Crawling Into View

A 37-year-old woman presented with a 3-month history of intermittent fever, chills, myalgias, and epigastric pain. Her travel history was significant for visits to Brazil, Uruguay, and Argentina 8 years prior to presentation and to Indonesia and Hong Kong 5 months prior to presentation. During her travels, she only drank bottled water, but ate fruits and vegetables. Over the 3-month illness, she received empiric courses of amoxicillin and clarithromycin, resulting in transient improvement of her symptoms. On examination, her temperature was 39.4°C; her blood pressure was 153/90 mmHg; and her heart rate was 136/minute (regular). Cardiac, respiratory, and abdominal examinations were normal. She had no rashes and no lymph node enlargement. Laboratory investigations revealed a white blood cell count of 10.2 × 109/L (normal, 2.00–7.50 × 109/L), and an elevated peripheral eosinophil count of 3.32 × 109/L (normal, 0.04–0.4 × 109/L). Aspartate and alanine aminotransferases, alkaline phosphatase, and bilirubin were normal, and 3 blood cultures were negative. Stool cultures and examination for ova and parasites on 4 occasions over a 2-month period were also negative. Chest radiography and a 2D echocardiogram were normal. An abdominal ultrasound, followed by a computed tomography scan, demonstrated heterogeneous cystic regions in the left lobe of the liver following the portal triads, suggestive of liver abscesses, with associated segmental biliary dilatation (Figure 1). Prior to antibiotic administration, a tube was inserted into 1 of the lesions to sample for infectious etiologies and for drainage. Bacterial and mycobacterial cultures were negative. Microscopic examination of the aspirate for ova and parasites was also negative. She was initiated on empiric amoxillin-clavulanate at 875 mg/125 mg orally twice daily for treatment of presumed liver abscesses. Sequential, coronal, contrast-enhanced computed tomogram of the abdomen, demonstrating tract-like appearance of microabscesses, arranged in a serpiginous pattern within the left lobe of the liver. Sequential, coronal, contrast-enhanced computed tomogram of the abdomen, demonstrating tract-like appearance of microabscesses, arranged in a serpiginous pattern within the left lobe of the liver. What is your diagnosis? Crawling Into View Diagnosis: Fascioliasis and presumed secondary pyogenic liver abscesses. A follow-up abdominal ultrasound 1 month later, on antibiotic therapy with the drain in situ, captured a video of a mobile structure within a bile duct (Figure 2 and Supplementary Video 1). The patient’s initial clinical and radiologic presentation was compatible with a pyogenic liver abscess. This diagnosis, however, could not account for the peripheral eosinophilia. Given her travel history, a parasitic infection was considered, and based on the biliary abnormalities on imaging, a diagnosis of fascioliasis was deemed most likely. This was confirmed by positive serology for Fasciola hepatica by an enzyme-linked immunosorbent assay (ELISA) and was supported by finding a mobile parasite within a bile duct. Her subacute presentation suggests infection likely occurred during her travels to either Indonesia or Hong Kong 5 months earlier. She did not report eating watercress. She was treated with triclabendazole 10 mg/kg orally on 2 consecutive days and a 15-week course of amoxicillin-clavulanate for presumed secondary pyogenic liver abscesses. Her symptoms, as well as peripheral eosinophilia, entirely resolved by 4 months following therapy. Trans-abdominal ultrasound images of the left lobe of the liver, demonstrating echogenic material within the bile duct with a worm-like morphology measuring approximately 2.3 cm in length and 0.3 cm in width. The white arrowheads denote the contours of a live Fasciola parasite. Trans-abdominal ultrasound images of the left lobe of the liver, demonstrating echogenic material within the bile duct with a worm-like morphology measuring approximately 2.3 cm in length and 0.3 cm in width. The white arrowheads denote the contours of a live Fasciola parasite. Fascioliasis is caused by the liver flukes, Fasciola hepatica and Fasciola gigantica. Fasciola hepatica is found worldwide, whereas Fasciola gigantica is found only in tropical areas, commonly in Asia and Africa [1]. Live flukes produce eggs that are passed from the biliary ducts into the stool of infected mammals (cattle, sheep). Eggs land in fresh water, where they hatch as miracidia, infecting snails as the intermediate host. Within the snail, they undergo several developmental stages into cercariae, which are released back into water. Landing on vegetation, they encyst to become metacercariae, which can remain viable for months and tolerate prolonged periods of transport [2, 3]. Humans acquire infection by consuming vegetation, commonly watercress, contaminated by metacercariae. Within the duodenum, the metacercariae excyst and migrate through the intestinal wall, across the peritoneal cavity, and into the liver parenchyma, finally reaching the biliary ducts, where they mature into adults. This process can take 3–4 months. From within the bile ducts, they release up to 20 000–24 000 eggs per day that are passed in their stool [4]. The acute phase of fascioliasis is caused by parasite migration and can persist for 1–3 months. Symptoms may include fever, right upper quadrant pain, anorexia, nausea, vomiting, cough, or urticaria [5]. The chronic biliary phase typically occurs 6 months after infection and can persist for 10 years [1]. Adult flukes cause thickening and dilatation of the bile ducts, which can lead to biliary obstruction. Symptoms may include fever, right upper quadrant pain, nausea, vomiting, jaundice, and weight loss. Patients may present with cholangitis and liver abscess, although this is rare [5, 6]. Laboratory findings of the acute phase typically include marked peripheral eosinophilia [7]. In the chronic phase, peripheral eosinophilia can be variable, and liver enzymes can be elevated, particularly if there is associated cholangitis [2]. Stool studies for ova and parasites are typically negative during the acute phase, but can become positive during the biliary phase [8]. Computed tomographic and ultrasonographic findings of the acute phase commonly include multiple subcapsular hepatic abscesses, clustered around the migratory tract of the liver fluke, giving a serpentine-like appearance [9–11]. In the biliary phase, these lesions regress and biliary duct thickening and dilation may be seen. Occasionally, as in this patient, mobile flukes can be demonstrated within the bile ducts or the gallbladder [9, 11, 12]. The mixed imaging findings in this patient suggested more recent infection. Serology can be used to diagnose fascioliasis. The ELISA performed on this patient was developed and validated by the Canadian National Reference Centre for Parasitology at McGill University in Montreal, Canada (95% sensitivity and 95% specificity for Fasciola species) [13]. Additionally, eggs can be detected in stool specimens during the chronic biliary phase, when adult parasites are within the bile ducts. However, this has low sensitivity, as egg release can be sporadic and is dependent on the parasite burden [8]. In the late phase, adult flukes may be visualized by endoscopic retrograde cholangiopancreatography (ERCP) and on ultrasound [12, 14]. The treatment of choice is triclabendazole, with a cure rate of >90% [15–17]. Resistance of Fasciola hepatica to triclabendazole has been reported in Europe, South America, and Australia [16, 18]. Alternative therapeutic regimens include bithionol and nitazoxanide [19, 20]. The primary complication from therapy is biliary obstruction by dead parasites, which may require removal by ERCP [6, 21]. Supplementary materials are available at Clinical Infectious Diseases online. Consisting of data provided by the authors to benefit the reader, the posted materials are not copyedited and are the sole responsibility of the authors, so questions or comments should be addressed to the corresponding author. Acknowledgments. The authors thank the patient discussed in this manuscript for her written informed consent. Potential conflicts of interest. All authors: No reported conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.

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