A 55-year-old male patient presents to pain clinic with suprapubic pain. He also has dysuria, haematuria and nocturia. Investigation showed he has hydronephrosis, sterile pyuria and an increased eosinophil count. He has a history of drug abuse and has been homeless recently. He smokes cannabis and mixes ketamine with tobacco to feel high. He has seen his GP who referred him to the pain clinic for further management of his pain.