A marked elevation in serum creatinine/cystatin C ratio may indicate pseudo-acute kidney injury due to urinary ascites: a case report and literature review

Background Urinary ascites represents a scarcely observed pseudo-acute kidney injury in clinical settings. Protracted or missed diagnosis may hold grave ramifications for patient outcomes. Case presentation We reported a case involving an elderly female patient experiencing pseudo-acute kidney injury accompanied by ascites, wherein her renal dysfunction persisted despite medical intervention and hemodialysis. Urinary ascites was identified via a methylene blue test and by contrasting creatinine levels in serum and ascites. This patient’s kidney function was multiple typified by a marked elevation in serum creatinine/Cystatin C ratio (> 2 L/dL), potentially serving as a clue for the clinical diagnosis of pseudo-acute kidney injury engendered by urinary ascites. Conclusions This case suggested the potential diagnostic value of an asynchronous increase in serum creatinine and serum CysC (or an increased ratio of blood creatinine to blood CysC) in patients with pseudo-acute kidney injury.