Serial electrodiagnostic testing (EDX) is required in Guillain-Barré syndrome (GBS) to correctly identify the underlying pathophysiological process at play, research suggests.
A study of 46 adults admitted to the Royal North Shore Hospital between 2012 and 2016 found most cases (64%) had primary demyelinating features – largely consistent with the predominance (78%) of acute inflammatory demyelinating polyneuropathy (AIDP).
Electrodiagnostic features were normal (14%) or equivocal (14%) in less than a third of patients while primary axonal features were noted in 9% of patients.
The most common clinical features observed were sensory and motor manifestations (76%), bulbar involvement (50%) and pain (43%).
Upper respiratory tract infections (37%) and gastrointestinal illness (24%) were the most common antecedent events.
Lead author Dr Stephanie Barnes, from the neurology department at Concord Repatriation General Hospital, told the limbic testing performed early – within the first week of symptoms – often returned normal or non specific/equivocal results that do not allow the underlying pathophysiology to be defined.
“Repeat testing, eg three months down the track, can be helpful to establish pathophysiology and demonstrate progress/recovery.”
“It can provide useful information in almost all cases but would only usually be performed in situations where patients are clinically not improving or improving very slowly or if they develop new symptoms and signs. In these scenarios, the result of repeat EDX can be helpful to guide prognosis and may also lead to changes in management ie further treatment.”
She said cost and long waiting lists were barriers to repeat testing.
The study, only the second clinico-epidemiological study of GBS in Australia, found most patients received intravenous immunoglobulin (IVIg) therapy.
Length of hospital stay was highly variable (12 +/- 10 days), sometimes involving ICU admission (13%) but no patients required mechanical ventilation and there were no deaths.
Many patients (46%) subsequently required rehabilitation and almost three quarters of patients (71%) reported residual deficits such as sensory symptoms or minor weakness six months later.
The study concluded that outcomes were very good and might improve further if eculizumab becomes available.
“At this stage, phase 2 trials show that it is safe and suggest that it may be beneficial but these trials were underpowered for efficacy,” Dr Barnes said.
“Phase 3 trials are currently underway. It is currently not licensed for use in GBS and if that were to change in the future, the cost is likely to be prohibitive and restrict its use to only those very severe GBS cases.”