REVIEWS OF INFECTIOUS DISEASES • VOL. 12, NO.2. MARCH-APRIL 1990 © 1990 by The University of Chicago. All rights reserved. 0162-0886/90/1202-0017$02.00

INTERNATIONAL REPORT Ultrasonography in the Diagnosis and Management of 52 Patients with Amebic Liver Abscess in Cairo Lalla Ahmed, Abushady EI Rooby, M. Ibrahim Kassem, Zakaria A. Salama, and G. Thomas Strickland

Clinical characteristics of 52 patients with amebic liver abscess are reported. Forty-two percent had an acute illness, usually with high fever, vomiting, sweating, pain in the abdominal right upper quadrant, and leukocytosis. The other 58010 had a more chronic illness, usually with a dull ache in the right upper abdomen, weight loss, fatigue, moderate or low-grade pyrexia, and anemia. Hepatomegaly and hepatic tenderness were present in all patients; fever occurred in 75%. The diagnosis was strongly suggested by amebic antibodies in high titer and hepatic abscesses demonstrated by sonography. Mean abscess diameter was 9.2 em; 37% were larger than 10 em. Most abscesses were solitary (81%), in the right lobe (73%), rounded or oval (7811,10), cystic (57%), and had a well-defined wall (53%). However, 43% were initially solid or heterogeneous. The latter lesions always developed a cystic pattern when ultrasonography was repeated. The diagnosis was confirmed by a good clinical response to metronidazole in 50 patients. Complications included right-sided pleural effusions or empyema (13 %), ascites (13 %), and jaundice (13%). Drainage of large abscesses was performed in four patients. All 52 patients survived and were cured.

people are infected with Entamoeba histolytica and 36-48 million suffer from invasive amebiasis. The latter, in the international and extraintestinal forms, accounts for 40,000-110,000 deaths annually [1-4]. Most of those infected with E. histolytica pass cysts asymptomatically, The most common clinical presentation is diarrhea or dysentery due to invasive infection of the colon [5, 6]. The most frequent site of infection outside of the colon is the liver. There have been excellent recent clinical reviews of amebic liver abscess [7-12]. However, computerized tomography (CT) and, more recently, ultrasonography have made major contributions to the diagnosis and management of amebic liver abscess. We are aware of only one brief description of amebic liver abscess in Egypt, published in an international journal {l3]. There may be geographic variations in clinical manifestations of amebic liver abscess. This study presents the clinical features, including the findings on abdominal ultrasonography, of 52 Egyptian patients with amebic liver abscess. It also demonstrates unusual presentations and complications in some of these patients.

Amebiasis is a protozoal infection with global distribution, although prevalence is greater in countries where sanitation is poor than it is in North America and Europe. It has been estimated that 480 million

Receivedfor publication 14December 1988and in revised form 26 July 1989. This research was partially supported by the U.S. AID-funded University Linkages Project; grant no. 830503 through the Foreign Relations Coordination Unit of the Supreme Council of Universities, Cairo, Egypt; and by the Naval Medical Research and Development Command, Naval Medical Command, National Capital Region, Bethesda, Maryland, work unit no. 3MI61102BS13.AK.311. Professors Ahmed EI Garem and M. Farid Abdel-Wahab provided advice and encouragement. The authors thank Dr. Afaf Farag Ibrahim and the residents and other staff members of the Department of Tropical Medicine at the Kasr EI Aini Hospital for their assistance in this project. Dr. Michael Kilpatrick, the Commanding Officer of U.S. Naval Medical Research Unit No. 3 in Cairo, read the manuscript and provided excellent advice. Please address requests for reprints to Research Publications Division, U.S. Naval Medical Research Unit No.3, FPO, New York, New York 09527-1600.

