Clinicopathological features of acute autonomic and sensory neuropathy
Acute autonomic and sensory neuropathy is a rare disorder that has been only anecdotally reported. We characterized the clinical, electrophysiological, pathological and prognostic features of 21 patients with acute autonomic and sensory neuropathy. An antecedent event, mostly an upper respiratory tract or gastrointestinal tract infection, was reported in two-thirds of patients. Profound autonomic failure with various degrees of sensory impairment characterized the neuropathic features in all patients. The initial symptoms were those related to autonomic disturbance or superficial sensory impairment in all patients, while deep sensory impairment accompanied by sensory ataxia subsequently appeared in 12 patients. The severity of sensory ataxia tended to become worse as the duration from the onset to the peak phase of neuropathy became longer (P < 0.001). The distribution of sensory manifestations included the proximal regions of the limbs, face, scalp and trunk in most patients. It tended to be asymmetrical and segmental, rather than presenting as a symmetric polyneuropathy. Pain of the involved region was a common and serious symptom. In addition to autonomic and sensory symptoms, coughing episodes, psychiatric symptoms, sleep apnoea and aspiration, pneumonia made it difficult to manage the clinical condition. Nerve conduction studies revealed the reduction of sensory nerve action potentials in patients with sensory ataxia, while it was relatively preserved in patients without sensory ataxia. Magnetic resonance imaging of the spinal cord revealed a high-intensity area in the posterior column on T2*-weighted gradient echo image in patients with sensory ataxia but not in those without it. Sural nerve biopsy revealed small-fibre predominant axonal loss without evidence of nerve regeneration. In an autopsy case with impairment of both superficial and deep sensations, we observed severe neuronal cell loss in the thoracic sympathetic and dorsal root ganglia, and Auerbach’s plexus with well preserved anterior hone cells. Myelinated fibres in the anterior spinal root were preserved, while those in the posterior spinal root and the posterior column of the spinal cord were depleted. Although recovery of sensory impairment was poor, autonomic dysfunction was ameliorated to some degree within several months in most patients. In conclusion, an immune-mediated mechanism may be associated with acute autonomic and sensory neuropathy. Small neuronal cells in the autonomic and sensory ganglia may be affected in the initial phase, and subsequently, large neuronal cells in the sensory ganglia are damaged.