A modified definition of Lemierre syndrome to unify existing variation: An observation study and brief review of the...

Wide variability of how clinicians diagnose Lemierre Syndrome (LS) exists within the literature leading to "Lemierre-like" conditions. Some clinicians use Fusobacterium bacteremia as key defining feature, while some use internal jugular septic thrombophlebitis. The source of infection varies as well between oropharyngeal and skin and soft tissue infection.

This literature-based observational analysis utilized existing case reports to find common clinical patterns in diagnosis to construct a clinical decision tree framework. 149 LS cases from PubMed and Google Scholar over a 13-year period between January 2012 and December 2024 were obtained. A novel clinical framework was constructed based on a testing cohort of 111 cases and applied to a separate cohort of 38 cases.

LS has been rising in recent years, with 88 cases within the past five years. Among all included cases, the most common findings included bacteremia (123/149;82.6%), internal jugular venous septic thrombophlebitis (123/149;82.6%), pulmonary septic emboli/cavitary lesion (99/149;66.4%). Fusobacteria species comprised 39.6% (59/149) of positive blood cultures. 74.5% of 149 cases were oropharyngeal infections while 25.5% were skin and soft tissue infections. Based on these patterns, we organized a clinical framework consisting of "Presumed Lemierre," "LS Type I," "Type II," "Type III," and "Type IV/Variant". Compared to the historical definition, our proposed modified definition of LS effectively assigned reported LS cases from the literature into a subtype based on clinical features.

Our study is hypothesis-generating and offered a modified definition of LS and incorporated clinical observations into a unifying framework to address the existing ambiguity and variation with this entity.