|Year : 2022 | Volume
| Issue : 2 | Page : 113-118
Clinical and laboratory profile of patients with amoebic liver abscess
Yashik Bansal1, Vinod Maurya1, Vibhor Tak1, Gopal Krishna Bohra2, Deepak Kumar2, Akhil Dhanesh Goel3, Taruna Yadav4, Vijaya Lakshmi Nag1
1 Department of Microbiology, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
2 Department of General Medicine, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
3 Department of Community Medicine and Family Medicine, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
4 Department of Radiology, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
|Date of Submission||09-Apr-2020|
|Date of Decision||13-Jul-2020|
|Date of Acceptance||10-Sep-2020|
|Date of Web Publication||24-Nov-2022|
Department of Microbiology, All India Institute of Medical Sciences, Basni Phase-2, Jodhpur - 342 005, Rajasthan
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Context: Amebic liver abscess (ALA) occurs in 3%–9% of the amebiasis cases, with complications seen in 20%–40% of the cases and 2%–18% mortality rate. Successful treatment thus requires the accurate identification of these cases.
Aims and Objectives: We aimed to assess the seropositivity and profile of ALA patients in western Rajasthan.
Materials and Methods: This retrospective study was conducted at a tertiary care center in western Rajasthan from November 2017 to May 2019. Serological diagnosis of ALA was done by detecting immunoglobulin G (IgG) antibodies in the serum of the patients by ELISA. The derangements in laboratory profile (hematological and biochemical parameters) and ultrasonography findings were assessed from the hospital records. Statistical analysis was performed using Mann–Whitney U-test.
Results: Among the total cases (n = 34), 20 were diagnosed as ALA. Twenty-one (61.8%) were positive for anti-amebic IgG antibodies. Among ALA patients, 14 (70%) were >40 years old and only 6 (30%) patients were of age ≤40 years. Male: female ratio was 5.7:1, and ultrasonography records of 15 ALA patients revealed the presence of hepatomegaly (n = 7, 46.7%), pleural effusion (n = 3, 20%), lung collapse (n = 2, 13.3%), and vascular involvement (n = 1, 6.7%). The right lobe of the liver was involved in majority of the patients (n = 12, 80%). Total white blood cell count (P < 0.001), absolute neutrophil count (P = 0.001), total serum bilirubin (P = 0.019), and serum alkaline phosphatase (P = 0.018) were significantly elevated in ALA patients.
Conclusions: Seroprevalence shows that ALA still remains the dominant etiology in liver abscess patients in this region. There are significant derangements in the laboratory profile that require a larger study for corroboration.
Keywords: Amebic liver abscess, Entamoeba histolytica, enzyme-linked immunosorbent assay, serology, seroprevalence
|How to cite this article:|
Bansal Y, Maurya V, Tak V, Bohra GK, Kumar D, Goel AD, Yadav T, Nag VL. Clinical and laboratory profile of patients with amoebic liver abscess. Trop Parasitol 2022;12:113-8
| Introduction|| |
Liver abscess or collection of purulent material in liver parenchyma is mainly caused by bacterial or parasitic (amebic) agents and rarely by fungi. Majority of the cases in developing countries are of amebic etiology, whereas more people suffer from pyogenic liver abscess (PLA) in developed parts of the world. Entamoeba histolytica, the causative agent of amebiasis, is a protozoan parasite of humans that is estimated to cause amebic liver abscess (ALA) in around 50 million people across the globe. It is the third leading parasitic cause of death after malaria and schistosomiasis, with an estimated mortality of 100,000 people per year.
The burden of amebiasis is mainly present in tropical countries which are predominantly attributable, but not limited to, poor sanitation and lower socioeconomic status of the population. It is reported that approximately 20% of the Indian population is infected with this parasite. ALA occurs in 3%–9% of the amebiasis cases, with complications seen in 20%–40% of the cases and mortality in 2%–18% of the cases. There is a considerable similarity in the clinical features and radiological findings of ALA and PLA cases. Successful treatment thus requires the accurate identification of these cases.
