in development of the disease but in the United States , a study revealed that almost one-third of U . S . patients diagnosed of amebic liver abscess have not visited endemic areas . 5 Amebic liver abscess in this population is more prevalent in immigrants from endemic region , immunosuppressed individuals including people with HIV , people who are malnourished with severe hypoalbuminemia , or the ones with a history of alcohol abuse . 5
Figure 1 . T1 image . MRI showing large hypodense abscess prior to drainage .
able . Serum alpha-fetoprotein ( AFP ) was normal . Indirect hemagglutinination ( IHA ) serology was positive for immunoglobulin antibody G ( IgG ) to entemoeba histolytica with a titer of 6.66 IU . Stool microscopy , antigen detection , and molecular testing were not done . Magnetic Resonance Imaging ( Fig . 1 ) done to characterize the CT findings showed a 15.4 x 12.9 x 16.3 cm mass with no septations consistent with CT findings . He subsequently had CT-guided drainage and removal of 1.7 Liters of pus from the liver . He was started on IV metronidazole and levofloxacin empirically and levofloxacin was discontinued on day two once serology was suggestive of Entamoeba histolytica . Gram stain of abscess fluid revealed moderate polymorphnuclear cells and culture yielded no growth . AFB smear was negative for acid-fast bacilli by fluorescent microscopy and culture was negative for mycobacteria after six weeks of incubation . Fungal culture was negative and pathology report was also negative for any malignancy . Infectious Disease team was involved in managing patient and they suggested 10-day course of
Physicians should be aware that amebic liver disease could be seen in patients who have not traveled outside of United States to endemic regions . oral metronidazole 750mg three times daily ( TID ) and subsequently paramomycin 750mg TID for seven days , which was completed by patient . He showed remarkable improvement on oral metronidazole while in the hospital . He was discharged with the aforementioned antibiotics . A pigtail drain was left on discharge and he was to follow up with his primary care physician ( PCP ) in two weeks . The CT scan at discharge revealed significant decrease of abscess cavity to 12.5 x 9.2 x 11.8 cm . He had two follow-up appointments within two months of discharge with his PCP , by which time his symptoms had resolved and the patient had gained a remarkable 23 pounds .
DISCUSSION
Amebic liver abscess is caused by ingestion of infected Entamoeba histolytica cysts through fecal-oral route . Humans ingest infected food or water ; cysts degrade in the small intestine releasing trophozoites that invade the mucosa causing disease . Clinical features include fever , chills , right-sided abdominal pain and tenderness , nausea , vomiting , right-sided pleuritic chest pain , weight loss , and anorexia . ALA is ten times more common in males than females , possibly due to hormonal factors and sex differences in the background of liver disease . 4 High occurrence in men is also believed to be associated with increased alcohol intoxication leading to impaired kupffer cell function resulting in immunosuppression . 5 Travel to endemic regions plays a major part
The most common complication is hepatic rupture . Other possible complications are peritonitis , paralytic ileus , and toxic megacolon . 6 The right lobe of the liver is more affected than the left due to blood supply from superior mesenteric vein . Mild to moderate leukocytosis , elevation of liver enzymes can be seen . Since 70 % of patients with amebic liver abscess do not have detectable parasites in the stool , serological or antigenic testing should be used for confirmatory purposes . Serology may be negative in the first week of infection but usually is positive at presentation in most cases . 7 This does not differentiate between current and past infections and thus remains unreliable in endemic areas . Enzyme immunoassay becomes a valuable test in diagnosing amebic infection in non-endemic areas . Other diagnostic options are liver exudate antigen assay or polymerase chain reaction ( PCR ) on material from liver abscess . Ultrasound , CT , MRI , nuclear hepatic scan are various imaging options for evaluating suspected patients , but only the nuclear hepatic scan can differentiate amebic liver abscess from pyogenic abscess . 8
Treatment of choice is metronidazole 750mg three times daily for 10 days , followed by luminal agents like paramomycin , iodoquinol , or diloxanide fumigate . Patients usually respond to medical therapy . Therapeutic aspiration is considered when abscess is greater than 5 cm in size , if abscess is located in the left lobe of liver or in cases that fail to respond to medical management in 5-7 days . 9 Imaging-guided percutaneous needle drainage combined with antibiotics is considered standard modality of treatment and surgery remains an option only after failure of such initial treatment . Early recognition and treatment is associated with better outcomes . Poor prognostic factors include albumin less than 2.0mg / dl , bilirubin level greater than 3.5mg / dl , and patients with encephalopathy . 10 Radiologic disappearance of abscess can take between 3-19 months ; hence repeat imaging is unnecessary if clinical improvement is discernible . 11
256 • THE JOURNAL OF THE ARKANSAS MEDICAL SOCIETY VOLUME 114