Did you know that after an injury to the liver, an infection of the abdomen can spread from the portal circulation and cause a pus-filled swelling in the liver, known as a liver abscess? These liver abscesses are rare and can be classified as pyogenic or amoebic. E. coli, Klebsiella, Streptococcus, Staphylococcus, and anaerobes are some of the organisms that are more frequently found in pyogenic abscesses despite being typically polymicrobial.2 There are three mechanisms by which a pyogenic liver abscess may develop. One of them is the transmission of bacteria from an infectious site or the drainage of pus from the portal vein. Another mechanism involves, the bile duct getting obstructed due to strictures, mass, or gallstones, resulting in blockage and allowing for the direct spread of infectious material to the liver, leading to abscess development. Lastly, PLAs can be produced by the direct spread of systemic bacteria through the bloodstream, such as that brought on by bacterial endocarditis or periodontal infections.
Causes of pyogenic liver abscess
Even though there are many reasons why pyogenic abscesses occur, some of the main reasons include the following:
- The majority of pyogenic liver abscesses occur due to biliary lithiasis pathology (the presence of stones within the biliary system). Infections in the biliary system, such as ascending cholangitis or infections brought on by gallstones, can result in the formation of liver abscesses
- Bacteria can enter the liver through the circulation, which can result in the development of an abscess. Infections in other organs, such as the appendix, diverticula, or gastrointestinal system, are frequent causes of bloodstream infections1
- Trauma to the liver or surgical operations affecting the liver might make it easier for germs to enter the body, increasing the likelihood that an abscess will form. Individuals may be more susceptible to pyogenic liver abscesses after undergoing surgical procedures including liver resection, liver biopsy, or liver transplantation
Procedures like endoscopic retrograde cholangiopancreatography (ERCP) or endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), which are invasive can result in liver injury, causing abscesses to form.
Signs and symptoms of pyogenic liver abscess
One of the major symptoms of pyogenic liver abscess manifests itself in the form of the traditional symptoms of stomach discomfort, fever/chills, and malaise. However, only around 30% of patients suffering from pyogenic abscesses experience symptoms of the traditional triad.
Other more common symptoms include rigours, nausea/vomiting, anorexia, weight loss, and widespread weakness.
Less frequently, patients may complain of coughing, hiccups, or transferred right shoulder discomfort from an irritated diaphragm.
Management and treatment for pyogenic liver abscess
Pyogenic liver abscesses can be managed by a combination of therapies involving antibiotics, drainage of the abscess, and surgical removal of the pus, this depends on the size and diameter of the abscess. Although the original method of treating pyogenic liver abscesses was surgical drainage, this method has now been replaced with i.v. broad-spectrum antibiotics and imaging-guided percutaneous drainage, either by needle aspiration or percutaneous catheter drainage.
- Antibiotic Therapy: The prescription of antibiotics to treat the infection is the main treatment for pyogenic liver abscesses. If the size of the abscess is 3-5 cm, antibiotics alone are a sufficient line of treatment. The selection of antibiotics is based on the bacteria thought to be responsible for the abscess and may be modified depending on the findings of culture and sensitivity tests. Oral antibiotics are given after intravenous antibiotics are first administered. Currently, drugs such as the beta-lactam-beta-lactamase inhibitor or a carbapenem are being used in combination with or without Metronidazole as the main treatment of a live abscess.4
- Percutaneous Drainage: When the abscess is larger than 5 cm and continuous fever despite 48-72 hours of medicinal therapy, and there are indications that the abscess may rupture, then sonographic or CT-guided aspiration and drainage are the first-line treatments. However, this procedure is only used if the abscess is large or producing symptoms. To drain the pus, a needle or catheter must be inserted through the skin and into the abscess, and this is directed by computed tomography (CT) or ultrasound imaging. To determine the etiologic microorganisms and direct antibiotic therapy, the drained fluid is submitted for culture
- Surgery is often used in situations where percutaneous drainage is impractical when an abscess is not responding to medical treatment, or when there are complications like rupture or numerous abscesses. Depending on the specific circumstances, open surgery or laparoscopic surgery (a surgical procedure to look inside your stomach with a camera) are both surgical possibilities. Surgical drainage can be done in multiple situations, such as when there is an abscess rupture, the primary pathology is not addressed, there is incomplete percutaneous drainage, symptoms persist even after 4–7 days of percutaneous drainage, or there are multiloculated abscesses.1
- Supportive care includes pain treatment, fluid and electrolyte replenishment, and dietary assistance as required.1
Diagnosis of pyogenic liver abscess
PLA can be diagnosed with the help of physical examinations, blood investigations, and radiographic imaging investigations.
Key diagnostic factors in a physical examination include the presence of risk factors, fevers and chills, right upper abdominal region tenderness, and hepatomegaly (swollen liver). Other diagnostic factors include weight loss, fatigue, abdominal pain, nausea, and vomiting
Diagnostic initial blood investigations include the following:
- Full blood count (FBC)
- Serum Liver function tests (LFTs)
- Blood cultures
- Prothrombin time and activated partial thromboplastin time
More investigations include:
- Serum antibody test for Entamoeba histolytica
- Stool test for detection of Entamoeba histolytica antigen
- Antigen testing or polymerase chain reaction (PCR) of aspirated abscess fluid
The preferred imaging modalities for diagnosing PLA are computed tomography (CT) and ultrasonography, with CT being somewhat more sensitive. Two stages of PLA can be distinguished with the help of CT scans. On a CT scan, pre-suppurative pyogenic hepatic abscesses resemble tumours because they are heterogeneous, hypodense, and have irregular shapes. While the suppurative phase may appear multiloculated with more rounded outlines and a ring or peripheral enhancement(8).