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From the Department of Tropical Medicine, Kasr El Aini Hospital, Cairo University Faculty of Medicine; the U.S. Naval Medical Research Unit No.3, Cairo, Egypt; and the International Health Program and Departments of Microbiology and Immunology and of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, Baltimore, Maryland

Amebic Liver Abscess in Cairo

Patients and Methods

Results

Subjects. Only six of the 52 patients werefemales (table 1).The patients' ages ranged from 4 to 67 years and averaged 36 years. Half were from the city of Cairo. There were no sex or age differences between the groups with acute and insidious onset of symptoms. Concomitant illnesses. The results of serum marker studies for hepatitis B virus were: HBsAgpositive, one (2070), and antiHBs-positive, 11 (21070). Schistosoma mansoni ova were present in the stools of eight (15070); Schistosoma haematobium ova were detected in the urine from 10 (19070) patients; and

Table 1. Characteristics of 52 patients with amebic liver abscess. No. of patients (%) Insidious onset

Characteristic

Acute onset

No. in group Sex Male Female Age (mean ± SO) 40 Y

22

30

52

20 (91) 2 (9) 38.0 ± 14.5 3 (14) 12 (55) 7 (32)

26 (87) 4 (13) 34.4 ± 10.4 2 (7) 18 (60) 10 (33)

46 (88) 6 (12) 36.3 ± 12.4 5 (10) 30 (58) 17 (33)

Total

five (10070) had infections with both parasites. One patient had a urinary tract infection. Clinical manifestations. The duration of symptoms before the patients sought medical assistance varied from 4 days to 4 months. The onset was acute, usually with high fever, chills, vomiting, and right upper-quadrant abdominal pain in 22 patients. Insidious onset, often with cachexia, weight loss, a dull abdominal discomfort and distension, progressive fatigue, and moderate or low-grade pyrexia, occurred in 30 patients (table 2). The most common symptoms were fever, right upper-quadrant pain, nausea and vomiting, and anorexia and fatigue. One-third to one-half complained of abdominal discomfort, chills, and weight loss (table 2). Patients with an acute onset of illness were more likely to complain of fever (P = .09) and nausea and vomiting (P = .025). Those with insidious onset more frequently complained of abdominal pain (P = .04), weight loss (P = .000005), and diarrhea (P = .096). The most common signs were hepatomegaly; hepatic, intercostal, and epigastric tenderness; and fever (table 2). Of the nine patients with splenomegaly, seven had schistosomiasis as well. One was an HBsAg carrier with chronic active hepatitis. Another had hepatic cirrhosis and was antiHB spositive. Patients with an acute illness were more likely to have high fever (P = .0004), whereas those with an insidious onset weremore often afebrile (P = .0000002) and had epigastric tenderness (P = .05), localized intercostal tenderness (P = .027), and an epigastric or right hypochondrial bulge (P = .007) (figure 1). Laboratory findings. Most patients were anemic (table 3). Sixty-two percent had leukocytosis on ad-

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The subjects were 52 patients diagnosed as having amebic liver abscess who were admitted to the Tropical Medicine Department in the Kasr El Aini Hospital, Cairo, Egypt, from July 1983through October 1986.All had the following studies performed: complete medical and social history, complete physical examination, blood tests (complete blood cell count; serum bilirubin, aspartate aminotransferase [AST], alanine aminotransferase [ALT], alkaline phosphatase, total proteins, albumin, and globulins; serologic tests for amebic antibodies with indirect hemagglutination [IHA] and micro-ELISA; and serologic tests for hepatitis B virus markers [HBsAg and antiHBs] by the micro-ELISA [Abbott Laboratories, North Chicago, Ill.]), stool examination for ova and parasites with the merthiolate iodine formaldehyde (MIF) fixation and stain technique [14], chest roentgenogram, and abdominal ultrasonographic liver scanning in the frontal and right lateral mode by use of a real-time machine (Hitachi Eu B-25 with linear transducer, 3.5 MHz). The criteria for diagnosis of amebic liver abscess were clinical findings suggestive of amebic liver abscess, a positive serologic test for amebic antibodies at a titer of ~ 1:100, one or more abscesses of the liver shown by ultrasonography, and a response to chemotherapy with metronidazole. No patients wereexcluded by the last criterion although a few responded slowly. The patients were divided into two groups: those with an acute illness who sought medical care within 2 weeks of onset of symptoms and those with a more chronic illness who did not seek advice during the first 14 days of their illness. The findings in the two groups werecompared by Fisher's exact test using a computer program.

