Diagnóstico diferencial na fraqueza induzida pelo exercício em cães – revisão de literatura e relato de caso

Abstract

Exercise-induced weakness has a multifactorial character and may be caused by hydroelectrolytic, metabolic imbalances, neurological disorders and orthopedic disorders. The present paper reports the case of an 11-year-old male castrated Yorkshire Terrier dog seen at HOVET-UFMG. With a history of alteration in ambulation characterized by walking with difficulty in the hind limbs, progressing to the thoracic, aphonia and after three days presenting these clinical signs, stopped moving. Physical examination revealed normal vital parameters. At the neurological examination, she was alert, with outpatient tetraparesis, decreased withdrawal reflex in all four limbs even before the exercise. After the exercise, this exam was redone, and the results obtained were similar to the previous ones. During the wheelbarrow test, the animal had its head bent to the ground and exhibited general weakness. Blood counts, serum biochemistry (liver and kidney) and serum glucose measurements were performed. Serological tests for toxoplasmosis and neosporosis were negative. After intravenous infusion of anticholinesterase (neostigmine methylsulfate) the animal showed no improvement. The treatment instituted was the use of pyridoistigmine bromide and prednisone. On the second return, the tutor reported improvement before the medication and only a few reports of falls during the use of the medication. Pictures of exercise-induced weakness include several diseases in the differential diagnosis, some of which are not ruled out by the complementary exams performed. It is believed that it would be necessary to assess basal rates of thyroid hormones, parathyroid hormones, hormone assessment of the adrenal gland; electromyographic examinations, muscle and peripheral nerve biopsy, demonstration of circulating antibodies against nicotinic acetylcholine receptors in the musculature and orthopedic examinations. The conduction of the clinical case until the diagnostic conclusion in patients with exercise weakness is sometimes impaired by the limitation of the complementary exams.