A progressive neuronopathy in the young cairn terrier

The clinical signs and neuropathological changes of a nervous disease of pedigree cairn terriers are described. Three animals, of both sexes, between five and seven months of age showed hind leg weakness, quadriparesis, ataxia, loss of superficial and deep reflexes and tremor of the head. Pathologically there was chromatolysis of neurons in the spinal cord and brain stem. Although Wallerian-type degeneration was present in the spinal cord and peripheral nerves, its severity did not correlate with the intensity of the neuronal changes. This suggests that the chromatolysis observed may reflect a primary neuronal abnormality rather than represent a secondary change resulting from a primary degeneration of peripheral axons. Although the age of onset and some of the clinical signs are similar to those seen with globoid cell leucodystrophy (an inherited disease which also affects cairn terriers), the presence of lower motor neuron paralysis and the absence of signs of severe brain involvement in progressive neuronopathy should enable the conditions to be distinguished clinically.