Jaundice

Sometimes skin looks yellow.

This can also happen to the white of the eyes. It happens when too much yellow color builds up in the body. This color comes from old blood cells breaking down.

Many babies get this. It is common in their first week of life. Adults can get it too. It can make a person feel very itchy.

The body makes this yellow color as it works. It travels through the blood to the liver. The liver helps clean it out.

Sometimes the path is blocked. This can make urine look dark. It can also make poop look pale. Doctors can help fix these problems.

Jaundice makes the skin and the white of the eyes look yellow.

This happens when there is too much bilirubin in the body. Bilirubin is a yellow color made from old red blood cells.

When red blood cells get old, they break apart. This makes a green color called biliverdin. Then, the body changes it into yellow bilirubin. This yellow part travels through the blood to the liver. The liver works to change it so it can leave the body.

Sometimes the body has problems with this way. If blood cells break too fast, bilirubin builds up. If the liver is sick, it cannot clean the blood well. Sometimes, the tubes that carry bile are blocked.

Jaundice can cause itchy skin. It can also make urine look dark and stool look pale. Many babies get jaundice in their first week of life. For adults, it often means there is an issue with the liver or bile ducts. Doctors treat it by finding the cause.

Jaundice is a sign that something is happening inside the body. It makes the skin and the white parts of the eyes look yellow or even greenish.

This happens because of a substance called bilirubin. Bilirubin is a yellow pigment that is made when old red blood cells break down. In a healthy body, bilirubin levels stay below 1.0 mg/dl. If levels rise above 2 or 3 mg/dl, jaundice becomes visible.

It is important to know that jaundice is not a disease itself. Instead, it is a signal that points to other health issues.

To understand jaundice, we must look at how the body handles heme. Heme is a part of red blood cells. When these cells reach the end of their 120-day life, they rupture.

Special cells called macrophages break the heme into two parts. First, an enzyme creates a green pigment called biliverdin. Next, another enzyme changes that green pigment into yellow bilirubin. This yellow substance is called unconjugated bilirubin. It travels through the blood to the liver. In the liver, an enzyme changes it into conjugated bilirubin. This new version can dissolve in water so it can leave the body.

Scientists and doctors group jaundice into three main categories. The first is prehepatic, which happens before the liver gets involved. This is often caused by red blood cells breaking down too quickly. The second is hepatic, which means the problem is inside the liver cells. This can happen if the liver is damaged by infections or certain medications.

The third type is posthepatic, also called obstructive jaundice. This occurs when the tubes that carry bile are blocked. For example, gallstones or other growths can stop the bile from moving.

There are many specific facts about how jaundice appears. In adults, the yellowing is often easiest to see in the whites of the eyes. These are called the sclera. Doctors sometimes use the term conjunctival icterus to describe this.

People with darker skin may show yellowing in their palms or the soles of their feet. Jaundice can also cause itchy skin or dark urine. In some children, it can even cause teeth to look yellow or green. This happens if bilirubin builds up while the teeth are still forming.

Many people encounter the idea of jaundice through babies. It is very common for newborns to have it. About 80% of babies are affected during their first week of life.

Doctors might use special lights, called phototherapy, to help treat them. For adults, the treatment depends on why the jaundice started. If a tube is blocked, a person might need surgery. If the cause is a medicine, a doctor might tell them to stop taking it. Understanding these steps helps people stay healthy and strong.

Jaundice, also called icterus, is a visible sign of physiological changes. It presents as a yellowish or sometimes greenish pigmentation of the skin and the sclera. The sclera is the white part of the eye.

This condition is not a disease itself. Instead, it indicates an underlying issue with bilirubin levels in the body. In healthy individuals, blood bilirubin levels remain below 1.0 mg/dl. When these levels rise above 2 to 3 mg/dl, jaundice becomes apparent.

This pigmentation is often accompanied by intense itchiness, dark urine, and pale feces.

To understand why this happens, we must follow the pathway of heme metabolism. Red blood cells live for about 120 days. When they age or become damaged, they rupture. This process releases hemoglobin into the circulation. Specialized cells called macrophages then ingest this hemoglobin and split it into heme and globin.

An enzyme called heme oxygenase first converts the heme into a green pigment called biliverdin. Then, an enzyme called biliverdin reductase reduces that green pigment into a yellow substance called bilirubin. This initial form is known as unconjugated bilirubin. Because it is not water-soluble, it must travel through the blood attached to a protein called albumin.

Once unconjugated bilirubin reaches the liver, the next stage of metabolism begins. Inside the liver, an enzyme called UDP-glucuronyl transferase performs a process called conjugation. It combines bilirubin with glucuronic acid to create bilirubin diglucuronide. This is known as conjugated bilirubin. Unlike the unconjugated form, conjugated bilirubin is water-soluble. This allows it to be excreted into the gallbladder and eventually into the intestinal tract via bile.

In the intestines, bacteria convert this substance into urobilinogen. Most of this is further processed into stercobilin, which gives feces its brown color. A small amount is reabsorbed and eventually excreted by the kidneys as urobilin, which colors urine yellow.

Medical professionals classify jaundice into three distinct categories based on where the process fails. The first is prehepatic or hemolytic jaundice. This occurs before the liver can process the bilirubin. It is usually caused by an increased rate of erythrocyte hemolysis, or the rapid breakdown of red blood cells. Conditions like sickle-cell anemia or malaria can cause this.

The second category is hepatic or hepatocellular jaundice. This happens due to damage to the liver cells themselves. This damage can be caused by infections like hepatitis, medications, or genetic conditions like Gilbert's syndrome. In these cases, the liver cannot effectively transport bilirubin.

The third category is posthepatic or cholestatic jaundice. This occurs after the liver has successfully conjugated the bilirubin. It is caused by a physical blockage in the biliary tract that prevents bile from exiting.

Common causes include gallstones, known as choledocholithiasis, or pancreatic cancer. Such blockages can lead to visible dilation of the bile ducts.

When this happens, conjugated bilirubin can leak back into the blood. This results in dark urine because the water-soluble bilirubin is filtered by the kidneys.

Jaundice presents differently depending on a person's age and skin tone. In adults, the yellowing of the sclera is a very reliable sign. While some call this scleral icterus, the more accurate term is conjunctival icterus. This is because the bilirubin actually deposits in the conjunctival membranes.

For people with darker skin, doctors look at the palms, soles, or oral mucosa for signs. In developing children, high bilirubin levels during tooth calcification can cause yellow or green tooth discoloration. This specific dental issue is not seen in adults with liver disease.

Treatment is always focused on the specific underlying cause rather than the color change itself. If a patient has a bile duct blockage, surgery is often required to clear the path. For other causes, medical management is used. This might include treating an infection or stopping a specific medication.

Newborns are a special case. About 80% of babies experience jaundice in their first week of life. If their bilirubin levels are between 4 and 21 mg/dl, doctors may use phototherapy, which involves special lights, to help the body process the pigment.