Slightly Elevated Liver Enzymes (100 U/L or less): 7 Causes Explained.
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Key facts about slightly elevated liver enzymes.
In laboratory investigations, ALT (SGPT) and AST (SGOT) are the two most commonly used liver enzymes. We frequently encounter slightly elevated liver enzymes in asymptomatic patients.
The commonly used reference ranges for liver enzymes are in the table below:
|Gender||Age range (years)||ALT levels (U/L)|
|18 or more||<33|
|18 or more.||<45|
Any elevation of liver enzyme ALT above the reference ranges is considered abnormal and should be investigated.
Today, we will specifically explain the common causes of a slight elevation of liver enzymes (from 50 to 100 U/L) and their significance.
Slight elevations of ALT and other liver enzymes often reflect a mild inflammatory process inside the liver (usually chronic).
1 . NAFLD (commonest).
The most common cause of slightly elevated liver enzymes is a nonalcoholic fatty liver disease (NAFLD) known as (fatty liver).
NAFLD is very common; the worldwide prevalence of NALD is around 25%; the table below shows the prevalence of fatty liver diseases in different regions of the world (reference):
Who is more likely to have NALD (risk factors) (reference):
- Diabetes (type two).
- Dyslipidemia (increased lipids such as cholesterol and triglycerides).
- Males are more likely to develop NASH than females.
- Age also plays a role, the prevalence of NAFLD increases with age.
- Race Hispanics have the highest prevalence of fatty liver (NAFLD), followed by Caucasians and African Americans.
- Most commonly, people with fatty liver (NAFLD) are asymptomatic.
- Vague symptoms such as fatigue and malaise.
- Rarely, vague Right upper quadrant pain (liver pain).
- Risk factors are often present (obesity, diabetes, hypertension, etc.).
- Symptoms of complications (late stage): fatty liver can lead to fibrosis or cirrhosis of the liver. Symptoms of cirrhosis include jaundice, weight loss, abdominal distension (ascites), swelling of the lower limbs, and vomiting of blood.
How is NALFD diagnosed?
Advanced fatty liver diseases (NAFLD) lead to inflammation of the liver (steatohepatitis), which is often the cause of slight elevations of liver enzymes.
The fatty liver is diagnosed based on risk factors, fat accumulation in the abdominal imaging, and the characteristic slight elevation of liver enzymes in some cases (particularly those with steatohepatitis).
The diagnosis also includes excluding other causes of sling elevation of liver enzymes such as chronic hepatitis C or B, medications, and alcohol intake.
2. Medications and toxins.
The second most common cause of slightly elevated liver enzymes is medications, herbal supplements, and toxins.
More than 1000 medications and supplements cause injury to the liver. You can see the complete list HERE.
Some cause severe elevation of liver enzymes and/or bilirubin and may end in liver failure. Others cause a slight elevation of the liver enzymes.
The condition is widespread among people who are taking multiple medications.
Medications and herbal supplements are often overlooked as a cause of slight elevation of liver enzymes because:
- Medication-induced liver injuries are often asymptotic in mild cases.
- Sometimes, nonspecific symptoms present as nausea, loss of appetite, fatigue, right upper abdominal pain, and pruritus).
- Also, The onset of injury can be delayed for over six months after starting the offending medication.
- We must exclude other causes of the slight elevation of liver enzymes at first (such as NAFLD and viral hepatitis).
- Obtaining drug level analysis is not always helpful, especially in the cases of a slight elevation of liver enzymes.
Possible offending medications include:
- Statins: drugs used to lower cholesterol levels.
- Nonsteroidal anti-inflammatory drugs such as ibuprofen.
- Some antibiotics such as sulfa drugs, amoxicillin, and ceftriaxone.
- Oral contraceptive pills.
- Some anti-hypertensive medications such as bisoprolol, candesartan, and carvedilol.
This is a small sample of the possible drugs that can cause elevation of liver enzymes. The fully searchable database is HERE.
3. Alochol-induced liver injury.
People who drink significant amounts of alochol often will have liver problems. Liver injury can be in many forms:
- Fat accumulation in the liver (steatosis).
- Inflammation with elevated liver enzymes (steatohepatitis).
- With chronic use, liver cirrhosis may develop.
Fat rapidly accumulates in the liver of people who drink; fatty liver can develop as soon as two weeks of regular consumption (reference). In addition, slight elevation of liver enzymes (AST is often higher than ALT in people who drink) is commonly seen.
Fortunately, steatosis and steatohepatitis often resolve rapidly after abstinence. But if you continue to drink for several months or years, the damage may become irreversible.
Which amount is considered significant?
The amount that may put you at risk of developing liver disease varies with age, gender, concomitant diseases.
