Molecular Diagnosis of Rickettsial Meningoencephalitis With Concurrent Herpes Simplex Virus Type 2 Infection in a Young Female Presenting With Acute Febrile Encephalopathy: A Report on a Rare Case

Rickettsial CNS infections have been increasingly reported in tropical countries, including India, and are associated with significant morbidity and mortality.Early diagnosis is challenging due to nonspecific presentations, absent rash/eschar, and limited sensitivity of conventional serological tests in the acute phase.Concurrent CNS infection with herpes simplex virus type 2 (HSV-2) is exceedingly rare and further complicates clinical diagnosis and management.This report presents the case of a 28-year-old previously healthy female from Aligarh, Uttar Pradesh, who presented with a 10-day history of intermittent fever, headache, vomiting, decreased appetite, and progressively worsening altered sensorium.Four days before admission, she developed recurrent seizurelike episodes characterized by upward deviation of the eyeballs and jaw clenching.On admission, a neurological examination revealed a Glasgow coma scale (GCS) score of E2V2M5 with neck rigidity suggestive of meningeal irritation.Owing to progressive neurological deterioration and impaired airway protection, she required endotracheal intubation and mechanical ventilation.Laboratory investigations demonstrated mild neutrophilic leukocytosis, thrombocytopenia, elevated alanine aminotransferase levels, and hypoalbuminemia.A CSF analysis revealed normal glucose and protein concentrations with minimal pleocytosis, while Gram stain and bacterial cultures were negative.Contrastenhanced computed tomography (CECT) and MRI demonstrated only a small calcified occipital granuloma without evidence of acute inflammatory changes.Extensive investigations for common bacterial and tropical infections, including malaria, dengue, enteric fever, scrub typhus, leptospirosis, and bacterial meningitis, were negative.Multiplex real-time polymerase chain reaction (PCR) performed on peripheral blood detected Rickettsia spp.DNA.Subsequent molecular analysis of CSF also demonstrated Rickettsia spp.DNA, confirming CNS involvement, while real-time PCR simultaneously detected HSV-2 DNA, establishing the diagnosis of concurrent Rickettsia spp.meningoencephalitis and HSV-2 encephalitis.The patient initially received empirical intravenous ceftriaxone, vancomycin, and acyclovir.Following molecular confirmation of Rickettsia spp.infection, doxycycline (100 mg twice daily) was initiated while antiviral therapy was continued.The patient demonstrated progressive neurological improvement with recovery of sensorium and a favorable clinical outcome.This case highlights the diagnostic challenges associated with rickettsial CNS infection, particularly in patients lacking classical clinical features and presenting with normal CSF biochemistry and nonspecific neuroimaging findings.Simultaneous molecular detection of Rickettsia spp. in peripheral blood and CSF together with HSV-2 in CSF emphasizes the importance of considering mixed infectious etiologies in patients presenting with acute febrile encephalopathy.Early application of molecular diagnostics enabled prompt institution of targeted therapy and contributed to successful clinical recovery.To the best of our knowledge, this represents one of the very few reported cases of concurrent molecularly confirmed Rickettsia spp.meningoencephalitis and HSV-2 encephalitis worldwide and is likely the first such case reported from India.