Jaundice B Pharma 2nd Semester Pathophysiology notes pdf

Objective

At the end of this lecture, student will be able to

•      Summarize different types of Jaundice

•      Describe the pathophysiology

•      Explain the diagnosis of jaundice

Jaundice

Normal Range of Bilirubin

•       1～16mmol/l  (0.1 ～1mg/dl) 4/5 are unconjugated bilirubin, others  are conjugated bilirubin.

•       <1mg/dl normal

•       1-2mg/dl occult Hyperbilirubinemia

•       >2mg/ dl jaundice Hyperbilirubinemia

Hyperbilirubinemia

Hyperbilirubinemia: the concentration of blood bilirubin are more than 1mg/dl.

Occult: the concentration of blood bilirubin are increased, but have no clinic sympotom, normally 1-2mg/dl.

Jaundice: (also called icterus) refers to the yellow color of the skin and scleare caused by deposition of bilirubin, secondry to increased bilirubin levels in the blood.

Although not a disease itself, jaundice is usually a symptom of an underlying disorder.

Mechanism of Jaundice

Based on pathophysiology, jaundice may result from one or more of the following mechanism:

1. Increased bilirubin production (excessive red cell destruction)

2. Decreased hepatic uptake (ligandin, drug, prolonged starvation, and sepsis)

Decreased hepatic conjugation (enzyme,drugs, cirrhossis)

3. Decreeased excretion of bilirubin into bile (gallstone, tumour)

Pathophysiology of Jaundice

Jaundice is a condition characterized by the yellowing of the skin, eyes, and mucous membranes due to the accumulation of bilirubin in the body. Bilirubin is a yellow pigment produced during the breakdown of hemoglobin in red blood cells and is typically processed by the liver and excreted from the body.

The pathophysiology of jaundice involves disturbances in the normal metabolism and excretion of bilirubin, which can result from various underlying causes. Here’s how it occurs:

1. Hemolysis: One of the primary sources of bilirubin in the body is the breakdown of old or damaged red blood cells. Hemolysis, the increased destruction of red blood cells, can lead to an elevated bilirubin level in the bloodstream. Conditions such as hemolytic anemia, hereditary disorders, or incompatible blood transfusions can cause excessive hemolysis, resulting in an overload of bilirubin.

2. Impaired Bilirubin Processing: After being produced in the body, bilirubin is transported to the liver, where it undergoes a series of chemical changes to become water-soluble and less toxic. These changes, collectively referred to as conjugation, allow the bilirubin to be excreted in bile.

3. Obstruction of Bile Flow: Bilirubin, once conjugated in the liver, is excreted into the bile. Bile is a digestive fluid produced by the liver and stored in the gallbladder. It contains bilirubin and helps in the digestion and absorption of fats. In some cases, conditions such as gallstones, tumors, or inflammation of the bile ducts can obstruct the flow of bile, preventing bilirubin from being excreted efficiently. This can lead to an accumulation of bilirubin in the blood, resulting in jaundice.

4. Hepatic Dysfunction: Liver diseases, such as hepatitis or cirrhosis, can impair the liver’s ability to process and excrete bilirubin. In such cases, even if bilirubin is properly conjugated, the liver may not be able to release it into the bile, causing a buildup in the bloodstream.

5. Neonatal Jaundice: In newborns, jaundice is often seen as a normal physiological response. During the first few days of life, the immature liver may not effectively process and excrete bilirubin, leading to a temporary condition known as physiological jaundice. However, when bilirubin levels become too high, it can lead to a more severe form of jaundice called neonatal hyperbilirubinemia, which requires treatment.

Simple Classification of Jaundice

•       Accordingly, a simple classification of jaundice is to divided into 3 predominant type:

①  Pre-hepatic (hemolytic jaundice)

②  Hepatic jaundice

③  Post – hepatic cholestatic (obstructive jaundice)

Hemolytic Jaundice

•  massive lysis of red blood cells (for example, in patients with sickel cell anemia or malaria) may produce bilirubin faster than the liver can conjuagte it.

•  More bilirubin is excreted into the bile, the amount of the urobilinogen entering the enterohepatic circulation is increased, and urinary urobilinogen is increased.

