Areflexia or hyporeflexia is a mandatory clinical criterion for the diagnosis of Guillain-Barré syndrome (GBS). A systematic review of the literature from 1 January 1993 to 30 August 2019 revealed 44 sufficiently detailed patients with GBS and hyper-reflexia, along with one we describe. 73.3% of patients were from Japan, 6.7% from the USA, 6.7% from India, 4.4% from Italy, 4.4% from Turkey, 2.2% from Switzerland and 2.2% from Slovenia, suggesting a considerable geographical variation. Hyper-reflexia was more frequently associated with antecedent diarrhoea (56%) than upper respiratory tract infection (22.2%) and the electrodiagnosis of acute motor axonal neuropathy (56%) than acute inflammatory demyelinating polyneuropathy (4.4%). Antiganglioside antibodies were positive in 89.7% of patients. Hyper-reflexia was generalised in 90.7% of patients and associated with reflex spread in half; it was present from the early progressive phase in 86.7% and disappeared in a few weeks or persisted until 18 months. Ankle clonus or Babinski signs were rarely reported (6.7%); spasticity never developed. 53.3% of patients could walk unaided at nadir, none needed mechanical ventilation or died. 92.9% of patients with limb weakness were able to walk unaided within 6 months. Electrophysiological studies showed high soleus maximal H-reflex amplitude to maximal compound muscle action potential amplitude ratio, suggestive of spinal motoneuron hyperexcitability, and increased central conduction time, suggestive of corticospinal tract involvement, although a structural damage was never demonstrated by MRI. Hyper-reflexia is not inconsistent with the GBS diagnosis and should not delay treatment. All GBS variants and subtypes can present with hyper-reflexia, and this eventuality should be mentioned in future diagnostic criteria for GBS.
Keywords: Guillain-Barré syndrome; H-reflex; anti-ganglioside antibodies; hyper-reflexia; pathophysiology.
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