Ertapenem-induced Encephalopathy in a Patient With Systemic Lupus Erythematosus and Preserved Renal Function: A Diagnostic Challenge.

Carbapenem antibiotics are recognized for their efficacy against multidrug-resistant infections but are occasionally associated with neurotoxicity, particularly encephalopathy, predominantly in elderly patients with renal impairment. We report a case of an elderly female patient with systemic lupus erythematosus (SLE), hypertension, and preserved renal function who developed encephalopathy shortly after initiation of ertapenem for a multidrug-resistant Escherichia coli urinary tract infection. The patient manifested vivid hallucinations and confusion, prompting an extensive evaluation that ruled out infectious, metabolic, and autoimmune etiologies. Discontinuation of ertapenem alongside empiric intravenous thiamine resulted in rapid and marked clinical improvement. This case underscores the potential for ertapenem-induced neurotoxicity even in the absence of renal dysfunction.