Lemierre’s Disease: A Diagnostically Complex Case of Vape Associated <em>F</em>. <em>necrophorum</em>

Background: Lemierre’s syndrome, previously termed the “forgotten disease” after the introduction of modern antibiotics, is a rare and potentially fatal infection of the neck resulting in septic thrombophlebitis of the internal jugular and other neck veins. There has been an increased resurgence of this disease in more recent years and it remains an important diagnosis with life threatening potential to consider when presenting with multifocal cavitary pneumonia. Fusobacterium necrophorum, an obligate anaerobic gram-negative bacterium is the most isolated culprit organism involved in this condition, however often fastidious and difficult to culture. The use of gene sequencing using 16rRNA can aid in this diagnosis when uncertainty exists. Methods: This case report describes an otherwise healthy 17 year-old male with a history of vaping presenting with upper respiratory infectious symptoms who ultimately was diagnosed with multi-focal necrotizing pneumonia. There was significant diagnostic uncertainty throughout the case as traditional microbiologic culture mechanisms failed to identify a causative organism for tailored antimicrobial treatment. This was despite direct empyema fluid analysis and pulmonary-bronchial biopsy. Novel gene sequencing was performed using 16s rRNA typing, a promising new way to identify a catalog of host organisms, detecting F. necrophorum. This diagnosis prompted further diagnostic imaging of the neck, confirming a small internal jugular clot and diagnosis of Lemierre’s Disease. Results: This case highlights the need for suspicion of Lemierre’s disease in patients presenting with multi-focal pneumonia. Furthermore, it re-iterates the idea of culture-negative infection, whereby fastidious organisms or tissue samples do not readily provide a diagnosis. Lastly, it further introduces hypotheses regarding the use of vaping and associated significant infection and lung injury. Conclusions: The use of 16s rRNA sequencing for the detection of fastidious, opportunistic organisms is another tool for physicians to ensure adequate diagnostic clarity and appropriate treatment.