LIVER ABSCESS

Liver - most subject to abscess formation Solitary or multiple Arise from

◦ hematogenous spread of bacteria ◦ local spread from contiguous sites of infection

within the peritoneal cavity Most common source- associated disease

of the biliary tract

Liver Abscess

Harrison’s Principles of Internal Medicine, 17th ed

Primary Infection from other sites (Biliary tree, Peritoneal Cavity, Pelvis)

Transmission via Portal vein, arterial supply, biliary tract, direct invasion

Secondary Infection of Liver and Abscess Formation

Pathogenesis

The right hepatic lobe is affected more often than the left hepatic lobe by a factor of 2:1.

Bilateral involvement is seen in 5% of cases.

The predilection for the right hepatic lobe can be attributed to anatomic considerations.

Liver Abscess

Pyogenic Parasitic

Amebiasis

Hydatid disease

Fungal

Liver is probably exposed to portal venous bacterial loads on a regular basis

Inoculum of bacteria exceeds the liver's ability to clear it Abscess

Potential routes of hepatic exposure to bacteria:    ◦ Biliary tree ◦ Portal vein ◦ Hepatic artery ◦ Direct extension of a

nearby focus of infection ◦ Trauma

Pyogenic Liver Abscess

Sabiston Textbook of Surgery, 18th ed.

Etiology: Ascending cholangitis

◦ Enteric Gram Negative aerobic Bacilli and Enterococci

Infection from the pelvis and other intraperitoneal sources◦ Mixed infection with aerobic and anaerobic

species is common◦ Bacteroides fragilis- species most frequently

isolated Hematogenous spread- S. aureus, S. milleri

Harrison’s Principles of Internal Medicine, 17th ed

• Extraintestinal infection by E. histolytica• Trophozoites invade veins to reach the liver

through the portal venous system • Travelers of endemic areas - more

susceptible • Young patients- present w/ acute phase with

symptoms of <10 days duration• Older patients - subacute course of 6

months with weight loss and hepatomegaly

Amebic Liver Abscess

Harrison’s Principles of Internal Medicine, 17th ed

CLINICAL FEATURES AMEBIC ABSCESS PYOGENIC ABSCESS

Age (yr) 20-40 >50

Male-to-female ratio ≥10:1 1.5:1

Solitary vs. multiple Solitary 80%[*] Solitary 50%

Location Usually right liver Usually right liver

Travel in endemic area Yes No

Diabetes Uncommon (∼2%) More common (∼27%)

Alcohol use Common Common

Jaundice Uncommon Common

Elevated bilirubin Uncommon Common

Elevated alkaline phosphatase

Common Common

Positive blood culture No Common

Positive amebic serology

Yes No

Table 52-5   -- Features of Amebic Versus Pyogenic Liver Abscess

Sabiston Textbook of Surgery, 18th ed.

caused by the larval/cyst stage of Echinococcus granulosus, in which humans are an intermediate host

In the human duodenum, the parasitic embryo releases an oncosphere containing hooklets that penetrate the mucosa, allowing access to the bloodstream

In the blood, the oncosphere reaches the liver (most commonly) or lungs, where the parasite develops its larval stage known as the hydatid cyst

Hydatid Disease

Sabiston Textbook of Surgery, 18th ed.

Candida spp. Follow fungemia in patients receiving

chemotherapy from cancer Often present when PMNs return after a

period of neutropenia

Fungal Liver Abscess

Harrison’s Principles of Internal Medicine, 17th ed

• Fever - most common presenting sign • Pain, guarding, punch and rebound

tenderness localized to the right upper quadrant *

• Hepatomegaly *• Jaundice *Non-specific symptoms: • Chills• Anorexia • Vomiting

CLINICAL FEATURES

Harrison’s Principles of Internal Medicine, 17th ed

Patient Liver Abscess

Vague RUQ pain – 3 months RUQ pain

Low-grade fever Fever – most common presenting sign

Weight loss Weight loss in older patients with a chronic subacute course

Past Medical History•PTB•Acute Viral Hepatitis

Biliary tract diseaseRuptured appendicitisPylephlebitis

Personal, Family History• Smoker• Half a bottle of gin everyday since age 30

• Mother died of HCC

Travel to an endemic area

PE findings•Pale palpebral conjunctivae•Icteric sclerae•Spider angiomas, palmar erythema•Slightly distended abdomen•Liver palpable with a span of 14cm, tender, nodular