The diagnosis of ALA is based on microscopic examination of the aspirated pus that has a characteristic anchovy sauce appearance. Microscopic examination is, however, of little utility due to low sensitivity, especially in the hands of a less experienced observer. More accurate tests with higher sensitivity and specificity such as polymerase chain reaction (PCR) and DNA probe-based dot blot assays are impractical in resource-poor developing countries owing to the need of high technical expertise, infrastructure, and high costs of the equipment.,,
The WHO has emphasized the need for the development of better diagnostic methods in developing countries, and serology is one such diagnostic modality that is practical to the need of the diagnostic laboratories in view of significant presence of this entity in the country. Enzyme-linked immunosorbent assay (ELISA)-based serological test is relatively cost-effective and has a sensitivity and specificity of around 90%.
This arid part of Rajasthan is a water-scarce region, and various studies have highlighted problems with the quality of drinking water including contamination with various microorganisms., Water supply in many parts is ensured through public water tanks, and a previous study has highlighted a significant association of water-borne diseases with the use of such public water supply as compared to personal water pumps and water sources. There is a lack of data on ALA from this part of the state. Here, we present our pilot study to assess the seropositivity and profile of ALA patients attending a tertiary care center in western Rajasthan.
| Materials and Methods|| |
The present study was a retrospective study conducted in the department of microbiology at a tertiary care center from western Rajasthan. All patients who presented to our institute with liver abscess from a period of November 2017 to May 2019 in whom amebic liver serology was ordered were included in the study. The liver abscess patients for whom amebic liver serology was not done were excluded from the study.
Patients presenting with clinical features such as fever, pain abdomen/pain in the right hypochondrium, hepatomegaly, and tenderness underwent ultrasonography, after which the relevant investigations were done based on radiological findings of abscess or cystic lesion. The workup of patients with radiological evidence of abscess included aerobic bacterial culture of aspirated pus, microscopic examination of aspirated pus, and amebic serology besides routine hematological and biochemical parameters listed below.
For microscopic examination, the aspirated pus from the liver was sent for demonstration of the amebic parasite. Gram's stained smears and Ziehl–Neelsen staining were performed for demonstration of bacteria and acid-fast bacilli, respectively. For serological diagnosis of ALA in these patients, 4–5 ml blood samples were collected in vacutainers with a gel column without additives (BD Vacutainer, New Jersey, US) from all patients. Serum was separated from these samples, and amebic serology was performed by ELISA (Ridascreen E. histolytica immunoglobulin G (IgG), R-Biopharm AG, Germany) to detect anti-amebic IgG antibodies in these samples. The procedure of performing the ELISA test was as per the manufacturer's instructions provided in the supplied kit literature.
Bacterial cultures of the aspirated pus were performed as per the requisition slip by inoculating the specimen onto 5% blood agar, chocolate agar (heated blood agar), MacConkey agar, and brain heart infusion broth (BHIB) for enrichment. The culture plates were incubated aerobically at 37°C. Any growth obtained on the culture plates was investigated for identification by standard microbiological methods. As a protocol, subcultures were performed from BHIB tubes after overnight incubation onto fresh plates of 5% blood agar, chocolate agar, and MacConkey agar, and these plates were again incubated for further 24 h to look for any growth of bacterial colonies before labeling the culture as sterile.
A patient was classified as a case of ALA as described previously by Dhanalakshmi and Parija, i.e., if the clinical and radiological findings were corroborated by a sterile aerobic bacterial culture and an improvement following treatment with a trial of anti-amebic drugs. The patients not fulfilling the above criteria were classified as patients with non-ALA or hepatic disorders. This group was labeled as another category for analysis and discussion purpose.