Risk factors for pyogenic liver abscess include pre-existing biliary tract disease, liver disease, and underlying hepatobiliary or pancreatic disease, which compromise the immune system and increase susceptibility to infections.
Pyogenic liver abscesses are more common in males and older adults with an age above 50 years.
Excessive alcohol consumption can damage the liver and impair immune function, increasing the risk of developing liver abscesses.
People with weaker immune systems are more prone to infections, including pyogenic liver abscesses. Examples of such people include those with HIV/AIDS, those undergoing chemotherapy, and those on immunosuppressive drugs. In up to 15% of cases, PLA is the initial manifestation of an occult intra‐abdominal malignancy.
Having diabetes mellitus raises your chance of getting infections, such as liver abscesses. Poorly managed diabetes weakens the immune system and reduces the body's capacity to successfully fight bacterial infections.7
It is extremely crucial to remember that having these risk factors does not guarantee the possibility of developing a pyogenic liver abscess but rather just increases the likelihood of getting the disease.
The complications of a pyogenic liver abscess include rupture of the abscess, septic shock, recurrence of the abscess, or even liver failure.
Acute liver failure can happen when a pyogenic hepatic abscess is big enough to cause a mass effect. But with drainage and medicines, this is curable.5
If there is a delay in accessing medical treatment, the abscess may rupture, posing itself as one of the complications. If septic shock and diffuse abdominal pain are present in a patient with a pyogenic liver abscess, together with elevated levels of bilirubin, aspartate aminotransferase, and blood glucose, a ruptured pyogenic liver abscess should be suspected. The only available therapy for this problem is surgery.3
A bacterial infection from the abscess can spread to the bloodstream, causing sepsis. Sepsis is a life-threatening condition characterized by a systemic inflammatory response that can lead to organ dysfunction and failure.6
Even after effective treatment, the pyogenic liver abscess can occasionally recur. This may occur if the underlying issue, such as a persistent bile tract blockage, is not sufficiently treated(6).
How can I prevent a pyogenic liver abscess?
The best defence against liver abscesses is prompt treatment for intraabdominal infections. Following drainage, four to six weeks of antibiotic medication may almost guarantee the absence of problems. Future abscess development can be avoided with antimicrobial therapy during chemoembolization or endoscopic retrograde cholangiography.2
How common is a pyogenic liver abscess?
Pyogenic liver abscesses are relatively rare disorders, as there are around 2.3 cases per 100,000 people each year who suffer from them, and they are seen to be more common among males as compared to females. Age is also a significant factor since a liver abscess caused by trauma is more likely to occur in people between the ages of 40 and 60.7
When should I see a doctor?
It is essential to see a doctor as soon as you notice the initial symptoms of the triad, such as abdominal pain, fever, and malaise, as well as other symptoms like nausea and vomiting so that prompt diagnosis can be done and appropriate treatment can be provided to avoid any complication.
To summarise, pyogenic liver abscesses are rare disorders that manifest as pus-filled pockets in the liver and are produced by a number of microorganisms. Although there are many reasons for the development of the disease, the most common cause is an infection in the biliary system. Minimising the risk of complications related to pyogenic liver abscess requires prompt diagnosis, adequate medical care, and occasional draining of the abscess. It is essential to consult a doctor if you think you have a liver abscess or have been told you have one in order to get the right care.
- Abusedera, Mohammad Alaa, and Ashraf Mohammad El-Badry. ‘Percutaneous Treatment of Large Pyogenic Liver Abscess’. The Egyptian Journal of Radiology and Nuclear Medicine, vol. 45, no. 1, Mar. 2014, pp. 109–15. DOI.org (Crossref), https://doi.org/10.1016/j.ejrnm.2013.11.005.
- Akhondi H, Sabih DE. Liver Abscess. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2023. [accessed 19 May 2023] Available from: http://www.ncbi.nlm.nih.gov/books/NBK538230/
- Chou FF, Sheen-Chen SM, Lee TY. Rupture of pyogenic liver abscess. Am J Gastroenterol. 1995 May;90(5):767–70 https://pubmed.ncbi.nlm.nih.gov/7733086/ - rupture of the abscess
- Ciprofloxacin Plus Metronidazole Vs Cefixime Plus Metronidazole Therapy for the Treatment of Liver Abscess - Full Text View - ClinicalTrials.Gov’. Cochrane Library, 2019, https://clinicaltrials.gov/ct2/show/NCT03969758.
- Elmusa E, Raza MW, Orlando M, Boyd S, Kulchinsky R. Acute Liver Failure Secondary to Pyogenic Hepatic Abscess. Cureus. 2023 Jan 27; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9968402/.
- Kokayi A. Septic shock secondary to a pyogenic liver abscess following complicated appendicitis. Cureus [Internet]. [cited 2023 May 19];13(9):e18359. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8553378/.
- Longworth, Sarah, and Jennifer Han. ‘Pyogenic Liver Abscess: Pyogenic Liver Abscess’. Clinical Liver Disease, vol. 6, no. 2, Aug. 2015, pp. 51–54. DOI.org (Crossref), https://doi.org/10.1002/cld.487.
- Simmons, Rachel, and Lawrence Friedman. ‘Liver Abscess - Symptoms, Diagnosis and Treatment | BMJ Best Practice’. BMJ Best Practice, 2021, https://bestpractice.bmj.com/topics/en-gb/640.