Autoimmune Hepatitis

Published on 09/08/2015 by admin

Filed under Radiology

Last modified 22/04/2025

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(Left) Venous phase CT shows heterogeneous liver parenchyma with evidence of periportal edema image, a nonspecific sign often seen in acute hepatitis, among other causes.

image
(Right) CT section in the same case shows subcapsular and peripheral wedge-shaped foci of hyperdensity image, representing confluent fibrosis and is usually seen in advanced and more chronic liver damage. Liver biopsy showed acute and advanced liver injury due to autoimmune hepatitis (AIH).
image
(Left) Axial CECT of an autoimmune hepatitis-primary sclerosing cholangitis (AIH-PSC) overlap shows a nodular, cirrhotic liver with signs of portal hypertension, including splenomegaly, ascites, and varices image. The intrahepatic ducts image are dilated with an abnormal arborization, suggestive of PSC.

image
(Right) Axial CECT in the same patient shows dysmorphic liver, ascites, varices, and dilated, irregular intrahepatic bile ducts typical of primary sclerosing cholangitis.

TERMINOLOGY

Abbreviations

• Autoimmune hepatitis (AIH)

Synonyms

• Chronic active hepatitis

Definitions

• Chronic hepatitis of unknown etiology characterized by hyperglobulinemia, circulating autoantibodies, and inflammatory changes on hepatic histology

IMAGING

General Features

• Best diagnostic clue

image Dysmorphic liver with prominent periportal fibrosis ± signs of portal hypertension ± irregular intrahepatic ductal dilation

– Widened fissures, deep gallbladder fossa, ↑ caudate:right lobe ratio

Radiographic Findings

• AIH is not diagnosed specifically by imaging criteria

CT Findings

• CECT

image Typical signs of cirrhosis + portal hypertension
image Bands of fibrosis may show persistent, increased, delayed enhancement
image Irregular dilation of intrahepatic ducts in autoimmune hepatitis-primary sclerosing cholangitis (AIH-PSC) overlap disease

MR Findings

• Signs of cirrhosis ± portal hypertension
• MRCP is best for detecting irregular dilation of intrahepatic ducts in AIH-PSC overlap disease

Imaging Recommendations

• Best imaging tool

image MR with MRCP

DIFFERENTIAL DIAGNOSIS

Primary Biliary Cirrhosis (PBC)

• Imaging and other features may simulate or coexist with AIH: AIH-PBC overlap disease
• PBC typically affects middle-aged women
• Leads to early cholestatic injury (pruritus + jaundice)
• Imaging: Prominent regenerative nodules, lace-like fibrosis, large perihepatic lymph nodes

Primary Sclerosing Cholangitis (PSC)

• Imaging and clinical features may simulate or coexist with AIH: AIH-PBC overlap disease
• Often associated with ulcerative colitis
• Irregular dilation and arborization of bile ducts with thickened walls

Viral Hepatitis

• Imaging and clinical features may be identical to AIH
• Differentiation relies on serologic testing and evidence of viral antigens ± antibodies

Alcoholic Hepatitis

• Imaging evidence of steatosis
• History of alcohol use, biopsy evidence of steatosis, hepatocyte inflammation, and necrosis

PATHOLOGY

Staging, Grading, & Classification

• May exist as classic or typical form (type 1 AIH)

image Accounts for ∼ 80% of AIH cases in USA
image Lab tests

– ↑ serum alanine aminotransferase (> 5x upper limit of normal)
– Immunoglobulin G (IgG) > 2x normal
– + anti smooth muscle antibodies
– + antinuclear antibodies (ANA)
• Type 2 AIH

image Antibodies to liver and kidney microsomes
image Usually diagnosed in childhood
image 40% have other autoimmune diseases
• “Overlap” or “variant” syndromes

image Clinical and serologic features of other autoimmune diseases (20% of all patients with AIH)

– PBC
– PSC
– Autoimmune cholangitis
image AIH-primary biliary cirrhosis overlap

– Histologic features of AIH
– Serologic features of PBC

image Antimitochondrial antibodies (AMA)
– Histologic features of PBC but absent AMA

image May have antinuclear antibodies or smooth muscle antibodies
image Sometimes referred to as autoimmune cholangiopathy, autoimmune cholangitis, “AMA-negative PBC”
image AIH-primary sclerosing cholangitis overlap

– Serologic features of AIH but cholangiographic abnormalities characteristic of PSC
– Overlap prevalence may be 1-10% of all patients with AIH
– Affected patients have more cholestatic symptoms, laboratory and histologic findings than those with typical AIH

image ↑ alkaline phosphatase (2x normal)
image Pruritus, jaundice
– May have other autoimmune diseases

image Ulcerative colitis
image Diabetes mellitus
image Polyglandular autoimmune disease
image Thyroiditis
image Addison disease (adrenal insufficiency)
image Systemic lupus, rheumatoid arthritis
image Glomerulonephritis, etc.

