Doença vestibular central por infarto isquêmico secundário a hipotireoidismo em cão / Central vestibular disease due to ischemic stroke secondary to hypothyroidism in a dog

ABSTRACT

Background: Hypothyroidism in dogs can cause lethargy, weight gain, dermatological signs and, uncommonly, neurological signs. These may involve the peripheral or central nervous system, leading to a decreased level of consciousness, central or peripheral vestibular disease, epileptic seizures, cognitive dysfunction, facial nerve paralysis, laryngeal paralysis, and polyneuropathy. There are few cases reported in the literature relating hypothyroidism and central vestibular disease. The aim of this study was to report a case of a stroke secondary to hypothyroidism that resulted in central vestibular syndrome in a dog. Case A 13-year-old female Pitbull, weighting 37 kg, was referred to a Veterinary University Hospital with a two weeks history of dyspnea, coughing and walking difficulty. On neurological examination, the animal presented vertical nystagmus, somnolence, non-ambulatory tetraparesis, decreased postural reaction in all limbs and normal spinal reflexes. The laboratory exams revealed a mild leukocytosis and increased creatinine, glucose, cholesterol and triglycerides levels. Due to historical, clinical, neurological and laboratory tests findings, the animal was diagnosed with central vestibular syndrome secondary to an intracranial neoplasm. Clinical treatment was instituted with corticosteroids, however the animal did not respond and died. On necropsy, the heart was enlarged and coronary arteries were thicker. No macroscopic changes were found in the brain. On histological analysis, the coronary arteries were congest by lipids that almost occluded the arterial lumen. The same alteration were found in splenic and renal arterioles, and in the brain’s leptomeninges. Also in the brain, it was observed perivascular infiltration of mononuclear cells and focal gliosis. The thyroid was atrophied and fibrosed bilaterally. Therefore, those changes were compatible with atherosclerosis secondary to hypothyroidism...