Human Parvovirus B19-Associated Guillain-Barre Syndrome Diagnosed by Cerebrospinal Fluid Targeted Next-generation Sequencing: A Case Report and Literature Review

Guillain - Barre syndrome (GBS) is a post - infectious autoimmune disorder of peripheral nerves. Human parvovirus B19 (B19V) is a rare trigger for GBS, and its diagnosis requires advanced molecular techniques. A 24 - year - old male presented with acute symmetrical limb weakness, paresthesia, diarrhea, fever, and joint pain. Cerebrospinal fluid (CSF) analysis showed albuminocytological dissociation, and electromyography indicated acute motor and sensory axonal neuropathy (AMSAN). Conventional serology for common pathogens was negative. Targeted Next - generation Sequencing (tNGS) of CSF revealed a high read count of B19V DNA, leading to the diagnosis of B19V - associated GBS. The patient was treated with intravenous immunoglobulin (IVIG), with significant clinical improvement at discharge. At 3 - month follow - up, the patient had lower limb joint pain with persistent B19V - IgM/IgG positivity, which resolved rapidly after retreatment with IVIG, and finally achieved a G - DS score of 1 with mild residual paresthesia. This case emphasizes B19V as an uncommon cause of GBS and the critical role of CSF tNGS in identifying atypical pathogens like B19V. B19V - associated GBS responds well to immunomodulatory therapy such as IVIG and has a favorable prognosis. tNGS should be considered in GBS cases with unclear etiology.