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Table 2. Clinical manifestat ions of 52 pat ients with amebic liver abscess .

Table 3. Laboratory blood test results in 52 patients with amebic liver ab scess.

No. of patients (% )

Symptom or sign

Acute onset « 14 d)

Insidious onset (> 14 d)

Total

19 (86) 16 (73) 15 (68) 17 (77) 7 (32) 10 (45) 0 3 (4) I (5) 1 (5)

20 (67) 18 (60) 17 (57) 14 (47) 18 (60) 12 (40) 17 (57) 10 (33) 2 (7) 2 (7)

39 (75) 34 (65) 32 (62) 31 (60) 25 (48) 22 (42) 17 (33) 13 (25) 3 (6) 3 (6)

4 (18) 10 (45) 8 (36) 220(0) 22 (100) 14 (64) 8 (36) 18 (81)

27 (90) 3 (10) 0 300(0) 30 0(0) 20 (67) 19 (63) 30 (100)

31 (60) 13 (25) 8 (5) 52 (100) 52 (100) 34 (65) 27 (52) 48 (92)

13 7 4 5 5

15 (29) 9 (17) 7 (13) 7 (13) 7 (13)

2 2 3 2 2

(9) (9) (14) (9) (9)

1 (5)

(43) (23) (13) (17) (17)

2 (7)

Test Hemoglobin 12-14 g/iOO mL 10-12 g/l00 mL 3 ,200 ELISA 200-800 1,600-6,400 >6 ,400

Acute onset (n = 22)

Insidious onset (n = 30)

II (50) 6 (27) 5 (23)

0(0) 15 (50) 15 (50)

11 (21) 21 (40) 20 (38)

2 (9) 7 (32) 4 (8) 9 (40) 17 (77) 11 (50)

5 (17) 6 (20) 10 (33) 9 (30) 10 (33) 3 (10)

7 (3) 13 (25) 14 (27) 18 (35) 27 (52) 14 (27)

10 (45) 3 (14) 1 (5) 10 (45) 14 (64)

19 (63) 4 (13) 12 (40) 21 (70) 15 (50)

29 (56) 7 ( 3) 13 (25) 31 (60) 29 (56)

10 (45) 9 (41) 3 (4)

5 (17) 10 (33) 15 (50)

15 (29) 19 (37) 18 (35)

9 (41) 11 (50) 2 (9)

6 (20) 12 (40) 12 (40)

15 (29) 23 (44) 14 (27)

Total = 52)

(n

3 (6)

Figure 1. Patient with two amebic liver abscesses: a 15cm cystic lesion in the left lobe and an 8-cm abscess in the right lobe, which caused obstructive jaundice. The bottles contain abscess fluid removed during pericutaneous needle aspiration. An abdominal bulge is seen beneath his left index finger.

mission. Those with an insidious onset of symptoms were more frequently anemic than those with an acute illness (P = .‫סס‬OO1) . Mild elevations of the AST, ALT, and alkaline phosphatase levelswere frequent, as were reduced concentrations of serum albumin and elevated levels of globulins (table 3). Elevated AST (P = .(02) and ALT (P = .(02) were more likely in patients with an acute onset of symptoms. Reduced levelsof total protein (P = .(03) and albumin (P = .067)weremore common in those with insidious onset. All patients had amebic IHA antibody titers >100 and amebic ELISA antibody titers >200 (table 3). Thirty-seven (710/0) had IHA titers of ~800 and ELISA titers of ~1.600. Those with an insidious onset of symptoms had higher IHA (P = .(06) and ELISA (P = .013)titers than those in the group with an acute onset.

