Transient 2:1 atrioventricular block following anaphylactic reaction to low-ionic strength computed tomography contrast agent

Abstract

T he present report describes a unique response following an anaphylactic reaction to a low-ionic contrast dye used for computed tomography (CT) in a patient admitted to the hospital with sepsis. A description of the case and review of the literature is presented. case presentationA 75-year-old woman with a history of chronic obstructive pulmonary disease (COPD) was admitted to the hospital following three days of pleuritic chest pain, cough and intermittent fevers. Her baseline medications included salbutamol and ipatropium. She had had a previous skin reaction to latex but had no known drug allergies.The initial examination revealed a febrile elderly woman in moderate respiratory distress. Respiratory examination demonstrated coarse crackles to the right base. Laboratory investigations confirmed mild leukocytosis with a predominance of neutrophils. Arterial blood gases demonstrated moderate hypoxia. Baseline cardiac enzymes were normal and her initial electrocardiogram showed normal sinus rhythm at 70 beats/min. A chest x-ray confirmed right lower-lobe pneumonia and the patient began treatment with intravenous moxifloxacin and vancomycin. She was admitted to the general medicine ward with a diagnosis of COPD exacerbation with community-acquired pneumonia.During the next 72 h, despite administration of intravenous (IV) antibiotics, the patient continued to have intermittent fevers. Blood cultures confirmed the presence of methacillin-sensitive staphylococcus aureus and the patient was switched to IV cloxicillin and continued on moxifloxacin. A number of investigations were performed to identify the source of sepsis. Ultimately, a bone scan identified a large paraspinal abscess from T5 to T7, and a confirmatory contrast CT of the thoracic spine was recommended to identify whether the abscess was amenable to percutaneous drainage.Unfortunately, immediately following administration of the contrast dye for the CT scan, the patient developed marked hypotension (blood pressure 80/60 mmHg), bradycardia (heart rate 40 to 45 beats/ min) and laryngeal edema. She was resuscitated with IV diphenhydramine, epinephrine and methylprednisolone sodium succinate, as well as crystalloid fluids. She was intubated and transferred to the intensive care unit.Approximately 2 h after her episode, she had an abrupt rhythm change that was noted on the cardiac monitor. Rhythm strips and a 12-lead electrocardiogram revealed a 2:1 atrioventricular block (AVB) with narrow QRS complexes and a prolonged QT interval (Figure 1). Atropine was given without an effective change in her heart rhythm. She was hemodynamically stable and, therefore, temporary pacing was deemed not necessary. The patient gradually reverted back to sinus rhythm during the next 24 h (Figure 2). She was extubated and transferred to the coronary care unit for further observation. No further episodes of AVB were noted. She completed treatment for her pneumonia and paraspinal abscess, and the rest of her hospitalization was uneventful. DiscussionWe describe a case of transient...

Caspofungin-induced fatal complete heart block: Another manifestation of Kounis syndrome

“…[7] Transient 2:1 atrioventricular block has been reported following anaphylactic reaction to low-ionic strength computed tomography contrast agent in an elderly woman. [8] In this patient, transient prolonged QT interval was also a unique finding and it was attributed to transitory ischemia through adenosine-mediated vasospasm or a possible histamine-mediated process. Transient release in histamine levels following antigen challenge was detected in partially sensitized guinea pig hearts.…”

Transient Complete Atrioventricular Block Resulted from Cardiac Anaphylaxis Caused by Sugammadex

“…Anaphylaxis caused by a clinical dose of sugammadex has already been reported [3], but there are no reports of cases such as ours with complete AVB. Among symptoms and signs of cardiac anaphylaxis, there are few reports describing delay of atrioventricular conduction during anaphylaxis [4], and this feature of cardiac anaphylaxis is not widely recognized.…”

Author's reply

“…[7] Transient 2:1 atrioventricular block has been reported following anaphylactic reaction to low-ionic strength computed tomography contrast agent in an elderly woman. [8] In this patient, transient prolonged QT interval was also a unique finding and it was attributed to transitory ischemia through adenosine-mediated vasospasm or a possible histamine-mediated process. Transient release in histamine levels following antigen challenge was detected in partially sensitized guinea pig hearts.…”