Visual evoked potentials in patients with neuropathy and macroglobulinemia

Visual evoked potentials were studied in 11 patients with neuropathy and macroglobulinemia. The P100 latency was increased bilaterally in 5 of the 6 patients whose IgM M-proteins reacted with myelin-associated glycoprotein (MAG) and in 1 of the other patients. In patients whose M-protein bound to MAG, abnormal visual evoked potentials correlated with the presence of the M-protein in the cerebrospinal fluid. Subclinical involvement of the central nervous system is frequent in patients with neuropathy and anti-MAG M-proteins and may be due to the binding of M-proteins to central nervous system myelin.     

Immunofluorescence study of patients with neuropathy and IgM M proteins

Immunofluorescence histochemistry was used to study the pathogenesis of polyneuropathy in patients with an IgM M protein. Seventeen patients had an M protein that reacted with myelin-associated glycoprotein (MAG), and their serum immunostained myelin sheaths of normal peripheral nerve of humans and certain other species. The staining was specific for the M protein idiotype and was abolished by prior absorption of serum with MAG. The sural nerve biopsy specimens from these 17 patients had pathological features of primary demyelination and deposits of IgM on the myelin sheaths. Sural nerve specimens of 2 patients with an M protein reactive with chondroitin sulfate showed axonal degeneration and diffuse deposits of IgM in the endoneurium. Serum of one of these patients immunostained connective tissue; the staining was specific for the M protein idiotype and was blocked by absorption of the serum with chondroitin sulfate. The antigenic specificity of the IgM M protein in another 9 patients with neuropathy is not known; however, sural nerve specimens obtained from some of the patients showed axonal degeneration and endoneurial deposits of IgM, and the serum IgM immunostained axons in some instances. The findings suggest that IgM M proteins may cause the neuropathy and that more than one autoantigen is involved.     

Peripheral neuropathy in scleroderma

Because patients with scleroderma report neuropathic symptoms including numbness, paresthesias, and dysesthesias, we assessed peripheral nerve function in such patients. Fourteen scleroderma patients underwent complete neurologic examination, nerve conduction studies (NCS) and quantitative sensory testing (QST). Neurologic examination revealed reduced vibration (7) or pinprick (4) sensation in the upper or lower extremities, focal atrophy or proximal weakness (2), and decreased deep tendon reflexes (2). NCS showed reduced sensory nerve action potentials (1) and carpal tunnel syndrome (1). QST of the upper and lower extremity revealed increased cold or vibration detection thresholds in 8 of 14 patients. Our findings suggest that peripheral neuropathy occurs in patients with scleroderma at a higher frequency than previously appreciated. These findings cannot be ascribed to compression neuropathies, but rather involve large and small fibers in a non-length-dependent fashion. Larger, prospective studies using the more sensitive QST as well as pathologic studies of nerve, including cutaneous innervation, are needed to further assess the characteristics and etiology of the neuropathy.     

Peripheral neuropathy in CADASIL

Background Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is a hereditary cerebral microangiopathy associated with mutations in the Notch 3 gene. The clinical phenotype is characterized by cerebral impairment even though typical microvascular changes are diffuse. Objective To assess peripheral neuropathy in patients with CADASIL. Patients and Methods We enrolled eleven CADASIL patients with variable phenotype including clinical signs of peripheral nerve involvement. In all patients electromyography and nerve conduction velocities were performed. Peripheral nerve biopsy was performed in three cases. Results We found sensory motor neuropathy in 7/11 patients. Nerve biopsy revealed axonal and demyelinated findings. Conclusion Our findings suggest that peripheral neuropathy may be part of the CADASIL phenotype.     

Peripheral neuropathy in abetalipoproteinemia

We studied the peripheral neuropathy of three sisters with abetalipoproteinemia. Clinically, a sensory neuropathy progressively increased in severity. There was a diminution in the amplitude of sensory action potentials and a slight-to-moderate slowing in maximum sensory conduction velocity, initially most marked in distal portions of the nerves. Motor conduction was normal, although EMG indicated subclinical signs of partial chronic denervation. The sural nerves showed a decreased number of large fibers (greater than 7 micron); in the patient with the neuropathy of shortest duration, small fibers and clusters of regenerating fibers indicated regeneration. In the two patients with advanced neuropathy, one-half the segments of teased fibers showed paranodal demyelination. Also, unmyelinated fibers showed evidence of regeneration.     

Oral session IV: Peripheral neuropathy

Journal of Neurology -     

Peripheral neuropathy in mitochondrial disease

Clinical, electrophysiological, histological and biochemical studies of two patients with mitochondrial disease revealed a moderately advanced axonal neuropathy with mitochondrial paracrystalline inclusions in Schwann cells, fibroblasts and muscle fibers. In addition there was a myopathy, and the activity of muscle cytochrome c oxidase was diminished by more than 50%. There were electrophysiological signs of myopathy, neuropathy and failure of excitation-contraction coupling in both patients. The partial enzyme deficiency raises some questions as to its pathogenetic role in these neuromyopathies.     

Peripheral neuropathy in cerebrotendinous xanthomatosis

We performed a sural nerve biopsy in a patient with cerebrotendinous xanthomatosis (CTX) because of electrophysiologic evidence of peripheral neuropathy. The sections showed a striking loss of myelinated axons, the distribution of which suggested a compressive and/or ischemic process. Biochemical analysis disclosed large amounts of cholestanol, a cholesterol derivative that characteristically accumulates in CTX. However, the biochemical abnormality was not associated with any obvious structural alterations in the myelin lamellae or with abnormal storage material in Schwann's cells.     

Peripheral neuropathy and livedoid vasculopathy

Journal of Neurology - Livedoid vasculopathy (LV) is a chronic dermatosis associated with micro-thrombosis of the vessels of the dermis, leading to ischemic lesions and painful skin ulcerations of...     

Peripheral neuropathy in cardiofaciocutaneous syndrome

A young adult male with cardiofaciocutaneous syndrome developed gait deterioration in childhood, with later evolution of distal wasting. His physical examination revealed intention tremor, distal weakness of the upper limbs with atrophy of the thenar, hypothenar, and interossei muscles, a wide-based gait, and large-fiber sensory loss in all limbs. Neuroimaging revealed stable mild chronic communicating hydrocephalus. Nerve conduction studies and electromyography demonstrated a moderately severe axonal neuropathy. The present case is, to our knowledge, the first reported case of peripheral neuropathy in association with cardiofaciocutaneous syndrome. The latter is a rare disorder, with significant comorbidities, in which a peripheral neuropathy may be under-recognized as a late cause of functional deterioration.