JAUNDICE

MED.TECH CHOTA ALEX

JAUNDICE The word jaundice comes from the French word jaune, which means “yellow”• Jaundice, or icterus, is used to describe the

yellow discoloration of the skin, eyes, and mucous membranes most often resulting from the retention of bilirubin

• Jaundice is most commonly classified based on the site of the disorder: prehepatic, hepatic, and posthepatic jaundice.

Jaundice cont

• Prehepatic and posthepatic jaundice, as the names imply, are caused by abnormalities outside of the liver, either before, as in “prehepatic,” or after, as in “posthepatic.”

• In these conditions, liver function is normal• This is not the case with hepatic jaundice,

where the jaundice is due to a problem with the liver itself—an intrinsic liver defect or disease.

CAUSES OF JAUNDICE1.Prehepatic Jaundice• Problem causing the jaundice occurs prior to liver

metabolism.• most commonly caused by an increased amount of

bilirubin being presented to the liver such as that seen in acute and chronic hemolytic anemias.

• This type of jaundice may also be referred to as unconjugated hyperbilirubinemia because the fraction of bilirubin increased in people with prehepatic jaundice is the unconjugated fraction.

2. Hepatic Jaundice• Occurs when the primary problem causing the

jaundice resides in the liver (intrinsic liver defect or disease).

• This intrinsic liver defect or disease can be due to disorders of bilirubin metabolism and transport defects (Crigler-Najjar syndrome, Dubin-Johnson syndrome, Gilbert disease, and neonatal physiologic jaundice of the newborn) or due to diseases resulting in hepatocellular injury or destruction.

2. Hepatic Jaundice cont.• Gilbert disease, Crigler-Najjar syndrome, and

physiologic jaundice of the newborn are hepatic causes of jaundice that result in elevations in unconjugated bilirubin.

• Conditions such as Dubin-Johnson and Rotor syndrome are hepatic causes of jaundice that result in elevations in conjugated bilirubin.

2. Hepatic Jaundice cont.a) Gilbert Syndrome• It is a benign hereditary disorder characterized by

intermittent unconjugated hyperbilirubinemia in the absence of hemolysis and underlying liver disease due to a defective conjugation system.

• usually manifests during adolescence or early adulthood.

• The molecular basis of Gilbert syndrome is related to the glucuronyltransferase superfamily, which is responsible for encoding enzymes that catalyze the conjugation of bilirubin.

2. Hepatic Jaundice cont.b) Crigler-Najjar syndrome

• Is a syndrome of chronic nonhemolytic unconjugated hyperbilirubinemia.

• is an inherited disorder of bilirubin metabolism resulting from a molecular defect within the gene involved with bilirubin conjugation.

• Crigler-Najjar syndrome may be divided into two types:

• type 1, where there is a complete absence of enzymatic bilirubin conjugation, and type II, where there is a mutation causing a severe deficiency of the enzyme responsible for bilirubin conjugation.

• Crigler-Najjar syndrome is rare and is a more serious disorder than Gilbert syndrome

2. Hepatic Jaundice cont. C) Physiologic jaundice of the newborn

• is a result of a deficiency in the enzyme glucuronyl transferase, one of the last liver functions to be activated in prenatal life since bilirubin processing is handled by the mother of the fetus.

• This deficiency results in rapid buildup of unconjugated bilirubin, which can be life threatening

• When this type of bilirubin builds up in the neonate, it cannot be processed and it is deposited in the nuclei of brain and nerve cells, causing kernicterus.

• Kernicterus often results in cell damage and death in the newborn, and this condition will continue until glucuronyl transferase is produced.

• usually treated with UV radiation to destroy the bilirubin some infants may require an exchange transfusion.

2. Hepatic Jaundice cont.d) Dubin-Johnson syndrome

• Rare inherited disorder caused by a deficiency of the canalicular transporter protein

• The liver’s ability to uptake and conjugate bilirubin is functional but the removal of conjugated bilirubin from the liver cell and the excretion into the bile are defective.

• This results in accumulation of conjugated and, to some extent, unconjugated bilirubin in the blood, leading to hyperbilirubinemia and bilirubinuria.

• A distinguishing feature of Dubin-Johnson syndrome is the appearance of dark-stained granules (thought to be pigmented lysosomes) on a liver biopsy sample.

• People with Dubin- Johnson have a normal life expectancy, so no treatment is necessary

2. Hepatic Jaundice cont.e) Rotor syndrome• defect causing Rotor syndrome is not Known. • It is hypothesized to be due to a reduction in

the concentration or activity of intracellular binding proteins such as ligandin.

• liver biopsy does not show dark pigmented granules.

• Excellent prognosis, and therefore treatment is not warranted.

• clinically similar to Dubin-Johnsonsyndrome

3. Posthepatic jaundice• Results from biliary obstructive disease,

usually from physical obstructions (gallstones or tumors), that prevent the flow of conjugated bilirubin into the bile canaliculi.

• Since the liver itself is functioning, bilirubin is effectively conjugated but it is unable to be properly excreted from the liver.

• Since bile is not being brought to the intestines, stool loses its pigment and becomes clay-colored.

Effects of jaundiceEyes, Skin, Mucous Membranes• causes a yellow tint in the whites of the eyes, skin

and mucous membranesDark Urine• It typically occurs because of bile duct blockage due

to gallstones, cysts, tumors, Change in Stool Color• may turn pale or a clay color. This change in stool

color is also linked to a blocked bile duct. This symptom is often accompanied by vomiting or nausea and a fever