Abstract: Guillain?Barre´ syndrome (GBS) is an acuteonset,
immune-mediated disorder of the peripheral nervous
system. In early GBS, arbitrarily established up to 10 days
of disease onset, patients could exhibit selective manifestations
due to involvement of the proximal nerves,
including nerve roots, spinal nerves and plexuses. Such
manifestations are proximal weakness, inaugural nerve
trunk pain, and atypical electrophysiological patterns,
which may lead to delayed diagnosis. The aim of this paper
was to analyze the nosology of early GBS reviewing
electrophysiological, autopsy and imaging studies, both in
acute inflammatory demyelinating polyneuropathy (AIDP)
and acute motor/motor-sensory axonal neuropathy
(AMAN/AMSAN). Early electrophysiology showed either
well-defined demyelinating or axonal patterns, or a nondiagnostic
pattern with abnormal late responses; there may
be attenuated M responses upon lumbar root stimulation as
the only finding. Pathological changes predominated in
proximal nerves, in some studies, most prominent at the
sides where the spinal roots unite to form the spinal nerves;
on very early GBS endoneurial inflammatory edema was
the outstanding feature. In the far majority of cases, spinal
magnetic resonance imaging showed contrast enhancement
of cauda equina, selectively involving anterior roots in
AMAN. Both in AIDP and AMAN/AMSAN, ultrasonography
has demonstrated frequent enlargement of ventral
rami of C5?C7 nerves with blurred boundaries, whereas
sonograms of upper and lower extremity peripheral nerves
exhibited variable and less frequent abnormalities. We
provide new insights into the pathogenesis and classification
of early GBS.
