Very early Guillain-Barré syndrome: A clinical-electrophysiological and ultrasonographic study

Abstract

Objectives: Using recent optimized electrodiagnostic criteria sets, we primarily aimed at verifying the accuracy of the initial electrophysiological test in very early Guillain-Barré syndrome (VEGBS), ≤4 days of onset, compared with the results of serial electrophysiology. Our secondary objective was to correlate early electrophysiological results with sonographic nerve changes.

Methods: This is a retrospective study based on consecutive VEGBS patients admitted to the hospital. Each patient had serial nerve conduction studies (NCS) in at least 4 nerves. Initial NCS were done within 4 days after onset, and serial ones from the second week onwards. Electrophysiological recordings of each case were re-evaluated, GBS subtype being established accordingly. Nerve ultrasonography was almost always performed within 2 weeks after onset.

Results: Fifteen adult VEGBS patients were identified with a mean age of 57.8 years. At first NCS, VEGBS sub-typing was only possible in 3 (20%) cases that showed an axonal pattern, the remaining patterns being mixed (combining axonal and demyelinating features) in 6 (40%), equivocal in 5 (33.3%), and normal in 1 (6.7%). Upon serial NCS, 7 (46.7%) cases were categorized as acute demyelinating polyneuropathy, 7 (46.7%) as axonal GBS, and 1 (6.6%) as unclassified syndrome. Antiganglioside reactivity was detected in 5 out of the 7 axonal cases. Nerve US showed that lesions mainly involved the ventral rami of scanned cervical nerves.

Conclusions: Serial electrophysiological evaluation is necessary for accurate VEGBS subtype classification. Ultrasonography helps delineate the topography of nerve changes.

Significance: We provide new VEGBS pathophysiological insights into nerve conduction alterations within the first 4 days of the clinical course.

Keywords: Axonal degeneration; Demyelination; Endoneurial inflammatory oedema; Guillain-Barré syndrome; Ultrasonography; Very early Guillain-Barré syndrome.

Fig. 1

Flow chart of VEGBS patient ascertainment according to initial (≤4 days after onset) and subsequent electrophysiological evaluations (dates listed in Table S2, Supplementary material). The middle panel of boxes indicates that initially accurate GBS sub-typing was only possible in 3 (20%) cases categorized as axonal pattern. Initial mixed pattern (combining criteria of both axonal failure and demyelination) evolved into either AIDP or AMSAN. Initial equivocal pattern resulted in AIDP, AMSAN or normalization. For all 3 axonal GBS patients, sub-typing did not change. The only VEGBS patient showing initial normal NCS evolved into axonal GBS. Note that after serial electrodiagnosis, disease sub-typing was not possible in 1 (6.7%) case (No. 10).

Fig. 2

Three serial NCS of median nerve and peroneal nerve in case 15, performed on days 2, 11 and 28 after onset (for clinical data see Table 1, and for initial nerve conduction values, Table S2, Supplementary material). On day 2, median nerve shows marked amplitude reduction of dCMAP (upper tracing, 1 mV; normal, ≥4 mV), pCMAP/dCMAP amplitude ratio <0.7, and pCMAP/dCMAP duration ratio >130%. There is minimal alteration of DML and MCV, dCMAP duration being preserved. On day 11, note 300% increase of dCMAP amplitude (upper tracing, 3 mV), its duration declining from 7.6 ms to 6.5 ms; consequently, these changes are indicative of RCF. pCMAP/dCMAP amplitude and duration ratios remain abnormal. MCV velocity is normal (55.4 m/s). Note CMAP temporal dispersion in three bottom tracings. On day 28, electrophysiological features are comparable to the previous study. With regard to peroneal nerve, on day 2 there is marked amplitude reduction of dCMAP that exhibits normal duration. While DML is clearly prolonged, MCV is minimally slowed (see Table S2 for values). Note the presence of CMAP desynchronization in two bottom tracings. On day 11, there are minimal variation of recordings in comparison with the previous study, excepting for an increase of dCMAP duration (8.7 ms), and decrease of MCV (30.5 m/s; 72% LLN). On day 28, the main variations are an evident increase of DML (first tracing, 9.9 ms; +180% ULN) and further decrease of MCV (28.1 m/s; 67% LLN). In short, initial mixed electrophysiological pattern has evolved into AIDP. It is worth noting that despite persistent dCMAP amplitude reduction of lower-limb nerves, clinical evolution was favourable, his GBSd score passing from 5 at admission to 1 eight months after onset. Abbreviations: APB = abductor pollicis brevis; dCMAP = distal compound motor action potential; DML = distal motor latency; EDB = extensor digitorum brevis; ER = extensor retinaculum; FH = fibular head; PF = popliteal fossa; LLN = lower limit of normal; MCV motor conduction velocity; pCMAP = proximal CMAP; ULN = upper limit of normal.

Fig. 3

US of the ventral rami of the left fifth and sixth cervical nerves of case 12 with initial equivocal electrophysiological pattern evolving into AIDP (see Table 1 and Fig. 1); sonograms were obtained on day 6 after onset. (A and B) Short-axis sonograms showing enlarged CSAs of both cervical nerves (dotted green tracings; for values see Table 2); note that perineurial hyperechoic rims are not identified and that the edge between the nerve and the surrounding fat is not clear. (C) Sagittal sonograms showing blurred of boundaries of both nerves (asterisks). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 4

US of the ventral rami of the sixth cervical nerves of case 13 with a final diagnosis of axonal GBS (see Table 1 and Fig. 1); sonograms were obtained on day 5 after onset. (A) Short-axis sonogram showing marked CSA enlargement of the right C6 nerve (dotted green tracing; for values, see Table 2), 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; for values, see Table 2) 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. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)