Mixed Streptococcus pneumoniae and herpes simplex virus meningoencephalitis confirmed by PCR: A case report and review of the literature

This case report describes a rare and severe instance of meningoencephalitis caused by a dual infection with Streptococcus Pneumoniae (pneumococcus) and Herpes Simplex Virus type 1 (HSV-1). The patient, a previously healthy 53-year-old woman, was admitted with symptoms of fever, intense headache, neck stiffness, photophobia, vomiting, otalgia, and altered consciousness progressing to seizures. Lumbar puncture revealed a turbid cerebrospinal fluid (CSF) with lymphocytic pleocytosis, low glucose, and high protein. Gram staining showed Gram-positive cocci, and multiplex PCR identified both S. pneumoniae and HSV-1. Despite early treatment with ceftriaxone, acyclovir, corticosteroids, and supportive care, the patient's condition deteriorated, with neurological decline and respiratory distress necessitating intensive care. Imaging showed bilateral pulmonary consolidation but no focal brain lesions. Follow-up CSF analysis showed improvement, though her clinical condition required ongoing critical support. This case highlights the diagnostic and therapeutic challenges of co-infections in the central nervous system. Dual bacterial-viral meningoencephalitis is rare but associated with high morbidity and mortality. Early and accurate diagnosis via multiplex PCR and a multidisciplinary management approach, including antimicrobial and antiviral therapy along with intensive supportive care, are critical to improving outcomes. Long-term neurological monitoring is recommended due to the risk of lasting complications.