Jaundice is the yellow discoloration of the sclera, skin and mucous membrane resulting from an increased bilirubin concentration in the body fluid (more than 3mg dl).
It is a very important topic for examination because your patient may have acute or chronic liver disease, congenital hyperbilirubinemia, hemolytic anemia or recurrent jaundice.
MECHANISM OF JAUNDICE PRODUCTION
The increase of bilirubin in the blood may arise in 4 different ways.
1- Overproduction: Increased bilirubin load on liver cells e.g. hemolytic states.
2- Decreased hepatic uptake: Disturbance in the process by which bilirubin diffuses into the cells from the sinusoid and is actively transported to the microsome for conjugation (intracellular bilirubin transport).
3. Decreased conjugation: Disturbance of bilirubin conjugation e.g. due hepatic to deficiency of enzymes which conjugate it.
4. Disturbance of excretion: It may result from intrahepatic dysfunction or extrahepatic mechanical obstruction: Intrahepatic cholestasis: difficulty in canalicular transport of bile microsome to main bile ducts e.g. viral hepatitis, some drugs. Extrahepatic cholestasis: obstruction of main bile ducts due to common bile duct stone, carcinoma of the head of pancreas from, etc.
1. Hemolytic jaundice
2. Congenital hyperbilirubinemia
3. Cholestatic jaundice may be intrahepatic or extrahepatic.
This results from increased destruction of red blood cells resulting in increased bilirubin production.
1. Extra- erythrocytic abnormalities
• Physical trauma (e.g. burns, prosthetic heart valve).
• Chemical trauma (drugs e.g. dapsone)
• Metabolic (e.g. uremia).
2. Intra-erythrocytic defects:
• Enzyme Glucose
• Dehydrogenase deficiency
• Vitamin B12 and folic acid deficiency.
Jaundice: mild. because a healthy liver can excrete a bilirubin load 6 times greater than normal. Bilirubin is not more than 4-6 mg/dl in uncomplicated hemolytic anemia. If bilirubin is more than 6 then there is concomitant hepatic injury.
a- Pallor: due to anemia
c- Stool: dark in color due to excessive stercobilinogen which bilirubin
d- Urine: dark due to increased urobilinogen.
1. LFT: Plasma unconjugated bilirubin is usually raised but less than 6mg/dl. Liver enzymes and albumin are normal.
2. Urine D/R: No bilirubinemia, because the hyperbilirubinemia is unconjugated which is not water-soluble and therefore cannot pass into the urine. Increased urinary urobilinogen.
Cholestasis is a failure of bile flow due to obstruction in intrahepatic or extrahepatic bile ducts.
Hepatocellular Jaundice (intrahepatic cholestasis) results from the inability of the liver to transport bilirubin into the bile canaliculi due to swelling of hepatocytes in the parenchyma of damaged liver or due to an excretory dysfunction of the bile canaliculi at a cellular level. Hepatocellular jaundice is discussed in the section of acute viral hepatitis.
Obstructive jaundice (Extra-hepatic cholestasis)
It occurs due to large bile duct obstruction of bile flow at any point in the biliary tract distal to the bile canaliculi. Owing to obstruction the bilirubin is unable to enter the bile canaliculi and passes back into the blood, thus, progressively deepening jaundice.
CAUSES OF CHOLESTATIC JAUNDICE
Recurrent idiopathic cholestasis
Primary biliary cirrhosis
Primary sclerosing cholangitis
Drugs such as oral contraceptives, anabolic steroids.
Cirrhosis due to any cause
Common duct stones
Head of the pancreas
Bile duct (cholangiocarcinoma)
Traumatic biliary stricture
DRUGS CAUSING HEPATIC CHOLESTASIS
o Sex hormones
o Cimetidine ranitidine
o Oral hypoglycemics
EVALUATION OF JAUNDICE
The first step is to decide whether the hyperbilirubinemia is hepatobiliary disease. This difference can be identified easily by measuring (conjugated) and indirect (unconjugated) bilirubin.
In hemolysis, there is predominant unconjugated hyperbilirubinemia. There may be features related to hemolytic anemias. If jaundice is due to predominant conjugated bilirubin then decide whether it is the result of hepatocellular obstruction due to hemolysis or the direct intrahepatic cholestasis).
Diagnosis disease, biliary (intrahepatic biliary obstruction. Extrahepatic requires proper history, examination and then investigations.
In a long or short case investigations are not available all discussion is based on differential diagnosis in the contest of age, risk factors, incidence and available data from history and clinical examination.
Ask about the predisposing factors such as Transfusion, previous surgery, intravenous drug abuse, promiscuous sexual activity leading to viral hepatitis.
Alcohol abuse causing alcoholic hepatitis. History of medication is important especially the Drugs chlorpromazine or anabolic steroids, drugs that cause hepatocellular damage such as isoniazid or that cause cholestasis such paracetamol.
Look for signs of acute and chronic liver disease.
o Duration less than 1 month – due to hepatitis. Duration 1-2 months o Carcinoma or chronic hepatitis.
o Jaundice progressively deepens – obstruction due to malignancy.
Suggesting viral hepatitis
Associated rigors suggest cholangitis which occurs often with gallstone causing the biliary most obstruction.
Cholangitis presents with (a) Fever (b) Jaundice and (c) Right hypochondrial pain.
Mild to moderate in viral hepatitis Intense, obstructive jaundice; due accumulation of bile salts in the body.
Smooth & tender in hepatitis and extrahepatic obstruction and nodular in malignancy
Splenomegaly may indicate portal hypertension or chronic liver disease.
6. Signs of chronic liver disease
Clubbing, palmar erythema, anemia, bruises, spider nevi, ascites, gynecomastia, hepatosplenomegaly, and pitting edema.
7. Late features:
Prolonged obstructive jaundice secondary malabsorption develops due to deficiency of bile salts, presenting with:
Vit. K deficiency (bleeding)
Vit D deficiency (bone pain)
8. Palpable gall bladder: Suggests carcinoma of the gall bladder or head of the pancreas obstructing the bile duct.
9. Stool: Clay-colored, due to deficiency of bilirubin in obstructive jaundice.
10. Urine: It is dark in color owing to the renal excretion of conjugated bilirubin.
o Liver function tests (LFTs)
o Serum bilirubin
o Slightly increased bilirubin in hemolytic jaundice. Very high in obstructive jaundice and malignancy.
o Unconjugated – in hemolytic jaundice.
o Conjugated – in obstructive jaundice
o Mixed – in hepatocellular jaundice