A 6-year-old boy with a focal lesion of the liver: case description

CASE REPORT

A 6-year-old boy was admitted to the Pediatric Department due to fever and abdominal pain. In the interview, it was revealed that the boy had been experiencing fever every 4 hours for the past 4 days, reaching a maximum of 39.5°C, with a poor response to antipyretic medications. Additionally, for the past 2 days, he complained of crampy abdominal pain localized in the right lower quadrant. Furthermore, over the past few days, due to a respiratory tract infection characterized by symptoms such as rhinitis and non-productive cough, he had been receiving budesonide and bronchodilators. There was no history of international travel, including tropical regions, or contact with animals. Upon admission, the boy was in a generally good condition but significantly weakened. The physical examination revealed an enlarged liver, but no other abnormalities or signs of infection were observed. Laboratory tests conducted upon admission showed elevated inflammatory markers (C-reactive protein 360 mg/l, procalcitonin 16 ng/ml), elevated transaminase levels (alanine aminotransferase 73 U/l, aspartate transferase 51 U/l), gamma-glutamyl transferase (97 U/l), and hypoalbuminemia (33.4 g/l). Abdominal ultrasonography (USG) revealed a heterogeneous, polycyclic area of reduced echogenicity measuring 37 × 34 × 40 mm in the right lobe of the liver, with weak peripheral flow. Additionally, the liver was enlarged, and the parenchyma surrounding the lesion was heterogeneous. Further diagnostic investigation with abdominal computed tomography (CT) scan showed a multiloculated fluid collection in segments 6 and 7 of the right lobe of the liver, with proteinaceous content and numerous septations extending to the center, with mild contrast enhancement (Figure 1). Empirical antibiotic therapy with ceftriaxone and metronidazole was initiated.
During the first 4 days of hospitalization, the boy had high fever and complained of severe abdominal pain localized in the right upper abdomen. Additionally, his mother noticed a deterioration in his hearing. A head CT scan was performed, revealing intensified inflammatory changes in the structures of the temporal bone pyramids, bilateral involvement of the auditory ossicles with inflammatory masses and inflammatory changes in the paranasal sinuses. The presence of focal lesions in the central nervous system was ruled out.
Due to the identified focal lesion in the liver, a comprehensive differential diagnosis was conducted. In the performed serological tests, negative antibodies against both classes of Epstein-Barr virus (EBV), cytomegalovirus (CMV), and Mycoplasma were found, along with negative antibodies against Echinococcus spp. and Entamoeba histolytica, negative circulating antigen of Aspergillus spp., and a double (Ag/Ab) HIV test. The test for antibodies against SARS-CoV-2 was positive in the IgG class. The stool parasitological examination was negative.

FINAL DIAGNOSIS

On the 4^th day of hospitalization, information was received about the growth of Streptococcus intermedius in the blood culture and about a questionable result of testing for the circulating Candida albicans antigen.
Due to the positive blood culture result, the diagnosis of liver abscess was made, most likely originating from inflammatory changes in the sinuses and temporal bones. After obtaining information about the pathogen, the antibiotic therapy was modified to target based on ceftriaxone and vancomycin. Additionally, considering the uncertain result of circulating C. albicans antigen, voriconazole was added to the treatment.
Due to the diagnosis of a liver abscess, immunological diagnostics were also expanded, confirming normal lymphocyte levels, an elevated immunoglobulin response to the infection, and normal bactericidal function of granulocytes (excluding chronic granulomatous disease – CGD). The consulting immunologist recommended further diagnostic expansion in the event of recurrent bacterial infections or treatment failure.

HOSPITAL COURSE

The case of the boy was presented at the surgical-radiological consultation. After reviewing the available test results, the consulting specialists decided not to proceed with surgical intervention due to the unfavorable location of the liver abscess in the 6^th and 7^th segments of the right hepatic lobe. They recommended continuing with conservative treatment.
The antibiotic therapy was continued, with an improvement in the general condition and a reduction in inflammatory parameters being observed. After obtaining complete information about the drug sensitivity of Streptococcus intermedius, the decision was made to discontinue vancomycin. However, a fever relapse and an increase in inflammatory parameters were observed. Vancomycin was reintroduced, resulting in the resolution of symptoms and gradual normalization of biochemical parameters.
During hospitalization, abdominal USG was performed multiple times, showing a slight regression of the abscess. On the 26^th day of targeted treatment, an abdominal MRI was conducted, and also demonstrated partial regression of the lesion. The boy was examined by surgical specialists several times, and the decision for conservative treatment was upheld. The treatment with vancomycin and ceftriaxone was continued for a total of 42 days.
After discharge, the boy was placed under the care of the Surgical Outpatient Clinic. During follow-up imaging examinations, further regression of the lesion was observed until its complete resolution, which occurred 6 weeks after the end of antibiotic therapy.

