INTRODUCTION. Intermittent or continuous intraperitoneal administration of cefazolin and ceftazidime, a first- and third- generation parenteral cephalosporin, is a widely used regimen for the initial empiric treatment of peritonitis in the peritoneal dialysis (PD) patient. We describe a case of mental confusion and convulsions in a continuous ambulatory peritoneal dialysis (CAPD) patient after receiving intraperitoneal therapy with cefazolin for the treatment of PD-related peritonitis. Like other cephalosporin antibiotics, cefazolin has been reported to be epileptogenic in a number of circumstances, but to our knowledge, has not been previously reported in patients undergoing peritoneal dialysis (PD).

CASE REPORT. A 76-year-old male patient was admitted to our Department because of PD-related peritonitis (WBC 1,530/mm3). He was given intraperitoneal ceftazidime 500 mg/L dialysis fluid, and cefazolin 500 mg/L as a loading dose, followed by a maintenance dose of ceftazidime 125 mg/L and cefazolin 100 mg/L, intraperitoneally, 4 times daily. On day 3, the patient was discharged with an intermittent dose of intraperitoneal cefazolin (1.5 g) added to the nighttime dwell. On day 5, he was readmitted to the hospital because of progressive mental confusion, insomnia, and abnormal behaviour. On the same day, the patient suffered a generalized tonic–clonic seizure lasting three minutes, characterized by ocular twitching, repetitive arm movements, unresponsiveness, and postictal confusion. Electrolyte disturbances were excluded with normal sodium, potassium, calcium and magnesium levels. Computed tomography of the brain and electroencephalogram were unremarkable. Seizures due to drug-induced encephalopathy was suspected and cefazolin was thought to be the causative agent and was discontinued. The patient did not develop any more seizures after cefazolin was discontinued and his mental status gradually improved over the next 3 days, until he was discharged.

CONCLUSION. Our case well illustrated that intermittent intraperitoneal cefazolin can cause acute confusion and convulsions even with an apparently adequate dosage. In treating PD-related peritonitis, more attention should be paid to the elderly patient with predisposing factors.