Guillain Barre Syndrome

21 de January de 2020

Guillain-Barré syndrome (GBS) is the most common cause of acute neuropathic ascending paralysis in developed countries. Members of the IDIVAL Group of Neurodegenerative Diseases have carried out two studies on this syndrome.

In the first study, published in Acta Neurologica Scandinavica “A unicenter, prospective study of Guillain ‐ Barré syndrome in Spain” the clinical characteristics, subtypes and prognosis of the syndrome are described (Sedano et al, Acta Neurol Scand 2019; 139: 546‐ 54).

The series included 56 GBS patients treated in Valdecilla between January 2009 and June 2017, with ages ranging from 5 to 86 years (mean, 55). The clinical characteristics were comparable to those described by the IDIVAL Group almost three decades ago (Sedano et al, Acta Neurol Scand 1994; 89: 287-92). Next to the classic forms of GBS, 7 cases were identified with the paraparhetic form, 1 with Miller Fisher syndrome, and 1 case of acute sensory and ataxic neuropathy (ASAN in the Anglo-Saxon acronym).

Based on the neurophysiological findings, 35 (62.5%) of the patients were classified as demyelinating form (AIDP), 16 (28.6%) as axonal form (either AMAN or AMSAN), 1 (1.8% ) as an inexcitable form, and 3 (5.4%) as forms of GBS without definite neurophysiological findings. The relative high frequency of axonal shapes, usually observed in eastern countries, has recently been corroborated in the Italian region of La Spezia (Benedetti et al, JPNS 2019; 24: 80-6). As expected from the literature data, antiganglioside reactivity was only detected in axonal forms. Figure 1, corresponding to the ASAN patient, illustrates for the first time that distal sensory axonopathy is caused by a reversible blockade of conduction mediated by antiganglioside antibody (here anti-GD1a).

Figure 1. The original legend, taken from Figure 3 of Sedano et al (2019) is as follows: Seria l sensory conduction studies of median nerve in an ASAN patient.
(A) On day 4 after symptom onset, when the patie nt showed severe sensory ataxia, note severe amplitude reduction of both recorded SNAPs, D1‐wrist and D3‐wri st, which accounts for the observed SCV slowing.
(B) On day 13, there was a drastic increase of SNAP amplitudes, up to 4.3 µV on D1‐wrist and 1.7 µV on D3‐wrist, with normalization of SCVs. Mixed median nerve conduction velocity (wrist‐elbow) is preserved, though the mixed compound nerve action (MCNAP) potential amplitude is reduced (8.6 µV; normal, 15.5 µV).
(C) On day 50, median nerve sensory conduction parameters are entirely normal; in comparison with the previous study, note further increase of SNAP amplitudes, normalization of MCNAP amplitude, and increase of SCVs and mixed nerve conduction velocity. Note also normal morphology of SNAPs and MCNAPs, and particularly the absence of temporal dispersion. Sensory conduction changes of ulnar nerve were comparable. D1=digit 1; D3=digit 3.

The “Very early Guillain-Barré syndrome: A clinical-electrophysiological and ultrasonographic study” study published in “Clinical Neurophysiology Practice” describes the consecutive ‐ neurophysiological and ultrasonographic clinical findings in 15 patients with classical GBS, whose initial neurophysiological examinations will be carried out. carried out at a very early stage of the syndrome (VEGBS in the Anglo-Saxon acronym), ≤ 4 days of symptomatic onset (Berciano et al, Clin Neurophysiol Practice 2020; 5: 1-9). Initially, in 3 (20%) patients an axonal neurophysiological pattern was detected, in 6 (40%) a mixed pattern, in 5 (33.3%) an equivocal pattern, and in the remaining case (6.6%) as unclassifiable form. Nerve ultrasonography showed that the most relevant lesions are located in the ventral branches of the C6-C7 nerves (Figure 2). The two fundamental conclusions are the following: i / the consecutive neurophysiological study is necessary to discern subtypes in VEGBS; and ii / inflammatory edema of the proximal nerve trunks is pathogenic in the first four days of illness. We propose new pathophysiological perspectives of the initial disorders of nerve conduction.

Figure 2. The original legend, taken from Figure 4 of Berciano et al (2020), is as follows: US of the ventral rami of the sixth cervical nerves of case 13 with a final diagnosis of axonal GBS; sonograms were obtained on day 5 after onset.
(A) Short‐axis sonogram showing marked CSA enlargement of the right C6 nerve (dotted green tracing), its perineurial rim not being identified.
(B) In this sagittal sonogram the right C6 nerve (asterisks), note also disappearance of perineurial rim.
(C) Short‐axis sonogram of the left C6 nerve showing normal CSA (dotted green tracing) with preservation of the perineurial hyperechoic rim.
(D) Sagittal sonogram of the left C6 nerve (asterisks) illustrating quite well preservation of its perineurial hyperechoic rim.