Pathologic and molecular studies of enterovirus 71 infection in a fatal case from a recent epidemic in China: A case report

RATIONALE: Enterovirus 71 (EV71) is identified as the primary cause of hand, foot, and mouth disease (HFMD) and mainly infects the young infants. Though some fatal cases have been reported, the underlying mechanisms of EV71 infection remain elusive and more further pathologic and molecular studies of EV71 infection are needed. PATIENT CONCERNS: A 26-month-old girl with a history of fever and lethargy for 3 days and intermittent seizures for 2 hours associated with rash on 4 limbs was brought to a hospital. DIAGNOSES: The autopsy was performed to identify the cause of death for a medical dispute. The results of histologic examination, immunohistochemistry (IHC), nested reverse transcription polymerase chain reaction (RT-PCR), and viral isolation confirmed that this patient died of EV71 infection. INTERVENTIONS: The patient was transferred to neonatal intensive care unit and was intubated and mechanically ventilated. The other treatment included cardiopulmonary resuscitation and intravenous injection of adrenaline. OUTCOMES: The patient presented persistent coma and intermittent seizures and suddenly developed respiratory arrest and died 16 hours after admission. LESSONS: Our results suggest that EV71 might invade into the central nervous system (CNS) through peripheral nerves which control the digestive tract in the early stage of infection. In addition, we successfully isolated one EV71 strain. Phylogenetic analysis showed that the isolated strain clustered in the C4a of C4 subgenotype. This case also highlights that rapid deterioration in HFMD cases is still a challenge to physicians and they must pay special attention to the infants with HFMD symptoms, particularly in EV71 epidemic areas for early diagnosis and treatment.