Overview of Percutaneous Liver Biopsy
A percutaneous liver biopsy is a medical procedure where a needle is inserted through the skin and eventually into the liver to collect a sample. This sample helps doctors diagnose, understand the severity of, and develop treatment plans for various liver diseases. This procedure was first reported in 1923.
With advancements in imaging techniques like ultrasound, CT scan, and MRI, the way a percutaneous liver biopsy is done has become more advanced. Now, doctors can pinpoint and target specific regions in the liver for the biopsy. This helps improve accuracy of the biopsy and reduces the risk of complications.
There are other ways to perform a liver biopsy, through either a vein or a laparoscopic approach (a small incision in the abdomen). But in general, the percutaneous route, being less invasive and less expensive, is the preferred method.
Why do People Need Percutaneous Liver Biopsy
A percutaneous liver biopsy is a procedure where a doctor uses a needle to take a small sample of liver tissue for testing. This medical procedure is used for three main purposes: to help diagnose a disease, to determine the stage or progress of a disease, and to guide treatment plans and clinical decision-making.
Liver biopsies generally help doctors diagnose various liver diseases, especially when blood tests don’t provide enough information. For instance, the biopsy may help explain why a person’s liver function tests are abnormal when there are no other clues. There is a common condition, non-alcoholic fatty liver disease (NAFLD), that affects about 100 million Americans. A liver biopsy is the only way to definitively distinguish between NAFLD and a more severe condition called non-alcoholic steatohepatitis (NASH).
Additionally, if a patient has a persistent fever but doctors can’t determine the cause, a liver biopsy can sometimes help diagnose certain infections. For example, the procedure has helped identify cases of histoplasmosis and tuberculosis. Similarly, if autoimmune hepatitis (AIH)—a condition where the body’s immune system attacks the liver—is suspected but not confirmed by blood tests, a liver biopsy can be beneficial for diagnostic confirmation and treatment decisions. A biopsy can also be useful in diagnosing drug-induced liver injury, assessing the health of a liver transplant, and identifying rare liver conditions known as infiltrative or storage diseases.
Besides diagnosis, liver biopsies also provide important information about the state or progression of a disease. They can show the degree of inflammation or fibrosis (scarring) in the liver, which is crucial for people with chronic hepatitis B or C. For example, in patients with chronic hepatitis C, those with other conditions like chronic alcohol use or a liver condition called hepatic steatosis typically have faster liver disease progression. Also, those with a condition called hemochromatosis who have advanced fibrosis revealed in a biopsy are at higher risk of developing liver cancer.
Lastly, the results of a liver biopsy can also guide a doctor’s treatment plan. For example, diagnosing autoimmune hepatitis with a biopsy can lead to initiating steroid therapy, and then the results can later guide decisions about reducing or stopping these medications. Understanding the severity of fibrosis in conditions like PBC can also help a doctor decide on the best treatment approach.
When a Person Should Avoid Percutaneous Liver Biopsy
In some cases, a doctor may not be able to perform a percutaneous liver biopsy, which is a procedure where a small piece of the liver is taken to examine it. These situations can be divided into two categories: absolute and relative contraindications.
Absolute contraindications are situations where the procedure should not be done at all:
- If the patient cannot fully cooperate with the procedure.
- If the patient has serious blood clotting disorders or low platelet count (thrombocytopenia), unless these conditions can be improved before the biopsy.
- If the patient used anti-inflammatory drugs (including aspirin) in the last 5 to 7 days.
- If the patient refuses a blood transfusion or if a transfusion cannot be provided.
- If the patient possibly has a blood vessel tumor, or a cyst caused by a type of tapeworm (echinococcal cyst).
- If it’s not possible to find a good spot to take the biopsy from the liver through a physical examination or an ultrasound.
- If the patient has a blockage in the bile ducts outside the liver.
- If the patient has a large amount of fluid in the abdomen (ascites).
Relative contraindications are situations where the procedure could be done, but with considerable risk:
- If the patient is severely overweight.
- If the patient has a small amount of fluid in the abdomen.
- If the patient has a blood clotting disorder such as hemophilia.
- If there’s an infection in the right part of the chest cavity.
- If there’s an infection under the right side of the breathing muscle (diaphragm).
- If the patient has amyloidosis, a condition where abnormal proteins build up in organs and tissues.
Equipment used for Percutaneous Liver Biopsy
If a doctor is performing a percutaneous liver biopsy, which is a procedure where a small sample of your liver is taken for testing, they have a variety of needle sizes and types at their disposal. They mainly fall into three categories:
- Suction needles (such as Menghini needle, Klatskin needle, Jamshidi needle)
- Cutting needles (like Vim-Silverman needle, Trucut needle)
- Spring-loaded cutting needles that come with a triggering action
What needle the doctor uses mostly depends on various factors like what they prefer, what tools are available, and the specifics of your health condition; they look at the big picture of your health. If they suspect that you may have cirrhosis, a disease where the liver tissue becomes scarred, they might opt for a cutting needle over a suction needle. This is because scarred or fibrotic tissue tends to break into pieces when a suction needle is used.
Preparing for Percutaneous Liver Biopsy
Before a doctor performs a liver biopsy (a procedure where a small piece of the liver is removed for testing), it’s important for patients to know the risks, benefits, and other possible options. This helps the patients make an informed decision, and the doctor then seeks their consent for doing the liver biopsy. Usually, this test takes place in a hospital or clinic.
Before the biopsy, the doctor will take a patient’s medical history and do a physical examination. Regular blood tests like a complete blood count (which checks the number of red and white blood cells), platelet count (a measure of the cells that help your blood to clot) and PT/INR (which check how fast your blood clots) are also done. Some doctors might also want to know about the patient’s blood type, and how long it takes for their blood to clot.
