Probable Reversible Encephalopathy with Ceftazidime/Avibactam and Aztreonam: A Case Report

Abstract

A combination of ceftazidime-avibactam (CZA) and aztreonam (ATM) is a critical therapeutic option for infections caused by Metallo-β-lactamase (MBL) producing, multidrug-resistant Gram-negative bacteria. While neurotoxicity is a known adverse effect of β-lactam antibiotics, reports of encephalopathy associated with the CZA+ATM regimen are rare. Here, we present the case of a 30-year-old female renal transplant recipient, admitted for DJ stent replacement, who developed CRE & XDR Klebsiella pneumoniae bacteremia and received ceftazidime–avibactam 2.5g BD plus aztreonam 1g BD following inadequate response to prior antibiotics. No appropriate dose adjustment was made for her severe renal impairment (CrCl 8.1 mL/min). Four days after initiation of this combination regimen, she acutely developed restlessness, irritability, myoclonus, asterixis and a progressive decline in consciousness, consistent with new-onset encephalopathy. Both antibiotics were immediately discontinued, and the patient was managed supportively with electrolyte repletion and hemodialysis. Her neurological symptoms demonstrated complete and rapid resolution within 72 hours. The temporal relationship between drug administration and symptom onset, coupled with the swift recovery upon withdrawal, implicates the CZA+ATM combination as a probable causative agent, particularly in patients with renal impairment, and underscores the need for neurological monitoring during therapy.