Data of all the patients included in this study were accessed from the hospital information system (HIS) of the institute. The data collected included hemogram, liver function tests (LFTs), erythrocytic sedimentation rate (ESR), C-reactive protein (CRP), ultrasound (USG) abdomen, stool routine examination (RE), bacterial cultures of the aspirated liver pus, and amebic serology along with available clinical record of presenting signs and symptoms such as fever, abdominal pain, organomegaly, jaundice, and treatment.
Statistical analysis of the laboratory profile data of various tests was performed using SPSS software version 23 (IBM corp., Armonk, New York, USA). All values were expressed as median and interquartile range for the purpose of analysis, and P value was calculated using Mann–Whitney U-test.
The study was conducted as per the ethical guidelines for biomedical research on human subjects as given by the Central Ethics Committee on Human Research (CECHR) of Indian Council of Medical Research (ICMR), New Delhi, in 2006 and as given in the “Declaration of Helsinki” revision of 2013. Approval was granted by the Institute's Ethical Committee.
| Results|| |
Blood (serum) specimens from a total of 34 patients with liver abscess were sent to the Microbiology laboratory during this period. A clustering of the cases in summers was observed as majority (n = 22, 64.7%) of the cases presented to the hospital between April and July. Among the total cases, 21 were positive for anti-amebic IgG antibodies by ELISA, whereas the rest 13 were negative indicating a seropositivity of 61.8% in patients with liver abscess. Among 34 patients with liver abscess, 20 (58.8%) were diagnosed to be cases of ALA, whereas 14 (41.2%) were diagnosed to be non-ALA/hepatic disorder cases. Serology was positive in 19 (95%) ALA and 2 (14.3%) patients from other categories. Among ALA patients, 8 (40%) were in the age group of 41–60 years, whereas 6 (20%) were in the age group of 61–80 years. Only 6 (30%) patients were of age 40 years or less. In contrast, half (n = 7, 50%) of the other category patients in the study were of age 40 years or less [Table 1]. Males (n = 17) were more commonly affected by ALA as compared to females (n = 3) in a ratio of 5.7:1.
The chief complaints reported by the patients upon the first visit included pain abdomen (n = 25), fever (n = 2), cough (n = 1), respiratory distress (n = 2), dysentery (n = 2), vomiting (n = 1), and lump abdomen (n = 1). The clinical profile of the ALA and other category patients is compared in [Table 2]. Radiology records were available for 15/20 ALA and 8/14 other patients [Table 2]. A review of the radiological examination records of ALA patients revealed the presence of liver abscess (n = 15, 100%), hepatomegaly (n = 7, 46.7%), pleural effusion (n = 3, 20%), lung collapse (n = 2, 13.3%), and vascular involvement (n = 1, 6.7%). The right lobe of the liver was involved in majority of the patients (n = 12, 80%), whereas two (13.3%) patients had left lobe involvement. Both right and left lobes were involved in one (6.7%) patient. The mean volume of the pus observed radiologically was 118 ml (range, 10–390 ml). Multiple abscesses were seen in four (26.7%) patients.
|Table 2: Clinical and radiological profile of the liver abscess patients|
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The laboratory profile of ALA and other category patients was compared by compiling the results of various biochemical and pathology reports, as shown in [Table 3]. It was observed that hemoglobin (P = 0.023), TLC (P < 0.001), absolute neutrophil count (P = 0.001), total serum bilirubin (TSB, P = 0.019), and serum alkaline phosphatase (P = 0.018) were elevated to statistically significant levels in ALA patients as compared to other category patients. Bacterial cultures were done for all patients, and all cultures turned out to be sterile. The ALA patients were treated with oral metronidazole along with pigtail catheter insertion in cases of large abscess size to achieve faster resolution of abscess as well as relief from symptoms. Fourteen patients showed improvement upon initiation of therapy, whereas the rest were lost to follow-up. Among 14 patients from other categories, 10 were treated as cases of PLA, 3 for hepatic neoplasms, and 1 patient was diagnosed with colitis.
| Discussion|| |
This pilot study was conducted at an emerging tertiary care referral hospital in western Rajasthan, and the observed seropositivity of 61.8% is in concordance with other studies from India. A study from New Delhi estimated a seroprevalence of 66.7% by the end of the study (91.4% at the beginning of the study period), whereas another study by Ghosh et al. showed a seroprevalence of 72.5% by demonstration of IgM antibodies rather than IgG antibody ELISA done by most of the studies. The decreasing trend of seroprevalence could be attributed to improvement in sanitation and drinking water quality in the last decade following strong advocacy of the Swachh Bharat campaign.
