Approach
Treatment of liver abscess consists of prompt initiation of antibiotic therapy and drainage of the collection. The development of percutaneous drainage techniques, combined with the current armamentarium of antibiotics, has been associated with decreasing mortality from liver abscess. If untreated, liver abscess is often fatal.
Presumed pyogenic liver abscess: antibiotic therapy
Broad-spectrum antibiotic therapy should be started empirically whenever the diagnosis of liver abscess is suspected.[40][41] In severely ill or unstable patients, antibiotics should not be delayed in anticipation of a drainage procedure. In stable patients, antibiotic therapy may be deferred until after drainage or aspiration if the procedure can be performed soon after the diagnosis is suspected. Initial therapy should target gram-positive, gram-negative, and anaerobic organisms, including Bacteroides species.[8][19] There are no randomized controlled studies or specific treatment guidelines regarding the antibiotic treatment of liver abscesses. Once blood or abscess fluid cultures are reported as positive for a specific pathogen, antibiotic regimens can be narrowed. However, anaerobic coverage should be continued for the duration of antibiotic treatment because of the difficulty in isolating these organisms. Parenteral antibiotic therapy should be given initially.
Empiric therapy for Candida species in immunocompromised or neutropenic patients should be considered.[19] The duration of intravenous antifungal therapy depends on the clinical course and is usually ≥2 weeks. Infectious disease consultation is especially important to advise on management of these patients.
Hemodynamically unstable patients:
An antibiotic regimen that is particularly broad in its coverage is promptly initiated when the patient is acutely ill with signs of shock or is receiving care in the intensive care unit (ICU). In addition, general management of sepsis and septic shock, including resuscitative measures, intravenous fluid replacement, and supportive care, is commenced.[42]
Typical regimens include:
Imipenem/cilastatin
Meropenem
Ertapenem
Piperacillin/tazobactam
Cefepime plus metronidazole
Levofloxacin plus metronidazole
Ciprofloxacin plus metronidazole
Moxifloxacin plus metronidazole.
A fluoroquinolone should not be used as initial empiric therapy if the rates of fluoroquinolone-resistant Escherichia coli exceed 10% in the hospital or local community. Adverse effects of fluoroquinolones may include tendonitis, tendon rupture, arthralgia, neuropathies, and other musculoskeletal or nervous system effects.[43]
Gentamicin and other aminoglycosides are not routinely used as first-line therapy, because less toxic agents are now available.
Carbapenem antibiotic therapy (e.g., imipenem/cilastatin, meropenem, ertapenem) should be considered in all patients with risk factors for infection with extended-spectrum beta-lactamase (ESBL)-producing organisms. ESBL-producing organisms have broad antibiotic resistance. This is a particularly important consideration in people who are hemodynamically unstable. Risk factors for infection with ESBL-producing organisms include:[44][45]
Increased length of stay in the hospital or ICU
Presence of central venous catheter, arterial catheter, or urinary catheter
Increased severity of illness
Hemodialysis
Ventilatory assistance
Emergency abdominal surgery
Prior administration of any antibiotic
Gut colonization
Use of a gastrostomy or jejunostomy tube.
Vancomycin may be included in the regimen when the patient is severely ill, when the Gram stain reveals gram-positive cocci, or when a resistant enterococcal or staphylococcal infection is suspected.
Hemodynamically stable patients:
If possible, blood cultures are obtained before initiating antibiotics. Typical regimens are included as follows.
Ceftriaxone or cefotaxime plus metronidazole
Levofloxacin, ciprofloxacin, or moxifloxacin (plus metronidazole).
A fluoroquinolone should not be used as initial empiric therapy if the rates of fluoroquinolone-resistant E coli exceed 10% in the hospital or local community. Adverse effects of fluoroquinolones may include tendonitis, tendon rupture, arthralgia, neuropathies, and other musculoskeletal or nervous system effects.[43]
An alternative antibiotic regimen may be used in certain cases. Vancomycin may be included in the regimen when the patient is not improving with first-line antibiotic regimens. It may also be used when the Gram stain reveals gram-positive cocci, or when a resistant enterococcal or staphylococcal infection is suspected. Other alternative antibiotics may be used when drug-resistant or gram-negative pathogens are suspected. Antibiotics that cover gram-negative organisms include piperacillin/tazobactam, imipenem/cilastatin, meropenem, ertapenem, and cefepime. If a patient has risk factors for infection with ESBL-producing organisms (as described for hemodynamically unstable patients), treatment with a carbapenem antibiotic (e.g., imipenem/cilastatin, meropenem, ertapenem) while awaiting culture results should be considered. If amebic abscess is being considered (not as the most likely diagnosis but as a consideration along with other infective causes of liver abscess), then metronidazole should be included as part of the antibiotic regimen.
