Contrast media iodinated

A 70-year-old woman with a history of mastectomy developed syncope which lasted a few seconds. She had taken tamoxifen 10 mg bd for 10 years and had no history of allergic reactions. Doppler ultrasound showed aortic stenosis and coronary angiography was performed using 150 ml of iopromide (a non-ionic contrast medium, iodine 370 mg/ml). She had visual hallucinations (spiders on the wall, moving curtains) 30 minutes after the injection of iopromide. The symptoms resolved 72 hours later without any specific treatment. Neurological and psychiatric examinations were normal, as were brain MRI and Doppler ultrasound of the carotid and vertebral arteries. 

Extravasation of barium sulfate iato the peritoneal cavity through a perforated GI tract can produce serious adverse reactions. When a perforation is suspected, the use of a water-soluble iodinated contrast medium is iadicated. In this case, oral or rectal administration of sodium or meglumine-sodium salts of diatrizoic acid (6) and oral use ofiohexol (11) are the preferred procedures. 

In industry, iodine is used for dyes, antiseptics, germicides. X-ray contrast medium, food and feed additives, pharmaceuticals, medical soaps, and photographic film emulsions and as a laboratory catalyst to either speed up or slow down chemical reactions. 

All patients admitted to a hospital during 6 months who had taken at least one dose of metformin were retrospectively evaluated for susceptibility factors for metformin-associated lactic acidosis (8). There were 263 hospitalizations in 204 patients. In 71 admissions there was at least one contraindication, such as renal or liver disease, renal dysfunction, congestive cardiac failure, metabolic acidosis, or an intravenous iodinated contrast medium given within 48 hours of metformin. In 29 (41%) metformin was continued despite the contraindication. The most frequent contraindication was a raised serum creatinine, but in only eight of the 32 admissions was metformin withdrawn. Of nine patients using metformin who died (not necessarily directly related to metformin), six had an absolute contraindication. In two patients who died and in one who survived, blood lactate was increased and this was temporally related to the use of metformin. 

Radiocontrast media can induce acute renal insufficiency in patients taking metformin (139,140). Metformin should be withdrawn 2 days before an iodinated contrast medium is given (SEDA-21, 445) and the following protocol has been suggested (141) ... 

The effects of iopromide on thyroid function have been investigated in 20 pre-term infants with very low birth weights and 26 matched premature infants who did not receive contrast medium (571). The dose of iopromide (iodine 300 mg/ml) was 0.3-1.0 ml. Iopromide did not affect the concentrations of free thyroxine and thyroid stimulating hormone. This was attributed to the small amount of free iodide that iopromide contains... 

In three women (aged 63, 72, and 75 years) with sub-clinical goiters, hyperthyroidism developed after the intravenous administration of iodinated contrast medium (573). There was a marked rise in the concentration of free T4. The hyperthyroidism improved spontaneously in all three. 

Prophylaxis is generally not necessary Patients at risk should be closely monitored by endocrinologists after iodinated contrast medium injection In selected high-risk patients prophylactic treatment may be given by an endocrinologist this is more relevant in areas of dietary iodine deficiency Intravenous cholangiographic contrast media should not be given to patients at risk... 

Recommendation Isotope imaging of the thyroid should be avoided for 2 months after iodinated contrast medium injection. 

Dembinski J, Arpe V, Kroll M, Hieronimi G, Bartmann P. Thyroid function in very low birthweight infants after intravenous administration of the iodinated contrast medium iopromide. Arch Dis Child Fetal Neonatal Ed 2000 82(3) F215-7. 

Laissy JR Menegazzo D, Dumont E, et al. Hemodynamic effect of iodinated high-viscosity contrast medium in the rat kidney a diffusion-weighted MRI feasibility study. Invest Radiol 2000 35 647-652. 

Thomsen HS, Morcos SK. In which patients should serum creatinine be measured before iodinated contrast medium administration Eur Radiol 2005 15 749-754. 

