Urine is produced in the kidneys by glomerular filtration of blood and actively and passively transporting fluids and electrolytes between the urine and blood. The urine then travels down the ureters and is stored in the bladder. Urination is the process of discharging urine which is under voluntary control. Urine in the bladder is passed out into the environment via the urethra by contracting the detrusor muscle in the bladder wall and simultaneous relaxation of the sphincter muscle.
Any abnormality in the urine or the process of urination may indicate a problem either in other systems (pre-renal), or with production (renal), passage and storage (post-renal) or discharge (voiding).
Normal Urine Color, Odor, Output
Urine is yellow in color but this may vary from a pale yellow to clear in color to a darker yellow or mustard color. In some cases, urine can be discolored like plum red, greenish or orange due to the consumption of certain foods.
The odor of urine is that of ammonia, resembling household detergents containing ammonia. The odor may vary after consuming certain foods (example : asparagus) or drinks (example : large amounts of coffee).
The average adult will pass out between 1 to 2 liters of urine although this can be as low as 500ml or as high as 3 liters. Frequency of urination differs among individuals and depends on the urine volume passed in a day. In some cases, a person may only urinate twice in a 24 hour period while others may normally urinate 4 to 6 times in a day.
Different Types of Urinary Problems
- Total absence of urine output or urine output less than 100ml per day.
- Cloudy Urine
- Murky hue of the urine indicates the presence of pus or highly alkaline urine
- Passing out small amounts of urine after urinating (post-micturition dribble).
- Pain or discomfort upon passing out urine. This may vary from burning in the urethra to severe pain in the bladder, along the path of ureter or kidney pain.
- Presence of blood in the urine. This may not always be obvious (visibly bloody urine) and the urine may vary between a reddish to brownish color or there may be no difference in the color.
- Difficulty initiating urine. There may be straining as the person tries to pass out urine but the onset of the urine flow is delayed.
- Passing out urine involuntarily. This may range from dribbling to completely soiling oneself with urine.
- Awaking at night to pass urine frequently. Failure to do so may lead to nocturnal enuresis (incontinence).
- Diminished urine volume output, less than 400ml per day.
- Large urine volume output, more than 3 liters per day.
- Gas bubbles in the urine. This is often caused by gas-forming microorganisms causing a urinary tract infection (UTI) and should not be confused with foamy urine.
- Presence of protein (particularly albumin) in the urine. This is one of the main causes of foamy urine.
- Effort in maintaining a normal flow of urine during urination or impaired urine flow despite straining.
- Urinary frequency
- Frequent urination that is significantly more than the average number of times that a person urinates. This may vary among individuals. The volume may be small and within the norm for daily urine output or large in volume (polyuria).
- Urine Color, Odor or Discharge
- Changes in the color of the urine may not always be pathological. However, if the change is persistent and other signs and symptoms present, it should be investigated. *
- Change in the odor of the urine may be temporary and not a sign of pathology. As with changes in the color, if there is any other signs and symptoms, it should be investigated further. *
- The presence of any discharge along with the urine may be an indication of an infection (particularly STD’s) or in men, retrograde ejaculation has to be considered. Discharge should always be investigated.
* Changes in color or odor in the event of no change in the diet, or use of medication or supplements may be an indication of poisoning (intentional, accidental or environmental).
Article reviewed by Dr. Greg. Last updated on July 22, 2010