Urine may be red, bloody, or cola-colored gross hematuria with oxidation of blood retained in the bladder or not visibly discolored microscopic hematuria. Isolated hematuria is urinary RBCs without other urine abnormalities eg, proteinuriacasts.
Red urine is not always due to RBCs. Red or reddish brown discoloration may result from the following: Hemoglobin or myoglobin in urine Foods eg, beets, rhubarb, sometimes food coloring Drugs most commonly phenazopyridine, but sometimes cascara, diphenylhydantoin, methyldopa, phenacetin, phenindione, phenolphthalein, phenothiazine, and senna Pathophysiology of Isolated Hematuria Red blood cells RBCs may enter urine from anywhere along the urinary tract—from the Macro hematuria prosztatitis, collecting system and ureters, prostate, bladder, and urethra.
In females, normal or abnormal uterine bleeding may be misdiagnosed as hematuria. Etiology of Isolated Hematuria Most cases involve transient microscopic hematuria that is self-limited and idiopathic.
There are numerous specific causes see table Some Specific Causes of Hematuria. The most common specific causes differ somewhat by age, but overall the most common are.