Elevated Serum Creatinine and a Normal Urinalysis: A Short Differential Diagnosis in the Etiology of Renal Failure

Objective . The diagnosis of renal failure with a normal urinalysis represents a short differential diagnosis that has not been characterized in the literature. This study was designed to identify the specific disease states that encompass this interesting renal condition. Material . The Regenstrief database, which is an electronic medical record containing inpatient laboratory and other clinical data for patients admitted to Wishard Memorial Hospital, was utilized to provide data for this study. Methods . The database was culled to provide data for hospitalized patients admitted between March 1, 1992, and March 1, 2001, with the concurrent findings of a serum creatinine greater than or equal to 2 mg/dL, a normal urinalysis, and diagnoses of obstructive uropathy, multiple myeloma, prerenal azotemia, hypertensive nephrosclerosis, interstitial nephritis, renal vascular disease, hypokalemic nephropathy, and hypercalcemia, as identified by their corresponding ICD-9 codes. Results . A search of the Regenstrief database yielded a total of 190,343 patient admissions. There were 515 patient admissions with renal failure and a concurrent normal urinalysis. The largest specific diagnostic categories within this group were hypertension and prerenal azotemia. Conclusions . An elevated serum creatinine and normal urinalysis present a short differential for the etiologies of renal failure and include such entities as hypertensive nephrosclerosis, prerenal azotemia, obstructive nephropathy, interstitial nephritis, renal vascular disease, and various electrolyte abnormalities. An awareness of these specific disease states may lead to an earlier diagnosis and more effective treatment of renal failure.