Diagnostic and Therapeutic Challenges in Lemierre Syndrome: A Case Report Using Metagenomic Next Generation Sequencing.

Lemierre syndrome (LS) is a rare and life-threatening condition predominantly caused by Fusobacterium necrophorum. Currently, there are no standardized clinical guidelines for LS management. Here, we describe the case of a 40-year-old male with fever, productive cough, and dyspnea but no sore throat. Diagnostic radiological examinations revealed multiple pulmonary cavitary nodules and an internal jugular vein occlusion. Metagenomic Next-Generation Sequencing (mNGS) of the alveolar lavage fluid identified Fusobacterium necrophorum, thereby confirming the diagnosis of LS. Intriguingly, the patient exhibited a delayed clinical response despite receiving the appropriate antibiotic. After integrating tigecycline into the treatment to address potential co-infecting bacteria, we observed a marked improvement in his clinical symptoms. Subsequent follow-up over 12 weeks post-discharge revealed complete alleviation of symptoms, and a chest CT scan showed marked regression of the lung lesions.