Objective: To describe the clinical and laboratory features of a painful non-length-dependent, small fiber ganglionopathy (SFG).
Background: The syndrome of generalized SFG with early involvement of the face, trunk or proximal limbs is not well recognized and contrasts with the burning feet syndrome of small fiber neuropathy (SFN) and classical large fiber features of sensory ganglionopathy.
Methods: Retrospective case review including skin biopsies from 4 neuromuscular centers. Patients with pre-existing diseases associated with ganglionopathies were excluded.
Results: Twelve men and 11 women, with an average age of 50 years, were studied. Neuropathic pain developed over days in 8 and over months in the others. The face (12), scalp (10), tongue (6), trunk (15), and acral extremities (21) were involved. Symptoms began in the hands or face before the legs in ten. The pain was characterized as burning (22), prickling (13), shooting (13), or allodynic (11). There was loss of pinprick sensation in affected regions in 19, with minimal or no loss of large fiber sensibility. Laboratory findings included abnormal glucose metabolism in 6, Sjogren syndrome in 3, and monoclonal gammopathy, sprue, and hepatitis C infection in one each, with the remainder idiopathic. Sensory nerve action potentials were normal in 12 and were reduced in the hands but normal in the legs in six. Skin biopsy in 14 of 17 showed reduced nerve fiber density in the thigh equal to or more prominent than in the calf. Two of 7 improved with immune therapies, 13 symptomatically with analgesic medications, and the remainder had little improvement. Ten considered the pain disabling at last followup (mean, 2 years).
Conclusion: The pattern of symmetric, non-length dependent neuropathic pain with face and trunk involvement suggests a selective disorder of the dorsal ganglia cells subserving small nerve fibers. It can be distinguished from distal SFN. A potential metabolic or immune process was detected in half the cases, and the disorder was often refractory to treatment.
- neuropathic pain
- small fiber neuropathy