Curriculum · Nephrology and Urology
Evaluation of haematuria
What it is
Hematuria is described three ways: as microscopic or macroscopic, as initial, total or terminal, and as painful or painless. Painless hematuria is malignant until proven otherwise.
Asymptomatic microhematuria is defined as 3 or more RBCs/hpf on a properly collected urine specimen in the absence of an obvious benign cause. One positive urine sample is enough to prompt an evaluation, and a repeat urinalysis with microscopy is not needed to confirm it.
Causes and risk
The benign causes are ruled out first: vigorous exercise, viral illness, trauma and infection. Risk factors are asked for, and smoking is named. Hematuria in a patient on anticoagulation is not put down to the drug; it is still investigated for underlying urothelial pathology.
Among glomerular causes, IgA nephropathy, also called Berger disease, is the most common cause of glomerular hematuria and the most common primary glomerular disease. Asymptomatic recurrent hematuria with mild proteinuria is the usual picture in young adults, more often male, with recurrent episodes and at times hypertension. Alport syndrome, or hereditary nephritis, is inherited X-linked or autosomal dominant with variable penetrance. Thin basement membrane disease gives isolated microscopic hematuria with no proteinuria, normal renal function and a benign course, typically in a healthy individual with a family hx of hematuria. Bladder cancer and kidney stones cause hematuria with no casts, and the presence of casts is what marks a glomerular or renal tubular origin.