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Dear All,
I think my answer will be a descriptive enough to the question inquery and I hope every one will get the advantage after that:
== Many diseases and conditions can contribute to elevated liver enzymes. The doctor determines the specific cause of your elevated liver enzymes by reviewing your medications, your signs and symptoms and, in some cases, other tests and procedures.
ALT (Alanine Transaminase or Amino Transferase) is also called SGPT or GPT.
More common causes of elevated liver enzymes in concerning liver problems, including:
1- Acute viral hepatitis
- Hepatitis A
- Hepatitis B
- Hepatitis C
- Infectious mononucleosis
- CMV and other viruses causing an acute viral syndrome
2- Chronic viral hepatitis
- Hepatitis B
- Hepatitis C
- HIV
3- other infections
- Malaria
- Leptospirosis
- Typhoid
- TB
- Brucellosis
4- Nonalcoholic fatty liver disease
5- Alcoholic hepatitis (liver inflammation caused by drinking alcohol)
6- Autoimmune liver disease:
n Autoimmune hepatitis (formerly chronic active hepatitis, which is liver inflammation caused by an autoimmune disorder).
n Primary biliary cirrhosis
n Sclerosing cholangitis
7- Cirrhosis (liver scarring)
8- Liver Cancer
9- Hepatotoxicity (liver inflammation caused by drugs or toxins like Over-the-counter pain medications, including:
n Acetaminophen (Tylenol, others)
n Analgesics Salicylates
n Propoxyphene
n Antibiotics, like Erythromycin, Estolate, Tetracyclines, Flucloxacillin, Amoxycillin ± Clavulanate, or Sulphonamides.
n Anticonvulsants like Phenytoin, Carbamazepine, Sodium valproate, and Phenobarbitone
n Anti-TB drugs like Rifampicin
n Isoniazid
n Para-AminoSalicylic acid (PAS)
n Hormones like Oestrogens, Oral contraceptives, Androgens
n Others like Phenothiazines, and Halothane
n Cytotoxic drugs such as Allopurinol, Methyldopa, and Chlorpropamide
n Some herbal remedies
== AST/ALT ratio:
- In healthy persons the average ratio is about1.3.
- If AST and ALT are high and outside of reference range then the ratio can also be used, so
- In case of chronic liver disease (including alcoholic hepatitis, the ratio tends to rise and alcoholism affect levels of ALT and AST (ratio AST/ALT >1.5); by which AST concentrations are higher than ALT as a poor prognosis of alcohol hepatitis, and
- If ALT is higher than AST then this is often seen in Acute viral hepatitis, whereas the ratio tends to fall.
- In skeletal muscle damage, for a list of conditions to be considered. ALT elevations are much smaller than those of CK but if only the ALT has been tested, a myopathy or myocarditis can be missed.
- AST/ALT ratio >1 suggests cirrhosis in patients with hepatitis C.
== AST and ALT are usually also elevated to varying extents in liver disease. In the absence of acute necrosis or ischemia of other organs, elevated aminotransferase levels suggest hepatocellular damage. In severe viral hepatitis that causes extensive acute necrosis, significantly elevated serum aminotransferases levels may be found, whereas only moderate increases are found in less severe cases.
== Mild chronic or focal liver diseases, such as subclinical or anicteric viral hepatitis, alcoholic cirrhosis, granulomatous infiltration, and tumor invasion, may be associated with only mild abnormalities. Minimal elevations occur in biliary obstruction.
= AST is limited mainly to the elevation of hepatocellular disorder. Following congestive heart failure, AST levels also may be increased, probably reflecting liver involvement as a result of inadequate blood supply to that organ.
= AST levels are highest in acute hepatocellular disorders. In viral hepatitis, levels may reach100 times the upper limit of normal (ULN). In cirrhosis, only moderate levels – approximately4 times ULN – are detected.
= AST can be used to detect a liver injury or an active or chronic liver problem, shock, low blood pressure or any hypoxia.
= Clinical applications of ALT assays are confined mainly to elevation of hepatic disorders. Higher elevations are found in hepatocellular disorders than in extrahepatic or intrahepatic obstructive disorders, such as biliary tract obstruction (cholangitis, choledocholithiasis); liver abscess; metastatic or primary liver cancer; injury to liver (“shock liver”); and cholestasis or hepatotoxicity caused by drugs.
= ALT may indicate active hepatitis from any cause, including virus, drug or toxin. The patient with RA treated with a drug could have her ALT measured because this enzyme generally breaks down commonly used drugs.
= ALT is the preferred enzyme for evaluation of liver injury. Screening ALT in low-risk populations has a low (12%) positive predictive value.
= In acute inflammatory conditions of the liver, ALT elevation are frequently higher than those of AST and tend to remain elevated longer as a result of the longer half-life of ALT in serum (16 hrs and24 hrs, respectively).
== It is often helpful to conduct serial determinations of aminotransferases when following the course of a patient with acute or chronic hepatitis. However, one should exercise caution in interpreting these abnormal levels, because serum transaminases may actually decrease in some patients with severe acute hepatitis, owing to the exhaustive release of hepatocellular enzymes.
=1= Infectious mononucleosis: EBV can invade the liver causing elevation of liver enzymes to levels of200-500 units/L or occasionally higher. Alkaline phosphatase and GGT often show relatively greater elevations than the AST and ALT when compared with infectious hepatitis.
