Magnesium sulfate as an adjunct therapy in the management of severe generalized tetanus in a dog

Objective - To describe the use of magnesium sulfate in a case of generalized tetanus in a dog. Case Summary - A 1.5-year-old golden retriever was presented for a digital wound on the right thoracic limb and clinical signs associated with generalized tetanus. Initial case management consisted of wound debridement, treatment with metronidazole, tetanus immunoglobulin, methocarbamol, airway management via tracheostomy, and nursing care. Sedation to control severe muscle spasms became insufficient despite increasing doses of benzodiazepine, methocarbamol, and barbiturate continuous rate infusions. A magnesium sulfate continuous rate infusion was instituted on day 7 and muscle rigidity improved within 16 hours allowing discontinuation of sedative infusions over the subsequent 2 days. Clinical improvement continued and the dog was discharged on day 14. New or Unique Information Provided - This case demonstrates the use of supraphysiologic magnesium in the treatment of severe generalized tetanus with a positive outcome. No clinical signs associated with magnesium toxicity were noted during the course of therapy. Magnesium sulfate should be considered as a potential adjunct therapy in the management of spastic paralysis caused by severe tetanus in dogs.