AIDP / Guillain-Barré syndrome

Clinical History

This 50-year old patient with a past medical history of gastric sleeve operation presented with a two week history of back pain, ascending weakness, numbness and tingling involving their feet. Electrodiagnostic studies showed features of a severe mixed axonal and demyelinating sensorimotor neuropathy. Cerebrospinal fluid analysis showed elevated protein without increase in cellularity (albuminocytologic dissociation).

In the context of this patient’s clinical history what type of neuropathic process is documented in the provided images of electron microscopy (lower and higher magnification) and teased nerve preparation?

Answer:

Electron microscopy demonstrates stripping of myelin from an intact axon by macrophages.  The teased nerve preparation shows focal segmental demyelination.  These are features of active segmental demyelination, and in the context of the patient’s clinical history would support a clinical diagnosis of acute inflammatory demyelinating polyradiculoneuropathy (AIDP / Guillain-Barré syndrome).

Note the neurofilaments and microtubules seen on the higher magnification EM image enabling the identification of an intact axon with adjacent myelin debris within a macrophage.

Teased nerve preparations are labor intensive and time intensive, but of use in further assessing the nature of an increase in the number of thinly myelinated large diameter axons on light microscopy (i.e. axonopathic versus demyelinating process).

References/Additional Readings:

• Weis J, Brandner S, Lammens M, Sommer C, Vallat JM. Processing of nerve biopsies: a practical guide for neuropathologists. Clin Neuropathol. 2012 Jan-Feb;31(1):7-23. doi: 10.5414/np300468. PMID: 22192700; PMCID: PMC3663462.
• Bilbao, J. M., & Schmidt, R. E. (2015). Biopsy diagnosis of peripheral neuropathy, second edition. Springer International Publishing. https://doi.org/10.1007/978-3-319-07311-8