Hematuria

In medicine, hematuria, or haematuria, is the presence of red blood cells (erythrocytes) in the urine. It may be idiopathic and/or benign, or it can be a sign that there is a kidney stone or a tumor in the urinary tract (kidneys, ureters, urinary bladder, prostate-(In males only), and urethra), ranging from trivial to lethal. If white blood cells are found in addition to red blood cells, then it is a signal of urinary tract infection.

Occasionally "hemoglobinuria" is used synonymously, although more precisely it refers only to hemoglobin in the urine.

Types

Red discoloration of the urine can have various causes:

• Red blood cells
  • Microscopic hematuria (small amounts of blood, can be seen only on urinalysis or light microscopy)
  • Macroscopic hematuria (or "frank" or "gross") hematuria
• Hemoglobin (only the red pigment, not the red blood cells)
• Other pigments
  • Myoglobin in myoglobinuria
  • Porphyrins in porphyria
  • Betanin, after eating beets
  • Drugs such as Rifampicin and Phenazopyridine

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 more precise.

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

If combined with pain, it may be loin pain hematuria syndrome.^[1]

Per AUA (American Urologic Association) guidelines,^[2] the following should be performed for high-risk patients with significant microhematuria (greater than three red blood cells per high-powered field):

1. Upper tract imaging of which a CT urogram is the gold standard
2. Urine cytology
3. Cystoscopy

Causes

The most common causes of hematuria^[3] are:

• Urinary tract infection with viruses,^[3] other sexually transmitted diseases (particularly in women)^[3] or some bacterial species including strains of EPEC and Staphylococcus saprophyticus
• Kidney stones or ureter stones
• Benign prostatic hyperplasia, in older men, especially those over 50

Other, less common causes of hematuria include:

• IgA nephropathy ("Berger's disease") - occurs during viral infections in predisposed patients
• Trauma (e.g., a blow to the kidneys)
• Tumors and/or cancer in the urinary system,^[3] for example bladder cancer or renal cell carcinoma
• Kidney diseases^[3]
• Urinary Schistosomiasis (caused by Schistosoma haematobium) - a major cause for hematuria in many African and Middle-Eastern countries;
• Prostate infection or inflammation (prostatitis)^[3]

Rare causes include:

• Benign familial hematuria
• Paroxysmal nocturnal hemoglobinuria - a rare disease where hemoglobin of hemolyzed cells is passed into the urine
• Sickle cell trait can precipitate large amounts of red blood cell discharge, but only a small number of individuals endure this problem
• Arteriovenous malformation of the kidney (rare, but may impress like renal cell carcinoma on scans as both are highly vascular)
• Nephritic syndrome (a condition associated with post-streptococcal and rapidly progressing glomerulonephritis)
• Fibrinoid necrosis of the Glomeruli (as a result of malignant hypertension)
• Vesical varices may rarely develop secondary to obstruction of the inferior vena cava^[4]
• Allergy may rarely cause episodic gross hematuria in children ^[5]
• Left renal vein hypertension, also called "nutcracker phenomenon" or "nutcracker syndrome," is a rare vascular abnormality responsible for gross hematuria ^[6]
• Ureteral Pelvic Junction Obstruction (UPJ) is a rare condition beginning from birth in which the ureter is blocked between the kidney and bladder. This condition may cause blood in the urine ^[7]
• March hematuria secondary to repetitive impacts on the body, usually the feet
• Athletic nephritis secondary to strenuous exercise
• Medications can cause red discoloration of the urine, but not hematuria. Some examples include: sulfonamides, quinine, rifampin, phenytoin^[3]

References