Contrast medium allergic reactions

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. 

Hearing disturbances attributable to contrast agents are extremely rare. The hearing loss in this patient developed more than 1 hour after the injection of iohexol, without any evidence of other causes. The authors suggested that the hearing disturbance might have been attributable to cochlear impairment caused by a delayed allergic reaction or chemical toxicity of the contrast medium. 

The rectal administration of Gastrografin 400-1000 ml in patients with suspected diverticular disease before CT examination of the abdomen has been investigated in 308 patients (aged 19-97 years) (147). None of the CT scans showed extravasated contrast material in the peritoneal cavity as a sign of bowel perforation. No patient had sudden clinical deterioration after the examination. All tolerated the contrast medium well and there were no allergic reactions. High-quality diagnostic examinations were obtained in all patients. 

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). 

Lorenz R. Allergic reaction to contrast medium after endoscopic retrograde pancreatography. Endoscopy 1990 22(4) 196. 

In humans the allergic reactions from contrast media resemble those elicited by histamine injection, and the unpleasant side effects are rarer after fast injection than after slow injection of the same dose of contrast medium (489). Seidel et al. (724) showed that usual doses of chemically different contrast media were able to affect the plasma histamine levels in venous blood of healthy persons. Histamine release ceases when the dose rate is reduced to 0.17 g kg min This may explain the advantage of administering urographic agents by infusion to avoid reactions. 

An allergic or idiosyncratic reaction related to the contrast medium can occur after HSG, although the incidence is unknown and is presumably quite low. 

Risk factors for acute reactions to contrast media are summarized in Table 10.4. The most significant risk is for patients who have experienced a previous immediate reaction to an iodinated contrast medium. Reexposure to the same or structurally similar ionic preparation is said to carry with it a 21-60 % risk of a repeat reaction. This risk is one-tenth as great if a nonionic contrast medium is substituted for the repeat injection. Comparable figures for nonionic media used for the initial and the repeat administrations do not seem to be available. Other important risks are bronchial asthma, the use of p-blockers, cardiac disease, and subjects who are highly allergic. Procedures and efforts to reduce the risks of an acute reaction are set out in Table 10.4. Some of... 

Observational studies Polyvinyl alcohol fibers and films are used in medicine and pharmacology because of their ability to swell, absorb toxic products, decompose necrotic masses, and reduce blood loss [78 ]. A mixture of polyvinyl alcohol with ketoprofen has been used to reduce pelvic pain after uterine artery embolization [79 ] in a randomized prospective study in 80 patients, 40 of whom received ketoprofen mixed with polyvinyl alcohol particles and 40 polyvinyl alcohol alone. During embolization, only five patients recorded a pain score of 1-2. One had an allergic reaction to the contrast medium 13 of the patients who received pol)rvinyl alcohol alone reported severe or very severe pain, compared with none of those who received ketoprofen plus poljrvinyl alcohol. 

Vasovagal reaction (bradycardia, pallor, and loss of consciousness) is related to pain rather than contrast medium. The lower limbs are elevated atropine is sometimes useful. Mild allergic accident (itching, urticaria) can be treated by corticoids and an anti-histaminic medication. 

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