JaundiceTenderness over the liverHepatomegaly

DIAGNOSIS

DIAGNOSIS Laboratory work-up Amebic serologic testing (positive in 95% of

cases) ELISA test for Echinoccocal antigens ( positive for

85% of infected patients) Imaging studies

◦ Ultrasound◦ CT scan

LABORATORY FINDINGS

Elevated serum concentration of Alkaline Phosphatase

• Single most reliable laboratory finding• Documented in 70% of patients with liver abscesses

Other tests of liver function may yield normal results

• 50% of patients have elevated serum levels of bilirubin• 48% have elevated concentrations of aspartate aminotransferase

Other laboratory findings

• Leukocytosis in 77% of patients• Anemia (usually normochromic, normocytic) in 50%• Hypoalbuminemia in 33%

Concomitant bacteremia is found in one-third of patients

UltrasoundSensitivity 80-90%

Hypoechoic masses with irregularly shaped borders.

Internal septations or cavity debris may be detected.

Allows for close evaluation of the biliary tree and simultaneous aspiration of the cavity.

The major benefits of this technique are its portability and diagnostic utility in patients who are too critical to undergo prolonged radiologic evaluation or to be moved out of monitored setting.

Operator dependence affects its overall sensitivity.

Computed Tomographic Scan(Sensitivity 95%-100%) Well-demarcated areas hypodense to the

surrounding hepatic parenchyma. Peripheral enhancement is seen when IV

contrast is administered. Gas can be seen in as many as 20% of lesions. CT scan is superior in its ability to detect lesions

less than 1 cm. This technique also enables the evaluation for an

underlying concurrent pathology throughout the abdomen and pelvis. Indium-labeled WBC scans are somewhat more sensitive in this regard.

CT examination: Unenhanced axial scan: Round-shaped, hypodense masses

of 5-6 cm of diameter, with isodense wall, are visible in both liver lobes (arrows). A small amount of hypodense fluid is

observed within the liver capsule

CT examination: Postcontrast axial scan

The irregular hypodens lesions of variable sizes (arrows) are better

visualized in the contrast-enhancing liver parenchyma.

Chest X-ray

Basilar atelectasis Right hemidiaphragm elevation Right pleural effusion are present in

approximately 50% of cases Before advancements in radiologic

technique, these served as diagnostic clues.

MANAGEMENT

Drainage, either percutaneous or surgical, is the mainstay of therapy for intraabdominal abscess◦ Percutaneous needle aspiration◦ Percutaneous catheter drainage◦ Surgical drainage (open or laparoscopic)◦ Medical therapy

Percutaneous needle aspiration

Solitary dominant abscess Under CT scan or ultrasound guidance, needle

aspiration of cavity material can be performed. Needle aspiration enables rapid recovery of

material for microbiologic and pathologic evaluation.◦ Gram’s stain and culture

Needle aspiration can be performed with the initial diagnostic procedure.

Percutaneous catheter drainage

• Complex abscess or an abscess containing particularly thick fluid

• Small cysts A catheter is placed under ultrasound or CT guidance using

the Seldinger technique The catheter is flushed daily until output is less than 10

cc/d or cavity collapse is documented by serial CT scanning.

Multiple abscesses have been drained successfully by this method.

Failure to respond to catheter drainage is the main reported complication and is also an indication for surgical intervention.

Surgical drainage• Was the standard of care until the introduction of

percutaneous drainage techniques in the mid 1970s• For cysts greater than 5 cm • Ruptured cysts• Multiloculated cysts• Failure of percutaneous drianage

Lack of response in 4-7 days

Medical Therapy Diagnostic aspirate of abscess should be

obtained before initiation of empirical therapy◦ Empiric drug therapy – covering gram negative

aerobic, facultative and anaerobic organisms◦ Adjusted to specific antibiotic when results for

Gram’s stain and culture become available

Parasitic Liver Abscess Hydatid disease

◦ Oral antihelmintics, albendazole, is the mainstay of treatment

◦ For those with anatomically appropriate lesions PAIR: percutaneous aspiration, instillation of absolute alcohol, respiration

◦ If refractory to PAIR: open/laparoscopic cyst removal with instillation of scolicidal agent

Parasitic Liver Abscess Amebiasis

◦ Metronidazole for at least 1 week◦ Most patients will respond rapidly with complete

defervescence within 3 days. ◦ Aspiration of the abscess is rarely necessary and

should be avoided, except in patients in whom secondary infection from pyogenic organisms is suspected.

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