Liver Abscess in Children: A 10-year Single Centre Experience

Background/Aim: Although liver abscess is more prevalent in developing countries than in developed countries, there is scant data about the characteristics of pediatric liver abscess in our region. We aimed to analyze the characteristics of pediatric liver abscess in our region and compare these with those of developed countries. Materials and Methods: The clinical features, laboratory, imaging, microbiologic findings, management strategy, and final outcome were extracted from the patients’ records retrospectively. Results: There were 18 cases of liver abscess including 16 pyogenic liver abscess, one amebic liver abscess and one candida liver abscess. Fever and abdominal pain were the most common clinical findings and leukocytosis was the most common laboratory finding. The most predisposing factors of liver abscesswere immune deficiency, minor thalassemia. Origin of liver abscess was appendicitis in two patients, the rest were considered as cryptogenic. While one patient was treated with antibiotics alone, five cases were taken for open drainage, and 12 cases were treated with percutaneous aspiration. Percutaneous aspiration failed in two patients who were later ttaken for open drainage, with an overall mortality rate of 5.5%. Conclusion: The overall characteristics of liver abscess in children in our society are not so different from developed countries. However, in contradiction to cases reported in developed countries, most cases of liver abscess were seen in healthy patients in our centre. Moreover, liver abscess was reported in our patients at a younger age and was more commonly seen in male children. Mortality rate was similar to that of developed countries.

Liver abscess (LA) is a serious infectious disease, which is responsible for hospitalization and mortality worldwide. [1]A is rare with an incidence of 25 per 100,000 admissions in USA; however, in studies conducted in developing nations it was reported in 1 out of 140 admissions. [2]Although it is supposed that in developing countries as in Iran, infectious diseases like LA are more prevalent than in developed countries, there is little data about the characteristics of pediatric liver abscess in our region, and management of our patients has been based on data provided through studies conducted and published in developed countries.The aim of this study has been to identify the characteristics of LA in children referred over the last decade to our center and to review their clinical features, predisposing factors, management, and mortality and compare them with the results in developed countries.

MATERIALS AND METHODS
The records of all patients less than 18 years who were admitted in pediatric wards at Nemazee Hospital, referral center in South of Iran, with diagnosis of LA between 1998 and 2008 were reviewed.Age, sex, symptoms and their duration, clinical signs at presentation and any underlying predisposing factors were noted.Results of the diagnostic work-ups including ultrasonography (US) findings and organisms isolated, management including details of antibiotic therapy and drainage procedure were all recorded.In-hospital mortality was defined as mortality that occurred within the same hospital.Length of hospital stay was defined as total days since admission to discharge.There was a two-year follow-up on all patients to check for any recurrences or complications.The patients were subsequently followed up in the clinic.Statistical package for social sciences (SPSS, version 15.0; Chicago, IL, USA) was used for data analysis.

RESULTS
There were 18 cases (11 boys and 7 girls) including PLA (n:16), amebic liver abscess (n:1), and candida LA (n:1).The median age was eight years (range, 50 days-17 years).The predisposing factors of LA were seen in six cases including immune system diseases with one case of severe combined immunodeficiency (SCID) and one case of chronic granulomatous disease (CGD), minor thalassemia (n:2), acute lymphocytic leukemia (n:1), and kala-azar (n:1).Median time of delay between the beginning of the symptoms and the diagnosis was 13 days (range, 3-90 days).Origin of LA was appendicitis in two cases (11.1%) and cryptogenic (i.e.without a definite cause) in sixteen cases (88.9%).
Fever and abdominal pain were seen in 94.4% and 88.9% respectively.Tenderness in the right hypochondrium was present in all cases [Table 1].
US showed single lesion in 12 cases, two abscesses in four cases, and multiple lesions in two cases.LA was seen in Amebic liver abscess (ALA) was seen in a three-year-old boy who was referred due to fever and anorexia.The diagnosis of ALA was established by US evidence of a single hypoechoic lesion in right lobe of the liver with positive indirect hemagglutination test (>1:250).He was treated with intravenous metronidazole, followed by percutaneous drainage due to non-improvement in clinical situation.Liver aspirate showed eosinophil cells and charcot leidon body in favor of ALA.
Diffuse candidiasis occurred in a 50 days infant with SCID.US showed numerous target lesions in liver in favor of candidiasis and urine culture grew candida.Abscess was multiple and located in both lobes.Despite open drainage and broad spectrum antifungal treatment, he did not respond to therapy and died two weeks after admission due to septic shock and multiorgan failure.

DISCUSSION
PLA has been described to be rare in infancy and childhood, but it still remains a major cause of high mortality in children. [1]In developed countries, LA occurred in children with immune system disease especially CGD. [3]However in our center like other developed countries, [4] the majority of patients were healthy.This might be due to high rate of environmental infection in developing countries.
The median age at presentation was eight years which is similar to other developing countries like Taiwan [5] and Brazil. [2]owever, in United Kingdom, median [6] age at diagnosis was 10 years.These findings suggest an earlier age trend of LA in patients in developing countries compared to that in developed countries which may be due to earlier contact with infection.Despite studies from both developing and developed countries that reported no difference between girls and boys, [5][6][7] in our series boys were involved more than girls.
Staphylococcus is the most common cause of LA in children, [6] which is similar to our study.Pus and blood culture was positive for 55% and 58% of patients. [8]The most common organism identified was Klebsiella species followed by Escherichia coli. [8]Anerobic organisms are increasingly being reported as a causative agent in PLA in children. [3,9]he low level of positive blood culture in our study could partly be due to prior antibiotic therapy before admission and non availability of facility for anerobic culture in most cases.
There were no differences about symptoms and signs of LA [10] and also initial use of US to diagnose LA. [6] Increased alkaline phosphatase and low albumin have been reported as the most common abnormal laboratory findings; [11] however, elevated levels of billirubin and aminotransferase and leukocytosis are also common. [12]In our cases leukocytosis was the most common abnormal finding, followed by anemia (Hb<11 mg/dl).

Table 1 : Demographic data, clinical characteristics, imaging findings (location, size, number of liver abscess), type of management, and outcome of patients No. Type of abscess Time of presentation Sex/age (years) Symptoms Associated conditions Imaging findings
CGD: chronic granulomatous disease; M: Male; F: Female, SCID: severe combined immunodeficiency; ALL: acute lymphoblastic leukemia