Plasma next-generation sequencing for diagnosis of amebic liver abscess in a non-endemic area

Amebic liver abscess (ALA) is a common condition in the developing world but is rare in the United States without a clear exposure risk. It is even less common to develop in an infant. The diagnosis of ALA can be logistically difficult and often requires invasive procedures and testing with slow turnaround times. We present an 18-month-old boy initially admitted with fever, abdominal pain, and diarrhea with rapid progression to respiratory failure. He was found to have a significant pleural effusion accompanying a large solitary liver lesion with abdominal ascites. There was no infectious exposure history or travel history, and thus pyogenic liver abscess was suspected, and aspiration performed while he was on empiric antimicrobials. The bacterial culture was negative. Molecular testing with 16 s and 18 s rRNA PCR on the fluid were non-diagnostic. The diagnosis of Entamoeba histolytica was confirmed within 48 hrs via plasma next-generation sequencing. Serum IgG for E histolytica resulted positive multiple weeks after the patient was discharged. The patient made a full recovery after metronidazole and paromomycin. This case illustrates the need to maintain ALA in the differential diagnosis for liver abscess in an infant even in the absence of risk factors. Additionally, plasma next-generation sequencing may play a role in more rapid diagnosis of ALA and has the potential to reduce the need for more invasive testing.