Liver abscess is one of the most frequent intra-abdominal infections encountered in clinical practice, particularly in tropical and subtropical countries such as India. It continues to represent a major public health issue due to its association with significant morbidity and occasional mortality despite modern advances in imaging and antimicrobial therapy【1,2】. The disease occurs in two principal forms — amoebic liver abscess (ALA), caused by Entamoeba histolytica, and pyogenic liver abscess (PLA), resulting from bacterial infection, most commonly Escherichia coli and Klebsiella pneumoniae【3,4】. While the relative incidence of ALA has declined with improved sanitation, both types remain prevalent in endemic areas. The pathophysiology of liver abscess involves hepatic parenchymal destruction due to infection, with abscess formation resulting from hematogenous spread via the portal circulation or biliary tract, or secondary to local extension from contiguous structures【5】. Certain host factors such as alcoholism, diabetes mellitus, malnutrition, and immunosuppression increase susceptibility and severity【6,7】. Males in the fourth to sixth decades are particularly affected, possibly due to hormonal and lifestyle influences. Clinically, patients usually present with fever, right upper quadrant abdominal pain, and hepatomegaly, often accompanied by anorexia, malaise, and weight loss【8】. Without prompt management, complications such as rupture into the pleural, peritoneal, or pericardial cavities can occur, resulting in sepsis and death【9】. Traditionally, open surgical drainage was considered the definitive treatment, especially for large or complicated abscesses. However, this approach was associated with considerable morbidity, prolonged hospitalization, and postoperative complications【10】. With the advent of real-time ultrasonography (USG), less invasive modalities emerged. Percutaneous drainage techniques, including needle aspiration and catheter drainage, have now become the preferred treatment options in most cases【11】. Among these, ultrasound-guided pigtail catheter drainage (PCD) offers several advantages. It allows continuous evacuation of pus, prevents reaccumulation, facilitates irrigation, and enables serial monitoring of cavity size and resolution. Compared to single-time aspiration, PCD has shown superior outcomes in terms of symptom relief, faster cavity closure, and reduced recurrence rates【12,13】. Moreover, USG guidance minimizes the risk of injury to adjacent structures, providing a safe, effective, and bedside-feasible alternative even in resource-limited settings【14】. Despite widespread acceptance, few prospective studies from South India have documented the detailed clinical spectrum, procedural metrics, and outcomes of USG-guided pigtail catheter drainage. Therefore, the present study was conducted to evaluate the clinical profile, ultrasonographic characteristics, technical aspects, and treatment outcomes of patients with liver abscess managed using ultrasound-guided pigtail catheter drainage at a tertiary care hospital. The findings aim to reinforce the role of minimally invasive techniques as the first-line therapeutic approach in the management of liver abscess.

Study Design and Setting A prospective observational study was conducted over a period of two years in a tertiary care hospital in South India. The study included patients diagnosed with liver abscess based on clinical evaluation and ultrasound confirmation. All enrolled patients were admitted for evaluation, management, and follow-up. The objective was to assess the clinical presentation, diagnostic findings, and treatment outcomes of liver abscess cases managed with ultrasound-guided pigtail catheter drainage. Study Population Fifty patients diagnosed with liver abscess based on clinical and ultrasonographic findings were included. Inclusion Criteria • Solitary or multiple liver abscesses ≤10 cm • Both pyogenic and amoebic etiology • Patients fit for percutaneous drainage Exclusion Criteria • Ruptured abscess • Jaundice or ascites • Toxic or terminally ill patients Procedure After baseline hematological and imaging assessment, patients received empirical intravenous ciprofloxacin / third-generation cephalosporin plus metronidazole. Ultrasound-guided pigtail catheter (16 Fr) insertion was performed using the Seldinger technique. The abscess cavity was aspirated until pus flow decreased, and continuous drainage was maintained. Catheter output was recorded daily until resolution. Outcome Assessment • Symptomatic relief • Reduction of abscess cavity size on ultrasound • Duration of catheterization and hospital stay • Complications (pain, blockage, secondary infection)

