[Neurologic symptoms in relation to hypothyroidism in the dog: review of the literature and case reports].

Primary hypothyroidism is commonly associated with lethargy, alopecia, hyperpigmentation, alterations in skin and hair coat, anestrus and bradycardia. However, there is also a neurological manifestation of hypothyroidism with neuromuscular signs. Four dogs with generalized polyneuropathy are described. Two dogs had peripheral vestibular signs, two other lower motor neuron disease with megaesophagus. Diagnosis was based on neurological examination, TSH-stimulation test and electrodiagnostic findings including electromyography, motor nerve conduction velocity and brainstem evoked potentials. On histological examination lymphocytic thyroiditis was diagnosed in two cases. Three dogs recovered after supplementation with Eltroxine (Levothyroxine) and one dog was euthanatized because of megaesophagus and concomitant aspiration pneumonia.