Before discussing about the abnormal constituents of urine we must have some idea about the normal constituent of urine. Is it not? After knowing the normality it will be very easy to understand about the abnormal constituents of urine of human beings. In our previous page we have discussed about the normal constituents of human urine.
What is the meaning of abnormal constituents of urine?
Some substances which are normally absent in urine may appear in it under pathological conditions. Such pathological constituents are referred to as abnormal constituents of urine. In addition, some other substances which are present in normal urine in traces only, may be found in remarkably higher levels under certain pathological or abnormal conditions. Then those substances may called the abnormal constituents.
Presence of an abnormal constituent in urine of a person indicates happening of certain abnormality or diseases in the person. For this reason, qualitative and quantitative analysis of urine for the presence of abnormal constituents in it is very important in clinical practice. The common abnormal constituents of urine and the implication of their presence are discussed below in short.
Protein as abnormal constituents of urine
Normal human urine is usually devoid of protein or it may contain negligible quantity of protein (about 20-80 mg in daily urine). In various situations, the urinary protein level may become abnormally high, as much as 20 g in daily urine; this is known as proteinuria. Depending on the cause, proteinuria may be of two types—
It means presence of large quantity of protein in urine due to some physiological variation, e.g., severe exercise, high protein intake, pregnancy, etc.
It caused by some disease, for example, presence of albumin (albuminuria) in nephritis (inflammation of glomeruli) due to an increase in the size of filtering pores.
Glucose and other sugars as abnormal constituents of urine
In normal urine sugars are not detectable; but in diabetes mellitus caused by insulin deficiency, glucose may be excreted in urine as a result of rise in blood glucose level called hyperglycemia. Presence of glucose in urine is termed glycosuria. Sometimes, in severe diabetes mellitus, fructose may also be present in urine named as fructosuria. Nursing babies who are fed with milk only, may excrete galactose in urine, which may call as galactosuria. In lactating mothers, urine may contain lactose i.e., lactosuria. Hereditary defects of pentose sugar metabolism may lead to emission of pentose sugar in urine.
Ketone bodies as abnormal constituents of urine
In normal human being, about 3-15 mg of ketone bodies may be excreted in the urine every day. An abnormal increase in the level of urinary ketone bodies is termed ketonuria. It occurs when there is too much catabolism of fat such as in starvation, diabetes mellitus, pregnancy etc.
Blood as abnormal constituents of urine
Generally, normal urine does not contain blood or blood cells; but in cases of lesion of kidney or urinary tract caused by inflammation or trauma, blood may appear in urine and this symptom is termed hcmaturia in which urine becomes cloudy. Hematuria is also observed in renal stones, cancer, tuberculosis like diseases.
Pigments as abnormal constituents of urine
Some traces of pigments like bilirubin, bilinogen etc., resulting from catabolism of hemoglobin are normally found in urine. In jaundice, the urinary level of these pigments becomes abnormally high, rendering the urine yellow in colour. When the rate of hemolysis is very high, the hemoglobin is released into plasma and excreted in as the abnormal constituents of urine.
Calculi as abnormal constituents of urine
Calculi or stones and the casts i.e., masses of molded material formed in the kidney by deposition of mineral salts or other materials may be found in urine. It also creates some abnormalities in human body.
Pus cells as abnormal constituents of urine
Normally the pus cells are not found in urine to a significant extent; but they are found in urine in large numbers as a result of suppuration i.e., formation of pus in any part of the urinary tract which may occur due to urinary tract infections such as that caused by B. Colli, a bacterial infection.