metrizamide and Neuromuscular-Diseases

Topics: Adult; Biopsy; Brain Neoplasms; Cerebral Infarction; Child, Preschool; Cysts; Diagnosis, Differential; Diagnostic Errors; Hematoma; Humans; Intracranial Aneurysm; Male; Metrizamide; Middle Aged; Neuromuscular Diseases; Paranasal Sinus Neoplasms; Spinal Cord; Spine; Subarachnoid Hemorrhage; Tomography, X-Ray Computed

Benign focal amyotrophy is an uncommon variant of neuron disease characterized by the gradual development of atrophy usually involving one upper extremity with a subsequent nonprogressive course. Previous descriptive reports have included normal radiological studies. We present a case of benign focal amyotrophy with a metrizamide CT myelographic finding of segmental cord atrophy in a distribution consistent with the patient's clinical findings.

Topics: Adult; Atrophy; Electromyography; Humans; Male; Metrizamide; Motor Neurons; Myelography; Neuromuscular Diseases; Spinal Cord; Tomography, X-Ray Computed

Marked asterixis occurred in two patients following metrizamide myelography. One also suffered generalized seizures and the other had severe stuttering speech for seven days. The spectrum of toxic manifestations of metrizamide is reviewed with emphasis on the unusual lethargy and other depressive effects seen with this relatively safe agent. The hypothesis that metrizamide exerts a ouabain-like effect on the cortical surface was tested. Metrizamide in concentrations as high as 20 mM had no inhibitory effect on rat cerebral K+-para-nitrophenylphosphatase, a partial reaction of (Na+K+)-adenosine triphosphatase. Because metrizamide is a 2-deoxyglucose analogue, a competitive inhibition of hexokinase at the first step in glycolysis was also postulated. Metrizamide was found to competitively inhibit commercial (microbial) hexokinase. The Michaelis constant for glucose rises from 0.13 to 0.25 to 0.33 to 0.91 mM in the presence of 0, 0.4, 1.0, and 2.0 mM metrizamide, respectively. Since the concentration of metrizamide over the cerebral cortex after routine myelography may be approximately 50 mM compared with a glucose concentration of only 3.6 mM (65 mg/dl), it is postulated that impaired brain glucose metabolism may be responsible for some of the toxic effects of metrizamide.

Topics: Animals; Brain Diseases, Metabolic; Confusion; Hexokinase; Humans; Male; Metrizamide; Middle Aged; Myelography; Neuromuscular Diseases; Rats; Stuttering