Complications of Metrizamide Myelography in the Dog: A Summary of 107 Clinical Case Histories

Abstract

The case histories of 107 dogs undergoing metrizamide myelography at two veterinary hospitals were reviewed. Twenty‐three variables, including body weight, injection site, dose of contrast medium, and medical complications during and after recovery from anesthesia, were submitted to statistical analysis by computer. Partial or generalized seizures were the most common medical complications, occurring in 54 percent of the dogs weighing more than 29 kg. Other less frequent medical complications were exacerbation of neurologic signs the day following myelography (11 percent), transient apnea during contrast medium injection (9 percent), vomiting (5 percent), hyperesthesia (3 percent), pyrexia (1 percent), and death (1 percent). The incidence of medical complications associated with metrizamide myelography in this study is higher than in previous reports. The most likely variables associated with seizures were high injection volumes and metrizamide injection at the cisterna magna. The preanesthetic administration of intramuscular pentobarbital did not significantly reduce seizure incidence. Seizures were controlled by anticonvulsant medication.

Inadvertent Intrathecal Administration of Diatrizoate Meglumine and Diatrizoate Sodium During Myelography in a Dog

“…Metrizamide has the highest seizure rate of the currently used agents with the incidence being approximately 1 5 4 0 % . [11][12][13] Seizures associated with metrizamide appear to be dose related, being reported more commonly in dogs over 29 kg.12,13 Seizures following metrizamide myelography were found to occur in 47% of dogs receiving 7 ml or more of contrast rnedium.l3 In addition, removal of one third of the initial dose of metrizamide reduced the incidence of post-myelographic complications in dogs.14 Iopamidol has a seizure rate of 7% while iohexol has a reported incidence of 1% for postmyelographic seizures. [15][16][17] The lower incidence of postmyelographic seizures has resulted in iohexol and iopami-do1 replacing metrizamide as the contrast medium of choice for myelography in animals.…”

LOW OSMOLAR CONTRAST MEDIA A Review

“…The largest study consisted of 107 examinations in which almost one half of the dogs suffered some side effect, although these figures were acknowledged to be higher than in other studies. 61 The most common complications were either focal or generalized seizures that occurred in 32% of dogs; these were usually associated with cisternal rather than lumbar injections and with high volumes of contrast medium. These seizures were most likely to occur in large dogs (weighing more than 29 kg) receiving more than 7 ml of contrast medium by the cisternal route.…”

Iohexol and Iopamidol Myelography in the Dog: A Clinical Trial Comparing Adverse Effects and Myelographic Quality

“…Metrizamide, the drug of choice for myelography in the 1970's, has been associated with a high incidence (1544%) of postmyelographic seizures and other neurotoxic effects in dogs. [1][2][3][4][5][6][7][8][9] Iohexol and iopamidol are currently the most popular agents used for routine veterinary and human myelography .…”