CLINICAL, MRI, AND SKIN BIOPSY FINDINGS IN SENSORY GANGLIONOPATHIES

Abstract

Unlike peripheral motor disorders, sensory disturbances are rarely diagnosed by the probable site of pathology. This approach is useful in the differential diagnosis between chronic sensory axonal neuropathies and ganglionopathies, in which routine clinical and neurophysiological evaluation alone often do not provide definite clues.Methods: Thirty patients with peripheral sensory disturbances were investigated. MRI was performed at cervical level in all cases. Four patients also underwent thoracic and lumbar MRI. Seventeen patients underwent skin biopsy at the proximal thigh and the distal leg. In 4 of them, further skin biopsies were taken at C5 dermatome and at the hand. Density of intra‐epidermal nerve fibers (IENF) was quantified.Results: In 22 patients, sensory ganglionopathy was suspected. Disease was idiopathic in 7 cases; paraneoplastic in 3 cases; and associated with Sjögren, AIDS, autoimmune chronic hepatitis, and cisplatin neurotoxicity in 4 cases. One patient had a hereditary sensory autonomic neuropathy. Four patients had vitamin E deficiency and 3 patients a spinocerebellar syndrome. In 8 patients, sensory axonal neuropathy related to diabetes, alcoholism, and AIDS on antiretroviral treatment, and monoclonal gammopathy of undetermined significance was diagnosed.MRI findings: All ganglionopathy patients showed posterior columns hyperintensity on T2‐weighted MRI. Conversely, MRI was negative in all axonal sensory neuropathy patients.Skin biopsy findings: In neuropathies, IENF density was significantly lower at the distal leg than at the proximal thigh, while ganglionopathies did not show any change with respect to the rostral:caudal orientation. A similar pattern of epidermal denervation was observed in the arm.Discussion: The degeneration of both central and peripheral sensory pathway in a fashion that is not length‐dependent localizes the disease to T‐shaped sensory neurons Early ataxia and cutaneous sensory symptoms involving the proximal regions of the body reflect this pattern of denervation and should prompt the diagnosis of ganglionopathy. This can be confirmed by T2‐weighted hyperintensity in the posterior columns and a distinct pattern of IENF loss.