Pediatric guillain-barré syndrome and autonomic dysfunction.

Guillain-Barré sydrome (GBS), the most common cause of acute childhood paralysis worldwide, is an acute inflammatory demyelinating polyradiculoneuropathy with the ability to affect all myelinated peripheral nerves.1 Heart rate variability (HRV), which is recognized as a quantitative marker of the autonomic nervous system, may be used for the early detection of autonomic dysfunction (AD) in childhood GBS.2 However, other factors such as diabetes mellitus, thyroid disorders, higher body mass index and blood pressure may have a confounding effect on HRV.3,4 In addition, patients who are planned to undergo HRV analysis should also undergo echocardiographic evaluation to exclude valvular (mitral valve prolapsus), myocardial (dilated cardiomyopathy) and congenital (atrial septal defects) abnormalities, all of which may also potentially effect HRV.5,6 Lastly, although frequency domain indices of HRV is usually presented in absolute value of power, the representation of low frequency and high frequency in normalized unit may represent the controlled and balanced behaviour of the sympathetic and parasympathetic branches of the autonomic nervous system.7 These mentioned factors seem to have been overlooked by Samadi et al. in the ‘‘Assessment of Autonomic Dysfunction in Childhood Guillain-Barré reporting AD in half of children with mild GBS with no significant association with disease activity.8 Ethical issues: Not applicable