Authors: Ali Al Hassani , Zaid Al Hassani , Fatima AlKindi , Tariq Hamdan , Yousef Boobes

Abstract

Background: Acute motor axonal neuropathy (AMAN) is a severe Guillain-Barré syndrome (GBS) variant that may deteriorate rapidly, particularly when early bulbar weakness and respiratory failure occur. Cerebrospinal fluid (CSF) protein may remain normal early in the disease course, and coexisting upper-airway findings can create diagnostic uncertainty.

Case Presentation: A 43-year-old previously healthy man developed severe dysphagia, sialorrhea, and nasal speech after febrile pharyngitis, followed by rapidly progressive limb weakness. Examination showed flaccid tetraparesis, preserved sensation, and evolving bulbar dysfunction. Nasopharyngoscopy demonstrated mild non-obstructive epiglottic inflammation, initially suggesting an upper-airway or infectious cause. Within 24 hours, he developed ineffective cough, neck flexor weakness, and impending respiratory failure requiring intensive care admission and endotracheal intubation. Post-intubation examination showed generalized areflexia and autonomic instability. Day 1 CSF showed no pleocytosis and normal protein. Day 2 nerve conduction studies demonstrated severe predominantly motor axonal polyneuropathy with relatively preserved sensory responses, consistent with AMAN. Intravenous immunoglobulin was initially started but discontinued before completion of a full therapeutic course, and five plasma exchange sessions were performed alongside intensive supportive care. Clinical improvement was observed during hospitalization, allowing extubation by Day 5 and discharge on Day 10 with mild residual upper-limb weakness.

Conclusion: Fulminant bulbar-predominant AMAN may mimic upper-airway pathology and present before CSF protein elevation. In this case, neurological improvement occurred after initiation of plasma exchange and intensive supportive care; however, causality cannot be inferred from a single case. Normal early CSF findings and mild non-obstructive ENT abnormalities should not delay electrodiagnostic evaluation, respiratory monitoring, and timely immunomodulatory treatment.

Keywords: Guillain-Barré syndrome, acute motor axonal neuropathy, dysphagia, plasma exchange, respiratory failure, peripheral nervous system diseases.