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Fever Right upper quadrant pain Anorexia, fatigue Nausea, vomiting Abdominal pain Chills Weight loss Diarrhea Dysentery Chest pain, cough Highest temperature 39°C Hepatomegaly Abdominal tenderness Right upper quadrant Epigastric Intercostal tenderness Epigastric/right hypochondral bulge Splenomegaly Jaundice Ascites Peripheral edema Rales, rhonchi, decreased breath sounds

No. of patients (%)

Amebic Liver Abscess in Cairo

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insidious onset were more likely to have well-defined (P = .012) and cystic (P = .014) abscesses. A larger proportion of their abscesses were subcapsular (P = .10). Complications. Seven patients had ascites and peripheral edema. Seven also were jaundiced, three of those with ascites. One patient with multiple hepatic abscesses had an amebic splenic abscess. None had peritonitis, pericarditis, rupture into the biliary tract, or brain abscess. Eighteen patients (35%) had intrathoracic complications: 11 (21%) had only a raised right hemidiaphragm (figure 3); three (6%) had a mild to moderate right-sided pleural effusion. Four patients had a massive right-sided pleural empyema. One of these had a hepatopulmonary fistula with expectoration of chocolate-colored pus. The four patients with massive pleural empyema had dyspnea, cough, and right-sided chest and back pain. All had chronic illnesses with marked anorexia, weight loss, and fatigue and had been treated with several courses of antibiotics before the correct diagnosis was made. The diagnosis of amebic abscess

Table 4. Ultrasonographic findings in 67 amebic liver abscesses. No. of abscesses (%)

Characteristic No. in group Solitary Multiple Site Right lobe Left lobe Both lobes Shape Rounded Oval Dome-shaped Irregular Periphery Well-defined Ill-defined No wall Peripheral halo Consistency Cystic Solid Heterogeneous Posterior enhancement Subcapsular

Acute onset

Insidious onset

Total

28 19 (86) 3 (14)

39 23 (77) 7 (23)

67 42 (81) 10 (19)

18 (64) 8 (29) 2 (7)

31 (79) 3 (8) 5 (13)

49 (73) II (16) 7 (10)

17 (61) 8 (29) 1 (4) 2 (7)

15 12 6 6

(38) (31) (15) (15)

32 20 7 8

(48) (30) (10) (12)

10 12 4 2

(36) (43) (14) (7)

26 8 4 1

(67) (21) (10) (3)

36 20 8 3

(54) (30) (12) (4)

11 7 10 18 12

(39) (25) (36) (64) (43)

27 6 6 28 24

(69) (15) (15) (72) (62)

38 13 16 46 36

(57) (19) (24) (69) (54)

Figure 2. Ultrasonography demonstrating a 10 x 13-cm abscess in the right lobe of the liver. It is a characteristic lesion: round or oval, has well-defined borders, is cystic, and has posterior enhancement. Small arrows point to the abscess wall; the large arrow in the right frame points to the gall bladder.

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Stool examinations on all patients demonstrated E. histolytica trophozoites in four and cysts in eight (23070). Ultrasonography. The 52 patients had 67 abscesses. The diameter of the abscesses ranged from 1 em to 22 em, The mean diameter was 9.2 em; 25 (37%) were >10 em in size. A solitary abscess was demonstrated in 42 (81%) of the patients (table 4). Seven patients had two abscesses, two patients had three, and one had five. Three-quarters of the abscesses were in the right lobe, the same proportion were round or oval, and half had a well-defined wall. More than half of the abscesses were cystic (figure 2), but many were solid or heterogeneous, having both cystic and solid components. Forty-six (69%) of the abscesses had posterior enhancement, 54% were subcapsular, and three (6%) of the 52 patients had pleural effusion detected by sonography. Abscesses in patients with acute onset of illness were more likely to be in the left lobe of the liver (P = .026), rounded (P = .06), and ill-defined (P = .045). They were more frequently solid or heterogeneous (P = .014)as well (table 4). Patients with

