The color of excretions are known to vary to some degree but most of us can differentiate between normal and abnormal hues. When it comes to urine we expect it to be a yellowish color, sometimes ranging from a darker mustard color and at other times a very pale yellow or even clear. Green urine is not just abnormal, it is also extremely uncommon but can occur in certain instance.
Why is urine green?
It is important to first understand the chemistry behind the normal color of urine, namely the yellow hue. FIrstly, urine is not composed entirely of waste substances like urea. It also contains electrolytes, micronutrients like the excess of certain vitamins and sometimes macronutrients. The composition of urine constantly changes depending on a host of factors.
The yellow color of urine is caused mainly by urobilin, also known as urochrome. This compound comes from the breakdown of red blood cells. Normally the byproduct of red blood cell degradation, known as bilirubin, is passed out into the bowels with bile. It is broken down by gut microbes to give stool the characteristic brown color. Some bilirubin is reabsorbed into the bloodstream, chemically altered and passed out in urine as urobilin.
Green urine is rare. When the color of urine turns green it is either due to internal or external factors. Dyes and medication are some of the external factors. Infections can also cause these alterations in color as well as long terms inflammation even when there is no infection. The latter results in a breakdown of neutrophils, a type of immune cells, which releases a green pigment known as verdiperioxidase.
Causes of Green Urine
Some of the more likely causes of green urine are discussed below. Green urine is a symptom on its own and may be accompanied by various other symptoms. The presence of these other symptoms may be useful in identifying the underlying conditions.
The other urinary and pelvic symptoms present with green urine are discussed below. It is important to note that green urine needs to be immediately investigated in the event of pain that is worsening, bleeding or a very high fever. Urgent medical treatment may be necessary.
Food and Beverages
The most likely cause of green urine is from the dyes that may be found in certain foods and drinks, especially when it is consumed in large quantities. Although dyes and colorants are present in a a number of different foods and beverages, it is usually broken down or present in very small quantities to be noticed in urine or in stool.
Usually the dye or colorant in the food or beverage that causes green urine is also green. However, blue dyes or colorants may also cause green urine. It is usually due to the strong artificial colorants but can also occur with natural pigments like those found in asparagus.
Symptoms: There are usually no other symptoms present with green urine caused by foods and beverages. Alcoholic beverages with strong green or blue colorants may cause frequent green urine, as alcohol is a diuretic.
Treatment: No treatment necessary in most instances as the abnormal color may pass with time. Increasing water consumption may hasten the resolution.
Bladder and Kidney Infections
Urinary tract infections are common, especially in females. Most of these infections are caused by bacteria. These bacteria usually enter the urethra from the environment and travel to the bladder where the infection becomes established. A bladder infection is known as cystitis.
Sometimes the infection can spread further up the ureters to the kidneys. A kidney infection is known as pyelonephritis. It is also possible that the bacteria travels from another site of infection and reaches the kidney through the bloodstream. Bladder infections are usually more common than kidney infections.
It is possible for urinary tract infections to have little to no symptoms. These silent infections can persist for long periods of time. Usually these infections present with:
- Frequent urination
- Burning when passing urine
- Urging to urinate
- Difficulty urinating (straining)
- Foul-smelling urine
- Pelvic pain (bladder) or flank pain (kidney)
Treatment: Consult with a doctor. Antibiotics or other drugs are often necessary.
Prostate Gland Infection
The prostate is a small gland that sits under the bladder in males. The prostate can become inflamed for various reasons but usually it arises with a bacterial infection. This is more commonly seen in males younger than 50 years in contrast to conditions like enlarged prostate which more frequently affect men older than 50 tears.
Prostate gland infection (prostatitis) can be acute or chronic. The latter can be bacterial or non-bacterial. As with other long term inflammation, the breakdown of neutrophils is more likely to lead to green discharge. Prostatitis may be associated with a bladder infection, with sexually transmitted infection and trauma to the pelvis.
Symptoms: The signs and symptoms of acute prostatitis are similar to a bladder infection although chronic prostatitis can preset with very mild symptoms or even be asymptomatic. Other symptoms include testicular pain, pain during ejaculate and sometimes blood semen.
Treatment: Consult with a doctor. Antibiotics or other drugs may be necessary.
Drugs and Investigations
A number of drugs can change the color of urine although green urine is an uncommon side effect. This alteration of urine color may occur for various reasons. It may be seen with tricyclic antidepressants like amitriptyline, cancer drugs like doxorubicin, hypnotics such as propofol, drugs for blood disorders like methylene blue and NSAIDs like indomethacin. Fluorescein is an orange dye used in diagnostic investigations which can sometimes cause green urine.
Symptoms: The presence of other symptoms with the green urine depends on the type of drug used and the underlying condition. As a side effect, it is possible that green urine occurs on its own without any other symptoms.
Treatment: In most cases green urine due to the use of certain drugs or substances utilized for medical purposes (iatrogenic causes) does not require treatment. Never stop using a drug due to the presence of side effects without first consulting with a medical doctor or pharmacist.