Diagnosis of Streptococcus pneumoniae-associated Hemolytic Uremic Syndrome

Background: Hemolytic uremic syndrome related to pneumococcal infection (P+HUS) can be difficult to diagnose due to the lack of a specific test and the absence of a consensus for definite diagnostic criteria. Methods: A retrospective study was conducted on the cases that have been considered as P+HUS in the participating centers during the past 10 years. Diagnostic strategy and criteria used for the diagnosis of P+HUS were evaluated and compared with a review of literature data. Results: A total of 17 children were studied. Tests ruling out other causes of HUS were performed in 94% of cases. Direct confirmatory tests for P+HUS were done in a minority of cases as Thomsen-Friedenreich antigen testing using lectin assay were done in only 2 patients (11%). Retrospectively, the diagnosis of P+HUS was confirmed in 28% to 89% of cases depending on the already published criteria used. A literature review focused on the last 15 years confirmed these diagnostic difficulties due to variable definition criteria and bring a new light on the potential usefulness of tests used to reveal T activation in this setting. Conclusion: To date, in a context of suspicion of P+HUS, no precise, practical and consensual strategy exists for T-antigen exposure diagnosis. The T-antigen activation test using peanut lectin might be the most appropriate test for a direct diagnosis of P+HUS. A large prospective study is required to confirm this hypothesis. However, before such data are available, its use could be of help when a suspicion of P+HUS is present given the therapeutic impact of such a diagnosis.