Is urodynamic study a good witness to the progression of ketamine-associated cystitis?

Objectives: Ketamine abuse may cause variable lower urinary tract symptoms and severe cystitis. In this study, we evaluated the relevance of urodynamic parameters according to the dose and duration of ketamine use and investigate the value of urodynamic studies in determining the severity of ketamine-associated cystitis (KC). Methods: The urodynamic study results of 30 patients with KC between January 2009 and December 2012 were analyzed retrospectively. All patients had been diagnosed based on their history and clinical features before urodynamic investigations. Cystoscopy was performed to confirm the diagnosis and measure the maximum anesthetic bladder bladder capacity (MBC) (under spinal anesthesia). Results: The mean (± standard deviation) age of patients with KC was 22.0±3.3years. The mean duration of ketamine abuse was 39.0±20.8months. Maximum cystometric capacity was 115±66.6mL. Seventy-five percent of patients had a high maximal urethral closure pressure (MUCP) (>90cmH₂O). There was no significant difference of urodynamic parameters between the high-dose (≥5gm/day) and low-dose groups (<5gm/day) or the long-duration (≥3years) and short-duration (<3years) groups. However, the MBC was significantly lower in high-dose and long-duration groups compared to the low-dose and short-duration groups (191.3±68.5 vs. 299.0±99mL; P=0.01; 219.0±59.7 vs. 325.5±104.5mL; P=0.002). Conclusions: The urodynamic test results help diagnose KC, but may not be useful in determining the severity of the disease. The MBC measured under anesthesia may be a better predictor of the disease progression in KC.