Prevention of postmetrizamide myelographic seizures in dogs, using 5% dextrose solution.

Diuresis by IV administration of 5% dextrose in a balanced electrolyte solution (BES) reduced the frequency of occurrence of postmyelographic seizures in dogs. In the first study, a single myelogram was obtained in 8 dogs without dextrose diuresis. Two of these dogs weighed greater than 15 kg and both had seizures after metrizamide myelography. The remaining 6 dogs weighed less than 15 kg and only 2 had seizures. Greater body weight may have increased the risk of postmyelographic convulsions. In a crossover study, myelograms were obtained in 12 dogs weighing 20 to 31 kg. Six dogs were given 5% dextrose in BES (20 ml/kg of body weight/hr [diuresed]) and 6 were given BES alone (10 ml/kg/hr [not diuresed]). When myelography was repeated 10 days later, the 6 dogs that had been given 5% dextrose in BES were given BES only and the 6 dogs that had been given BES alone were given 5% dextrose in BES. The frequency of convulsions after metrizamide myelography was lower when dogs were given dextrose (33%) than when they were not (100%).

Canine and feline thyroid function assessment with the thyrotropin-releasing hormone response test.

A canine and feline pituitary-thyroid function test based on thyrotropin-releasing hormone (TRH) stimulation of endogenous thyrotropin is described. Serum thyroxine is measured before and after stimulation with TRH. A positive response to TRH indicated a functionally intact pituitary-thyroid axis. At TRH doses of 0.002 to 10.0 mg/kg of body weight, dose response of serum thyroxine to TRH stimulation was determined. Increasing the dose of TRH increased the duration, but not the magnitude, of thyroxine stimulation. At TRH doses greater than 0.1 mg/kg, drug side effects were salivation, defecation, urination, vomition, miosis, tachycardia, and tachypnea. A useful procedure for pituitary-thyroid function testing was serum thyroxine measurement before and 6 hours after TRH (0.1 mg/kg) stimulation.