Abstract

Objective: To present a case of suspected colistin-induced neurotoxicity, likely resulting from drug accumulation during treatment of multidrug-resistant Pseudomonas aeruginosa (PA) bacteremia.
Case report: An 18-year-old female with no prior medical history was admitted to the coronary care unit with fulminant myocarditis, requiring mechanical circulatory support and ultimately left-ventricular assist device implantation. Three weeks later, she developed PA bacteremia. Despite multiple targeted antibiotic regimens, PA persisted in subsequent blood cultures. Colistimethate sodium (CMS) was initiated at 2 × 4.5 MIU, the recommended dose according to serum creatinine-based renal function (eGFR ~ 133 mL/min/1.73m²). On day 4, the patient developed an acute confusional state with hallucinations. While serum creatinine remained stable, cystatin C and 24-hour urine clearance indicated impaired renal function (eGFR ~ 32 mL/min/1.73m²). As therapeutic drug monitoring (TDM) was unavailable, the CMS dose was reduced to 2 × 2.5 MIU based on cystatin C-estimated renal function, leading to resolution of neurological symptoms within 3 days. CMS was continued for 10 days, leading to improved inflammatory markers and clinical stabilization.
Conclusion: Colistin-induced neurotoxicity should be considered in patients with new-onset neuropsychiatric symptoms, particularly in the setting of renal dysfunction or high cumulative exposure. Reliance on serum creatinine alone may misrepresent renal function; incorporation of cystatin C or urine clearance can improve dosing accuracy and reduce toxicity risk. When therapeutic alternatives are limited, dose reduction rather than discontinuation may be an appropriate strategy. Broader implementation of TDM is essential to optimize dosing and minimize adverse outcomes in clinical practice.

Author Details

Authors

• Mirna Momcilovic¹
• Marko Siroglavic¹
• Vedran Pasara¹
• Vito Mustapic²
• Vanja Nedeljkovic¹
• Antun Zvonimir Kovac¹
• Ivan Situm¹
• Daniel Lovric¹

Departments

• ¹ University Hospital Center Zagreb, Zagreb, and
• ² Magdalena Clinic for Cardiovascular Diseases, Krapinske Toplice, Croatia

Address

Mirna Momcilovic, MPh, CPS
University Hospital Center Zagreb
Kispaticeva 12
10000 Zagreb, Croatia
Email: [email protected]

Citation