Autoimmune hepatitis (AIH)
Autoimmune hepatitis (AIH) is a non-contagious, chronic, inflammatory, autoimmune disease in which one’s own immune system attacks healthy, normal liver cells. The cause of liver cell destruction in this disease is unclear, but may be related to an imbalance in some of the immune system cells (effector and regulatory). The persistent inflammation within the liver observed in AIH can result in scarring, ultimately leading to cirrhosis, liver failure requiring a liver transplant, and even death.
Although autoimmune hepatitis is usually seen in young women, it can occur in either sex at any age. The incidence, which has been rising, and prevalence are estimated to be 8.5 and 107 per million population, respectively.
What causes Autoimmune Hepatitis?
The cause of most cases of Autoimmune Hepatitis is not clear; but is thought to be a mixture of:
- autoimmunity – the process of your immune system making autoantibodies, which ‘attack’ and damage your body’s own cells and organs
- environmental triggers – causes starting outside of the body; for example getting a virus, taking certain medications, or coming into contact with other toxins
- genetic predisposition – inheriting genes which may make it easier for a trigger to set off the disease.
Signs and symptoms
The onset is usually insidious, but about 20% of cases present with acute (occasionally fulminant) hepatitis and some cases follow a viral illness (such as hepatitis A, Epstein-Barr infection, or measles) or exposure to a drug or toxin (such as nitrofurantoin, minocycline, hydralazine, methyldopa, or infliximab).
Exacerbations may occur postpartum.
Amenorrhea may be a presenting feature, and the frequency of depression appears to be increased.
Thirty-four percent of patients, and particularly elderly patients, are asymptomatic. Typically, examination reveals a healthy-appearing young woman with multiple spider telangiectasias, cutaneous striae, acne, hirsutism, and hepatomegaly.
Patients, especially elderly patients, with autoimmune hepatitis are at increased risk for cirrhosis, which, in turn, increases the risk of hepatocellular carcinoma (at a rate of about 1% per year).
How is autoimmune hepatitis diagnosed?
As many people have either no symptoms or symptoms that are common for many other conditions, in the early stages of Autoimmune Hepatitis it is often diagnosed by a medical professional either when you have had routine tests, or tests for an unrelated condition.
For those who have symptoms, diagnosis is usually made though a mixture of taking a careful medical history, performing a physical examination, a range of blood tests and a liver biopsy. A diagnosis of Autoimmune Hepatitis is usually made by looking at your test results and ruling out other causes of liver disease such as fatty liver disease or viral hepatitis.
Prednisone with or without azathioprine improves symptoms; decreases the serum bilirubin, aminotransferase, and gamma-globulin levels; and reduces hepatic inflammation.
Prednisone is given initially in a dose of 30 mg orally daily with azathioprine, 50 mg orally daily, which is generally well tolerated and permits the use of lower corticosteroid doses than a regimen beginning with prednisone 60 mg orally daily alone.
Intravenous corticosteroids or prednisone, 60 mg orally daily, is recommended for patients with acute severe autoimmune hepatitis. Budesonide, 3 mg orally two or three daily, may be at least as effective as prednisone in noncirrhotic autoimmune hepatitis and associated with fewer side effects.
Blood counts are monitored weekly for the first 2 months of therapy and monthly thereafter because of the small risk of bone marrow suppression. The dose of prednisone is lowered from 30 mg/day after 1 week to 20 mg/day and again after 2 or 3 weeks to 15 mg/day. Treatment is response guided, and ultimately, a maintenance dose of 10 mg/day should be achieved. While symptomatic improvement is often prompt, biochemical improvement is more gradual, with normalization of serum aminotransferase levels after an average of 22 months. Histologic resolution of inflammation lags biochemical remission by 3–6 months, and repeat liver biopsy is recommended at least 3 months after the aminotransferase levels have normalized. Failure of aminotransferase levels to return to normal invariably predicts lack of histologic resolution.