A 47-year-old man with chest pain and a myeloproliferative disorder had a CT scan of the abdomen with contrast enhancement (the type of contrast medium was not stated) (67). He had no significant past medical history or history of allergy. During a later CT scan of the abdomen infusion of 60 ml of the non-ionic monomer iohexol (iodine 300 mg/ml) caused a sudden cardiac arrest. Resuscitation was ineffective and postmortem examination showed intramural acute and old organizing infarctions in the entire left ventricular wall. 

Six hours after 10 ml of iohexol (Omnipaque, iodine 240 mg/ml) had been injected into the left lateral ventricle during an operation on the thalamus of a 63-year-old man with Parkinson s disease, his level of alertness deteriorated and he became disorientated and confused. A CT scan of the head showed the surgical lesion and artefacts due to contrast medium, but no other abnormalities. After 24 hours, he became more alert, with coherent speech, but there was still mild disorientation. These symptoms resolved within the next 2 days. 

The right hemisphere was more affected in this case, because the contrast medium injected into the left ventricle or ascending aorta during angiography is likely to reach the right brachiocephalic artery first. The hyperdensity of the affected cerebral hemisphere seen on CT scanning was due to leakage of the iodinated contrast medium into the extracellular space, because of an increase in the permeability of the blood-brain barrier. 

Acute reduction in renal perfusion is considered important in the pathophysiology of contrast agent-induced nephrotoxicity. Color-coded duplex sonography has been used in assessing intrarenal vascular resistance in 10 patients (mean age 51 years) after intravenous injection of 100 ml of the low-osmolar contrast medium iopamidol (iodine 300 mg/ml) (182). The resistive index was measured at 1-minute intervals over 10 minutes after injection in each patient. There was a statistically significant rise in resistive index at 2, 3, 4, and 5 minutes after injection, mean values 0.74, 0.75, 0.72, and 0.75... 

A study from Germany has shown that the antioxidant acetylcysteine plus intravenous saline 0.45% prevented the reduction in renal function induced by contrast agents (190). The authors prospectively studied 83 patients with chronic renal impairment (creatinine clearance under 50 ml/minute). The patients took oral acetylcysteine 600 mg bd for 1 day before and 1 day after the contrast medium. Saline 0.45% was given intravenously at a rate of 1 ml/kg/hour for 12 hours before and 12 hours after 75 ml of iopromide (iodine 300 mg/ml) intravenously. All the patients were encouraged to drink if they were thirsty. A matched control group received placebo and saline. The mean serum creatinine in the control group (42 patients, mean age 65 years) rose from a mean of 212-226 pmol/l 48 hours after contrast injection. In those... 

Theophylline, a non-selective adenosine receptor antagonist, has also been recommended, since adenosine has been suggested to be an important mediator of contrast-induced nephrotoxicity. Patients undergoing coronary angiography with the high-osmolar contrast medium dia-trizoate (iodine 370 mg/ml) were randomized to receive either theophylline (200 mg bd orally 24 hours before and for 48 hours after coronary angiography, n = 35, mean age 54 years, mean dose of contrast medium 78 ml) or placebo (n = 35, mean age 52 years, mean dose of contrast medium 80 ml) (197). The glomerular filtration rate... 

In 17 of 53 cases with obstructive lymphedema there was an increase in Umb volume after lymphangiography with Lipiodol ultrafluid (iodinated poppy seed oil), and 10 cases had features resembling Ijmphangitis. In one patient there was an allergic reaction, with rapid development of edema and an increase in limb volume by 2 liters. Whereas contrast medium virtually disappears from normal Ijmphatics within 8 hours, in cases of obstructive lymphedema Lipiodol remains in the lymphatics for several days and it appears to cause a low grade chemical inflammation with obliteration of the lymphatics (SEDA-7, 454). 

Shimura H, Takazawa K, Endo T, Tawata M, Onaya T. T4-thyroid storm after CT-scan with iodinated contrast medium. J Endocrinol Invest 1990 13(l) 73-6. 

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