=2= Hepatitis: Hepatitis is characterized by elevations of ALT and AST and a histological picture on biopsy which may be diagnostic. When ALT and AST are above1000 U/L with ALPand GGT can be below300 U/L, the cause will usually be viral infection. In chronichepatitis, changes in ALT are used as an indication of disease activity.
a- Hepatitis C Virus: A positive HCV Ab test should be followed by HCV RNA test and ALT. An ALT >60 units indicates active disease but a level <60 does not exclude activity. The patient who is HCV Ab +ve but HCV RNA -ve is presumed to be free of active hepatitis provided the ALT is <60. The ALT should be monitored annually and the HCV RNA for at least2 years to confirm it is staying -ve.
b- Hepatitis B Virus: in case of HBs Ag +ve patients following up, ALT is the test used to decide whether the patient has active disease that should be considered for anti-viral therapy. If the ALT >60 units, it should be repeated in4 months. If the elevation >60 persists, the patient should be referred for specialist follow-up. HBe Ag should also be checked and repeated annually if found to be positive.
=3= Celiac disease and Liver disease: like the rest of your body, your liver isn't immune to the effects of celiac disease — in fact, celiac frequently affects your liver. It's not unusual for people with just-diagnosed celiac disease to hear they also have mildly elevated liver enzymes, which sometimes — but not always — indicates a problem with your liver. Fortunately, once celiac disease treatment begins in the form of the gluten-free diet, these enzymes typically return to normal levels.
- But celiac disease also is associated with a higher risk of more serious liver conditions, ranging from fatty liver disease to severe liver failure.
- Physicians use a panel of common medical tests to monitor your liver's function, including measurements of the liver enzymes AST and ALT. If your liver doesn't function properly due to injury or illness, these tests will show a high result, i.e., elevated liver enzymes. Even if you have elevated liver enzymes, it doesn't necessarily mean you have a problem with your liver.
- Fatty Liver Disease, Celiac Disease Linked: Non-alcoholic fatty liver disease (i.e., fatty liver disease that's not associated with alcohol abuse) is on the rise in the United States and worldwide, largely because it's strongly linked to obesity and diabetes. When you liver's cells accumulate fat molecules, and the entire organ enlarges. Most people with fatty liver disease don't have symptoms, and the condition only is considered serious if it begins to progress to liver inflammation and damage.
- Celiac Found In6% of Autoimmune Hepatitis Patients: In autoimmune hepatitis, your immune system attacks your liver. Drug therapy with corticosteroids may slow down the condition's progression, but eventually, it may progress to cirrhosis and liver failure, which necessitates a liver transplant.
Thanks for your precious time,
Lubna Al-Sharif
AST (SGOT) and ALT (SGPT) are sensitive indicators of liver damage or injury from different types of diseases or conditions. But it must be emphasized that higher-than-normal levels of these liver enzymes should not be automatically equated with liver disease. They may mean liver problems or they may not. For example, elevations of these enzymes can occur with muscle damage. The interpretation of elevated AST and ALT results depends upon the entire clinical evaluation of an individual, and so it is best done by physicians experienced in evaluating liver disease and muscle disease.
Moreover, the precise levels of these liver enzyme test do not correlate well with the extent of liver problems or the prognosis (outlook). Thus, the exact levels of AST (SGOT) and ALT (SGPT) cannot be used to determine the degree of liver disease or predict the future. For example, individuals with acute viral hepatitis A may develop very high AST and ALT levels (sometimes in the thousands of units/liter range). But most people with acute viral hepatitis A recover fully without residual liver disease. Conversely, people with chronic hepatitis Cinfection typically have only a little elevation in their AST and ALT levels while having substantial liver injury and even advanced scarring of the liver (cirrhosis) from ongoing minor inflammation of the liver.
Liver cirrhosis, faty liver, liver cancer, hepatospleno megaly & hepatitis elevate liver enzymes.
AST (SGOT) is normally found in a variety of tissues including liver, heart, muscle, kidney, and brain. It is released into the serum when any one of these tissues is damaged. For example, AST level in serum is elevated in heart attacks or with muscle injury. It is therefore, not a highly specific indicator of liver injury as its elevation can occur as a result of other injured tissues.
ALT (SGPT) is, by contrast, normally found largely in the liver. This is not to say that it is exclusively located in the liver, but that is where it is most concentrated. It is released into the bloodstream as the result of liver injury.
Thus, it serves as a fairly specific indicator of liver status.
ast and alt are liver enzymes but alt is more specific. alt increases in cases such as fatty liver. hepatitis and cirrhosis as a result of hepatic cell destruction
yes and no! because they are non specific and in most cases are not true indicator of liver disease. both ALT and AST are usually elevated in liver disease but are not true markers of liver damage because asid the liver these two enzymes are situated in other organs of the body especially AST which is predominant in kidneys, muscles, heart and even the brain and Alt been very sensitive is usually increased in mild liver disturbances like is seen in most african ciuntries where mosquitoes and malaria parasites are endemic
so in conclusion elevated AST and ALT Eenzymes MAY indicate liver disease but shuoldnt be a conclusive test for diagnosis of liver disease and as such should be combined with other tests like alkaline phosphatase, serum/urine bilirubin, plasma albumin
NB true liver function tests are
1) BROMOSULPHTHALEIN EXCRETION TEST
2) PLASMA BILE ESTIMATION
