Hepatic Granulomas
Hepatic Ganulomas have numerous possible causes and are usually asymptomatic However, the disorder causing the granulomas may produce extra hepatic manifestation and or hepatic inflammation, fibrosis, and portal hypertension.
Diagnosis is based on liver biopsy, but biopsy is necessary only if a treatable underlying causes (e.g infection) is suspected or other liver disorders are ruled out.
Treatment is determined by the underlying disorder
Hepatic granulomas may be insignificant but more often reflect clinically relevant disease.
The term granulomatous hepatitis is often used to describe the condition, but the disorder is not true hepatitis, and the presence of granulomous does not imply hepatocellular inflammation.
Etiology and Pathophysiology
A granuloma is a localized collection of chronic inflammatory cells with epithelioid cells and giant multinucleated cells. Caseation necrosis or foreign body tissue ( e.g schistosome eggs) may be present .
Most granulomas are in the parenchyma, but granulomas may occur in the triads in primary biliary cirrhosis.
Granuloma formation is incompletely understood. Granuloma may develop in response to poorly soluble exogenous or endogenous irritants. Immunologic mechanism is involved.
Hepatic granuloma have many causes.More often drugs and systemic disorders have ( often infections) than primary liver disorders . The infections are important to recognize because they require specific treatments.
TB and schistosomiasis are the most important infectious causes worldwide, viral causes are less common.
Sarcoidosis is the most important noninfectious cause, the liver is involved in about two third of patients and occasionally is the dominant clinical manifestation.
Granulomas are much less common in primary liver diseases, of which primary biliary cirrhosis are the only important cause .Small granulomas occasionally occur in other liver diseases but are of no clinical significance.
Idiopathic granulomatous hepatitis is a rare syndrome of hepatic granulomas and recurrent fever,myalgias,fatigue, and other systemic sysmptoms often occurring intermittently for yrars.
Some experts believe it is a variant of sarcoidosis.
Hepatic granulomas rarely affect hepatocellular function. However when granulomas are part of broader inflammatory reaction involving the liver (e.g drug reactions, infectious, mononucleosis), hepatocelullar dysfunction is present.
Sometimes inflammation causes progressive hepatic fibrosis and portal hypertension, typically with schistosomiasis and occasionally with extensive sarcoidal infiltration.
Symptoms, Signs and Diagnosis
Granulomas themselves are typically asymptomatic, even extensive infiltration usually produces only minor hepatomegaly and little or no jaundice. Symptoms, if they occur, reflect the underlying cause (e.g constitutional symptoms in infections, hepatosplenomegaly in schistosomiasis)
When Hepatic Granulomas are suspected,liver function tests are generally obtained ,but the results are non specific and are rarely helpful in diagnosis.
Alkaline phosphatase( and gamma glutamyl transferase) is often mildly elevated but occasionally may be markedly elevated ,other test results may be normal or may reveal abnormalities that reflect additional hepatic damage (e.g wide spread hepatic inflammation due to a drug reaction .
Imaging tests such as ultrasound, CT, or MRI usually are not diagnostic; they may show calcification (if chronic) or filling defects particularly with confluent lesions.
Diagnosis is based on liver biopsy .However, biopsy is usually indicated only to diagnose treatable causes ( e.g infections) or to differentiate from non granulomatous disorders (e.g chronic viral hepatitis ).
Biopsy sometimes reveals evidence of the specific causes (e.g schistosomal ova, caseation of TB, fungal organisms). However, other studies e.g ( cultures, skin tests, laboratory tests, x-rays, other tissue specimens) are often needed.
In patients with constitutional or other symptoms suggesting infection ( e.g FUO), specific measures are taken to increase the diagnostic sensitivity of biopsy for infections ( eg, sending a potion of fresh biopsy specimen for culture and performing a special stains for acid – fast bacilli, fungi, and other organisms). Often, cause cannot be established.
Prognosis and treatment
Hepatic granulomas caused by drugs or infection regress completely after treatment.
Sarcoid granulomas may disappear spontaneously or persist for years, usually without clinically important liver disease.
Progressive fibrosis and portal hypertension rarely develop (sarcoidal cirrhosis).
In schistosomiasis, progressive portal scarring is typical (pipestem fibrosis). Liver function is usually preserved, but marked splenomegaly and variceal hemorrhage can occur.
Treatment is directed at the underlying cause.
When cause is unknown, treatment is usually withheld and follow up instituted with periodic liver function test. However if symptoms of TB ( e.g prolonged fever ) and deteriorating health occur, empiric anti tuberculosis therapy may be justified .
Patients with progressive hepatic sarcoidosis may improve with corticosteroids, however are not indicated for most patients with sarcoidosis and are warranted only if TB and other infections can be excluded confidently.
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