AST/ALT Ratio In Acute, Uncomplicated Falciparum Malaria Infection: Comparison In Relation To The AST/ALT Ratios In Diseases Of The Liver
I Garba, U Gregory
aminotransferases, diseases, falciparum, malaria, patients, tropics
I Garba, U Gregory. AST/ALT Ratio In Acute, Uncomplicated Falciparum Malaria Infection: Comparison In Relation To The AST/ALT Ratios In Diseases Of The Liver. The Internet Journal of Anesthesiology. 2006 Volume 14 Number 2.
Introduction: Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were assayed in 110 adult patients (age range 18-40 years) presenting with acute, uncomplicated falciparum malaria infection and a control group of 80 age and sex-matched adults.
Methods: Patient selection was done by simple random sampling of adult males and females presenting at the Bauchi State Specialist Hospital with a history of fever and malaise not lasting more that seven days and who were subsequently confirmed to be malaria-positive by microscopic examination of Giemsa-stained thin blood slides.
Results: The mean serum AST and ALT activities were found to increase significantly relative to the AST and ALT values in the control group. Serum AST activity was 38.29 ± 1.37 IU in the falciparum malaria patients and 30.19 ± 1.37 IU in the healthy controls, p < 0.05. Similarly serum ALT activity was 31.06 ± 0.58 IU in falciparum malaria patients and 24.96 ± 0.92 IU in the control group, p < 0.05. The mean AST/ALT ratio in acute falciparum malaria infection was found to be 1.22 ± 0.14. This ratio differs significantly from the AST/ALT ratios reported for patients with Non-alcoholic steatohepatitis, chronic hepatitis C, alcoholic liver disease, hepatitis B and cirrhosis, p < 0.05.
Conclusion:An AST/ALT ratio greater than 1 during acute falciparum infection contradicts earlier reports that the ratio is highly specific to cirrhosis alone or has application as marker of liver disease only. Therefore the application the AST/ALT ratio as a non-invasive means of assessing liver disease must be done with caution in the tropics where P. falciparum malaria infection is among the leading causes of hospital attendance.
The transaminases are two closely related enzymes of clinical significance 1, particularly in the assessment of liver function. Among the duo, aspartate aminotransferase (AST) is known to exist in two electrophoretically distinct forms; a cationic isoenzyme associated with the mitochondria 2 and the anionic form associated with the cytoplasm 3. Tissue levels of AST are highest in the heart and liver 4. Significant amount are also found in skeletal muscle and kidney, with lower levels in pancreas, spleen and lung. Low levels of AST are also found in erythrocytes 5. Alanine aminotransferase (ALT) is present in varying concentrations in the liver, heart, skeletal muscle, kidney, pancreas, spleen, lung and red blood cells 6. Both enzymes increase in many disorders related to the liver damage; hence they have been proven to be sensitive indicators of liver-cell injury 7. In particular, patients with viral hepatitis present with marked increases in the serum activities of both ALT and AST frequently before clinical symptoms of the disease become apparent 8,9. ALT is more elevated than AST in various necro-inflammatory conditions of the liver, reflecting its greater efficiency as a liver disease marker 10. Other conditions associated with increased serum ALT are infectious mononucleosis and intra-hepatic cholestasis. Serum AST levels are found to increase in myocardial infarction, muscle disease and hemolytic anemia 11. Other reported causes of elevated serum aminotransferase activities include alcohol abuse 12,13, medication 7 autoimmune hepatitis 14,15, hepatic steatosis and non-alcoholic steatohepatitis, hemochromatosis 18, Wilson's disease and alpha1-antitrypsin deficiency 7. However, it is not only diseases affecting the liver that are associated with elevated serum aminotransferases. Non-hepatic causes of raised serum aminotransferases include occult celiac sprue 7, muscular dystrophy 19,20, acute appendicitis 21 obesity 22 and circulating aminotransferase-immunoglobulin complexes (macro-enzymes) 23. Because of their usefulness as serum markers of liver diseases, the AST/ALT ratio has been postulated to be good indicators of hepatic diseases in adults 24,25. In particular, the AST/ALT ratio has been used to distinguish cirrhotic from non-cirrhotic patients 26 and patients with non-alcoholic steatohepatitis from those with alcoholic liver disease 17. In this study we assayed for the serum activities of both AST and ALT in adult presenting with acute P.
Subjects And Methods
The normal healthy reference values for both aspartate and alanine aminotransferases in the selected study locale are as follows: 30.19 ± 1.37 IU (AST) and 24.96 ± 0.92 IU (ALT), table 1. ALT and AST values in acute
The normal, healthy values for serum AST and ALT as reported by Pratt and Kaplan7 and later supported by Prati et al., 35are in the range of less than 30-40 U per liter. These values are above the normal range obtained in our study as shown in table 1. The differences in the normal, healthy ranges are not unexpected. This is because the normal, healthy ranges differ from one laboratory to another7. The possible reasons for such variations include environmental, nutritional status and anthropometric indices 36. Acute P
This is not an unexpected finding since alcohol consumption has a more damaging effect on centriportal liver cells which are rich in AST. In addition, this high AST/ALT ratio in alcoholic liver disease is a reflection of the low serum activity of ALT in patients with this disease 12. The comparatively low AST/ALT ratios in the other disease can be explained by the differences in the etiologies of these conditions relative to that of
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