Delayed Anaphylaxis to Intravenous Colistin in a Critically Ill Cancer Patient: A Case Report

Introduction:Anaphylaxis is an acute, life-threatening, multi-system syndrome that has been reported with a wide range of medications. Though anaphylaxis usually has a rapid onset, we describe a patient who developed anaphylaxis to intravenous colistin after 28 days of daily administration. Case presentation:A 20 years-old Caucasian male patient, with a history of relapsed acute myeloid leukemia, was transferred from the medical floor to our intensive care unit with septic shock. The source of infection was presumed to be a recto-cecal abscess and arm cellulitis. Cultures were positive for extended spectrum beta-lactamase (ESBL) and carbapenem-resistant enterobacteriaceae (CRE) Escherichia coli. for which he was receiving broad spectrum antibiotics, as well as intravenous colistin, started about 4 weeks earlier. On day 2 of ICU admission, and during the administration of colistin, the patient experienced an anaphylactic reaction. He developed hypotension requiring the initiation of norepinephrine, shortness of breath, hypoxia, tachycardia, and tachypnea. The reaction was resolved after supportive therapy but it was thought to be related to septic shock and therefore the patient continued on colistin the following day. The patient tolerated colistin for the next 3 days before developing another similar, but more severe, reaction. Colistin was discontinued and the symptoms resolved following supportive therapy. Conclusion:This case highlights the importance of being aware of delayed serious reactions that may occur several weeks after initiation of drug therapy. In addition, successful re-initiation may not necessarily rule out the recurrence of such reactions and therefore close monitoring is crucial.