Pantopaque Meningitis Due to Hypersensitivity

The discovery and wide utilization of pantopaque as a contrast medium in the study of lesions in and about the spinal canal has led to the realization that the substance is relatively safe but not entirely innocuous. Pantopaque (ethyl iodophenylundecylate) is a mixture of isomeric ethyl esters. The literature gives ample evidence that there is an inflammatory and proliferative meningeal reaction in certain instances following the introduction of the material intrathecally (1, 2). Systemic reactions with mild fever, headache, malaise, and cerebrospinal fluid changes, including increase in cell count and protein have been observed. These reactions have been immediate in onset and occasionally have been associated with demonstrable histologic changes in the leptomeninges (3). The reactions, however, have proved in almost all instances to be transient and have not been considered contraindications to continued use of the medium as a diagnostic aid. The purpose of this paper is to present evidence of meningeal reaction to pantopaque, delayed in onset and associated with certain phenomena which strongly suggest hypersensitivity. Because of the occurrence of several severe reactions to the intrathecal injection of pantopaque, a procedure was instituted as a precaution against possible sensitivity. This consisted of the intradermal injection of 0.1 ml. of pantopaque and twenty minutes subsequent observation for the appearance of a wheal and/or erythema, the sign of a positive immediate skin reaction. The skin test was done thirty minutes preceding myelography and in over 40 cases no positive reactions were observed. More recently, however, 2 cases have been seen presenting delayed meningeal reactions accompanied by flare-ups at the original skin test sites. Case Histories CASE 1: A 22-year-old male was admitted to the hospital because of atrophy of the left lower extremity, of some five years duration, associated with persistent aching pain for the past year. The family history was essentially negative. The past history failed to reveal any episodes suggestive of poliomyelitis. The patient, had, however, suffered annual attacks of ragweed hay fever. The physical examination disclosed generalized weakness in the atrophic muscles, but no adventitious movement. The deep tendon reflexes were equal except for the left Achilles, which was absent. There were no sensory disturbances. Cerebrospinal fluid studies were within normal limits. It was felt that this patient probably had had unrecognized poliomyelitis, with his present complaints originating from a postural imbalance associated with the atrophy. A myelogram was deemed advisable, however, in order to complete the data. An intracutaneous skin test with 0.1 ml. of pantopaque was done with no immediate local reaction, and 6 ml. of pantopaque was introduced intrathecally one-half hour later.