Myasthenia gravis in an exotic shorthair cat

ABSTRACT

Background: Myasthenia gravis is a neuromuscular transmission disorder resulting from the deficiency or functional disturbance of the acetylcholine receptors at the neuromuscular junction with consequent impairment of action potential transmission from nerve to muscle and it can be either congenital or acquired. Acquired myasthenia gravis has been described less frenquently in cats. The purpose of this paper is to describe a case of acquired myasthenia gravis in a 6-month-old male Exotic Shorthair cat. Case A 6-month-old male Exotic Shorthair cat was referred to the Veterinary Clinic with a 2-day history of flaccid paralysis of the four limbs. The cat was feeding well and defecating normally. Physical examination was unremarkable. On neurological examination the patient was bright, alert and responsive. Flaccid paralysis of the four limbs was evident with loss of muscular tonus and presence of superficial and deep nociception. All spinal reflexes were absent. Hematologic analysis was within normal parameters. Thoracic radiographs were taken and showed no abnormalities. Creatine kinase activity was elevated. Myasthenia gravis was suspected and the cat was submitted to an neostigmine methylsulfate injection and further pyridostigmine bromide administration. Within 15 days there was clinical improvement with muscular tonus and spinal reflexes recovery. The treatment was continued...