Lemierre's Syndrome Caused by Klebsiella pneumoniae: Case Report and Review of the Literature.

Klebsiella pneumoniae is an uncommon but increasingly recognized cause of Lemierre's syndrome, a condition classically associated with Fusobacterium necrophorum. This report describes a 32-year-old woman with poorly controlled type 2 diabetes mellitus who presented with a progressive odontogenic infection complicated by internal jugular vein thrombosis and cavitary septic pulmonary emboli. Imaging demonstrated a deep neck abscess with adjacent thrombophlebitis, and cultures from surgical drainage yielded K. pneumoniae with a wild-type susceptibility profile. The patient required invasive mechanical ventilation, broad-spectrum antibiotics, surgical source control, and therapeutic anticoagulation, resulting in complete clinical recovery. A review of published cases from 1996 to 2025 was performed, highlighting diabetes as the predominant risk factor, odontogenic or oropharyngeal disease as the most common source, and septic pulmonary emboli as a hallmark manifestation. This case represents the second documented instance of K. pneumoniae-associated Lemierre's syndrome in Nicaragua and reinforces the need for early imaging, prompt surgical management, and targeted antimicrobial therapy in diabetic patients presenting with deep neck infections.