Severe acute encephalopathy related to human parainfluenza virus type 2 infection in an infant: a case report

Introduction:We present here a rare case of severe acute encephalopathy with extra-pulmonary symptoms in a two-year-old girl caused by human parainfluenza virus type 2 (HPIV2) infection.Case Presentation:The patient was brought in by ambulance, presenting with fever, hypoxia and generalized tonic-clonic seizure, and was admitted into Fukuyama Medical Center. She had a depressed level of consciousness with drowsiness. Her Glasgow coma score was 6. Based on the results of laboratory examinations, brain computed tomography, brain magnetic resonance imaging and electroencephalography, we diagnosed her with acute encephalopathy. Treatment was initiated with high-dose intravenous immunoglobulin, methylprednisolone pulse therapy and edaravone along with mechanical ventilation. We confirmed HPIV2 infection using samples of sputum from the intra-tracheal tube, throat swab and blood using next-generation sequencing and the PCR method. After continued steroid and anti-inflammatory therapy, the patient recovered completely.Conclusion:Extra-pulmonary symptoms in parainfluenza viral infections are rare. HPIV2 infection can cause severe acute encephalopathy via a systemic immunological reaction along with airway symptoms.