A25-21 Integrating Electroencephalogram (EEG) and Dialysis Metrics in the Management of Cefepime Neurotoxicity

Introduction Neurotoxicity from Cefepime has been reported at serum levels above 22mg/L, particularly in patients with GFR<35.0 mL/min/1.73 m2. Currently the FDA does not specify an exact threshold for toxicity and there is no available Cefepime blood level test. Discussion A 68-year-old woman with PMH of HTN, COPD, AIDS and ESRD on hemodialysis (HD). Initially admitted with septic shock and course complicated with Subarachnoid hemorrhage; Cerebellar infarct and dependency on mechanical ventilation. After stabilization, her mental status was alert and oriented to person and place, mouthed words, and followed commands. Four days prior, the patient was started on Cefepime for pneumonia. On day 4 of Cefepime she developed acute encephalopathy characterized by inability to follow commands and mutism, labs were stable with a BUN 48, pH 7.36 and normal pCO2. CT imaging confirmed hydrocephalus, and a lumbar drain was placed, but her neurological status failed to improve after 72h of drain placement despite radiologic resolution of hydrocephalus. Extensive diagnostic workup-neuroimaging, infectious and autoimmune-was performed. Initial EEG (fig1) demonstrated generalized slowing with periodic triphasic discharges, highly suggestive of Cefepime induced neurotoxicity. Cefepime was stopped and HD was performed; due to hypotension, she had poor clearance during the three hours session of HD, manifested by a single pool Kt/V of 0.7 and a urea reduction ratio (URR) of 50%. EGG after one session of HD still showed periodic discharges with triphasic morphology. Pte had a successive HD session (12h apart) with a single pool Kt/V of 0.7 again and a URR of 46%. After stopping Cefepime and two consecutive HD sessions, EEG showed resolution of the periodic triphasic discharges(fig. 2), and the patient’s mental status was back to her baseline. Two consecutive HD sessions provided a combined URR of 73% based on BUN drop from 48 to 13mg/dl after 6h of HD without ultrafiltration. All autoimmune and infectious workups were negative. Conclusions This case highlights the diagnostic and management challenges of Cefepime neurotoxicity in the ICU population. EEG proved valuable for supporting the diagnosis and monitoring resolution, while Kt/V and URR guiding dialysis adequacy facilitated clinical recovery through enhanced drug clearance. The resolution of periodic triphasic discharges in EEG might be used in combination with dialysis adequacy markers to determine proper Cefepime clearance in cases of neurotoxicity, given the fact that there is no FDA approved Cefepime blood test to monitor drug levels.