|Year : 1997 | Volume
| Issue : 8 | Page : 270-274
"Significance of serum gamma glutamyl transpeptidase in cholestatic jaundice"
Kailash Chand, Surinder Thakur
Department of Medicine, Indira Gandhi Medical College, Shimla-171 001., India
Department of Medicine, Indira Gandhi Medical College, Shimla-171 001.
|How to cite this article:|
Chand K, Thakur S. "Significance of serum gamma glutamyl transpeptidase in cholestatic jaundice". Indian J Med Sci 1997;51:270-4
The differentiation between mechanical biliary obstruction and intrahepatic cholestasis represents one of the classcial diagnostic challenges in clinicall medicine. History, physical examination and review of routine laboratory tests are the most important initial steps in the evaluation of patient with cholestatc jaundice.  The earliest clinical studies demonstrated that serum gamma-glutamyl transpeptidase (G.G.T.) is a sensitive index of hepatobiliary dysfunction.  In cholestatic liver disease, serum G.G.T. may rise to values averaging 12 times the upper reference limit.  While comparing serum G.G.T. determination and those of other marker enzymes of biliary stasis, such as alkaline phosphates and leucine aminopeptidase, the relative elevations of serum G.G.T. are very much greater, conferring superior sensitivity in the diagnosis of biliary tract disorders. The values of serum G.G.T. are gene rally higher in extrahepatic obstruction than intrahepatic cholestasis.  The present study was thus directed to find out the value of serum G.G.T. estimation in evalution of cholestatic jaundice.
| ¤ Material and Methods|| |
The study was conducted on forty patients of hepato-biliary diseases admitted in Indira Gandhi Medical College, Shimla. They were clinically divided into four groups, each group comprising of ten patients each of acute hepatitis without cholestasis cirrhosis, intrahepatic and extrahepatic cholestasis. Criteria for selection of patients with cholestasis included jaundice, pruritis, light coloured stools, conjugated hyperbilirubinaemia and raised alkaline phosphatase (usually to more than 3 times of normal). In all patients, serum bilirubin (total and conjugated) transaminases (SGOT, and alkaline phosphatase were measured. In cholestasis groups, real-time ultrasonography allowed distinction between extrahepatic cholestasis with dilated bileducts within the liver and intrahepatic cholestasis, where intrahepatic biliary radical dilatation was not seen. Serum G.G.T. activity was measured in all to hforty patients, employing the methods of Szasz, Rosalki and Tarlow, as described in the method of enzymatic analysis (1974) by using the kit of transasis-Biomedicals Pvt. Ltd. Nonhepatic disorders such as acute pancreatitis, congestive cardiac failure, acute myocardial Infarction, diabetes mellitus, alcoholics and patients taking hepatic microsomal enzyme inducting drugs, where serum G.G.T. is raised, were excluded from cholestasis group by appropriate history, clinical examination and relevant investigation. The mean values were estimated for all biochemical parameters and statistical significance of difference between means was estimated.
| ¤ Results|| |
In the present study, the mean serum G.G.T a tivities in intrahepa:ic and extrahepatic cholestasis were found to be 75.6±28.36 lu/L and 165.6±47.02 lu/L respectively. Although serum G. G. T. activities were higher in both types of cholestasis when compared with normal mean value (17.5 l.U/L), the rise was significantly higher in extrahepatic cholestasis as compared to intrahepatic cholestasis (p<0.01). The mean serum G.G.T. activities in acute hepatitis and cirrhosis group were found to be 58.8±31.59 I.U/L and 78.3±71.39 lu. L, mean serum G.G.T. values being higher in both groups as compared to normal mean value (17.5 IU/L). However serum G.G.T. values were significantly higher in extrahepatic cholestasis group when compared with acute hepatits group (p<0.01) end cirrhosis group (p<0.05). In inrahepatic cholestasis group, rise in serum G.G.T was not significantly higher when compared with acute hepatitis group and cirrhosis group (p<0.05). [Table 1])
While comparing serum G.G.T. and alkaline phosphatase in extrahepatic cholestasis group, both enzpmes showed a rise of more than 3 times the normal mean value. Both serum G.G.T. and alkaline phosphatase were raised in 100% cases of extrahepatic obstruction. [Table 2].
| ¤ Discussion|| |
Serum G.G.T. rises in cholestasis and mean serum G.G.T. activity are considerably higher in extrahepatic cholestasis than intrahepatic cholestasis. , In the present study, rise in mean serum G.G.T. activity was significantly higher in extrahepatic cholestasis as compared to intrehepatic cholestasis (p<0.001). In extrahepatic cholestasis group, biliary obstruction was caused by calculus disease in 30% cases and maligant disease in 70% cases mean serum G.G.T. activity in two groups was found to be 206±48.59 IU/L and 150.85± 42.41 IU/L respectively. The mean serum G.G.T. activity in malignant, disease and calculous disease causing extrahepatic biliary obstruction did not show any statistically significant difference. In contrast, Rutenberg et al  found serum G.G.T. activity to be considerably higher in extrahepatic obstruction caused by malignant disease than in other caused of cholestasis. Highest serum G.G.T. activity was seen in a case of cholangitis, as was also reported by Szczeklik et aI.  In cholestatic liver disease, serum G.G.T. may rise to values averaging 12 times the upper reference limit and is more often raised than alkaline phosphatase.  However, in our study, serum G.G.T was not increased more often and to a greater - extent, when compared with alkaline phosphatase, similar observations being made in a study conducted by Betro et al.  Raised serum G.G.T activity is seen in patients with acute hepatitis.  In cirrhosis, serum G.G.T activity tends to be variable. Occasionally it may be very high, while at other times, serum G.G.T. may be normal. , In the present study, mean serum G.G.T activity in acute hepatitis group and cirrhosis group was found to be 58.8+ _ 31.59 IU/L and 75.6±28.36 I.U/L respectively. In both groups, serum G.G.T. was found to be higher as compared to normal mean value (17.5.I.U./L).
| ¤ Summary|| |
In conclusion, our study showed that serum G.G.T rises in cholestasis, and the rise is significantly higher in extraphepatic cholestasis as compared to intrahepatic cholestasis. Serum G.G.T has not shown any superiority over alkaline phosphatase in the evaluation of cholestatic liver disease. However, two considerations must caution against the use of serum G.G.T. alone for evaluation of hepatobiliary disease. The first of these is the lack of specificity for hepatobiliary disease. Serum G.G.T. activity can be elevated in some non-hepatic disorders such as acute pancreatitis, congestive cardiac failure, myocardial infarction, diabetes mellitus and alcoholism. Determination of serum G.G.T. in these patients is of no value. Second, the possibility that changes in serum G.G.T. activity results from drug administration in man. 
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[Table 1], [Table 2]