Transient relapsing neuromyopathy during potassium bromide therapy in a dog

A 2-year-old Australian Shepherd dog was referred because of exercise intolerance and gait abnormalities. The dog had a history of idiopathic epilepsy treated with phenobarbitone and potassium bromide (KBr). The neurological examination was indicative of a generalized lower motor neuron disease. A generalized peripheral neuropathy caused by KBr was suspected. Electrodiagnostic investigation and muscle and nerve biopsies were indicative of unspecific neuromyopathy. KBr was suspended with complete resolution of neuromuscular signs within 1 month but the dog developed cluster seizures refractory to other antiepileptic therapies. KBr was reintroduced with the improvement of the epileptic seizures but relapse of the neuromuscular signs was seen. This relapse confirmed the suspicion of neuromyopathy related to KBr. Bromide intoxication should be suspected in cases of generalized neuromuscular signs also in dogs with normal serum values. An early identification of the cause and suspension of KBr leads to a complete resolution of the symptoms.