Hematuria

Hematuria is the presence of blood in the urine. When the blood is visible to the naked eye, it is called gross hematuria; when it is detectable only on microscopic examination, it is microscopic hematuria. Gross hematuria may appear red, pink, or brown and can be accompanied by clots, while microscopic hematuria is defined as the presence of red blood cells on urine microscopy, usually quantified as three or more red blood cells per high-power field.

Causes of hematuria are diverse and differ by age and the location of bleeding within the urinary tract. Glomerular diseases, such as certain nephritides or IgA nephropathy, can cause dysmorphic red blood cells and proteinuria. Non-glomerular causes include infections (urinary tract infection or pyelonephritis), kidney or bladder stones, tumors in the kidney, ureter, or bladder, trauma, obstruction, and congenital or acquired structural abnormalities. Coagulopathy or anticoagulant therapy, and medications such as nonsteroidal anti-inflammatory drugs, can also contribute. In older adults, malignancy and upper tract pathology are important considerations; in children, infections and minor trauma are more common.

Evaluation begins with history and physical examination, focusing on pain, systemic symptoms, medications, and risk factors such as smoking. Urinalysis with microscopy and urine culture are essential. Additional tests may include renal function tests, complete blood count, and coagulation studies if bleeding risk is suspected. Imaging often starts with ultrasound; CT urography or MRI may be used for suspected upper tract pathology. Cystoscopy is commonly performed in adults with persistent gross hematuria or unexplained microscopic hematuria to evaluate the bladder and urethra.

Management targets the underlying cause. Hydration, avoidance of unnecessary anticoagulation, treatment of infections, and procedures for stones or tumors as indicated. The prognosis depends on the cause and the patient’s age and comorbidity. Persistent or recurrent hematuria warrants medical evaluation.