[Atypical Guillain-Barre syndrome clustering: is it necessary to reconsider the diagnostic criteria and microbiological protocol?]

INTRODUCTION

Guillain-Barre syndrome is classically defined as a symmetrical ascending acute polyradiculoneuropathy, although there are atypical variants that make diagnosis difficult.

CASE REPORTS

The medical data of six patients in our hospital area are collected during the first quarter of 2013. Lumbar punctures, imaging, neurophysiological studies, ganglioside antibodies and serologies have been proposed in all cases. We focus on the atypical features as late hyporeflexia, increased frequency of asymmetry and distal paresis and initial fever. From a neurophysiological point of view, all patients presented sensorimotor axonal forms. The most consistent datas in early studies is the F wave's alteration. A Miller Fisher variant associated with faciocervicobraquial paresis and cerebral reversible vasoconstriction syndrome has been detected. A bilateral brachial paresis and lumbar polyradiculopathy in the context of influenza A infection is other interesting case. The saltatory variant with cranial nerve involvement and lower limbs paresis has been demonstrated in one patient. Bands in cerebrospinal fluid are positive in three cases and anti-ganglioside antibodies in one patient. The syndrome of inappropriate secretion of antidiuretic hormone may explain some of the hyponatremias registered. The first line of treatment are inmunoglobulins in all patients. Plasmapheresis exchanges has been used as an additional therapy in four cases.

CONCLUSIONS

These clusters of six axonal cases with atypical clinical features justifies the need for knowledge of these variants in order to achieve an early treatment. Late hyporeflexia and brachialfaciocervico, saltatory and lumbar forms should be considered in the spectrum of Guillain-Barre syndrome. The etiological study should rule out a lots of pathogens as influenza A.

Corrosion behaviour of AZ31 magnesium alloy with different grain sizes in simulated biological fluids

The corrosion behaviour of AZ31 magnesium alloy with different grain sizes immersed in simulated body fluids was compared in chloride solution (8 gl(-1)) and in phosphate-buffer solution (PBS). The influence of immersion time was also analyzed. Electrochemical techniques such as open circuit potential, polarization curves, transient currents and electrochemical impedance spectroscopy, complemented with scanning electron microscopy and energy dispersive spectroscopy, were used. Immediately after the immersion in the corrosive media the corrosion resistance was similar for both grain sizes of the AZ31 alloy and higher in NaCl solutions than in PBS. However, this corrosion behaviour was reversed after longer periods of immersion due to the stabilizing of the corrosion products of MgO by P-containing compounds. These P-compounds contribute to a higher level of protection by hindering the aggressive action of chloride ions. The best corrosion behaviour of the AZ31 alloy was obtained for the finest grain alloy associated with the highest transfer resistance value, after long periods of immersion in PBS.