Kidney Diseases and Elevated Levels of Blood Urea, Uric Acid and Creatinine

There could be minimal to gross impairment of renal function during the onset and progression of a kidney disease or renal disorder. This impairment of renal function may range from subclinical to complete renal failure. Urine analysis and blood biochemistry have been of great help in the assessment of renal function. Simultaneous increase in the levels of blood urea and uric acid has been observed during a variety of renal disorders. Uric acid is an end product of purine (a component of nucleic acids and nucleoproteins) metabolism. The level of uric acid in the blood depends on its endogenous production through purine metabolism as well as from the exogenously taken purines in the food items. Normal range of uric acid in blood is 2 - 6mg/dl. Elevated level of uric acid is also observed in gout. Urea is an end product of protein metabolism and its normal range in blood is 20 - 40mg/dl.

Formation of Urea: The amino acids derived by the digestion of proteins of the food we eat are absorbed by the villi of the small intestine and brought to the liver through the portal vein. The essential amino acids required for the growth and repair of body tissues are passed on to the blood circulation by the liver and others are used to produce the blood proteins and useful proteins for the body. Useless proteins are broken down in the liver to form bioenergy composed of carbon, hydrogen and oxygen and a waste product urea. Urea is a water soluble substance and carried away buy the blood stream.

The uric acid level may increase earlier than the blood urea level during the course of renal disease. The serum uric acid could be found markedly increased from the normal level of 2 -6mg/dl to 10 - 30mg/dl with minimal impairment of renal function. The creatinine level in blood starts rising after 2 to 4 fold rise in the blood urea level. The level of urea may rise in a variety of conditions, but increased level of creatinine is considered more severe than the increased level of blood urea. The creatinine is derived from the creatine and is a waste product; on the other hand the creatine is necessary for the muscle contraction and is related to the phosphocreatine breakdown. The normal level of creatinine in the blood plasma or serum is 1 - 2mg/dl and its normal daily excretion ranges from 1 to 2 grams. The serum creatinine values of up to and even exceeding occasionally 20mg/dl have been seen in the later stages of renal failure. The major cause of increased levels of serum creatinine and blood urea is the poor clearance of these substances by the kidneys rather than excessive production. In acute glomerulonephritis values from normal to over 300mg/dl are generally observed. In conditions such as malignant hypertension, chronic pyelonephritis and heavy metal poisoning 10 to 15 fold increase in blood urea level may be detected. However, in cases of hypoadrenalism (Addison's disease) blood urea level of about 100mg/dl could be detected. Fifteen to 20 fold increase in the level of blood urea (i.e. a level of 600 - 800mg/dl) may lead to uremic coma in more than 80% cases of cases affected by severe renal disease or renal failure.

What causes Pyelonephritis and How Serious is It?

The pyelonephritis is said to be very serious renal disease. The well documented cause of pyelonephritis is an infection of interstitial (intertubular) tissue with pyogenic bacteria, most frequently E. coli and Staphylococci, and sometimes Proteus vulgaris and Pseudomonas pyocyaneus. In almost 66% of cases the infection could be secondary to the urinary tract infection and in 33% of cases the infection could be primary through infection of blood. The ascending infection of kidney or kidneys from the urinary tract is quite common in infants. There could be ascending infection of kidneys in pregnant women and also in women with the cancer of the cervix. In the elderly male patients, the ascending infection of kidneys is possible if their prostate is enlarged and the urethra is obstructed causing partial or full retention of urine. Irrespective of the sex of the patient, the obstruction plays a vital role in causing the infection of kidneys. It has been proved through experimental study on rabbits that the obstruction of urinary system was the main cause of renal infection and pyelonephritis. In man infection of blood may cause unilateral or bilateral pyelonephritis depending on the obstruction. The obstruction may be functional or organic. The ultrasonography or the serial radiographical study is required to rule out the obstruction.

The pyelonephritis in its chronic form is very dangerous disease. The kidney may become a bag of pus due to infection with pyogenic bacteria cited above. The condition is also called pyonephrosis. A pure hydronephrosis (nephrosis caused due to back pressure of accumulated urine) in an advanced stage may become infected. The kidneys get much enlarged due to hydronephrosis or pyelonephritis. There is possibility of complete erosion of functional architecture in side the kidney due to pyogenic infection. Pyelonephritis may also develop in a gradual manner with little frank suppuration. The early detection of disease could be better for the patient as it could be treated effectively.