Blog #2 of Series 1: Abnormalities in urine and associated medical conditions
Recap: In the previous blog we studied about the composition and properties of normal urine produced by kidneys in healthy/physiological conditions.
Deviation from the normal urine is considered to abnormal. The abnormalities in urine may be due to changes in urine color, odor, pH and volume as well as presence of excess salts and bio-molecules. Presence of molecules or cells other than the normal constituents of urine may be a sign of a pathological condition of that individual.
Changes in Urine Color
Heme group [primary element is iron (Fe)] present in the hemoglobin of blood is broken down into water-soluble components in the liver. These water-soluble components are excreted through urine imparting a yellow color to it. This yellow pigment is termed as “Urochrome”. Urine color is a sign of a health condition/status.
Normal urine is pale yellow to deep golden in coloration. Tints of red, orange, green or brown are considered to be abnormal urine colors. The abnormal urine color can be observed due to certain medications, food habits, medical condition or due to dehydration. Figure 1 outlines the color of the urine on the basis of water intake of the individual.
Figure1. Change in color of the urine on the basis of water intake.
Figure 2 explains the probable causes and the suspected medical conditions that impart specific color to the urine.
Figure2. Urine color, probable causes and suspected medical conditions.
Changes in pH of Urine
Diet influences the pH of urine. Meats lower the pH, whereas citrus fruits, vegetables, and dairy products raise the pH. Medications also alter the pH of urine.
The normal pH of the urine is 6.0. Urinary pH below 5.0 is considered to be acidic. Medical conditions associated with acidic pH are diabetic keto-acidosis, diarrhea and starvation. pH of urine above 8.0 makes it alkaline, indicating the presence of kidney stones or kidney related disorders and urinary tract infections.
Changes in Urine Odor
Figure 3 provide information on correlation of odor of the urine with the suspected medical condition.
Figure3. Suspected medical conditions associated with the urine odor.
Medical Conditions related to Urine output
Different medical conditions exist based on the volume of urine output. These conditions are enlisted in Figure 4.
Figure 4. Urine output and related medical conditions.
Urine is sterile. Once it reaches the urethra, bacteria present in the lining of urethra get added to the urine. Presence of Bacillus, E.coli. and Yeast in urine is an indication of urinary tract infection. Cells are not normally absent in the urine. The presence of leukocytes (viz. White blood cells, WBCs) may also indicate a urinary tract infection.
Painful urination is termed as dysuria. Urinary tract infections are a common reason for dysuria in women. Whereas in men, urethritis (inflammation of the urethra) and prostate conditions are causes of painful urination.
Abnormal urine conditions based on presence of bio-molecules/cells
1. Proteinuria: Increased level of protein (< 150 mg/day) in urine is called Proteinuria. This condition is also called as Albuminuria (albumin is the major protein present in blood) and indicates kidney damage. Glomerulus is a loop of capillaries present in kidneys responsible to filter waste products and excess water from blood. It also reabsorbs proteins and prevents the excretion of proteins through urine. However, these homeostatic mechanisms do not work properly in few kidney disorders. More frequent urination, foamy or bubbly urine are the symptoms of proteinuria.
2. Glycosuria: It is a condition in which the sugar is observed to be present in urine. Renal glycosuria occurs when the kidneys are damaged. It is a rare condition which develops when a person’s blood sugar levels are normal, but the kidneys are unable to retain glucose. Normally, blood sugar is absorbed in the kidneys. Excess blood sugar (more than 180 mg/dl) reduces the efficiency of kidneys to absorb all the blood sugar and results in glycosuria. This condition is observed in diabetes. Accidental urination, polyuria, night-time urination, sweet ketone odor are symptoms of glycosuria.
3. Hematuria- Hematuria is the presence of blood in urine. There are two types of hematuria as explained below.
A) Gross hematuria: Blood is visible in urine. In this condition, color of the urine changes to red due to the presence of red blood cells.
B) Microscopic hematuria: In this condition, blood-like color cannot be seen in urine directly, but RBCs can be observed under a microscope. Urinary tract infections, glomerulonephritis, polycystic kidney disease may result in microscopic hematuria.
Meaning of scientific terms
1. Crohn's disease- It is an inflammatory bowel disease (IBD) and results in inflammation of digestive tract.
2. Diabetes insipidus – In this, blood glucose levels are normal; however, kidneys cannot balance fluid in the body.
3. Diabetes mellitus- Causes high blood glucose resulting from the body's inability to use blood glucose for energy.
4. Diuretics- A class of drugs that increase the flow of urine.
5. Heme group- Main component of hemoglobin.
6. Leukocytes- White Blood Cells (WBCs) responsible for providing immunity
7. Porphyria –genetic disorder in which body’s ability to make heme is disrupted.
8. Glomerulonephritis- Inflammation of the key parts of the kidneys viz. glomeruli
9. Polycystic kidney disease- Condition in which cluster of cysts (fluid-filled sacs) develop in the kidneys.
About the author:
Janhavi is a graduate in Microbiology from Fergusson College, Pune and holds a post-graduate degree in Biological Sciences from NMIMS University, Mumbai. She had been a project trainee at ACTREC, Navi Mumbai and was formerly associated as Assistant Professor in Biotechnology at CKT college of ACS, Navi Mumbai. The science of cancer biology, therapeutics, nanomedicine and immunology fascinates her the most. Besides this, she loves to cook, exercise and travel.