Acute flaccid myelitis associated with enterovirus type D68 infection

Abstract

Objective: To help clinicians in recognizing enterovirus D68 related acute flaccid myelitis (AFM), in differentiating it from other conditions, and in performing the right additional studies to make the diagnosis. Methods: Case report of two children admitted with acute flaccid paralysis following a respiratory infection with enterovirus D68. Results: Case 1. This 4-year-old boy developed rapid progressive asymmetric weakness of upper more than lower limbs, unilateral facial weakness and respiratory failure some days after an upper airway infection. CSF was normal. MRI of the brain and spinal cord showed abnormal high T2-signal of the dorsal pons and cervical and thoracic gray matter. Electromyography findings suggested anterior horn disease. Immunoglobulin treatment gave no improvement. After detection of enterovirus D68 in the nasal swab, a diagnosis of acute flaccid myelitis was made. The patient made minimal recovery and was still ventilator dependent after 4 months. Case 2. This 4-year-old boy was admitted because of progressive asymmetric weakness of the arms after a respiratory infection. CSF analysis showed a mainly mononuclear pleocytosis. Bacterial cultures and virologic tests were all negative. MRI revealed high T2-signal dorsally of the fourth ventricle and in the cervical gray matter. Enterovirus D68 was isolated from the nasal swab, pointing to the diagnosis of acute flaccid myelitis. After two months there was only minimal improvement of the strength in his upper limbs, with a persistent flaccid paralysis of his right arm. Conclusion: Progressive weakness after a respiratory tract infection should raise the suspicion of enterovirus associated acute flaccid myelitis. It can be distinguished from other conditions such as Guillain-Barré syndrome and acute transverse myelitis by the clinical evolution (rapid progression, asymmetrical weakness, more severe involvement of the upper limbs); typical findings on MRI and electromyography; and detection of enterovirus D68 in nasopharyngeal specimens but not in the CSF.