Dark Urine - An Overview

Introduction

Urine usually is pale yellow or straw-colored. This is due to the presence of pigments such as urobilin or urochrome. Dark urine indicates a higher concentration of these pigments or excess waste products is being circulated in the body, which can be hazardous. Dark urine is deeper in color than normal urine. Dark urine may present as brown, maroon, or deep yellow. Kidneys produce urine when there is an intake of fluid or food. This food or fluid is passed through the digestive system, followed by the circulatory system, and finally reaches the kidneys, where filtration occurs. From the kidneys, the extra fluid and toxic substances are excreted out of the body. The bladder helps in emptying urine through the urethra. The bladder is connected to the kidneys by the ureters.

What Are the Causes of Dark Urine?

These are causes that are not due to any underlying medical condition,

• Beets, fava beans, blackberries, and rhubarb are food that can turn the urine dark brown or reddish.

• Orange urine is often experienced in individuals who have consumed carrots or vitamin C supplements.

• Vitamin B supplements can give a greenish tinge to the urine.

• Temporary color changes can be seen in individuals who have consumed food or liquid with strong colored dyes.

• Dehydration can cause dark-colored urine.

Medications That Can Cause Dark Urine:

Certain medications are responsible for causing dark urine, and the individual taking them is advised to talk to their healthcare provider about the side effects.

• Chemotherapy medications cause orange urine.

• Antimalarial drugs such as Chloroquine and primaquine.

• Antibiotics such as Metronidazole and Nitrofurantoin.

• Laxatives containing Cascara and Senna.

• Muscle relaxants such as Methocarbamol.

Medical Conditions That Cause Dark Urine:

• Blood in the Urine (Hematuria): Blood in urine makes the urine appear dark. It is caused by prostate, bladder, or kidney inflammation, viruses, menstruation, sexually transmitted diseases, internal injury, cancer, and kidney or bladder infection.

• Hepatitis: Inflammation of the liver is called hepatitis; dark urine is the most common sign of hepatitis. Hepatitis is classified into three types hepatitis A, hepatitis B, and hepatitis C. When an individual has hepatitis, there is a buildup of orange-yellow colored pigments called bilirubin in blood and urine, turning the urine brown. Hepatitis symptoms also include loss of appetite, fever, fatigue, nausea, vomiting, pain in the abdomen, joint pain, clay-colored stools, yellow skin, and eyes.

• Cirrhosis of the Liver: Prolonged or chronic liver disease causes scars on the liver. This condition is called liver cirrhosis. Cirrhosis of the liver causes brown urine. Cirrhosis symptoms involve ankle edema, water retention in the abdomen, difficulty concentrating, trouble sleeping, poor memory, yellow skin or eyes, and muscle weakness.

• Kidney Disease: Kidney infection causes dark urine. Post-streptococcal glomerulonephritis is an infection of the kidney which causes reddish-brown urine. This is usually seen in children with a strep throat infection. In addition, kidney disease involves other symptoms such as swelling of the face, around the eyes, hands, and feet, decreased volume of urine, reduced urge to pass urine, and fatigue.

• Rhabdomyolysis: Intense exercise causes muscle cell rupture, leading to muscle fibers' leakage into the bloodstream. This is a serious condition that may lead to kidney damage. Symptoms include dark brown urine, muscle pain, and weakness.

• Anemia: Hemolytic anemia (a condition in which the red blood cells are destroyed faster than they can be replaced) causes dark urine. Other symptoms involve pale skin, pale tongue, yellow skin or eyes, fever, dizziness, weakness, confusion, difficulty concentrating, and increased heart rate.

• Melanoma: It is a type of skin cancer that affects melanocytes which are responsible for producing skin pigment. In melanoma, the skin pigments may leak into the bloodstream, causing dark urine, a rare condition. Signs of melanoma involve changes in the size and texture of moles.

• Tick-borne Disease: Babesiosis is a tick-borne disease that infects the red blood cells causing hemolytic anemia. Symptoms include dark urine, stomach pain, fever, headaches, and nausea.

• Lead or mercury poisoning can cause dark reddish urine.

What Is the Diagnosis and Treatment for Dark Urine?

The health care provider may examine the individual for dehydration or check for medications taken by them. If the above-mentioned reasons are not the cause of dark urine, then the doctor may advise further evaluation. The doctor may advise urine analysis along with a physical examination and detailed medical history.

Urine analysis is a laboratory test where a certain volume of urine is collected from the individual and is checked for bilirubin, bacteria, glucose, crystals, protein, red blood cells, and white blood cells. The urine is assessed under different categories, that are if the urine is clear, concentrated, cloudy, and color. A chemical test will check for ketones, blood, bilirubin, proteins, and glucose. Microscopic examination is used to check for viruses, bacteria, or parasites. The urine sample is collected early in the morning because it is more concentrated than the urine produced during other times of the day. Based on the urine analysis, the doctor may advise other tests, including blood tests and urine cultures. A urine culture helps identify the bacteria, and blood tests detect any abnormalities in kidney and liver function.

How to Prevent Dark Urine?

Dark urine caused by food can be avoided, and medications that cause dark urine should not be discontinued without the doctor's knowledge. Medications need to be taken unless asked to stop by the doctor. If the cause is dehydration, the individual needs to increase the water or fluid intake. Normally around three cups of urine are excreted in a day and void around four to six times. Other reasons need medical evaluation and treatment.

Conclusion

Urine is normally pale yellow or straw-colored. Dark urine is deeper in color than normal urine. Dark urine may present as brown, maroon, or deep yellow. Causes can be categorized as physiological and pathological. Physiological causes include certain food items which produce pigments in the urine and are harmless. Pathological causes include underlying medical conditions which precipitate as dark urine. Treatment involves avoiding food or medications and getting the underlying medical condition treated.