Severe deep neck infection due to Streptococcus pyogenes after influenza in previously healthy children: a case series

Deep neck infection (DNI) is severe and potentially life-threatening.We report two cases of severe DNI associated with invasive Streptococcus pyogenes (group A Streptococcus [GAS]) in previously healthy 11-year-old boys after influenza B infection.The first patient developed DNI 4 days after influenza B was diagnosed, complicated by descending necrotizing mediastinitis that required emergency transcervical incision and drainage with bilateral video-assisted thoracoscopic surgery.Intravenous immunoglobulin was administered because of concern for streptococcal toxic shock syndrome.The patient required 18 days of pediatric intensive care unit (PICU) management, including 14 days of mechanical ventilation, before transfer to the general ward, and he was subsequently discharged without infectious complications.The second patient developed progressive neck pain approximately 2 weeks after influenza B infection, which was confirmed by multiplex respiratory polymerase chain reaction; acute neurological deterioration subsequently developed.Imaging revealed septic left internal jugular vein thrombophlebitis with a posterior fossa brain abscess, brainstem compression, and obstructive hydrocephalus, consistent with Lemierre syndrome with extension to the sigmoid sinus and jugular foramen.He underwent left posterior fossa craniectomy for abscess decompression, immediately followed by transoral drainage of the retropharyngeal abscess.Intraoperative cultures grew GAS and methicillin-resistant Staphylococcus aureus.The patient required 9 days of PICU care, including 6 days of mechanical ventilation, and was treated with a 4-week course of combined intravenous vancomycin and ceftriaxone, with apixaban anticoagulation for septic thrombosis.These cases indicate that influenza may predispose otherwise healthy children to severe invasive bacterial DNI with life-threatening complications.Early clinical suspicion and timely imaging are essential to reduce the risk of disease progression.