What is a Kidney or Renal Biopsy?
If an abnormal growth or mass can be detected on physical palpation or is detected by a body imaging technique, a biopsy is commonly performed to determine the nature of the abnormality. A biopsy can also be performed to gauge the degree of organ injury or response to a particular therapy for a known disease. So, what exactly is a biopsy? A biopsy simply means removing some tissue from the organ in question to study for any abnormalities. The tissue is examined under a microscope to detect changes in the cells and the surrounding architecture. Cancer or other diseases and injuries can be identified through a biopsy.
A kidney or renal biopsy removes tissue from the kidney with a specific needle and the tissue is then processed for examination under a microscope. A kidney biopsy is used to determine if the kidney is functioning normally, if there are any defects in the kidney cells or if there are any abnormalities such as infection or cancer.
In a kidney biopsy, the pathologist looks for any accumulation, infection, or abnormal activity in the kidney cells. The cells are analyzed with CT scans, ultrasound, or fluoroscopy. Based on the assessment of the cells, the appropriate condition and related treatment can be prescribed. Issues with transplanted kidneys or the exact stage of progressive kidney failure are also analyzed with a kidney biopsy.
What are the Reasons for a Kidney Biopsy?
A kidney biopsy can detect an excess of protein in the urine called proteinuria. In addition, a kidney biopsy can detect defects in kidney function by observing a buildup of excreted products in the blood, and it is also useful to observe excess blood in the kidneys called hematuria. A kidney biopsy can determine if a transplanted kidney is functioning properly or if there is a tumor in the kidney and how advanced the tumor is. However, a recent study that examined the research findings over the past 20 years has not found a clear conclusion that kidney biopsies are able to predict the outcome of kidney transplantation. More data is required to confirm if a kidney either needs to or does not need to be transplanted. The effectiveness of a treatment to cure a condition of the kidney can also be determined with a kidney biopsy. When the filtering units of the kidney do not function properly, glomerular disease and nephrotic syndrome occur. A kidney biopsy can help detect this condition.
What are the Types of Kidney Biospsy?
There are 4 types of kidney biopsy. They are elaborated below:
Open biopsy – In this biopsy, the patient is given a general anesthetic. The surgeon makes a small cut in the skin and removes a small piece of the kidney tissue to be sent for analysis.
Percutaneous (needle) biopsy – In this biopsy, a special biopsy needle is used to extract a small piece of kidney tissue. The needle is used to pierce the skin lying over the kidney and CT scans or ultrasounds are used to direct the needle to the desired site. Recently, spring loaded automated biopsy “guns” are being utilized in order to decease the time it takes to get a sample. The patient is given a local anesthetic. This procedure is a desired operation for renal biopsies in children and adolescents. Complications in this procedure fluctuate between 0% to 45%.
Laparoscopic renal biopsy – This procedure is performed in individuals who cannot undergo percutaneous renal biopsy. Individuals with bleeding issues, obesity, and only one kidney, are at higher risk for complications from undergoing percutaenous kidney biopsies, so in these cases, paproscopic biopsy is recommended.
Transjugular renal biopsy – This is a reliable and safe alternative to percutaneous renal biopsy. Individuals with obesity, anticoagulation, bleeding issues are recommended to go through this procedure. However, experienced radiologists are required to perform this biopsy. Hence, there are very few centers that offer this procedure.
What is the Surgical Procedure of Kidney Biopsy?
Preparing for the Biopsy
A kidney biopsy in a patient involves a series of procedures. Prior to the procedure, the doctor advises the patient about the procedure and clarifies any doubts about the operation. The patient is then required to sign a consent form to agree to the procedure being performed on his or her kidneys. The patient is then made to undergo blood tests and a physical examination to confirm the good health of the patient for the procedure. If the patient is taking medications, the doctor should be informed in order to take into account the effect of these medications on a kidney biopsy. The patient will be asked to stop taking any medications before the procedure. Similarly, any use of medications that cause bleeding or the use of anticoagulants, should be stopped before a kidney biopsy. The patient’s platelet count and bleeding time should also be checked before the procedure. If a patient is suffering from conditions that are difficult to diagnose, such as lupus nephritis, diagnosis has to be effective to confirm the need for a kidney biopsy in such individuals. Appropriate preventive measures and treatment have to be followed. If the patient is allergic to medications, anesthetic drugs, latex, or tape, the doctor should be informed before a kidney biopsy. The patient is requested to fast after midnight on the day before the procedure. The doctor should be informed if the patient is pregnant.
During the Biopsy
The patient is asked to change into hospital clothing and given an intravenous (IV) drip. The patient is then made to lie either on the stomach or on the back (if transplanted kidney is being checked). The skin of the biopsy site is cleaned with an antiseptic solution and the doctor gives local anesthesia at the biopsy location. The patient should lie without moving during the procedure. The patient is asked to breathe in so that the diaphragm does not interfere with the positioning of the biopsy needle. Ultrasound is utilized to direct the needle to the site of choice in the kidney. There is some pain and discomfort when the needle withdraws the biopsy samples. After the biopsy samples are removed, the bleeding is arrested by pressing down firmly against the location of the biopsy. A bandage is placed at the location of the biopsy. The samples are sent to the laboratory for analysis.
What are the Risks Associated with Kidney Biopsy?
There are certain risks to this procedure, as is expected from surgery. Pregnant women should inform the doctor of their condition. X-rays used for the procedure pose minimal risks to the procedure since the frequency of the radiation is low. Some of the risks to the procedure are as follows:
- Internal bleeding at the site of the biopsy or into the urine
- Presence of infection near the biopsy location
- Injury at the biopsy location and associated discomfort
- The organs near the site of the biopsy may get injured during the procedure.
Individuals with either infections, or only one kidney, or high blood pressure are not advised to undergo a kidney biopsy. Blood transfusion is provided if there is excess bleeding at the site of the biopsy.
Recovery After Kidney Biopsy
The patient lies on the back after the proedure and blood is drawn for further tests, while the urine is checked for blood. Each individual recovers at a different rate based on the procedure involved. The site of the biopsy feels sore soon after the procedure and lasts for several days. Pain relief medications are prescribed although Aspirin tends to cause bleeding. The patient should take only the medications that are prescribed by doctors. Following the surgery, the patient is taken to a recovery room lying on his/her own back for a few hours, where the pulse, breathing, and blood pressure are monitored. Once the pulse and blood pressure are stabilized, the patient is discharged (minimum of 6 hours observation for an outpatient procedure) or is moved to a hospital room based on the requirement. If the patient undergoes a kidney transplant, the patient is made to lie on the stomach for a few hours. The doctor should be notified if the patient feels faint, observes blood in the urine for 24 hours following the procedure, has pain at the biopsy location, experiences fever, is unable to urinate, has dizziness, or has swelling, redness, or other bleeding at the biopsy location. The patient may resume with a normal diet unless there are other complications. Physical activities, such as bouncing, tennis, horseriding, or aerobics should be avoided for a few weeks until the biopsy location heals well.
Recent advances
A recent study on ultrasound-guided percutaneous renal biopsy has recommended that ultrasound should be performed before, during, and after the biopsy. The time to perform the ultrasound after the biopsy may range from a few days to a few weeks. Another study has demonstrated that a kidney biopsy done on an individual lying in the lateral position is effective as it reduces the distance that the needle requires to travel to the kidneys.
