Systemic lupus erythematosus (SLE), commonly known as lupus, is a chronic autoimmune disease that can affect multiple organs and systems in the body. One of the organs that can be impacted by lupus is the liver. Although liver involvement is relatively uncommon in lupus, mild abnormalities in liver tests are quite common and seen in up to 60% of lupus patients.
The Essential Functions of the Liver
The liver plays a crucial role in the body and has over 500 vital functions. It is involved in important processes like protein production, nutrient storage, waste removal, bile production, blood clotting factors synthesis, and drug detoxification. When lupus affects the liver, it can disrupt these essential functions and lead to a range of complications.
How Lupus Causes Liver Abnormalities
There are several ways in which lupus can cause liver abnormalities:
Autoimmune Hepatitis
Inflammation of the liver, also known as hepatitis, is one of the most common manifestations. This lupus-related hepatitis is termed autoimmune hepatitis. In autoimmune hepatitis, the immune system starts attacking and inflaming the liver tissues. This can happen directly due to lupus or can be triggered by medications used to treat lupus.
Autoimmune hepatitis usually does not cause symptoms initially but some patients may experience nausea, vomiting, fatigue, abdominal pain, or jaundice. It is typically diagnosed with blood tests showing elevated liver enzymes. Autoimmune hepatitis is classified into two types – Type 1 and Type 2. Type 1 is more common and can occur at any age, while Type 2 mostly affects young girls. Treatment involves immunosuppressants like steroids and azathioprine to control the overactive immune system.
Hepatic Vasculitis
Another mechanism is inflammation of the small blood vessels supplying the liver, known as hepatic vasculitis. This restricts blood flow to the liver cells and can result in cell death. It manifests as abnormalities in liver function tests. Advanced vasculitis can lead to tissue damage and scarring of the liver.
Medication Side Effects
Certain drugs used for lupus treatment like NSAIDs, methotrexate, sulfasalazine etc. are potentially hepatotoxic i.e can damage the liver. The frequency of abnormal liver tests is much higher in lupus patients on these medications. Hence, periodic monitoring of liver enzymes is important if such drugs are prescribed.
Fatty Liver
Besides autoimmune inflammation, the liver can also be affected by fatty infiltration. Lupus patients have a higher tendency for fat deposition in the liver which shows up as fatty liver or steatosis on imaging. This is usually seen in association with obesity, diabetes, hypertension or dyslipidemia. Fatty liver is generally asymptomatic but may present with fatigue or pain in the upper right abdomen.
Viral Hepatitis
Another significant cause for liver disease in lupus is coexisting viral hepatitis. Individuals with lupus are at increased risk for hepatitis B and C infections, either due to the disease itself or its treatment. These chronic viral infections can lead to progressive liver damage, cirrhosis and liver failure.
Overlap with Other Autoimmune Diseases
In some cases, lupus may coexist with other autoimmune liver diseases like autoimmune hepatitis, primary biliary cholangitis or primary sclerosing cholangitis. This overlap further aggravates liver abnormalities.
Diagnosis of Liver Involvement in Lupus
Diagnosing the exact cause of liver involvement in lupus patients can be challenging at times. The signs and symptoms of various liver disorders tend to overlap. Doctors need to investigate thoroughly and rely on clinical examination as well as laboratory and imaging tests to reach the right diagnosis.
Blood tests to check for liver enzymes (ALT, AST, ALP, GGT) and bilirubin provide a good initial screening for liver problems. Elevated enzymes point towards inflammation or injury. Low albumin levels can indicate reduced liver function. Further immunological testing helps identify autoimmune disorders. Imaging techniques like ultrasound, CT and MRI scans give information about liver enlargement, fatty changes, cirrhosis, blockage of bile ducts etc. Rarely, a liver biopsy is required for definitive diagnosis, where a small sample of liver tissue is examined under a microscope.
Treatment Options for Lupus Liver Disease
The treatment of liver disease in lupus depends on the underlying cause and severity. Mild cases of autoimmune or drug-induced hepatitis generally respond well to stopping the offending medication and adding a course of corticosteroids like prednisone to suppress the hyperactive immune system. For moderate to severe hepatitis, stronger immunosuppressive drugs like azathioprine, mycophenolate mofetil or cyclosporine may be needed. Close monitoring of liver tests is important to assess treatment response. Any coexisting conditions like obesity or diabetes also need to be controlled. Antiviral drugs may be prescribed if there is an active hepatitis viral infection. Regular medical care is key to preventing complications and progression to advanced liver disease.
Conclusion
In conclusion, the liver is one of the organs susceptible to damage from systemic lupus erythematosus and its treatment. Mild liver test abnormalities are common but significant hepatitis is relatively uncommon. The causes can be multi-factorial – autoimmune inflammation, drug toxicity, vascular disease, fatty liver, overlap syndromes and chronic viral hepatitis. Making an accurate diagnosis through investigations and tailored treatment can control symptoms and improve outcomes. With careful management and monitoring, severe liver disease can be prevented in most lupus patients.
