Table 1.

Distinguishing clinical findings, imaging features and treatment strategy of the three forms of amebic liver abscesses

	Acute aggressive	Subacute mild	Chronic indolent
Presentation	Acute (< 10 d)	Subacute (< 2-4 wk)	Chronic (> 4 wk)
Symptoms	Severe symptoms (RUQ pain, fever, toxicity, abdominal distention, leg edema, shock-like syndrome resembling sepsis, jaundice, signs of intraperitoneal or intrathoracic rupture)	Moderate symptoms(usually intermittent fever and RUQ tenderness)	Mild (usually RUQ tenderness, fever if secondary infection)
Laboratory tests	Marked leukocytosis (> 20000/μL), abnormal LFT, features of organ failure (hyperbilirubinemia, renal dysfunction)	Transient leukocytosis and transient elevation of LFT (returns to normal after treatment)	Usually normal
Imaging features	Incomplete or absent wall, ragged edge, interrupted or no enhancement, septations, heterogeneous content, widespread or wedge-shaped perilesional hypodensity	Relatively smooth outline, rim-enhancing wall with perilesional hypodense “halo” (double-target sign)	Smooth outline, thick non-enhancing wall, faint or no perilesional “halo”
Size and number	> 5-10 cm, multiple in over 50% of cases	< 5-10 cm, usually single	> 5-10 cm, usually single
Treatment	Antibiotics; Early drainage is often required to control severity	Antibiotic alone suffices in most cases; rapid recovery, drainage when symptoms persist	Mostly pre-treated with antibiotics, drainage not required unless pressure symptoms or secondary infection present

RUQ: Right upper quadrant; LFT: Liver function test.