Neurophysiology of Guillain-Barré syndrome in children

Abstract

Our aim was to evaluate sensitivity and specificity of conduction studies parameters for prognosis and differential diag nosis in children with acute motor axonal neuropathy (AMAN) & acute inflammatory demyelinating polyneuropathy (AIDP).
 Methods. 40 children were included: 20 healthy controls (7-14 years) and 20 patients (8-15 years) with AIDP or AMAN. All underwent conduction studies on 3-7 day since the clinical symptoms onset. We registered and evaluated motor conduction velocity, compound muscle action potential (CMAP) amplitude of nn. tibialis, peroneus, medianus, ulnaris; sensory conduction velocity & sensory nerve action potential (SNAP) amplitude for nn. medianus, suralis, peroneus superficialis, ulnaris, H-reflex threshold & latency, reactivity of neural conductivity (RNC) in short-term hand ischemia in acute phase (3-14 day since the disease onset) and in early recovery period (15-30 day since the symptoms onset). ROC-analysis was performed.
 Results. In 95% of the patients with Guillain-Barré syndrome H-reflex was absent. In first 10 days SNAP amplitude of median nerve >8.9 µV, peroneal nerve >3.6 µV, CMAP of peroneal nerve ≤0,4 µV with normal motor conduction velocity indicates AMAN presence. Motor axons of peripheral nerves in children in acute and recovery phase of AIDP are resistant towards ischemia. Prognostic criteria for long period of walk recovery (more than 30 days) in these patients are RNC on 10th minute of local ischemia ≤2.5%, ulnar nerve CMAP amplitude ≤1,1 mV and distal CMAP amplitude from median nerve ≤1.6 mV.
 Conclusions. Conduction studies may be implemented on all phases of Guillain-Barré syndrome in children for prognosis and differential diagnosis between its axonal and demyelinating forms. H-reflex absence in children in the first 5 days of acute polyneuropathy may serve as additional diagnostic criteria for Guillain-Barré syndrome. RNC parameters may be implemented for the prognosis of the walk period recovery duration.