Liver abscess is an imperative health issue in tropical countries. The common etiology of liver abscess are E. histolytica (amoebic), bacterial (pyogenic) and Mycobacterium tuberculosis. (5) Amoebic liver abscess is more common in tropical counties and its incidence is > 50 million cases and 1,00,000 death per year (6, 7). Involvement of right lobe was predominant (82.5%) in this study which was similar to previous studies (5, 8). Etiology could be ascertained in 89% cases, of which 78% were of amoebic etiology. The disease is more common in younger population so effective treatment is required for decrease in morbidity and mortality in productive age group. Common presenting complaints of liver abscess are abdominal pain, fever, loss of appetite and weight loss (9). With the wide availability of ultrasound, the diagnosis of liver abscess is become easier but effective treatment with judicious selection of antimicrobial and early source control still an area of debate. With the advent of interventional radiology, percutaneous treatment in the form of either PNA or PCD are preferred in management of liver abscess (4).
The mean cavity volume was significantly higher in Group C (PCD group) when compared to Group A and B in present study. Despite of this, Group C had comparable duration of hospital stay and duration of antibiotic therapy. Few important randomised control trials have been conducted to compare efficacy between PCD and PNA (1, 10, 11, 12, 13, 14) with variable results. Among them three trial showed PCD was preferred method for abscess drainage and was more effective if cavity size is > 10cm (1, 10, 13). Yu et al (11) concluded that, there was no significant difference if hospital stay and clinical outcomes when compared PCD vs PNA in abscess cavity size of around 5cm. However, Zerem and Hadzic et al (12) concluded that PNA was preferred method if cavity size is smaller than 5 cm. Metanalysis by Cai YL et al (4) also favoured PCD as preferred method of management and lower success rate with PNA. The success rate of PNA is considered low due to need of multiple attempts for aspiration in larger cavity size abscess and risk of re-accumulation. We also analysed the effect abscess volume and treatment strategies on the duration hospital stay. PCD was found as an effective choice of abscess drainage if volume was > 150 ml. However, PCD was associated with higher duration of hospital stay if used in abscess volume < 150 ml. Kulhari M et al (14) showed better clinical outcome with PCD in view of decreased cavity size and duration of hospitalization and the mean volume in both groups were similar (293.2 ± 130.3 mL in PCD group and 291.4 ± 138.8 mL in PNA group, P = 0.925). Rajak et al (10) also showed that higher abscess volume was associated PNA failure (425 ml vs 178ml, p < 0.005).
Comparison between the conservative treatment versus PNA also done in previous studies (15, 16, 17). These studies were mostly before gaining the popularity of PCD. Results of these studies showed that PNA was more useful in higher abscess volume (15, 16, 17). In this study, conservative management was non-inferior to PNA with respect to duration of hospitalization and duration of antibiotics used even when abscess volume was similar in both groups (130.8 ± 72.9 vs 177.2 ± 129.5 ml, p = 0.27).
PCD related complications were major issues in previous reports (15, 16). There was no significant complication related to PCD in this study. The recent studies also favour that complication rates were not significantly different in PCD vs PNA in management of liver abscess (1, 20). While PCD reduces cavity size and abscess volume faster and are associated with fewer complications than PNA.
Lobe involvement and etiology were not found to affect the outcome in different treatment strategies in our study.
Limitations of this study were retrospective analysis and selection bias regarding preferable use of pigtail catherization in patients with large abscess volume.