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334

Figure 3. Chest roentgenogram showing an elevated right hemidiaphragm in a patient with a l-rnonth history of fever and abdominal pain. He had five amebic liver abscessesand a splenic abscess demonstrated by ultrasonography.

was primarily based upon the chest findings in association with a hepatic abscess demonstrated by sonographyand markedly elevated E. histo/ytica antibody titers. Management. All 52 patients were treated with metronidazole in a dose of 750 mg three times per day for 10days. All were able to tolerate a full course of therapy; none had reactions requiring the discontinuation of treatment. All but two patients had a good therapeutic response to one course of metro- · nidazole. One patient was cured following additional treatment with emetine hydrochloride: 10 intramuscular injections of 60 mg each given over 10 days. The other patient was cured when a second course of metronidazole was given after surgical drainage of the abscess. In three patients, needle .aspiration of large liver abscesses was performed using sonographic guidance. A fourth patient had surgical drainage of a 15em abscess. The four procedures produced an opaque and reddish, brown, or pink pus that was bacteriologically sterile and in which E. histo/ytica trophozoites were not seen microscopically. Seven patients with pleural effusion were treated with needle aspiration and removal of some of the fluid, which also was sterile and did not have microscopically detected trophozoites. Outcome. All 52 patients responded to treatment and survived. Those with complications and with large and/or multiple abscesses usually were the slowest to respond to therapy. Twelve patients with

Discussion Amebic abscess of the liver in Cairo is very similar to that described elsewhere [7-12]. There was a predominance of infection in young and middle-aged males. Many of our patients had considerable delay before they were admitted to Kasr EI Aini Hospital and the correct diagnosis was made. During this time, they were often treated with one or several courses of antibiotics, which may have caused some variations in our findings, including the lower white blood cell counts in those treated with chloramphenicol. Three of the seven with leukopenia had received chloramphenicol before admission. Although these delays may have increased the morbidity in our patients, they did not increase mortality. Diagnosis. The combination of fever, abdominal pain, hepatomegaly, and hepatic and intercostal tenderness, with or without other symptomatology (e.g., weight loss, anorexia, nausea, vomiting, fatigue, abdominal distension, or hepatic bulge) or complications (e.g., right-sided pleural effusion or empyema, jaundice, ascites), makes an amebic antibody test and imaging of the liver a necessity. In those patients with amebic antibody titer elevations (e.g., IHA or ELISA >1 :200) and a liver abscess demonstrated by sonography, CT, or radionucleotide scan, the diagnosis of amebic abscess is strongly suspected. If the patient improves clinically following metronidazole therapy, the diagnosis is confirmed. Other findings (e.g., abnormal liver function test results, anemia, leukocytosis, detection of E. histolytica in the stool) are less diagnostically helpful. Alkaline phosphatase determination is the liver function test most likely to be abnormal in cases of amebic liver abscess [7, 9-12]. Since many of our patients also

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an elevated right hemidiaphragm and mild pleural effusion responded clinically to a course of metronidazole. The pleural fluid was rapidly absorbed. The two patients with a moderate amount of serous pleural effusion improved rapidly following treatment with metronidazole; ampicillin, 500 mg every 6 hours for 10 days; and repeated thorocentesis as needed. The four patients with amebic empyema were treated by insertion of a chest tube for drainage in addition to metronidazole and a combination of ampicillin and cloxacillin every 6 hours for 10 days. All responded rapidly to this therapy except for one patient; he was subsequently treated with emetine hydrochloride.

