Con-focal Microscopy Documents Significant Epidermal Nerve Demyelization in Patients With Clinical Neuropathy But Normal Neurophysiologic Studies (P7.107)

Objective: Utilizing a new technology that can visualize demyelization of small myelinated epidermal nerve fibers in patients with neuropathic complaints but normal electro-diagnostic studies. Background: Demyelization of peripheral nerves is usually immune mediated. When the immune target are small myelinated fibers it is difficult to document the process electro physiologically and the diagnosis is made indirectly, with varying degrees of success. With the lack of a proof of the mechanism of damage, adequate therapy is rarely provided. The ability to visualize demyelization in these conditions will allow appropriate treatment. Con-focal microscopy enables to follow a 3D structure through a multitude of foci and to present its entire structure in a 2D format. Methods: With the courtesy of Therapath, Inc., we were able to study two patients who suffered from chronic painful neuropathy after contracting Lyme disease in spite of adequate antibiotic treatment. Although clinically displaying neuropathic findings and low counts of epidermal and sweat gland nerve fibers,E MG and NCV studies were normal. Left lateral thigh skin biopsies were processed according to Provitera et al. Muscle & Nerve 2007; 35: 767-775. Results: Both patients (males, ages 53 and 62), showed many fibers undergoing demyelization and remyelization, with myelin loss and enlarged nodal gap. The inter- nodal length was 45 to 50 microns, compared to a (normal of 90 microns). 35 to 42% of the fibers showed segmental and para nodal demyelization and 43 to 50% of the fibers showed remyelization. 70 to 78% of the total fibers were affected. IVIg therapy was initiated in one patient with clinical improvement and normalization of his small fiber counts. Discussion: Inflammatory neuropathies of small fibers are difficult to document . The ability to see demyelization of small myelinated fibers of the skin through con-focal microscopy will enable the proper diagnosis and treatment. Disclosure: Dr. Katz has received personal compensation for activities with Forest Laboratories, Inc. as a speaker.