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The Presenting Symptoms Associated With Arachnoiditis And The Experience Of Living With Them In Everyday Life A thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Nursing at Massey University by Christine Hopkins - 1998 Appendix One.Iophendylate (Myodil, Pantopaque) Iophendylate is an ionic monomeric contrast medium that was formerly used for myelography. Myodil is the name by which iophendylate was known in New Zealand and Great Britain. In America, it was known as Pantopaque. It had an oily consistency and was thought to slowly clear over many years. Adverse effects were of two kinds: acute and chronic meningeal reactions, with the chronic reaction usually being described as adhesive arachnoiditis. Although up to 67% of patients were thought to develop asymptomatic arachnoiditis, symptomatic arachnoiditis was thought to occur in only possibly 1 to 2% of patients. Experimental studies indicated that blood in the CSF may increase menigeal reaction. Removal of iophendylate has been a controversial issue. Centres using small amounts tended not to remove it, others using large amounts sometimes sought to remove some of it. Junck, L. & Marshall, W. (1983). Neurotoxicity of radiological contrast agents. Annals of Neurology, 13, 469-484. Metrizamide (Amipaque) is a radiographic contrast medium used for lumbar, thoracic, and cervical columnar myelography, CT cisternography, ateriography, phlebography, urography and body cavities. It was introduced in 1974 and was hailed as a marked improvement over iophendylate in regard to neurological toxicity, including the development of arachnoiditis. Distribution in New Zealand ceased in 1986-7 and the product was noted in Ministry of Health files as being formally withdrawn in 1992, by which time it had not been distributed in New Zealand for a five year period (Private Communication, Department of Health, 1997). The Medical Adverse Reactions Committee (MARC) had no occasion to consider metrizamide and the Department of Health did not communicate anything to practitioners or specialists about metrizamide (ibid). Although short term effects have been reported, metrizamide is still widely considered to have no role in the subsequent development of arachnoiditis after its use, despite its development in high dose animal trials. The manufacturer, Winthrop, notes the most frequently occurring adverse reactions as headache, nausea and vomiting, usually occurring within 24 hours. Aseptic meningitis syndrome (chemical meningitis) is reported as rare, less than 0.1%, and usually preceded by pronounced headache, nausea and vomiting. Onset is 12 to 18 hours after the procedure and clears spontaneously about 10 hours after onset, with complete recovery over 2 to 3 days. Metrizamide is absorbed from the cerebrospinal fluid into the blood stream. Approximately 60% of the administered dose is excreted unchanged through the kidneys within 48 hours. It is noted that between 12 and 24 hours after administration, the surfaces of the cerebrum and cerebellum in contact with the subarachnoid space will develop a “blush” effect on the scan which will normally disappear in 36 to 48 hours. Metrizamide is contraindicated in people with a known hypersensitivity to metrizamide or other iodine-containing contrast media, and precautions are necessary in those with allergy histories, but sensitivity to iodine itself is not mentioned. Fatal reactions associated with water-soluble contrast media have mostly been attributed to chemical, allergic or idiosyncratic effects. Amipaque: An advanced concept in contrast media for myelography and ventriculography. Information sheet. Ermington, N.S.W.:Winthrop laboratories. (Undated). Iopamiro is a tri-iodinated, non-ionic, water-soluble, contrast medium suitable for intravascular, intrathecal and body cavity administration in radiographic procedures. It is indicated for lumbar and thoraco-cervical myelography and for CT enhancement. Although a number of adverse effects are mentioned on the data sheet, arachnoiditis is not among them. Iopamiro Data Sheet, Rhone-Poulenc Rorer, New Zealand Ltd., 1995 |