Demographic Profile Of 50 patients, 39 (78%) were males and 11 (22%) females. Most cases (34%) were between 31–50 years. Table 1: Laboratory Findings Parameter No. (%) Leucocytosis 38 (76%) Anaemia 13 (26%) Raised ALP 18 (36%) Hypoalbuminemia 4 (8%) Azotemia 2 (4%) Among the laboratory findings, leucocytosis was the most common abnormality, seen in 76% of patients, indicating an ongoing infectious or inflammatory process. Raised alkaline phosphatase (ALP) levels were noted in 36%, suggesting hepatic involvement and biliary irritation associated with abscess formation. Anaemia was present in 26% of cases, likely due to chronic infection and nutritional deficiencies. Hypoalbuminemia was observed in 8%, reflecting poor nutritional status and hepatic dysfunction, while azotemia was reported in 4%, possibly due to dehydration or systemic illness associated with sepsis. (Table 1) Table 3. Drain Output, Hospital Stay, Microbiology, Complications, and Outcome Parameter Category No. of Cases (%) Drain Output (ml) <400 5 (10%) 400–500 5 (10%) 500–700 21 (42%) 700–800 15 (30%) 800–900 4 (8%) Mean total output ~650 ml Mean duration of catheter in-situ 5.6 days Hospital Stay (days) 6–7 28 (56%) 8–10 22 (44%) Mean hospital stay 7.4 days Microbiology Culture positive 22 (44%) Sensitivity — Complications Minor Few cases Outcome Success rate 100% Mortality 0% The mean total drain output recorded was approximately 650 ml, with the majority of patients (42%) producing between 500–700 ml of pus, followed by 30% in the 700–800 ml range. This pattern indicates effective and sustained evacuation of abscess contents through the pigtail catheter, achieving rapid cavity decompression. The mean duration of catheter in-situ was 5.6 days, suggesting early resolution of the abscess cavity. This duration is shorter than that reported by Rajak et al. (7 days) and Wong et al. (25 days), reflecting both improved antibiotic response and efficient drainage in this cohort. In terms of hospitalization, more than half the patients (56%) were discharged within 6–7 days, while the rest (44%) stayed for 8–10 days, giving a mean hospital stay of 7.4 days. This short duration underscores the minimally invasive nature and faster recovery associated with ultrasound-guided pigtail catheter drainage. Microbiological culture was positive in 22 patients (44%), with Escherichia coli and Klebsiella pneumoniae being the predominant isolates. Both showed good sensitivity to amikacin and third-generation cephalosporins, validating the empiric antibiotic regimen used in this study. No major complications were encountered; only minor local pain occurred in a few patients, which subsided with conservative treatment. Importantly, no catheter blockage or recurrence was noted, and the procedure demonstrated a 100% success rate with 0% mortality.(Table 3) Collectively, these findings highlight that ultrasound-guided pigtail catheter drainage ensures effective abscess clearance, rapid clinical improvement, and excellent safety outcomes, confirming it as a highly reliable and minimally invasive treatment modality for liver abscess.

