A 29-year-old woman presented with a 19-day history of blurred vision and intolerance to bright light after a presumed viral illness (a sore throat and fever resolved 4 days before the onset of other symptoms). At presentation, she reported a dry mouth, mild constipation, abdominal bloating and hesitancy of micturition. Results of a clinical examination were normal apart from dilated, slightly asymmetric pupils (Figure, A), non-reactive to light and accommodation. The patient’s condition gradually improved over the subsequent 6 months.
Tests of heart rate and blood pressure showed normal cardiovascular autonomic function. Thermoregulatory sweat testing was undertaken by applying a starch and iodine paste to the skin; this changes colour to purple in the presence of sweat. Results showed an absence of sweating in the patient’s arms and legs (Figure, B and C) compared with an age-matched control volunteer (Figure, D and E).
These findings support a diagnosis of a subacute cholinergic neuropathy causing parasympathetic failure, which, in the clinical context, is likely to represent an uncommon variant of Guillain–Barré syndrome.1