Presumed pyogenic liver abscess: drainage therapy (general considerations)
For most abscesses, drainage is an important step in treatment, along with antibiotic therapy. Urgent drainage is warranted if patients are hemodynamically unstable with shock or with multiorgan dysfunction.
For hemodynamically stable patients, drainage is usually less urgent, and various types of drainage techniques may be considered. For liver abscesses <3 cm in diameter, antibiotics alone may be sufficient to treat the abscess.[40] The abscess can be drained by:
Needle aspiration (most commonly under radiographic guidance)
Placement of an indwelling catheter (most commonly under radiographic guidance)
Open or laparoscopic surgical drainage
Surgical resection of the abscess
Endoscopic drainage (in cases of a biliary origin of infection).
The choice as to which type of drainage procedure is performed depends on several factors, including the size, location, and complexity of the abscess.
Drainage techniques
Percutaneous drainage
Percutaneous drainage and antibiotics are often successful in treating moderate-sized collections, even in immunocompromised patients.[40][46][47][48] Systematic reviews comparing percutaneous needle aspiration and percutaneous catheter drainage found higher success rates with catheter drainage, but the included studies were heterogenous, limiting the strength of the conclusions.[51][52][53] For multiple abscesses, only the largest typically requires drainage.
Surgical drainage
Surgical drainage or resection (in combination with antibiotic therapy) may be associated with improved clinical outcomes compared with percutaneous drainage for large multiloculated abscesses >5 cm in diameter.[40][54][55] Surgery may be necessary in patients:[40][54][55][56]
With abscess rupture and peritonitis
With large multiloculated abscesses >5 cm
Who do not respond to antibiotics or percutaneous drainage
With concomitant biliary pathology.
Surgical drainage can be performed as an open or laparoscopic procedure. Liver abscess can also be resected surgically. Patients with severe illness and an Acute Physiology and Chronic Health Evaluation (APACHE) II Score (scoring that classifies severity of illness in ICU patients) ≥15 may benefit from surgical resection rather than percutaneous drainage.[57]
Endoscopic drainage
Endoscopic retrograde cholangiopancreatography (ERCP) and sphincterotomy and/or drainage procedure alone may be sufficient therapy for liver abscesses that communicate with the biliary tree.[58] If no communication can be found, patients with a liver abscess and biliary disease may be treated with a combination of endoscopic drainage and percutaneous drainage.
Endoscopic ultrasound-guided liver abscess drainage with stent placement has also been described for patients in whom percutaneous drainage was not recommended. This series is from a single center with one operator.[59]
Amebic abscess
Patients with amebic liver abscess (either confirmed diagnosis or presumed highly likely as the cause) are treated with either metronidazole or tinidazole (nitroimidazoles).[2][60][61] Drainage (e.g., percutaneous aspiration) of the liver abscess is not usually required but is necessary if:[2][11][60][61][62]
The patient does not respond to antibiotic therapy
The abscess is >5 cm in diameter
The abscess is in the left lobe of the liver
The diagnosis remains in doubt.
Duration of therapy
Pyogenic abscess
The duration of antibiotics, with or without antifungal therapy, depends on the patient's clinical course and the adequacy of drainage. Parenteral therapy is given initially. If the patient is improving and fever and leukocytosis have resolved, the patient can be switched to an oral anti-infective regimen.[41] Anti-infective agents can be stopped only if clinical symptoms and signs, including fever and leukocytosis, have resolved and the abscess has been adequately drained.[8] Oral fluoroquinolones have been effective in treating hepatic abscess when compared to intravenous antibiotics.[63][64] Follow-up imaging may help determine when anti-infective agents can be discontinued. The optimal duration of antibiotics for pyogenic liver abscess is not clear. Treatment duration typically ranges from 2 to 6 weeks with longer courses used in patients with hypervirulent Klebsiella pneumoniae, immunocompromise, inadequate source control.[1] Normalization of C-reactive protein values may also help determine when antibiotics can be stopped.[27]
Future studies are needed to determine the optimal duration of antibiotics.
Amebic abscess
Patients with amebic abscess should be treated with a luminal agent (paromomycin) following treatment with metronidazole or tinidazole.[2] Luminal agents eradicate gut colonization and prevent relapse of amebiasis infection.[65]
Abscess recurrence
There are no set guidelines or recommendations for treatment of a recurrent abscess that differ from the first occurrence. Patients with underlying biliary disease have the highest rate of recurrence (around 25%).[66] Potential etiologies include biliary obstruction and a fistula between the biliary tree and the intestine. If a liver abscess recurs, the authors would recommend that expert consultation by a gastroenterologist and investigation for biliary abnormalities by ERCP or magnetic resonance cholangiopancreatography should be considered.
How to insert a peripheral intravascular catheter into the dorsum of the hand.
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