[Clinical analysis of four cases of anti GQ1b syndrome]

Objective: To investigate the clinical manifestations, laboratory findings, treatment and outcome of anti-GQ1b antibody syndrome. Method: The clinical manifestations, laboratory examination, diagnosis, treatment and prognosis of (4 patients 4 male patients, from 4 to 12 years) with anti-GQ1b syndrome in Beijing Children's Hospital affiliated to Capital Medical University from 2015 to 2016 were retrospectively analyzed. Result: All 4 children presented with ataxia. Case 1 showed impaired speech, ptosis and weakness of arms; case 2 and 3 had external ophthalmoplegia, weakness of limbs; case 4 presented hypersomnia, irritability and hallucinations. Serum anti-GQ1b-IgG antibody was positive in all cases. Case 1-3 received lumber puncture at the course of 1-2 weeks, CSF presented albuminocytological dissociation, case 4 had CSF pleocytosis and increased protein level. Brain MRI of Case 1-2 were normal; Case 3 showed long T1 and T2 signal in cerebellar dentate nucleus, pons and corpus callosum; Case 4 showed long T1 and T2 signal in bilateral centrum semiovale, basal ganglia, external capsule, insula and cerebellum. Electromyograms of case 1-3 showed peripheral axonal lesion. All children were treated with IVIG. After treatment, condition of all patients were improved. According to the clinical manifestation, laboratory examination, and outcome after treatment, case 1 was diagnosed as anti-GQ1b antibody syndrome (Pharyngeal-Cervical-Brachial weakness overlapped with Miller Fisher syndrome), case 2 and 3 were diagnosed as anti-GQ1b antibody syndrome (Miller Fisher syndrome overlapped with Guillain Barré syndrome) and case 4 was diagnosed as anti-GQ1b antibody syndrome (acute ataxia hypersomnolence). Conclusion: When patients with the presence of prodromic infections, monophasic course, drowsiness, ataxia, ophthalmoplegia, weakness and the symptoms/signs are relatively symmetric, anti-GQ1b antibody syndrome should be considered. Anti-GQ1b antibody has important significance for diagnosis. Most children have a good prognosis. Early correct diagnosis can avoid unnecessary examinations and guide appropriate use of immunotherapy.