Amebic Liver Abscess in Cairo

1/100 and 1/400. Titers at these levels occasionally occur in Egyptians without evidence of amebic liver abscess or intestinal amebiasis and could lead to diagnostic confusion [15].The differences in antibody titers between those with the acute and those with the chronic syndrome also confirm that the latter patients were ill for a longer time and, thus, had more time to develop higher levels of antibodies [16]. A few of our patients with the acute onset ofsymptoms had considerable delays prior to the establishment of a diagnosis and the institution of specific chemotherapy. Some of these individuals developed more unusual and severe complications: obstructive jaundice (figure 4), portal hypertension with ascites and peripheral edema, and empyema of the chest. All of these complications have been reported in amebic liver abscess [7-13, 17-21], and, fortunately, none of our patients had abscesses that ruptured into the pericardium. This is considered the most dangerous complication of amebic liver abscess [8]. Ultrasonography. Ultrasonography is an excellent means for detecting hepatic abscesses. Some ultrasonographic characteristics suggest the diagnosis of amebic liver abscess [9-12, 22-27]. On sonography, the majority of the abscesses in our patients

Figure 4. Ultrasonography of the liver in the patient with obstructive jaundice. An 8- x lO-cm abscess of the right lobe of the liver is outlined by the small arrows. The larger arrows point to a distended intrahepatic bile duct. He also had a IS-em-diameter abscess in the left lobe of the liver.

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had schistosomiasis, which can also increase alkaline phosphatase concentrations, this test is less valuable in Egypt. Needle aspiration of the liver is sometimes diagnostically indicated, usually to rule out a pyogenic abscess [7, 8, 10, 12]. Clinical syndromes. Our patients with amebic liver abscess could be divided into two groups on the basis of clinical syndromes as described by Katzenstein et al. [9]. The majority (580/0) had the insidious onset of symptoms over 2 weeks to 4 months. They most commonly complained of weight loss, fatigue, anorexia, low-grade fever, and a dull progressive ache in the right hypochrondrium. Their most common physical findings were cachexia, pallor, lowgrade fever, hepatomegaly, hepatic tenderness, a right hypochondrial bulge, and evidence of a right-sided pleural effusion. They often had minimal or no leukocytosis but usually had anemia, reduced levels of serum proteins and albumin, and an elevated level of alkaline phosphatase. Patients with the chronic syndrome were more readily diagnosed than those with the acute syndrome since hepatic sonography was usually more characteristic and antibodies to E. histolytica were greater. The minority (42%) had the onset of symptoms within 2 weeks of hospitalization. They most commonly complained of pain in the upper abdomen, fever, chills, sweating, and vomiting. Their usual physical findings were moderate to high fever, hepatic and intercostal tenderness, and hepatomegaly. Their most common laboratory abnormality was a leukocytosis. Serum enzymes (AST, ALT, alkaline phosphatase) were usually slightly elevated and they usually had minimal or no anemia. Seventeen (61%) of the abscesses among the patients that had acute onset were either solid or heterogeneous on sonography. When rescanned at a later time, all of these abscesses had become more hypoechoic, suggesting that they had subsequently liquified. Thirty-three (85 %) of the abscesses in the 30 patients in the group that had chronic onset had classic round or oval hypoechoic cystic-appearing abscesses. This observation suggests that liquefaction had occurred during the longer illness of this group of patients. Amebic antibody titers were also higher in the chronic than in the acute group [9]. Twenty-four (80%) of those with the chronic syndrome had ELISA titers of ~1:1,600, which would be highly suggestive of amebic liver abscess. Ten (45%) of those with the acute syndrome had IRA titers between

