Case Presentation: A 59-year-old male with a past medical history of end-stage renal disease on hemodialysis, hypertension, diabetes mellitus, and a recent diagnosis of multi-microorganism osteomyelitis due to diabetic foot ulcer on intravenous vancomycin and ertapenem for the past 2 weeks presented to the hospital for visual and auditory hallucinations. The symptoms started shortly after the initiation of intravenous antibiotics and acutely worsened over the last 3 days. The hallucinations were described by the patient as seeing family members and hearing family members calling his name. Vital signs and physical exam were unremarkable. Labs were negative for any metabolic etiology. Brain MRI was unremarkable. Given the onset of symptoms with the administration of antibiotics, ertapenem was discontinued and after review of susceptibilities of the infection, he was started on ciprofloxacin 500mg PO and continued on vancomycin IV. Since the discontinuation of ertapenem, the patient did not experience any hallucinations and was subsequently discharged.
Discussion: Drug-induced neurotoxicity is a rare adverse reaction associated with carbapenem antibiotics. Seizures are the most frequently reported neurotoxicity. Imipenem has classically been associated with the highest incidence of neurotoxicity among the carbapenems. However, few cases have been reported about ertapenem related neurotoxicity (both seizure- and non-seizure-related). Isolated hallucinations without any other neurotoxicity symptoms have been reported in a few cases, and most of these cases were in patients with renal insufficiency. Our patient presented with isolated hallucinations without any other signs of neurotoxicity, and dramatic improvement was achieved after discontinuing the medication.
Conclusions: The use of carbapenems has increased and most likely will continue to increase due to the high prevalence of multidrug-resistant organisms. Providers should be aware of hallucinations as a toxicity of ertapenem, particularly in older patients and those with renal impairment. Furthermore, judicious use of ertapenem is recommended, especially in the elderly and patients with renal insufficiency.