Gross Pathologic & Surgical Features

• Moderate to severe lobular hepatic inflammation
• Advanced disease leads to cirrhosis

image Bridging fibrosis, cellular necrosis, regenerative nodules

Microscopic Features

• Histologic features alone are not diagnostic of AIH
• Lymphocytic, often lymphoplasmacytic inflammatory infiltrates extending from portal tracts into parenchyma
• Often associated with hepatocyte injury

CLINICAL ISSUES

Presentation

• Most common signs/symptoms

image May be asymptomatic

– Diagnosed only after detecting abnormal liver function
image Heterogeneous and fluctuating course
image Marked variability in clinical manifestations
image May have long indolent periods

– Or rapid progression to acute liver failure

image Usually following indolent and undiagnosed period
image More advanced disease

– Pruritus, jaundice
– Fatigue, abdominal discomfort
– Nausea, vomiting
• Other signs/symptoms

image After progression to cirrhosis

– Abdominal distention (ascites), variceal bleeding
• Diagnosis is based on several factors

image Exclusion of viral, alcoholic, or toxic hepatic injury
image Exclusion of genetic disease (e.g., α-1-antitrypsin deficiency)
image Marked elevation of serum aminotransferase + immunoglobulins
image Autoantibodies (e.g., antinuclear, anti-smooth muscle)
image Histology: Periportal &/or panlobular lymphoplasmacytic hepatitis

Demographics

• Age

image Occurs in children and adults of all ages

– Onset usually occurs by age 40 years
– Patients with later presentation often have evidence of chronic liver injury

image 25% have cirrhosis at time of initial diagnosis
• Gender

image Predominantly affects women (∼ 70%)

Natural History & Prognosis

• Most patients respond to immunosuppressive therapy

image Others progress to chronic injury with cirrhosis

Treatment

• Azathioprine, prednisone
• Sympathomimetic amines (e.g., dextroamphetamine sulfate)

DIAGNOSTIC CHECKLIST

Consider

• Role of imaging is to detect signs of acute or chronic liver injury, portal hypertension, associated abnormalities (e.g., biliary ductal disease)
image
Hematoxylin and eosin stain shows prominent lobular inflammatory cell infiltrates with large numbers of plasma cells image in a case of autoimmune hepatitis. (Courtesy L. Yerian, MD.)

image
Axial CECT in a patient with autoimmune hepatitis shows a heterogeneous liver parenchyma and periportal edema image, with subcapsular + parenchymal hyperdense bands image that represent fibrosis.
image
Axial CECT in the same patient shows peripheral fibrosis with retraction of the overlying hepatic capsule image, a finding usually associated with confluent fibrosis & indicative of chronic liver injury. Also note the widened fissures image, typical of cirrhosis but not specific for AIH.

SELECTED REFERENCES

1. Weidner, J, et al. Marked improvement of the autoimmune syndrome associated with autoimmune hepatitis by treatment with sympathomimetic amines. Clin Exp Obstet Gynecol. 2014; 41(4):460–461.

2. Sahni, VA, et al. Autoimmune hepatitis: CT and MR imaging features with histopathological correlation. Abdom Imaging. 2010; 35(1):75–84.

 

Culver, EL, et al. Systematic review: management options for primary sclerosing cholangitis and its variant forms – IgG4-associated cholangitis and overlap with autoimmune hepatitis. Aliment Pharmacol Ther. 2011; 33(12):1273–1291.

Czaja, AJ. Cryptogenic chronic hepatitis and its changing guise in adults. Dig Dis Sci. 2011; 56(12):3421–3438.

Jothimani, D, et al. Treatment of autoimmune hepatitis: a review of current and evolving therapies. J Gastroenterol Hepatol. 2011; 26(4):619–627.

Lohse, AW, et al. Autoimmune hepatitis. J Hepatol. 2011; 55(1):171–182.

Mayo, MJ. Management of autoimmune hepatitis. Curr Opin Gastroenterol. 2011; 27(3):224–230.

Mieli-Vergani, G, et al. Autoimmune hepatitis. Nat Rev Gastroenterol Hepatol. 2011; 8(6):320–329.

Potts, JR, et al. Optimizing management in autoimmune hepatitis with liver failure at initial presentation. World J Gastroenterol. 2011; 17(16):2070–2075.

Vergani, D, et al. Pharmacological management of autoimmune hepatitis. Expert Opin Pharmacother. 2011; 12(4):607–613.

Strassburg, CP. Autoimmune hepatitis. Best Pract Res Clin Gastroenterol. 2010; 24(5):667–682.

Bilaj, F, et al. MR imaging findings in autoimmune hepatitis: correlation with clinical staging. Radiology. 2005; 236(3):896–902.

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