Saturday, August 6, 2011
Liver biopsy is a diagnostic procedure for acquiring a portion of liver tissue. Microscopic
examination of liver tissue is used for identification of liver disease, its cause or stage.
What are the various types of liver biopsy?
The most commonly employed method for liver biopsy involves insertion of a needle into the liver for a fraction of a second through an appropriate spot on the body. The depth and angle of needle puncture at the spot is also determined by the physician by physical examination or ultrasound. The skin and the area under it are anesthetized followed by a needle puncture, in and quickly out of the liver. While about 50% individuals experience no pain after the procedure, the rest experience a brief, localized pain which may spread to the right shoulder. Patients may be discharged within 3 to 6 hours provided there are no complications.
In another technique, the needle is guided into the liver through the abdomen or chest aided by imaging techniques like ultrasound or Computer Tomography (CT). This is helpful in case of localized tumors to determine the precise location of the tumor and then guide the needle to it. Patients are normally allowed to go home on the same day.
Laparoscopy, transvenous or transjugular liver biopsy and surgical liver biopsy are other less commonly used techniques. In Laparoscopy, a small incision is made in the abdominal wall and a narrow, lit tubular instrument is guided through it. Gas introduced into the abdomen moves the internal organs away from the abdominal wall. Liver tissue samples are obtained by instruments passed through this lit instrument or via various punctures around the liver. Patients may be discharged after several hours of the procedure.
Transvenous or transjugular liver biopsy may be performed by a radiologist in special circumstances, e.g. when the patient has a significant problem with blood clotting (coagulopathy) or accumulation of a large amount of fluid within the abdomen (ascites). For this reason, transjugular liver biopsy is recommended for patients with advanced cirrhosis. In this procedure, a small tube is inserted into the internal jugular vein in the neck and radiologically guided into the hepatic vein which drains the liver. A small biopsy needle is then inserted through the tube and directly into the liver to obtain a tissue sample.
Surgical liver biopsy is done when a patient undergoes an open abdominal surgery which makes it easier for the surgeon to conduct detailed liver inspection and obtain as many biopsy samples as required.
In what instances is liver biopsy done?
Liver biopsy is used to determine the cause of chronic liver disease inferred by liver inflammation or elevated liver tests and also for diagnosis of liver tumors detected by imaging tests. While blood tests can well indicate chronic liver disease, liver biopsy helps confirm the diagnosis and also determine the extent of liver damage. Post-liver transplant biopsy helps determine the cause of elevated liver tests and also confirm likely rejection of the transplanted liver.
What are the risks associated with liver biopsy?
During liver biopsy, the primary risk encountered, though observed in only about 1% of cases, is bleeding from the site of needle puncture into the liver. Other likely complications may be puncture of other organs such as lung, kidney or colon. Mistaken biopsy of the gall bladder instead of the liver may lead to leakage of bile into the abdominal cavity which causes peritonitis. Fortunately, the risk of fatality from liver biopsy is a miniscule 0.1% to 0.01%.
As a precaution to minimize the risk of bleeding, the patient’s coagulation status is assessed by a Prothrombin Time test. If the Prothrombin Time is high or the platelet count low, then transjugular biopsy may be recommended instead of a standard one. Alternatively, clotting abnormalities may first be rectified by using Vitamin K or fresh frozen plasma.
Does liver biopsy have any alternatives?
In case liver biopsy is not possible for any reason, a physician may make the diagnosis of a liver disease through physical examination, patient’s medical history and blood test results. While blood tests may be sufficient for diagnosis of chronic liver disease in certain cases, at other times a liver biopsy may be deemed essential.
Are liver biopsies required to be repeated?
In most instances, a single liver biopsy is sufficient to confirm a suspected diagnosis of chronic liver disease. Repeated biopsies may however be required to track changes in clinical condition or the impact of medical therapy like drug treatment. Patients having undergone liver transplant may need repeated biopsies in the first few weeks to months from surgery to eliminate possibilities of rejection of the new liver or the onset of other complications.