Lemierre syndrome, first described by André Lemierre in 1936, is characterized by a primary oropharyngeal infection, followed by septic thrombophlebitis of the internal jugular vein and subsequent metastatic infections1. The syndrome is predominantly caused by Fusobacterium necrophorum, an anaerobic gram-negative bacillus that is part of the normal oropharyngeal flora2. While the incidence of Lemierre syndrome decreased significantly with the advent of antibiotics, there has been a resurgence of cases in recent decades. A nationwide Swedish study conducted from 2010 to 2017 reported an increasing incidence of invasive F. necrophorum infections from 2.9 to 5.0 cases per million per year3. This study identified 104 cases of Lemierre syndrome, representing 35% of all invasive F. necrophorum infections during this period. The re-emergence has been attributed to increased awareness, improved diagnostic techniques such as MALDI-TOF MS, and changing patterns of antibiotic prescribing for pharyngeal infections3, 4, 5.

The classic presentation involves internal jugular vein thrombosis, but variant forms with thrombosis at other sites have been reported6. The conceptualization of Lemierre syndrome continues to evolve. Riordan and Wilson noted in their review that André Lemierre initially classified anaerobic septicemias into six categories based on infection source, not limiting the definition to nasopharyngeal origins2. While some clinicians adhere to a strict definition requiring internal jugular vein thrombosis, mounting evidence supports a broader perspective that encompasses septic thrombophlebitis at various vascular sites following F. necrophorum bacteremia, regardless of the primary infection's location2, 7.

Early recognition of these atypical presentations is critical, as delayed diagnosis can lead to severe complications including septic shock, multiorgan failure, and death. Recent data show that while mortality rates have improved to approximately 2% with modern treatment, Lemierre syndrome still causes significant morbidity, with 43% of patients requiring intensive care unit admission3.

We present an unusual case of Lemierre syndrome with azygos vein thrombosis and thoracic vertebral osteomyelitis, highlighting the variability in clinical presentation and the need for a high index of suspicion to diagnose atypical cases.