DISCUSSION

Liver focal lesions can have diverse characteristics. They can be cystic or solid, of congenital or acquired etiology (including infectious or neoplastic). Various imaging techniques (USG, CT, MRI) are used for the diffe¬rentiation of these lesions, and in cases where diagnosis is challenging, a biopsy of the lesion is performed for histopathological verification. The characteristic clinical features and imaging findings are presented in Table 1.
According to their etiology, liver abscesses can be classified into bacterial, fungal, and amebic types. Bacterial abscesses are the most commonly observed [6]. Bacteria can enter the liver through the bloodstream, bile or via contiguous spread from infected surrounding tissues [5].
Risk factors include immunodeficiencies such as CGD, diabetes mellitus, oncological conditions, chemotherapy, and malnutrition. In immunocompetent patients, predisposing factors include intra-abdominal infections, bacteremia, and iatrogenic complications, such as umbilical vein catheterization and percutaneous liver biopsy [6, 16, 22, 23].
The most common etiological factor is Gram-negative enteric bacilli, which can originate from gastrointestinal tract perforation or appendicitis. Additionally, staphylococci or streptococci can cause abscesses in cases unrelated to the gastrointestinal tract [1]. In the described case, the most likely source of infection was sinusitis and middle ear infection with involvement of the temporal bone caused by Streptococcus intermedius. This is a Gram-positive, beta-hemolytic bacterium belonging to the Streptococcus anginosus group [2], which constitutes a normal part of the gastrointestinal and respiratory microbiota. In specific situations, such as dental procedures or abscesses in the head and neck region [2, 9], it can cause invasive infections [8].
The clinical symptoms of liver abscesses are nonspecific and most commonly include high fever, weakness, upper abdominal pain, nausea, vomiting, night sweats and weight loss. In laboratory tests, attention is drawn to leukocytosis, elevated markers of inflammation, hypoalbuminemia and increased levels of aminotransferases [5]. Such a presentation was also observed in the present patient; however, due to the nonspecific nature of these symptoms, the diagnosis required further diagnostic investigation.
Various imaging techniques are used in the diagnostic evaluation of liver abscesses. In abdominal X-rays, the abscess appears as an oval lesion with a fluid level, located outside the intestinal lumen. In USG, the abscess is visualized as a hypoechoic, heterogeneous lesion filled with dense material, often with a fluid level or additional echoes due to the presence of necrotic tissues, surrounded by a hyperechoic capsule [3]. For a more detailed assessment of focal liver lesions, CT is used, with a sensitivity and specificity of 90% [3]. The typical imaging feature for liver abscesses is the “double target sign” [1], which consists of a hypodense lesion with irregular margins surrounded by a thick capsule that shows peripheral enhancement after contrast administration, and a surrounding zone of hypoperfusion.
Complications of liver abscess can include perforation with the formation of pleural, peritoneal or pericardial abscesses, and splenic or portal vein thrombosis [1]. The treatment depends on the patient’s general condition, as well as the location and size of the abscess. Bacterial abscesses are often a complication of sepsis, so broad-spectrum antibiotic therapy is initiated before obtaining microbiological test results and then adjusted according to culture results [4].
Small abscesses (up to 3 cm) can be treated conservatively, which is supported by available literature data, such as a retrospective study conducted in 2008 by Dr. W. Hope, which demonstrated 100% effectiveness of antibiotic therapy alone in treating abscesses < 3 cm [7]. The duration of antibiotic therapy is usually around 4–6 weeks [6, 18].
In the case of larger lesions, risk of spontaneous rupture, or treatment failure – evidenced by persistent fever after 48–72 hours of antibiotic therapy, unrelenting symptoms, or further enlargement of the lesion – surgical intervention (aspiration biopsy or percutaneous drainage) should be considered. Surgical intervention is indicated for lesions above 5–6 cm in size [12, 18]. There are no clear guidelines for managing lesions 3–5 cm in size. In a study published in 2012 by Mangukiya et al. [20], which included 400 patients with liver abscesses of varying sizes, 32% of patients required only conservative treatment. The remaining patients needed surgical intervention using aspiration techniques (mean abscess size of 6.87 cm) or drainage (in abscesses with a mean size of 11.5 cm).

CONCLUSIONS

In developed countries, liver abscesses are rare in the pediatric population, but in developing countries, they still pose a significant problem [19]. The most common location for liver abscesses is the right lobe [21]. The treatment depends on the patient’s condition and the location and size of the lesion. In the described case, a liver abscess with dimensions of 46 × 38 mm was identified. The location of the lesion in segments 6 and 7 of the right hepatic lobe made it impossible to perform minimally invasive surgery and was associated with a high risk of postoperative complications. Therefore, conservative treatment was pursued, using antibiotic therapy for a total of 6 weeks, resulting in clinical improvement and gradual reduction of the lesion until its complete resolution in imaging studies after 12 weeks.

DISCLOSURES

1. Institutional review board statement: Not applicable.
2. Assistance with the article: None.
3. Financial support and sponsorship: None.
4. Conflicts of interest: None.

REFERENCES