The standard drink contains 14 grams of pure alochol. The illustration below shows the different types of drinks and their standard drinks (reference).
Below, The amounts that put you at risk of developing the alochol-related liver disease:
- Men under age 65:
– More than 14 standard drinks per week on average.
– More than four drinks on any day.
- Women and adults over 65:
– More than seven standard drinks per week.
– More than three drinks per day.
Sometimes, a slight elevation of liver enzymes may result from drinking lower amounts than the mentioned above. People who are at higher risk of developing liver injury following drinking include (reference):
- Obese persons with increased BMI.
- Co-existing conditions such as chronic viral hepatitis and NALFD.
4. Chronic viral hepatitis (Hepatitis B and C viruses).
We classify liver inflammation (hepatitis) into two broad categories:
- Acute hepatitis: Acute onset, rapidly progressive liver inflammation with very high liver enzymes.
- Chronic hepatitis: long-lasting minimal inflammation of the liver. The liver enzymes are often slightly elevated with the chronic type of inflammation.
The most common organisms that cause chronic hepatitis with slightly elevated liver enzymes are the viruses (particularly hepatitis B and C viruses).
Unfortunately, You may get infected with one of those viruses without any symptoms and without passing into the acute hepatitis stage.
Possible modes of transmission of hepatitis B and c viruses (HBV, HCV) include:
- Blood transfusion.
- Dental procedures.
- Sharing needles or syringes.
- Sexual contact with an infected person (particularly HBV).
- From a mother to her baby at birth (particularly HBV).
Symptoms of chronic hepatitis B and C:
- The condition may be completely asymptomatic in many cases.
- Mild symptoms such as chronic fatigue, anorexia, joint pain.
- Yellowish discoloration of the skin and eye whites.
- Dark urine, pale stool (only in acute flare-ups or in the end-stage disease).
- Abdominal pain.
Anyone with slightly elevated liver enzymes should be tested for HBV and HCV infection.
Blood tests are available to screen for both the viruses with excellent sensitivity and specificity. Therefore, your doctor will often request them as part of the slightly elevated liver enzymes investigations.
6. Less common causes:
Hemochromatosis is NOT a rare disease; It is one of the most common genetic disorders of individuals of European ancestry (reference).
A genetic defect leads to excess iron absorption from the intestine and iron overload in the liver leading to (hereditary hemochromatosis).
Hemochromatosis can be entirely asymptomatic for several years. However, slightly elevated liver enzymes and iron are often present. Therefore, iron levels and gene testing help the diagnosis of such a condition.
Learn More about hereditary hemochromatosis.
B. Liver congestion (congestive hepatopathy).
The liver drains its blood into a major vein called the inferior vena cava, which delivers the blood into the right heart chambers.
A specific type of heart failure called (right-sided heart failure) leads to the inability of the right chamber of your heart to receive blood. As a result, the liver becomes chronically engorged with blood (congestive hepatopathy).
Chronic liver congestion leads to liver enlargement, pain, and elevation of the liver enzymes (often a slight elevation).
Learn more about congestive hepatopathy.
C. Wilson’s disease.
Wilson disease is another less common genetic disease characterized by copper excess in your body (including your liver).
Wilson disease can present with acute hepatitis (highly elevated liver enzymes) or chronic hepatitis (slightly elevated liver enzymes).
Learn more about Wilson’s disease.
D. Autoimmune hepatitis.
It is an immune-mediated disease as your immune system attacks the liver cells. The condition can present at any age, which is more common in females.
The liver enzymes are typically over 100. However, some cases of autoimmune hepatitis may present with a slight elevation of the liver enzymes (about two-fold the upper limit of normal).
Learn more about autoimmune hepatitis.
E. Alpha-1 antitrypsin deficiency.
Another rare genetic disease causes liver damage and lung problems (detected by Alpha-1 antitrypsin level). Learn More.
Other liver diseases can also cause slight elevation of liver enzymes, such as primary hepatocellular carcinoma, gallstone complication by bile obstruction or acute cholecystitis, liver cirrhosis, secondary hemochromatosis, etc.
7. Extrahepatic diseases:
The liver enzymes (particularly AST) are found in other body organs such as skeletal muscles, heart muscles, bones, and the brain. Other non-liver diseases can cause slight elevation of the liver enzymes,
Examples of non-liver diseases associated with elevated liver enzymes:
- Thyroid diseases (hyper- or hypothyroidism.
- Celiac disease.
- Hemolysis (destruction of blood cells).
- Muscle diseases.
In conclusion, Any slight elevation of the liver enzymes should be evaluated by your doctor. NAFLD, medications, and herbal supplements are the two most common causes of a slight elevation of liver enzymes.