Coexistence of anti-GD1a and anti-Gq1b antibodies in a Patient with Mixed Phenotype between Pharyngo-Cervico-Brachial Variant and Miller Fisher syndrome

Introduction: Miller Fisher syndrome and the pharyngo-cervico-brachial variant have been considered as independent forms of Guillain-Barré Syndrome. However, in the light of current knowledge, these entities could be linked as their manifestations may overlap. Anti-ganglioside antibodies are a useful serological marker to define evolution and prognosis.The aim of this work is to present and analyze the clinical case of a patient with a craniobulbar paralytic syndrome resulting from the mixed phenotype between Miller Fisher and the pharyngo-cervico-brachial variant associated with anti-GD1a and anti-GQ1b antibodies.Case Presentation: A 43-year-old male patient was admitted to the emergency room due to dysphagia, dysarthria, ophthalmoplegia, facial and upper limb weakness, and areflexia that progressed to respiratory failure. Nerve conduction study showed an axonal polineuropathy and cerebrospinal fluid had albumin-cytologic dissociation. The anti-ganglioside antibody panel was strongly positive for anti-GD1a and positive for anti-GQ1b. Treatment was started with intravenous immunoglobulin, which had to be replaced by plasmapheresis due to renal impairment. After five weeks, the patient regained respiratory autonomy and was referred to a rehabilitation center, with full recovery after 6 months.Discussion: The differential diagnosis of paralytic craniobulbar syndrome includes neuromuscular junction diseases, brain stem or meninges structural lesions, and inflammatory polyradiculoneuropathies. The electrophysiological findings in this case are consistent with axonal polyneuropathy. The detection of anti-GQ1b and anti-GD1a antibodies provide relevant information for the understanding of this rare phenotype.Conclusion: This case illustrates the mechanisms, differential diagnosis, electrophysiological and serological manifestations of the overlap of different clinical phenotypes.