Effect of blood on arachnoiditis from aqueous myelographic contrast media.

Bloody cerebrospinal fluid is thought to increase the risk of arachnoiditis from myelography with iophendylate, but not with aqueous media. An experimental study was undertaken of the effects of metrizamide, iocarmate, and blood, independently and in mixtures, on the production of arachnoid fibrosis. Monkeys exposed to a mixture of iocarmate or metrizamide and blood developed no more significant arachnoid fibrosis than animals exposed to the contrast medium alone. Lumbar puncture with bloody cerebrospinal fluid, although a possible cause of adverse effects, is not a contraindication to proceeding with metrizamide myelography.