Feline neuromuscular disorders.

Feline neuromuscular diseases may be classifi ed according to their location as those involving peripheral nerves and/or nerve roots, those involving the neuromuscular junction, and those that involve muscle (1). Each of these neuromuscular diseases will produce lower motor neuron (LMN) disease, however signifi cant variations in clinical signs may occur. Peripheral nerve and muscle diseases result in varying degrees of paresis, muscle atrophy, hyporefl exia, and hypotonia. Hyporefl exia, hypotonia, ataxia and proprioceptive positioning defi cits are most characteristic of peripheral nerve disease. Some primary muscle disorders may be characterised by muscle hypertrophy rather than atrophy. Neuromuscular junction disorders (“junctionopathies”) result in a variety of clinical signs, that range from fl accid paralysis to exercise-induced weakness. Cervical ventrofl exion is a dramatic sign of generalised neuromuscular weakness in cats. The chin usually rests near the thoracic inlet, with the eyes positioned dorsally to maintain a straightahead gaze. Other common physical examination fi ndings are a slight protrusion of the dorsal aspects of the scapulae when weight is placed on thoracic limbs, and a stiff thoracic limb gait. A crouched, wide-based stance is often seen in pelvic limbs. Megaoesophagus rarely has been reported in cats, although a predisposition has been noted in Siamese and Siamese-related breeds. In most cats the cause of acquired megaoesophagus is unknown.