A longitudinal cardiovascular autonomic function study in mild Guillain-Barré syndrome

To identify subclinical autonomic dysfunction in mild Guillain-Barré syndrome (GBS), a set of autonomic function tests was serially performed for up to 6 months in 5 GBS patients with mild disability at the nadir. Parasympathetic autonomic function tests consisted of Valsalva ratio and R-R interval variation during rest and deep breathing. Sympathetic autonomic function was evaluated by blood pressure responses to sustained handgrip, hand immersion in ice water, and active standing. The results showed that abnormal parasympathetic and sympathetic function was frequently encountered in all 5 patients during the acute stage of the illness. Autonomic dysfunction occurred both in axonal and demyelinating types of GBS. There was a trend of improvement in most autonomic function tests after 3 months, comparable to the recovery of motor function. In conclusion, subclinical autonomic dysfunction was present in mild GBS. It was temporary and would resolve spontaneously.