Liver biopsy

Definition

Currently we have numerous non-invasive examinations, such as analytical determinations, X-rays, ultrasound, tomography or magnetic resonance imaging. Despite this, in certain situations it is necessary to resort to microscopic study of damaged tissues. This is the case of lesions that settle in the liver, in which, in order to determine their diagnosis, treatment, prognosis and follow-up, a microscopic study may become essential.

Liver biopsy is the method by which a sample of liver tissue is extracted for microscopic study. There are several procedures for obtaining a liver biopsy:

• Percutaneous biopsy. It is the most widely used technique for taking liver tissue. A puncture is made through a small incision in the abdominal wall. Requires local anesthesia. The puncture needle has a wide lumen that allows a cylinder of liver tissue to be obtained.
• Transjugular biopsy. It is an alternative to percutaneous puncture for those patients with a significant alteration of coagulation and a high risk of bleeding. It consists of the introduction of a biopsy needle through one of the veins located in the neck: the internal jugular vein on the right side. The set of veins located in the dome of the liver is reached and from there the tissue sample is taken. During its performance, it requires the control of the heart rhythm due to the risk of arrhythmias.
• Fine needle aspiration-puncture (FNA) guided by ultrasound or computed tomography (CT). Only local anesthesia is applied. The size of the sample obtained is variable. It can be useful in evaluating diffuse liver disease.
• Laparoscopic biopsy. An incision is made in the abdominal wall with sedation and local anesthesia. The patient remains conscious during the examination. It allows to visualize the surface of the liver to take the sample. Its use has decreased with the development of the previously listed procedures.

How is the study done?

In the different biopsy procedures, a short hospital stay is preferable, except in the case of fine needle puncture in which the test can be performed on an outpatient basis.

For percutaneous biopsy and FNAB, an ultrasound or axial tomography is usually used, which allow the exact puncture site to be selected. The patient should be placed on the examination table on the left side. If the biopsy is done through the abdominal wall, you will lie on your back with your right hand under your head and it is important to remain as still as possible. Sedative and analgesic medication can be administered orally or intravenously. The skin is then cleansed and a local anesthetic is injected with a small needle. A small incision is made and the biopsy needle is inserted. During the procedure, the doctor can guide the puncture with an ultrasound machine. The patient must hold their breath while the biopsy is taken, in order to reduce the possibility of puncturing the lung or tearing the liver.

In transjugular biopsy, the procedure is performed by inserting a catheter into the jugular vein. The patient should lie on a table on his back. The right internal jugular vein in the neck is located, the skin is cleansed, and a small needle is used to inject a local anesthetic. Then a needle is inserted to pass a catheter through the veins to the liver. Thanks to an X-ray equipment, called a fluoroscope, the location of the catheter is verified. Later, a special needle is inserted through the catheter to obtain the tissue sample.

Preparation for the study

It is essential that the patient is fasting. You must have recent coagulation tests, which may have been requested previously or at the time of urgent admission.

Any treatment carried out by the patient must be brought to the attention of the doctor. To reduce the risk of bleeding, it is recommended that patients stop taking aspirin or any other anti-inflammatory drug during the week prior to the procedure.

What does it feel like during and after the study?

When the anesthetic is injected, a burning sensation or burning pain is common. The biopsy needle may feel like deep pressure and a dull ache. In some people the pain can radiate and be felt in the shoulder. After the procedure, mild or moderate pain may persist, both in the right side and in the right shoulder, which can usually be easily controlled with analgesics.

In the case of percutaneous liver biopsy, it is advisable to stay stretched for 24 hours, on the side, over the puncture site, to facilitate hemostasis and prevent bleeding.

Study risk

It is considered a relatively safe test that in experienced hands has a very low risk of complications. Although, being an invasive diagnostic test, it is not without risks. The most important complication is hemorrhage, which occurs in less than 1% of cases. It is seen most often in people with blood clotting problems and in cancer patients. Other exceptional complications are pneumothorax, puncture of other organs (gallbladder, kidney, lung), peritonitis, and septic shock.

Study contraindications

Percutaneous liver biopsy is contraindicated in non-cooperative patients, with suspected hydatid liver cysts, with severe coagulation abnormalities or probability of vascular liver tumors. In these last two cases, the use of a transjugular biopsy can be considered, which reduces the risk of bleeding. In patients with morbid obesity or with the presence of abundant intra-abdominal fluid (ascites), the use of transjugular biopsy is also preferable.

Reasons why the study is carried out

The biopsy helps diagnose many liver diseases. It can be indicated to complete the study of an analytical finding that reflects a liver problem. It will be the liver biopsy that will determine if the cause of this alteration is a toxicological, infectious, tumor, congenital or autoimmune process. The procedure is of special interest in assessing the stage of liver disease. This is especially important in chronic hepatitis C virus infection and alcoholic liver disease.