Blood in urine

blood in urine

Hematuria is the presence of blood, namely, red blood cells in urine.

Description

Normally there are no red blood cells (RBCs) in urine. Different disorders may cause hematuria – the condition characterized by the presence of the RBCs in urine. The urine becomes pink, red or tea-colored when there are a lot of erythrocytes in urine. This color change may be detected without any special tests and therefore is known as gross or macroscopic hematuria. When the amount of erythrocytes is relatively small they may be identified only via microscopy, respectively, this type of hematuria is called microscopic hematuria. Sometimes hematuria may be an accidental finding on routine urinalysis. Periods may mimic hematuria as the menstrual blood mixes with urine.

Classification

  • Gross/macroscopic (visible without any specific tests) or microscopic (detected via microscopy when the RBCs are detected in urine)  hematuria;
  • Symptomatic or asymptomatic hematuria;
  • Transient or persistent hematuria;
  • Isolated hematuria or hematuria associated with proteinuria and other abnormalities in the urinalysis;
  • Glomerular or non-glomerular hematuria;

Risk factors

  • Kidney stones;
  • Family history of kidney disease (for example, Alport syndrome);
  • Benign prostate hyperplasia;
  • Kidney, bladder or prostate cancer;
  • Autoimmune disorders;
  • Administration of some drugs such as aspirin, warfarin, clopidogrel or  heparin;

Causes

  • Glomerular hematuria

Normally the RBCs do not pass through the glomerules. When the glomerular barrier is damaged the erythrocytes get into urine and cause hematuria. Casts of RBCs, dysmorphic erythrocytes in urine and proteinuria are characteristic for glomerular hematuria.

The possible diseases which lead to glomerular hematuria include the following conditions:

  • Glomerulonephritis
  • Benign familial hematuria
  • Alport syndrome
  • IgA nephropathy
  • Hemolytic-uremic syndrome
  • Lupus nephritis
  • Henoch-Schönlein purpura
  • Non-glomerular hematuria

Hematuria may be caused by the disorders of the upper and lower urinary tract when the glomeruli themselves remain intact. These conditions include:

  • Pyelonephritis
  • Urinary tract infection
  • Polycystic kidney disease
  • Kidney stones
  • Hypercalciuria (especially common in childhood)
  • Urinary tract polyps
  • Urinary tract trauma
  • Foreign bodies of the urinary tract
  • Prostate cancer or benign prostate hyperplasia
  • Kidney or bladder cancer
  • Fever
  • Strenuous exercise (so called “marathon runner’s hematuria”)
  • Coagulopathy
  • NSAIDs intake
Urine tract infection test

Urinalysis

The dip strip analysis appears to be highly sensitive and highly specific test for hematuria. It also detects the presence of haemoglobin and myoglobin in urine. The strip should be exposed to urine shortly and approximately 1 minute after the strip may be read.

The freshly voided urine will be examined via microscopy. Microscopically, hematuria is defined as the presence of 5 or more RBCs per high-power field in 3 of 3 consecutive centrifuged specimens which are obtained at least 1 week apart. Casts of RBCs, dysmorphic erythrocytes and proteinuria are suggestive of the hematuria arising from the glomelures of the kidney.

Other investigations

  • Blood test – blood test will be helpful to estimate anemia, check whether there is any inflammation or not. Thrombocytopenia (platelets deficit)  may also be verified by the blood test;
  • Ultrasound examination of the kidneys is necessary to evaluate the size and structure of the kidney, the presence of kidney stones or any tumor;
  • Coagulation test will be helpful to detect any coagulopathy which may contribute to hematuria;
  • Cystoscopy is the investigation performed to examine the lining of the bladder;
  • CT/MRI – both investigations may be performed to visualize the whole urinary system and other tissues nearby;
  • Kidney, bladder or prostate biopsy – biopsy is necessary to detect the tumor and determine whether it is benign or malignant;
  • PSA test is obligatory for males older than 40-45 years as screening method for prostate cancer;
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