Pharmacological prevention of delayed hypersensitivity reactions caused by iodinated contrast media

Background

Delayed hypersensitivity reactions (DHRs) to radiocontrast media (RCM) occur in approximately 0.5–23.0% of patients and are thought to be caused by T cell-mediated mechanisms. However, an optimal pharmacological preventive strategy is not yet established in patients with histories of delayed reactions to RCM.

Objective

We aimed to evaluate the efficacy of pharmacological prevention in patients with histories of delayed reactions to non-ionic low-osmolar RCM when re-exposed to RCM.

Methods

A retrospective review of electronic medical records of 117 patients with previous histories of DHRs to RCM who visited an allergy clinic for the prevention of reactions after the re-exposure to RCM was conducted. The effects of pharmacological prevention were compared according to the symptom scores of previous reactions based on their intensities and durations with electronic medical records (EMRs).

Results

Of the 117 patients who experienced DHRs after RCM injection, we confirmed the outcomes of RCM re-exposure in 101 patients. For pharmacological prevention, 92 patients (91.1%) received steroids before RCM injection and among them, 50 patients (49.5%) received additional steroids after RCM injection. With this pharmacological prevention, patients of symptoms improved or no recurrence, recurrence of similar previous symptoms, and recurrence of worse symptoms were 98 (97.0%), 2 (2.0%), and 1 (1.0%), respectively. The proportions of no recurrence after pharmacological prevention were lower in patients with severe reactions and higher symptom scores.

Conclusion

Pharmacological prevention showed a beneficial effect in most patients with delayed hypersensitivity to RCM. Further investigations are needed to establish an effective protocol for the prevention of delayed reactions to RCM.

Impact of pretreatment with carnitine and tadalafil on contrast-induced nephropathy in CKD patients

Objective: The present study assesses whether phosphodiesterase type 5 (PDE-5) inhibitor or carnitine exert nephroprotective effects against clinical contrast-induced nephropathy (CIN).

Materials and Methods: The present study consisted of three groups of CKD patients. The first group was control group, who were treated with N-acetyl-L-cysteine 1 day before and on the day of radiocontrast administration. The second one was carnitine group, where the patients were infused with carnitine over 10 min 2 h prior to the radiocontrast administration and 24 h post CT. The third one was PDE-5 inhibitor group, where patients were given tadalafil 2 h prior to the administration of the radiocontrast and in the subsequent day. Urine and blood samples were collected before and at the following time sequence: 2, 6, 12, 24, 48, and 120 h after the contrast administration, for creatinine and NGAL determination.

Results: Pretreated with N-acetyl-L-cysteine prior to administration of contrast media (CM) to CKD patients caused a significant increase in urinary but not of plasma neutrophil gelatinase-associated lipocalin (NGAL) and serum creatinine (SCr). In contrast, pretreatment with carnitine prevented the increase in urinary NGAL and reduced SCr below basal levels. Similarly, tadalafil administration diminished the elevation of CM-induced urinary NGAL.

Conclusions: These results indicate that carnitine and PDE-5 inhibitors may comprise potential therapeutic maneuvers for CIN.

Anaphylaxis to drugs

Drug-induced anaphylaxis is a common cause of anaphylaxis and a leading cause of fatal anaphylaxis. Antibiotics, radiocontrast, and nonsteroidal anti-inflammatory drugs are commonly implicated drugs. Vocal cord dysfunction can mimic anaphylaxis and is often overlooked. β-Lactams are a common cause of anaphylaxis; however, skin testing and drug challenge can usually determine tolerability of other classes of β-lactams. Nonionic contrast agents cause anaphylaxis less frequently than ionic contrast, and immunoglobulin E-mediated mechanisms may have a role in some of these reactions. Skin testing with radiocontrast may have a role in evaluating patients with anaphylaxis to nonionic contrast.

A Practical Approach to Preventing Renal Complications in the Catheterization Laboratory

Kidney injury following cardiac catheterization is an infrequent, though persistent, complication, which in some cases may be preventable. Patients at increased risk for renal complications following catheterization can be identified through individual and procedural risk factors, and several risk-prediction models are readily available. The authors advocate for the development of an easily implemented and standardized protocol, readily accessible to catheterization laboratory staff, for the identification and treatment of those patients who may be at increased risk for renal complications following cardiac catheterization.

Comparison of serum creatinine and spot urine interleukin-18 levels following radiocontrast administration

Radiocontrast administration is an important cause of acute renal failure. In this study, compared the plasma creatinine levels with spot urine IL-18 levels following radiocontrast administration. Twenty patients (11 males, 9 females) underwent radiocontrast diagnostic and therapeutic-enhanced examinations. The RIN Mehran risk score was low (≤5). The radiocontrast agents used were 623 mg/mL Iopromid (1.5 mL/kg), and 100 mL of 650 mg/mL meglumine diatrizoate as three-way oral and rectal contrast material for abdominal computed tomography (CT) scans. Serum blood urea nitrogen, creatinine, Na, K, Cl, Ca, P, creatinine clearance, and spot urine IL-18 levels were analyzed before and repeated at 24, 48, and 72 h after radiocontrast administration. Six and 24-h urinary IL-18 levels were measured with a human IL-18 ELISA kit following radiocontrast administration. An increase in plasma creatinine 24 and 48 h following radiocontrast administration was observed compared with precontrast values, but it was not statistically significant (P=0.052 and P=0.285, respectively). A statistically significant increase in IL-18 levels was observed at 6 and 24 h, compared with precontrast values (P=0.048 and P=0.028, respectively). A tendency for postcontrast 24-h urinary IL-18 levels to increase was observed compared with 6 h, but the increase was not statistically significant (P=0.808). Our results show that plasma creatinine starts to increase at 24^th hour; however, spot urine IL-18 levels go up at 6^th hour following radiocontrast administration implying urine IL-18 to be an earlier parameter for kidney injury.