(1223) Lemierre Syndrome Causing Acute Respiratory Distress Syndrome (ARDS) and Parvimonas micra Bacteremia

Introduction: Lemierre syndrome (LS) is a septic thrombophlebitis of the internal jugular vein (IJV), often arising from an oropharyngeal infection and classically linked to Fusobacterium necrophorum. ARDS, an acute form of respiratory failure caused by pulmonary inflammation and edema is a rare complication of LS. We present an unusual case of LS causing ARDS, associated with Parvimonas micra.

Description: A 37-year-old man with history of diabetes and a recent tooth extraction presented with 5 days of jaw and neck pain associated with fever, cough, and shortness of breath. Physical examination revealed tenderness submentally and over the right lateral neck. Ultrasound showed a thrombus of the right IJV concerning for LS, and CT of the neck showed submental soft tissue emphysema. CT of the chest revealed bilateral patchy opacities with cavitation. The patient was placed on HFNC for hypoxia, started on vancomycin and piperacillin/tazobactam, and admitted to the ICU for non-intubated ARDS with a SpO2/FiO2 ratio of 180.
His respiratory status worsened shortly after, necessitating intubation. With PaO2/FiO2 ratio (PFR) remaining above 100 on a low-PEEP strategy, he was classified as moderate ARDS and no proning or ECMO pursued. Blood cultures identified coagulase-negative staphylococci and Parvimonas micra. Due to ongoing fevers and re-imaging of the chest showing worsening cavitary lesions presumed to be from septic embolic seeding, antibiotic therapy was broadened to meropenem and vancomycin.
The patient improved rapidly on this regimen, was extubated after 9 days with PFR>300 and discharged to inpatient rehabilitation.

Discussion: While pulmonary sequalae are common in LS, ARDS remains a rare complication, only documented in case reports. This case likely involved rapidly improving ARDS, given quick recovery of PFR and symptoms, contrasting the severe ARDS cases so far reported in LS. While ARDS in LS is commonly linked to Fusobacterium necrophorum bacteremia, this is a rare example involving Parviomonas micra, a gram-positive anaerobe found in oral cavity and GI tract, potentially explaining the relatively benign course. This case underscores the need to maintain a high index of suspicion for ARDS, especially with new guidelines including non-intubated cases and highlights non-traditional triggers.