In the present study, liver abscess was found predominantly among middle-aged males (78%), with a mean age range of 31–50 years, corroborating observations from earlier Indian and international cohorts (15–17). The gender disparity has been attributed to higher alcohol consumption, poor nutritional status, and greater exposure to hepatic pathogens among men in tropical regions (18). Alcohol use was identified in 32% of patients, a proportion comparable to the 30–40% prevalence reported by Sharma and Ahuja and Seeto and Rockey, who both recognized alcoholism as a significant etiological cofactor that impairs hepatic immune mechanisms (5,6,19). Our clinical spectrum mirrored classical findings of right upper quadrant pain (86%) and fever (76%), consistent with studies by Chou et al. and Mohsen et al., where these symptoms were seen in 80–90% of patients (20,21). Tender hepatomegaly (52%) and tachycardia (44%) were also frequent, in line with tropical series from South Asia. The absence of jaundice in all patients indicates a non-obstructive pathology with limited biliary involvement. Similar observations were made by Kaplan et al. and Sharma et al., who noted that only a minority of cases with extensive biliary communication develop icterus (3) Leukocytosis was the most frequent laboratory abnormality (76%), while elevated alkaline phosphatase (36%) and hypoalbuminemia (8%) reflected hepatic parenchymal injury and systemic inflammation. These findings parallel those described by Ahuja and Sharma (2001) and Chu et al. (1996) (5,22). Ultrasonography confirmed the right lobe as the dominant site (72%), followed by the left lobe (22%) and both lobes (6%), consistent with Rajak et al. (68%) and Gerzof et al. (1985) (15,23). The right-lobe predilection is physiologically explained by its larger volume and greater portal venous inflow from the right colon. Most cavities were 7.5–10 cm in diameter (62%), appropriate for percutaneous drainage. Smaller abscesses (<5 cm), as shown in the studies by Branum et al. (1990) and Gerzof et al., often resolve with medical therapy alone(23,24). The most significant finding of this study was the 100% clinical success rate achieved with ultrasound-guided pigtail catheter drainage (PCD). All patients demonstrated symptom relief and radiological resolution without the need for open surgical intervention. The mean drainage duration of 5.6 days was notably shorter than that observed in prior studies—Rajak et al. (7 days) and K.P. Wong et al. (25 days) (15,16). This can be attributed to improved antibiotic regimens, uniform catheter size (16 Fr), and standardized saline irrigation, all of which facilitated faster cavity collapse and shorter hospital stays (~7 days). Compared with needle aspiration (NA), pigtail catheter drainage provides continuous decompression, reducing the likelihood of reaccumulation or residual infection. In their randomized trial, Rajak et al. (1998) reported significantly fewer treatment failures with PCD (4%) than NA (16%) (15). Our results reaffirm the superiority of PCD, particularly for large or multiloculated abscesses with thick pus. Pus culture was positive in 44% of cases, most commonly isolating Escherichia coli and Klebsiella pneumoniae, both sensitive to amikacin and third-generation cephalosporins. These findings align with those of Seeto and Rockey (1996) and Kaplan et al. (2004), who also identified gram-negative enteric bacilli as the dominant isolates in pyogenic liver abscesses(6,3). The relatively lower culture positivity is likely due to empiric antibiotic initiation before aspiration, a limitation frequently reported in developing-country settings(19). Only a minority (6%) had positive amoebic serology, reinforcing that many abscesses in endemic zones are mixed infections, where bacterial superinfection occurs in pre-existing amoebic cavities (25). The safety of the procedure was exemplary in our series. No major complications—such as hemorrhage, bile leak, or peritonitis—were recorded. Only transient pain at the insertion site occurred in a few patients, managed conservatively. Similar procedural safety has been documented by Sonnenberg et al. (1992) and Gerzof et al. (1985), who reported complication rates of 2–6%, primarily catheter obstruction or minor leakage(26,23). Our zero-mortality and zero-recurrence rates further reinforce that, when performed under image guidance, PCD is a safe, definitive, and minimally invasive method suitable for nearly all non-ruptured liver abscesses. When placed in the context of existing evidence, our outcomes are among the most favorable reported. The universal success rate (100%) surpasses that reported by Gerzof et al. (83%), Sonnenberg et al. (85%), and Chu et al. (90%), suggesting improved technical skill, imaging precision, and antibiotic synergy(23,26,22). The shorter drainage duration (5.6 days) and rapid recovery emphasize the procedural efficiency of USG-guided PCD in experienced hands. Our findings corroborate the consensus that percutaneous catheter drainage should be the first-line treatment for abscesses larger than 5 cm, those with thick or loculated contents, or in patients unfit for surgery(15,23,26). The procedure also significantly reduces hospital burden and healthcare costs, making it especially beneficial in resource-constrained environments. The study’s limitations include its single-center, non-randomized design and lack of long-term follow-up beyond three months. Amoebic serology was not available for all patients, restricting clear etiologic classification. Nevertheless, its prospective methodology, uniform protocol, and zero conversion or mortality rate add substantial clinical value. Future randomized controlled trials comparing needle aspiration versus pigtail drainage stratified by abscess size, viscosity, and microbial profile would help refine management algorithms. In summary, ultrasound-guided pigtail catheter drainage proved to be a safe, effective, and definitive treatment for liver abscess in this study. It achieved complete resolution with minimal morbidity, reduced hospitalization, and no major complications. When applied early and performed under proper guidance, this method offers an optimal balance between efficacy and safety, representing the standard of care for liver abscess management in modern clinical practice.

Ultrasound-guided pigtail catheter drainage offers a minimally invasive, highly effective, and safe management strategy for liver abscess. • Provides continuous, complete drainage with minimal morbidity. • Reduces hospital stay and avoids surgical intervention. • Particularly effective for abscesses ≤10 cm. Thus, it should be considered the first-line interventional approach for liver abscess, especially in resource-limited settings.

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