The most common feature of a patient in our study was a middle-aged male which is in agreement with previous studies, and it has been proposed that this association could be because of higher consumption of alcohol in men, increased liver iron in alcoholics, and testosterone., Females, on the other hand, have lower iron reserves, especially during the childbearing age,, and there is a stimulatory effect of estrogen on the phagocytic system, thereby increasing the efficiency of the immune response against invading E. histolytica in the host body. A study by Jha et al. from Patna identified male gender and older age (third to fifth decade) as a variable for complications besides other variables such as higher abscess volume, increased serum bilirubin, decreased serum albumin, hyponatremia, leukocytosis, smoking, and duration of alcohol consumption. In our study, majority of the ALA patients were more than 40 years of age which is in disagreement with the literature, where age more than 50 has been described as a demographic feature favoring of PLA.
Previous studies from some parts of India and Sri Lanka, have shown that consumption of locally made alcohol such as toddy, which is usually prepared in unhygienic conditions, is a significant risk factor for the development of ALA. No such association was found by Jha et al. Alcohol consumption also causes hepatic damage, and alcoholics often have poor nutritional status leading to relative immunodeficiency state, thereby increasing the chances of ALA.
The presence of jaundice in 33.4% of our cases is higher than its previously reported presence in 12%–26% of the cases, but the elevation in TSB in ALA cases was not statistically significant. Furthermore, the right lobe of the liver was involved in majority of the patients in accordance with the available literature. The left lobe was involved in a total of three patients, and its involvement is considered to be a cause of concern owing to high chances of rupture into the pericardium. One patient had evidence of vascular thrombosis that has been linked to severe disease.
A few previous studies have documented the role of neutrophils and monocytes in ALA pathogenesis and disease progression., Elevated counts of these cells were observed in these studies. Helk et al. found that inflammatory monocytes are directly responsible for tissue damage in ALA patients and contribute to the disease progression, mainly through tumor necrosis factor-α.
The sensitivity and specificity of anti-amebic IgG serology in our study were 95% and 87.5%, respectively, which is higher than that reported in a previous study by Dhanalakshmi and Parija (sensitivity: 56.47% and specificity: 92.11%). However, serology was performed immediately after the onset of symptoms that could explain the lower sensitivity as observed by the authors in that study. Serology is considered a reliable test with a very high sensitivity and specificity, but in endemic areas, this test suffers from specificity issues as the chances of false positivity are there owing to past exposure to the parasite.
This study has a few limitations. This pilot study was conducted at an emerging tertiary care referral hospital, so the number of cases included in the study is less despite the yearly increase in the patient footfall of late. Being a referral tertiary care center, patients usually come after having tried multiple treatment options including antimicrobials prescribed by local practitioners, and this could be one of the reasons for sterile cultures. Furthermore, being a retrospective study, the history of alcohol consumption could not be sought in the patients. Finally, serological testing was done using IgG ELISA kit, and previously infected patients may give a positive ELISA test. We tried to minimize this by correlating the serology results with the clinical, radiological features and response to treatment.
| Conclusions|| |
Although seroprevalence of ALA has been reported to be on a declining trend, it still remains as the dominant etiology in liver abscess patients. Serology offers a good cost-effective option of diagnosis, but its results should be interpreted with respect to the clinical and radiological parameters in endemic areas. The study highlights laboratory derangements in ALA patients, however, further studies involving large number of patients over a longer period of time are required to corroborate the findings of this pilot study and to better understand the impact of ALA in western Rajasthan.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]