Delayed severe anaphylactoid reaction following retrograde pyelogram: A case report

Outcomes in patients with known contrast allergy undergoing contrast-enhanced endourological procedures: a retrospective cohort study

BACKGROUND

Intravenous administration of iodinated contrast agents carries the risk of allergic reaction, yet this risk is unclear with administration into the urinary tract. We sought to evaluate patients with known contrast, iodine, or shellfish allergies for allergic response when undergoing urologic imaging requiring intraluminal, urinary tract contrast administration.

MATERIALS AND METHODS

We retrospectively reviewed consecutive patients undergoing endourologic procedures from 2010 to 2015 at our institution. Clinical records were reviewed for demographics, medical history, allergies, procedure details, fluids administered, anesthetic and pharmacologic agents administered, and continuous monitoring parameters. Patients with known allergies to iodine, shellfish, and/or contrast were identified and evaluated for clinical or hemodynamic signs of allergy. A convenience sample of 50 patients without allergy history was used as a comparison group.

RESULTS

We identified 1,405 procedures involving 1,000 consecutive patients. Procedures included retrograde pyelograms and antegrade nephrostograms. Eighty-six cases involving 58 patients with contrast, iodine, or shellfish allergies were identified. Of those with contrast allergy history, 18 (20.1%) cases involved patients with a history of anaphylactic reaction. Of these, 11 (61%) received steroid prophylaxis. No patients in either group (Allergy, No Allergy) were identified as having an allergic reaction during the procedure. There were no statistically significant differences in intraoperative intravenous fluids (p=0.931), procedure duration (p=0.747), or vasopressor use (p=0.973) between groups. Due to the zero event rate of contrast allergy, we used the Hanley and Lippman-Hand method, which places true population risk (95% confidence interval) of a significant event at less than 3.5%.

CONCLUSIONS

In 86 cases involving patients with a history of contrast allergy, we found no evidence of clinically significant allergic reaction to intraluminal endourologic contrast administration under continuous anesthesia monitoring. The risk of significant reactions to contrast administered within the urinary tract appears to be low in these patients, regardless of prophylaxis.

Anaphylactoid Reactions After Instillation of Contrast Material Into the Urinary Tract: A Survey of Contemporary Practice Patterns and Review of the Literature

OBJECTIVE

To assess drug reactions (ADRs) encountered by practicing urologists for contrast instilled into the urinary collecting system, and to describe current practice patterns regarding contrast administration into the urinary tract for patients with known contrast allergies.

METHODS

Endourological Society members were e-mailed a web-based survey about their prior experience with contrast-related ADRs and practices for contrast administration into the urinary tract among patients with known intravenous contrast allergies. Chi-squared analysis was used to compare management patterns between patients with established allergies and those without.

RESULTS

An estimated 2300-2500 e-mails were reached, resulting in an estimated response rate of 6.3%-8%. Over 75% of respondents were fellowship trained. Average time in practice was 16 years, and respondents performed a mean of 6.7 urologic contrast studies per week. Among respondents, 32.6%, 14.7%, and 4.0% had treated at least 1 patient with a mild, moderate, or severe reaction, respectively. Contrast-related ADRs were most commonly associated with retrograde pyelogram (50%). For patients with known contrast allergies, 5.4% pursue additional work-up before administering contrast in the urinary tract. Pretreatment with antihistamine or steroids is used by 24.8% and 23.4%, respectively. When performing retrograde pyelograms for such patients, urologists are more likely to use dilute contrast (P = .003), but otherwise do not significantly alter technique.

CONCLUSION

Contrast ADRs are encountered not infrequently among practicing urologists. There is notable practice variation in the management of patients with known contrast allergies, though the overall perceived risk of contrast use in these patients is low, provided good technique is used.