Hematuria - Definition and Overview

In medicine, hematuria is the presence of blood in the urine. It is a sign of a large number of diseases of the kidneys and the urinary tract, ranging from trivial to lethal.

Types

Red decolouration of the urine can have various causes:

• Blood
  • Microscopic hematuria (small amounts of blood, can only be seen on urinalysis or light microscopy)
  • Macroscopic (or "frank") hematuria
• Hemoglobin (only the red pigment, not the red blood cells)
• Other pigments (e.g. porphyrins in porphyria)

Analysis

A patient will be asked a number of questions:

• Have you passed any blood clots?
• Has a kidney stone been passed (noise in toilet bowl)?
• Is the red colour mixed in completely, or does the colour change during an episode of urination?
• Does it only occur after getting up?
• Have you recently had a sore throat?

Diagnosis

Often, the diagnosis is made on the basis of the medical history and some blood tests—especially in young people in whom the risk of malignancy is negligible and the symptoms are generally self-limited.

Ultrasound investigation of the renal tract is often used to distinguish between various sources of bleeding. X-rays can be used to identify kidney stones, although CT scanning is probably more precise.

In older patients, cystoscopy with biopsy of suspected lesions is often employed to investigate for bladder cancer.

Causes

Common causes of macroscopic hematuria include:

• IgA nephropathy ("Berger's disease") - occurs during viral infections in predisposed patients;
• Kidney stones (or bladder stones, now a rare disease);
• Bladder cancer;
• Renal cell carcinoma - occasionally presents with bleeding;
• Paroxysmal nocturnal hemoglobinuria - a rare disease where hemoglobin of hemolysed cells is passed into the urine.