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800 mg three times per day for 5 days. The experience of Katzenstein et al. [9] was also good. Among 49 patients treated with metronidazole alone, 75070 responded within 48 hours, and most of the remainder were afebrile within 6 days. Three of their six patients with superinfection of amebic abscesses with bacteria died despite appropriate antibiotics, amebicidal drugs, and surgical drainage. All of our patients survived, and all but two required only a single 10-day course of metronidazole. All 96 of the patients of Barnes et al. [12] responded to treatment with metronidazole and/or chloroquine. The median time for defervescence was 3 days, with 90010 afebrile by 1 week. They attributed the absence of mortality in their series to the fact that most of their patients were admitted to the hospital and diagnosed and treated during the acute phase of illness. However, many of our patients had prolonged courses before the diagnosis was correctly made and they received specific chemotherapy. The. therapeutic efficacy of metronidazole reported by Thompson et al. [11] was not as good as ours and that of the other groups. Although all 48 patients in their series survived, six were considered to have failed with metronidazole therapy and were switched to emetine and chloroquine. In the majority.of their failed cases, as well as in our cases requiring additional therapy, the abscesses either ruptured or required drainage. American physicians seldom aspirate amebic liver abscesses. Katzenstein et al. [9] used open drainage for four of their patients - two because of suspected relapse or treatment failure and two because of rupture of the abscess. Eight others among their 67 had unsuspected amebic liver abscesses discovered at abdominal surgery. They apparently did not perform percutaneous hepatic needle aspirations on their patients although several had thorocentesis for pleural effusion or empyema. Aspiration was performed in only two of the 96 patients of Barnes et al. [12]. The experience of Thompson et al. was similar [11]. Eight of their 48 patients had operative drainage of abscesses. Only three of these were planned prior to the surgery. Two had already ruptured. Three others had abscesses discovered and drained during diagnostic laparotomy. None of their patients had needle aspirations of abscesses. Our criteria for performing needle aspiration (in three cases) or surgical drainage (in one) were the presence of a large abscess that we feared would rupture or that the abscess was causing obstructive jaundice (figure 4) or portal hypertension. The clinical

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were solitary; located in the right lobe; rounded or oval; well defined with no prominent abscess well; cystic with predominately fine, low-level echoes; posteriorly enhanced (The structures distal to a cystic lesion appear to have more echoes than neighboring areas that are equidistant from the surface. This is because sound traveling through a fluid-filled structure is barely attenuated.); and in a peripheral location of the liver. However, many patients had abscesses that did not have all of these characteristics. Thirteen abscesses initially were poorly defined, having a solid consistency with mostly homogeneous echoes within the abscess. Another 16 were heterogeneous with both hypoechogenic and echogenic areas. When sonography was repeated in those patients having solid or heterogeneous lesions, they had become cystic. Repeat scanning of early and immature abscesses should improve the diagnostic sensitivity of ultrasonography [9, 10, 26]. During resolution of the abscesses, the reverse occurred [28]. Cystic lesions became smaller heterogeneous lesions, which then became solid before completely clearing. Berry et al. [27] have described a similar evolution of amebic liver abscess. This variation according to the duration of illness explains the differences in sonographic patterns seen. We agree that ultrasonography is not diagnostic [12, 22-27]. Lesions that could be mistaken by ultrasonography for amebic abscess include pyogenic abscess; hepatic malignancies, particularly primary hepatocellular carcinoma; echinococcal cysts; hemangioma; and cystic tumors of the liver. All of these may cause sonolucent focal lesions in the liver that could be confused with amebic abscess. These reasons all make the serologic test for amebiasis a very important diagnostic tool. Sonography also assists in detecting complications and in estimating the prognosis in amebic liver abscess [19]. It shows the number, size, and location of the abscesses. It guides the physician in performing needle aspirations for either diagnosis or therapy. Diagnosis of E. histolytica infection by identification of the parasite on aspirationis rare. However, if a bacterial abscess is possible, either singly or concomittantly with amebic liver abscess, an aspirate is indicated. Response to therapy. The excellent response of our patients to metronidazole is in agreement with other reports [7-11]. Adams and MacLeod [8] reported a 100070 cure rate in more than 100 patients with uncomplicated amebic liver abscess treated with

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Amebic Liver Abscess in Cairo

response to metronidazole therapy was initially slow in these patients as well. The four patients whose abscesses were drained had rapid clinical improvement following the removal of amebic pus and treatment with emetine or retreatment with metronidazole. References

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Ultrasonography in the diagnosis and management of 52 patients with amebic liver abscess in Cairo.

Clinical characteristics of 52 patients with amebic liver abscess are reported. Forty-two percent had an acute illness, usually with high fever, vomit...
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