Medical guidelines suggest that if a patient’s platelet count is too low (less than 50,000 platelets per microliter of blood), a platelet transfusion may be needed. Likewise, if the PT/INR values are too high (more than 1.5), they may need to be brought down before the biopsy.
For those who are taking blood thinning medicines, it’s crucial to decide the right time to stop and restart these medications before and after the biopsy. There’s no set rule about this; the timing can vary from 24 hours to 10 days before the procedure. The specific drug being taken also plays a part. For instance, a medicine named Warfarin is generally stopped at least five days before the biopsy, and typically resumed the day after. These decisions are made based on the specific situation of each patient, keeping their overall risk and benefit in mind.
Though not necessary, some doctors let their patients have a light breakfast before biopsy. While a liver biopsy usually doesn’t require sedatives, some patients who are anxious about the procedure might be given a sedative to help them keep calm.
How is Percutaneous Liver Biopsy performed
A doctor can use three different methods to perform what is known as a percutaneous liver biopsy, which is a procedure to collect a small sample of liver tissue for testing. These methods are (1) palpation/percussion guided, (2) image-guided, and (3) real-time image-guided.
The palpation/percussion guided method relies on the doctor’s physical examination. The image-guided method uses ultrasound imaging to help the doctor select the best spot for needle insertion before the procedure is carried out. The real-time image-guided method means the doctor uses ultrasound imaging throughout the entire procedure to help guide them.
During the procedure, the patient lies flat on their back on the bed, with their right side near the edge of the bed. Their right arm is positioned above their head and the legs are moved apart to make room for the procedure. The doctor will then tap the patient’s right upper belly area (also known as the abdomen) to find the best spot for the biopsy. Typically, this is between the seventh and eighth ribs on the side, at a point where the tapping sound is the most muted.
The doctor will use ultrasound imaging to confirm the chosen biopsy spot is proper and to ensure there are no intestinal parts in the path of the biopsy needle. Then, the target area of the skin will be cleaned and covered with a sterile drape to prevent any infections.
Next, a local anesthetic such as lidocaine is used to numb the biopsy area. A small cut is then made, the biopsy needle is inserted through that small cut, aimed towards the lower part of the breastbone, and is kept horizontal. The tiny sample of liver tissue is collected during the exhalation phase of the patient’s breathing.
After the procedure, the doctor will apply pressure to the biopsy site for a few minutes to control any bleeding and then place a bandage. The patient is instructed to lie on their right side to aid in limiting any further bleeding by compressing the liver against the body wall.
After the procedure, the medical team will keep monitoring the patient’s blood pressure, heart rate, and any pain every 15 minutes for the first hour, every half an hour for the next hour, and then every hour until the patient is ready to be discharged done. Usually, this takes about 2 to 4 hours. Patients will be advised not to lift more than 10 to 15 pounds (or 4.5 to 7 kg) for one week thereafter.
There’s another version of this procedure known as a plugged biopsy. This method is used for patients who are at a higher risk of bleeding. It is similar to the regular procedure, except at the end the biopsy path is filled with substances like collagen or thrombin as the needle is removed to limit bleeding.
Possible Complications of Percutaneous Liver Biopsy
After having a liver biopsy, some people can experience complications, but these are quite rare. Usually, about 60% of these problems develop within two hours, and most (96%) show up within 24 hours after the procedure. In a study involving over 61,000 patients, the risk of dying from the biopsy was found to be as low as 0.2%. The most common issue is pain at the biopsy site, or pain that feels like it’s coming from the right shoulder.
Other complications may include:
* Sudden drop in blood pressure (due to the body’s response to stress or blood loss)
* Bleeding (under the surface of the shoulder blade, within the liver, inside the abdomen, into the bile ducts, or into the chest cavity)
* Collapsed lung
* Inflammation in the lining of the abdomen due to bile leakage
* Temporary presence of bacteria in the blood
* Clotting in the vein that carries blood to the liver
* Accumulation of pus below the diaphragm
* Possible reactions in patients with certain types of cancer like carcinoid tumors
* Death – although the risk is extremely low
The exact reason why some people feel pain after a biopsy is not known, but it might be due to swelling or minor bleeding under the liver’s surface layer. Pain-relieving medicines, like anti-inflammatories, are given to ease the discomfort. However, if the pain doesn’t go away, a hospital stay and imaging tests like an X-ray or an ultrasound, might be needed.
Bleeding into the liver or under its surface layer can cause pain, but sometimes people may not have any symptoms. These usually don’t require any extra test or surgery.
Severe bleeding into the abdomen, although uncommon, is considered the most serious type of bleeding complication. Those affected may report severe pain and show signs of rapid heartbeat or low blood pressure. It is thought to happen due to a significant tear during the biopsy or injury to the blood vessel system within the liver. In these cases, an urgent meeting with surgeons and radiologists is necessary and imaging tests are conducted.
Bleeding into the bile ducts is rare and is characterized by bleeding from the gastrointestinal tract, pain related to the bile ducts, and yellowing of the skin and eyes (a condition called jaundice). This condition might go away with proper care and rest; if not, a procedure to stop the bleeding or surgery might be needed.
There have also been cases of bacteria in the blood, bleeding into the chest cavity, collapsed lung, inflammation due to bile leakage into the abdomen, blood clots in the liver’s vein, pus accumulation under the diaphragm, and severe reactions in patients with certain types of cancer.
What Else Should I Know About Percutaneous Liver Biopsy?
A percutaneous liver biopsy is a medical procedure where a small sample of your liver is taken out and studied under a microscope. This test helps doctors understand and identify a variety of liver diseases. It’s a key tool in diagnosing, predicting the likely course (prognosis), and creating a treatment plan for people with liver problems. It’s usually a safe process that provides valuable information about what’s going on within your liver.
