during the first week after treatment, every month for
the first 6 months after aspiration, and every 6 months thereafter. Treatment
was considered successful when the patient remained symptom-free and no focal
liver abscesses were detected on sonography. Follow-up studies were terminated
when findings on two consecutive sonographic examinations indicated that the
liver parenchyma had completely healed.
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Thirty-six (92.3%) of 39 patients were treated with a single percutaneous needle aspiration of a single pyogenic liver abscess in a single session. In three (7.7%) of 39 patients, two aspiration sessions were needed because fever did not remit and the size of pyogenic liver abscesses remained unchanged on sonographic examination (Table 5). Each aspiration session lasted 20-60 minutes (mean, 40 minutes). No patient needed imaging-guided percutaneous catheter drainage or open surgical drainage.
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Eighty-seven needle insertions 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 abscess cavity already aspirated in the right lobe of the liver, 31 (26.3%) of 118 pyogenic liver abscesses were aspirated without removal of the needle from the liver. The amount of aspirated pus ranged from 1.0 to 245.0 mL (mean, 83.0 mL). Patients with cholangitis did not have evidence of dilatation of the biliary tree on sonography, so none of them needed biliary drainage. In no case associated with cholangitis did the abscesses contain bile.
To ascertain the diagnosis of liver abscess, a 22-gauge needle was used in two abscesses smaller than 2 cm, an 18-gauge needle in 12 of 19 abscesses larger than 4 cm, and a 20-gauge needle in the other 104 abscesses. In eight abscesses larger than 4 cm, after the first puncture with a 20-gauge needle, an 18-gauge needle was used because the pus could not be aspirated owing to its viscosity. In all of these cases, aspiration of the abscess was feasible.
In 29 (80.6%) of the 36 patients treated in a single session with a single aspiration of each abscess, more than one needle insertion was needed (two needle insertions in 18 patients, three needle insertions in 11 patients). Twenty-seven (93.1%) of these patients had liver abscesses in the right and left hepatic lobes, and two (6.9%) of them had multiple abscesses in the right lobe. The patient with 15 liver abscesses was treated with three percutaneous needle aspirations in one session. The three patients treated in two sessions had a combined total of eight needle insertions in the first session and three needle insertions in the second session (Table 5). These three patients had 11, eight, and four pyogenic liver abscesses each. Abscess diameter per patient was 1.7-3.1 (mean, 2.6), 2.6-4.0 (mean, 3.2), and 2.7-4.2 cm (mean, 3.3 cm), and the amount of pus aspirated was 115, 144, and 87 mL in the first session and 25, 30, and 35 mL in the second session. In these three patients, a 20-gauge needle was used for aspiration of all abscess cavities.
All patients recovered (success rate, 100%). No patient needed conscious sedation. No major complications, such as hemoperitoneum, hemothorax, or pleural effusion, occurred. The only minor complication was mild pain at the right hypochondrium in two patients, one with eight and the other with 11 abscesses. In 21 cases, antibiotic therapy was changed in accordance with the results of pus culture. Fever resolved within 2.3 days (range, 1-6 days) after percutaneous needle aspiration, and leukocytosis resolved within 2-8 days after aspiration (mean, 3.8 days). Fever lasted 6 days in only the patient with 11 liver abscesses caused by Staphylococcus aureus. The patient underwent aspiration in two sessions and did not need additional needle aspiration or percutaneous catheter drainage. The hospital stay after percutaneous needle aspiration ranged from 5 to 12 days (mean, 5.7 days). Complete reconstitution of liver parenchyma occurred within a maximum of 80 days (range, 45-80 days; mean, 58 days) after discharge from the hospital. No abscesses recurred during the follow-up period (range, 7-42 months; mean, 18 months).
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In our series, all patients were treated with percutaneous needle aspiration of all cavities under sonographic guidance followed by antibiotic therapy. A 20-gauge needle was used in most cases. This needle is the best compromise between size and flexibility. In addition to facilitating aspiration of dense material, the needle can be easily moved and the needle path changed for drainage of more than one abscess cavity without removal of the needle from the liver. This treatment was effective in all patients; they healed completely and had no recurrences. For most patients a single session was sufficient for healing of multiple abscesses; only three (7.7%) of 39 patients needed a second session.
Our results were not operator dependent; all operators, however, were expert in interventional procedures. No major complications due to the procedure were encountered, and no mortality was observed. These findings are in keeping with a previous 13-year experience in the management of pyogenic liver abscess in one step with a single, thorough percutaneous needle aspiration combined with administration of systemic antibiotics [12]. Yu et al. [17] reported that in the setting of pyogenic liver abscess, patients treated with needle aspiration had a higher treatment success rate, shorter hospital stay, and lower mortality rate than patients treated with catheter drainage; this difference, however, did not reach statistical significance.
The efficacy of antibiotics increased over the 13 years of this study. During this period, however, the changes in efficacy did not significantly shorten hospital stay in our series of patients. They all had been treated with antibiotics alone for at least 16 days at other institutions before admission to our hospital and were seriously ill at admission.
This study did not have a control population treated with catheter drainage or surgery because all patients recovered after percutaneous needle aspiration; in no case were the other procedures needed. The advantages of percutaneous needle aspiration over catheter drainage are simplicity of technique, patient comfort, and lower cost. In our series, three patients needed a second aspiration session. They had been treated with antibiotics for a longer time before admission to our hospital and were in worse clinical condition than the other patients. Fever lasted 6 days in only one patient, who was critically ill at admission and had had symptoms suggestive of liver abscess for 4 months.
The differences between our results and those of others are mainly due to dissimilarities in patient populations [23]. Even though in our series cholangitis was the most frequent predisposing factor for pyogenic liver abscess, the cholangitis was caused by biliary stones in all patients; none had malignant disease. Moreover, none of our patients with cholangitis needed biliary drainage, and management was the same as for the other patients. In no cases associated with cholangitis did the abscesses contain bile. In our series, only three patients were immunocompromised because of underlying cirrhosis of the liver. These patients were successfully treated by percutaneous needle aspiration. In patients with cirrhosis who had liver abscesses, percutaneous needle aspiration should be the primary treatment mainly because of the high risk of bleeding. It is advisable to start treatment of these patients with a procedure that is less invasive than prolonged catheter drainage.
None of our patients had AIDS or underlying malignant disease; both of these conditions are associated with poor prognosis. In our series, there were only two cases of postsurgical pyogenic liver abscess, and neither of the patients had undergone liver transplantation. On the other hand, the patients in our series had protracted fevers, and most of them had body wasting. In addition, in 10 patients S. aureus infection, which often is resistant to antibiotic therapy [24], was the bacterial cause of abscess. A biliary origin from ascending cholangitis was most frequently found in our series of patients. This finding is similar to that reported by others [7, 9, 25, 26], even though malignant extrahepatic obstruction was not found in our series. Gramnegative organisms are the most commonly isolated, found in more than one half of cultures [7, 12, 19, 27].
None of the patients in this series died; all patients recovered without catheter drainage. This experience shows that percutaneous needle aspiration of multiple pyogenic abscesses under sonographic guidance is a safe, effective, and low-cost procedure that is acceptable to patients. Our data suggest that a trial of percutaneous needle aspiration should always be undertaken before catheter drainage or surgery.
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