Visceral larva migrans due to Toxocara canis in a 9-year-old boy mimicking hepatic hemangiomas.

Abstract

Toxocariasis is a worldwide human helminthiasis, attributed mainly to Toxocara canis causing visceral larva migrans, a syndrome that is clinically present with fever, hepatomegaly, pulmonary infiltration and eosinophilia.1 Direct contact with dogs is not required for T. canis infection since ingestion of soil containing infective parasite eggs is the main form of transmission. Eggs may persist for a long time in hot, humid environments, in that way children are more commonly affected by direct contact with contaminated play areas or sandpits. Hepatic toxocariasis in childhood has non-specific signs on computed tomography (CT) imaging (usually multiple low-density liver nodules), therefore it can be easily misdiagnosed as other clinical conditions.1 The differential diagnosis includes microabscesses, hemangiomas, granulomatous diseases, hepatocellular carcinoma or liver metastases. Few previously published cases showed that larva migrans could be misdiagnosed as liver tumour or lymphoma. 2-4 For the diagnosis of T. canis the current optimal choice remains the use of TES-ELISA by assessing specific IgG antibodies, followed by western blotting.5 Based on recent literature, specific immunoglobulin M (IgM) antibodies are not necessarily useful in diagnosing active and recent infection, since IgM antibodies can be found throughout the course of helminthiasis.6 Due to non-specific or vague symptoms, the final establishment of toxocariasis may be difficult and therefore clinical awareness, especially with the presence of otherwise unexplained symptoms along with blood eosinophilia, is crucial. Herewith, we present a rare case of a 9-year-old boy with multiple hepatic lesions and an initial misdiagnosis of hemangiomas based on the CT scan. After magnetic resonance imaging and positive IgM antibodies titers against T. canis the final diagnosis of hepatic toxocariasis was made. The boy was admitted with a 4-month history of abdominal pain and a 2-week history of fever. The pain was constant, accompanied by nausea, fatigue and night sweats. Unintentionally weight lost (1.5 kg) in the previous 3 months was reported. Travel history as well as exposure to animals was negative. Physical examination revealed normal heart, neurological and lung examination. A slight tenderness to palpation in the right upper quadrant of the abdomen and hepatosplenomegaly up to 3 cm below the costal margin was noticed. No lymphadenopathy was noted. Laboratory tests showed elevated white cell blood count (14.3 × 103 cells/μL), with mild peripheral eosinophilia (550/μL) (normal count <350 cells/μL). Serum electrolyte concentrations and liver specific test results were normal. Blood, stool and urine cultures, Widal and Wright tests, as serological tests for Typhoid disease and Brucellosis respectively, as well as antinuclear antibodies were negative. There was no serological evidence for a recent viral infection from hepatitis A, B and C human immunodeficiency virus, Ebstein-Barr virus, cytomegalovirus, Toxoplasma gondii, Bartonella henselae, Echinococcus and syphilis. Immunoglobulins, human chorionic gonadotropin and alpha-fetoprotein levels were in normal ranges. Initial imaging showed a normal chest X-ray, while liver ultrasound detected multiple hypoechoic nodules. A subsequent CT scan revealed diffuse patchy liver infiltrates suggestive of hemangiomas (Fig. 1). Further evaluation with magnetic resonance imaging showed multiple possible abscesses. A liver biopsy was not performed due to the risk of bleeding based on the initial misdiagnosis of possible hemangiomas. The child was initially treated with voriconazole, ceftriaxone and azithromycin. The final diagnosis was based on positive antibody for T. canis, therefore albendazole treatment was initiated. During a 3-month follow-up, the patient's symptoms had resolved and ultrasonography showed steadily decreasing in size and number of hepatic lesions. Up to date, 1 year from diagnosis, the boy is free of symptoms (Fig. 1).