Sensory neuronopathy in dogs: a study of four cases.

A neurological disease which selectively affects the primary sensory pathways was observed in 4 dogs. Clinical signs were dominated by ataxia due to impaired position sense. Deficient or abnormal pain sensation was also observed. Difficulty in eating probably arose from oral and lingual sensory deficit. The lesions were characterized by degeneration and loss of central and peripheral primary sensory axons, with a predilection for large myelinated fibres. The concept of a sensory neuronopathy was supported by the finding of neuronal degeneration and loss in dorsal root ganglia seen in 2 dogs. The cause of the disease is not known. The presence of mononuclear inflammatory cells in acute lesions suggests an infectious or autoimmune disease. Toxic and genetic factors are also to be considered.