Echinococcus multilocularis infection in solid organ transplant recipients

Résumé 0

Alveolar echinococcosis (AE) is a zoonosis caused by the ingestion of eggs of the tapeworm Echinococcus multilocularis, causing a severe infection most often localized in the liver. Its behavior is similar to that of a malignant tumor as it invades surrounding tissues and can metastasize to distant organs. If left untreated, the mortality of AE can be as high as 90% after 10 years. In the immunosuppressed host, a higher incidence of AE has been reported. Additionally, AE seems to have a faster evolution, with more severe manifestations. However, there are very few data on the epidemiology and clinical manifestations of AE specifically in solid-organ transplant (SOT) recipients. In this multicentric case series, we retrospectively collected de novo cases of AE in SOT recipients by searching the STCS database in Switzerland and the FrancEchino registry in France for cases from 01/2008 to 08/2018. We collected data about the clinical presentation, diagnosis, treatment and outcome at each center using a standardized collection form. A total of 7 patients were identified (kidney=5, heart=1, lung=1), 5 in France and 2 in Switzerland. Six patients presented with liver AE and one with lung AE. AE was asymptomatic at diagnosis in 4 patients and presented with abdominal pain in 2 of them. One had undocumented symptoms. The median time between transplantation and diagnosis was 66 months (ranging from 12 to 240). Two patients had no liver lesions 26 and 43 months prior to diagnosis, respectively. Diagnosis was done by serology in all cases (Western-blot was positive in all 7 cases, Em2+ was positive in 1/3, hydatic fluid antigen ELISA in 4/4 and indirect hemagglutination in 3/3). Imaging was atypical in 2 cases, with a pseudo-tumoral appearance in one case. Biopsies confirmed AE in 3 cases but led to an erroneous diagnosis in one case. Four of the 7 patients were operated (all incomplete resections) and 2 died following the operation. Albendazole was started in all surviving patients and was well tolerated by all patients (tolerance undocumented in one case). AE remained stable in 3 of the 5 cases and progressed in 1 case. The evolution is undocumented in one case. One patient died of cause unrelated to AE. The incidence of AE seems to be higher and its evolution faster in SOT recipients than in the general population. Our data also suggest that diagnosis of AE in this population is more challenging, with atypical imaging and sometimes misleading biopsies. In this series, post-operative mortality was high, perhaps suggesting that a more conservative approach is needed in this immunocompromised population.