Successful Medical Management of a Retroperitoneal Abscess: A Difficult Diagnosis in Pyrexia of Unknown Origin

Retroperitoneal abscesses are uncommon conditions with occult and insidious presentations. There is often a lack of abdominal signs and ultrasound findings, causing a delay in diagnosis and definitive treatment, leading to poor patient outcomes. We report a case of right-sided retroperitoneal abscess of a 28-year-old female patient with diabetes mellitus. Prior to admission, the patient reported a vague 2 weeks history of right-sided back and abdominal pain and dysuria. She presented to our medical ward with suspected pyelonephritis with right-sided renal abscess. A retroperitoneal abscess involving the right renal fossa was revealed on an urgent CT scan. The patient underwent percutaneous ultrasound-guided pigtail catheter drainage. Patient clinically and biochemically improved with medical management gradually over 2 weeks. This case report highlights the importance of investigating for recurrent urinary tract infections of diabetics which are often overlooked in general practice