Immediate Hypersensitivity to Contrast Agents: The French 5-year CIRTACI Study

BACKGROUND

Iodinated and gadolinium-based contrast media (ICM; GBCM) induce immediate hypersensitivity (IH) reactions. Differentiating allergic from non-allergic IH is crucial; allergy contraindicates the culprit agent for life. We studied frequency of allergic IH among ICM or GBCM reactors.

METHODS

Patients were recruited in 31 hospitals between 2005 and 2009. Clinical symptoms, plasma histamine and tryptase concentrations and skin tests were recorded. Allergic IH was diagnosed by intradermal tests (IDT) with the culprit CM diluted 1:10, "potentially allergic" IH by positive IDT with pure CM, and non-allergic IH by negative IDT.

FINDINGS

Among 245 skin-tested patients (ICM = 209; GBCM = 36), allergic IH to ICM was identified in 41 (19.6%) and to GBCM in 10 (27.8%). Skin cross-reactivity was observed in 11 patients with ICM (26.8%) and 5 with GBCM (50%). Allergy frequency increased with clinical severity and histamine and tryptase concentrations (p < 0.0001). Cardiovascular signs were strongly associated with allergy. Non-allergic IH was observed in 152 patients (62%) (ICM:134; GBCM:18). Severity grade was lower (p < 0.0001) and reaction delay longer (11.6 vs 5.6 min; p < 0.001). Potentially allergic IH was diagnosed in 42 patients (17.1%) (ICM:34; GBCM:8). The delay, severity grade, and mediator release were intermediate between the two other groups.

INTERPRETATION

Allergic IH accounted for < 10% of cutaneous reactions, and > 50% of life-threatening ones. GBCM and ICM triggered comparable IH reactions in frequency and severity. Cross-reactivity was frequent, especially for GBCM. We propose considering skin testing with pure contrast agent, as it is more sensitive than the usual 1:10 dilution criteria.

Indication for and technical refinements of submental intubation in oral and maxillofacial surgery

INTRODUCTION

In maxillofacial injuries, a choice has often to be made between different ways of intubation when surgical access to both the nasal and the oral cavities is necessary. Submental intubation is an interesting alternative to tracheotomy, especially when short-term postoperative control of the airway is foreseeable, and as control of the dental occlusion is complete, and access to the nose and mouth is undisturbed.

MATERIAL

This kind of intubation has been used in our department in 25 cases since 1997. All patients had fractures disturbing the dental occlusion plus either an associated fracture of the skull base, or a displaced nasal fracture.

RESULTS

There was no intra-operative complication, average intubation duration was 1.5 days. Post-operative complications consisted of one case with hypertrophic scarring and two cases of abscess formation in the floor of the mouth. All these completely healed following local conservative treatment.

CONCLUSION

Submental intubation demands certain technical skills but it is simple, rapid and may avoid tracheotomy in selected patients.

[IgE allergy due to formaldehyde paste during endodontic treatment. Apropos of 4 cases: 2 with anaphylactic shock and 2 with generalized urticaria]

We report 4 cases of allergic reaction to formaldehyde-containing root canal sealant after endodontic care: 2 anaphylactic shocks and 2 local reactions with generalized urticaria. Allergic IgE mediated mechanisms were suggested by the clinical presentation, skin tests and high levels of anti-formaldehyde IgE. These infrequent but potentially severe reactions after canal treatment led us to examine the involved mechanisms, the diagnostic procedure and the possibility of prevention in odontostomatology.

[Bilateral subdural hematoma following epidural anesthesia]

PURPOSE

The authors report a case of bilateral subdural hematoma (SDH) which occurred following epidural analgesia for labour, complicated by post dural puncture headache (PDPH). Physiopathological mechanisms are discussed.

CLINICAL FEATURES

A 27-yr-old woman displayed typical PDPH following epidural anaesthesia. On the fifth day she was given a blood patch (BP) which proved immediately effective. Further developments were marked by late recurrence of PDPH and by administration of a second BP on the 24th day. With the aggravation of the headaches, the disappearance of their postural nature and with the appearance of transitory focal neurological signs on the 30th day, a CT-Scan was done and showed bilateral subdural haematoma. Following surgical drainage, the patient made an uneventful recovery.

CONCLUSION

The presence of PDPH complicated by a typical neurological deterioration should prompt the anaesthetist to seek an immediate clinical and x-ray diagnosis in order to look for the existence of intracranial complications.

[Anesthetics responsible for anaphylactic shock. A French multicenter study]

Combined allergological and anaesthetic consultations have been started in the last few years in eight French Teaching Hospitals so as to explore peranaesthetic anaphylactoid shocks. A survey was carried out in these centers in order to collect patients investigated with the same protocol, for the assessment of the incidence of anaphylaxis in France, as well as the involved drugs. Investigations were always carried out at least 6 to 8 weeks after the accident. The tests used to diagnose IgE-dependent anaphylaxis were skin tests (prick and intradermal tests, carried out in all eight centers), the radioimmunological assay of specific anti-quaternary ammonium IgE, together with an inhibition test with thiopentone and propofol (six centers), leukocyte histamine release (five centers) and human basophil degranulation tests (three centers) for those drugs for which no specific antibody assay exists. The collected data involved 1,240 patients, investigated within the last four years. Anaphylaxis was diagnosed in 821 patients (66.2%). Muscle relaxants were responsible in 668 cases (80% of cases of anaphylaxis). Suxamethonium was the main cause (54.3% of shocks due to muscle relaxants), followed by vecuronium (15.3%). General anaesthetics (hypnotics and benzodiazepines) were responsible for 9.2% of all cases of anaphylaxis opioids for 2.6%. There were only three cases of shock due to local anaesthetic agents. Latex and ethylene oxide are becoming increasingly involved. It would therefore seem mandatory to carry out after any anaphylactoid accident an assessment with sensitive and specific tests for anaphylaxis. Diagnosing anaphylaxis means that the involved drug should be used never again in that patient. Because muscle relaxants are by far the most involved drugs, anaesthetists should use them only when really required.