•  Unconjugated bilirubin is elevated in blood.

Causes of Hemolytic Jaundice

Ø  Malaria

Ø  Side effects of certain drugs :antibiotic and anti-tuberculosis medicines, levodopa,

Ø  Certain drugs in combination with a hereditary enzyme deficiency known as glucose-6-phosphate dehydrogenase (G6PD)

Ø  Poisons Snake and spider venom, certain bacterial toxins, copper, and some organic industrial chemicals directly attack the membranes of red blood cells

Ø  Artificial heart valves

Ø  Hereditary RBC disorders sickle cell disease

Ø  Enlargement of the spleen

Ø  Diseases of the small blood vessels

Ø  Immune reactions to RBCs cancer

Ø  Transfusions

Ø  Kidney failure and other serious diseases

Hepatocellular Jaundice

•       Damage to liver cells (for example in patient with cirrhosis or hepatitis) causes a decrease in both bilirubin uptake and production of conjuagted bilirubin.

•       Unconjugated bilirubin occur in the blood and increased urobilinogen in the urine.

•       The urine is dark in color and stool are pale, clay color.

•       Level of AST and ALT are elevated and the patient experience nausea and anorexia.

Obstructive Jaundice

•       In this instance jaundice is results from obstruction of the bile duct.

•       The presence of a hepatic tumor or bile stone may block the bile ducts, preventing passage of bilirubin into the intestine, patients with obstructive jaundice experience GI pain, nausea and produce stools that are a pale, clay color.

Diagnoses of Jaundice

Summary

•       The main symptom of jaundice is a yellow discoloration of the white part of the eyes (sclera) and of the skin

•      Pre-hepatic jaundice is caused by anything which causes an increased rate of hemolysis

•       Hepatocellular (hepatic) jaundice can be caused by acute or chronic hepatitis, hepatotoxicity, cirrhosis, drug induced hepatitis and alcoholic liver disease

•       Complications of jaundice include sepsis especially cholangitis, biliary cirrhosis, pancreatitis, coagulopathy, renal and liver failure.

Frequently Asked Questions (FAQ) about Jaundice:

Q1: What causes jaundice? Jaundice can be caused by various factors, including liver disease, hemolysis (increased breakdown of red blood cells), biliary obstruction (blockage of the bile ducts), and certain medications. In newborns, it can result from the immaturity of the liver.

Q2: What are the common symptoms of jaundice? The primary symptom of jaundice is the yellowing of the skin, eyes, and mucous membranes. Other symptoms may include fatigue, dark urine, pale stools, itching, and abdominal pain. The specific symptoms depend on the underlying cause.

Q3: How is jaundice diagnosed? Jaundice is typically diagnosed through a physical examination and blood tests that measure the levels of bilirubin in the blood. Imaging studies, such as ultrasound, CT scans, or MRIs, may be performed to identify the underlying cause.

Q4: Is jaundice a disease or a symptom? Jaundice is not a disease itself but a symptom of an underlying condition. It serves as a visual indicator that there may be an issue with the liver, bile ducts, or the breakdown of red blood cells.

Q5: What is the treatment for jaundice? The treatment of jaundice depends on its underlying cause. For example, if jaundice is due to liver disease, the focus is on managing the liver condition. If it’s related to a bile duct obstruction, surgical intervention may be necessary. Newborns with jaundice may undergo phototherapy to help break down excess bilirubin.

Q6: Is jaundice a serious condition? The seriousness of jaundice depends on the underlying cause. In some cases, jaundice may be a temporary and benign condition. However, it can also be a sign of severe liver disease or other significant health issues that require immediate medical attention.

Q7: Can jaundice be prevented? Preventing jaundice often involves addressing the underlying causes. For example, taking precautions to prevent liver disease (such as avoiding excessive alcohol consumption) or following safe practices to reduce the risk of hepatitis can help prevent some cases of jaundice.

Q8: Is jaundice contagious? Jaundice itself is not contagious. It is a symptom of an underlying medical condition. The underlying causes of jaundice may or may not be contagious, depending on the specific condition.

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