Objective: To describe two paediatric cases with Guillain–Barré syndrome (GBS) variants presenting with severe dysautonomia and secondary Posterior Reversible Encephalopathy Syndrome (PRES) prior to the onset of motor symptoms.

Background: Classical GBS and its variant Miller Fisher syndrome (MFS) exist as several clinical subtypes with different neurological presentations. Reversible central dysautonomia can occur acutely in all GBS variants. PRES is a clinical-radiological entity of varied aetiology, generally occurring in the setting of severe arterial hypertension, and to date has rarely been described in this setting.

Case reports: Patient A, 3 years old, presented acutely following VZV infection, with encephalopathy, cerebellar signs, hypertension, lower limb weakness and respiratory decompensation. MRI brain showed occipital lesions consistent with PRES. Bilateral ophthalmoplegia and areflexia became evident after autonomic dysfunction. Nerve conduction studies were consistent with MFS. After IVIG and plasmapheresis, he improved clinically with resolution of radiological findings of PRES.

Patient B presented at 14 years with a history of headache, leg pain and significant hypertension. She became unresponsive with seizures and neuroimaging was consistent with GBS variant complicated by PRES. She was areflexic with lower limb weakness a few days after ICU admission and made a significant improvement after treatment with IVIG. Extensive investigations revealed no another cause for hypertension.

Conclusion: Both patients had clinical features and neuroimaging consistent with GBS variants complicated by PRES. These two cases illustrate that GBS variants could constitute an important differential aetiology in children presenting with autonomic dysfunction, even before signs of motor weakness become evident.