Pyelonephritis Information and Courses from MediaLab, Inc.

No blood is found in the urine of healthy individuals although samples from menstruating females, frequently, but not always, test positive for blood. Hematuria is associated with renal or genital urinary disorders in which the bleeding is the result of irritation to the involved organs or trauma. Examples include renal calculi, pyelonephritis, glomerulonephritis, tumors, trauma or exposure to toxic chemicals or drugs and/or strenuous exercise. Hemoglobinuria may be due to the lysis of red cells within the urinary tract. If it is caused by intravascular hemolysis, the hemoglobin is then filtered through the glomeruli. In the normal individual, the hemoglobin molecule attaches to haptoglobin and in this way bypasses the kidney filtration system. When the hemoglobin/haptoglobin system is overwhelmed, as in cases of hemolytic anemia, severe burns, transfusion reaction, infection or strenuous exercise, hemoglobin passes into the urine.

Severe proteinuria (greater than 3.5 g/day) is characteristically seen in patients with glomerulonephritis, lupus nephritis, lipoid nephrosis, and severe venous congestion of the kidney. Moderate proteinuria (0.5-3.5g/day) is seen in nephrosclerosis, multiple myeloma, diabetes nephropathy, malignant hypertension, and pyelonephritis with hypertension. Mild proteinuria (less than 0.5 g/day) may be seen with polycystic kidneys, chronic pyelonephritis, benign orthostatic proteinuria, and some renal tubular diseases. Transient proteinuria can also be due to physiologic conditions such as stress, exercise, cold exposure, and fever, in the absence of renal disease.