Lemierre Syndrome After Influenza A Virus Infection.

Lemierre syndrome is a rare condition characterized by septic thrombophlebitis of the internal jugular vein with metastatic septic emboli, most commonly affecting the lungs. We report a case of Lemierre syndrome temporally associated with influenza A infection in a previously healthy 21-year-old male. The patient initially presented to the emergency department with severe headache and tested positive for influenza A. Over the following seven days, his symptoms progressed to neck pain with decreased range of motion, hemoptysis, cough, and persistent myalgias. Despite four additional emergency department visits, his evolving neck symptoms were attributed to influenza-related myalgias and cervical strain. On the day of admission, examination demonstrated neck swelling, tenderness, restricted jaw opening, and pink foamy sputum. Laboratory studies were significant for severe thrombocytopenia, lactic acidosis, and sepsis. Imaging revealed right mastoid effusion, paranasal sinusitis, multifocal pneumonia, and a near-occlusive thrombus of the right internal jugular vein. Blood cultures grew beta-hemolytic group C Streptococcus and Peptoniphilus asaccharolyticus. The patient was treated with vancomycin, ceftriaxone, clindamycin, and metronidazole. Anticoagulation was initially deferred because of profound thrombocytopenia. Additional therapies included nebulized tranexamic acid, platelet transfusion, corticosteroids, and intravenous immunoglobulin for suspected immune-mediated thrombocytopenia. His hospital course was complicated by metabolic encephalopathy requiring intubation. The patient improved with treatment and was discharged after 17 days on oral antibiotics and rivaroxaban. He was subsequently readmitted 20 days later with a right empyema requiring bronchoscopy, chemical pleurodesis, and decortication. He has remained free of further hospitalization for one year. This case highlights the diagnostic challenges of Lemierre syndrome and the potential for diagnostic anchoring following an initially confirmed viral diagnosis. Although a causal relationship between influenza A infection and Lemierre syndrome cannot be established, clinicians should reassess the diagnosis when patients with confirmed influenza develop persistent or progressive focal symptoms, particularly neck pain or swelling, restricted jaw opening, respiratory symptoms, or systemic deterioration. Early recognition of Lemierre syndrome and prompt treatment are critical to reducing severe complications and morbidity.