A 65 –year-old man reported with visible Jaundice which he had noticed to be deepening in color. There was no history of pain, fever or any drug intake, but he complained of some weight loss and pales tools from the past few days. He was a moderate drinker. There was no history of such like episode before.
Blood Biochemistry revealed-
Serum Total bilirubin 20mg/dl
ALT- 92 U/L
What is the likely diagnosis?
Case discussion– In this case, by far the most likely diagnosis is Obstructive Jaundice which might be due to carcinoma of the head of the head of pancreas, obstructing the common bile duct. This classically gives rise to severe, painless, deep jaundice which is in keeping with a Bilirubin of 20 mg/dL. In this case obstructive Jaundice is characterized by high Alkaline phosphatase activity that is more than three times the upper limit of the reference range. The Aspartate and Alanine aminotransferase activities in the given case do not indicate severe hepatocellular damage.
1) The aminotransferase (transaminases) are sensitive indicators of liver cell injury and are most helpful in recognizing acute hepatocellular diseases such as hepatitis. The amino transferases are normally present in the serum in low concentrations. These enzymes are released into the blood in greater amounts when there is damage to the liver cell membrane resulting in increased permeability. Liver cell necrosis is not required for the release of the amino transferases, Levels of up to 300 U/L are nonspecific and may be found in any type of liver disorder. Strikingelevations—i.e., aminotransferase > 1000 U/L—occur almost exclusively in disorders associated with extensive hepatocellular injury such as (i) viral hepatitis, (ii) ischemic liver injury (prolonged hypotension or acute heart failure), or (iii) toxin- or drug-induced liver injury. Inmost acute hepatocellular disorders, the ALT is higher than or equal to the AST. An AST:ALT ratio > 2:1 is suggestive while a ratio > 3:1 is highly suggestive of alcoholic liver disease. In obstructive jaundice the aminotransferases are usually not greatly elevated.
2) Alkaline phosphatase The activities of three enzymes—alkaline phosphatase, 5′-nucleotidase, and γ-glutamyl transpeptidase (GGT)—areusually elevated in Obstructive liver diseases(Cholestasis). GGT elevation in serum is less specific for cholestasis than are elevations of alkaline phosphatase or 5′-nucleotidase. GGT estimation is done to identify patients with occult alcohol use. The normal serum alkaline phosphatase consists of many distinct isoenzymes found in the liver, bone, placenta, and, less commonly,small intestine. Elevation of liver-derived alkaline phosphatase is not totally specific for cholestasis,and a less than threefold elevation can be seen in almost any type of liver disease. Alkaline phosphatase elevations greater than four times normal occur primarily in patients with cholestatic liver disorders, infiltrative liver diseases such as cancer and bone conditions characterized by rapid bone turnover (e.g., Paget’s disease). In bone diseases, the elevation is due to increased amounts of the bone isoenzymes.In liver diseases, the elevation is almost always due to increased amounts of the liver isoenzyme. In intratrahepatic obstruction values are increased as in drug-induced hepatitis and primary biliary cirrhosis.Very high values arefound in Extrahepatic obstructive due to cancer, common duct stone, or bile duct stricture.The level of serum alkaline phosphatase elevation is not helpful in distinguishing between intrahepatic and extrahepatic cholestasis. Values are also greatly elevated in hepatobiliary disorders seen in patients with AIDS.