Kidney biopsy

Overview

A kidney biopsy is a test done by healthcare professionals (HCPs)to diagnose any kidney lesions, abnormalities, or diseases. HCPs take a tiny piece or sample of the kidney and send it to the laboratory for examination under the microscope. Observing the tiny sample under the microscope helps to better see the details of the tissue.

Kidney biopsy is also known as Renal biopsy. It is of two types. One is a Percutaneous biopsy, and the other is an Open biopsy. Percutaneous biopsy passes a needle through the skin over the kidney and guides it to the kidney tissue using an ultrasound. The open biopsy is done by taking the sample directly from the kidney during surgical procedures to the kidneys. A transplant kidney biopsy is a biopsy done on the kidneys received after transplantation. This is done to check the functioning state and rejection of the tissue by the body. 

The samples or tissues collected are stored in a liquid container and then sent to the pathology lab for observation under the microscope. 

Indication of the procedure

A kidney biopsy is indicated when a kidney problem cannot be identified with routine blood tests or radiographs. These are indicated whenever there is blood in urine due to bleeding from the kidney tissue, abnormal levels of proteins in the urine, which are constantly increasing, abnormal functioning of kidneys with products accumulating in the blood, and other disease conditions. Not all kidney or urine abnormalities need a biopsy. The HCP decides to get a biopsy based on many variables like initial examination, blood tests, signs and symptoms, and overall health. The indications include:

·Identify the extent of damage to the tissues, disease progression, and treatment planning and prognosis. 

·This is also used to monitor the health and functioning of the transplanted kidneys. 

·To identify any permanent damage to the kidneys. 

·To know if the kidneys' growing tissue is cancerous. 

Preparation for the procedure

Before undergoing a kidney biopsy, an individual should understand the importance and necessity of the procedure by discussing it with the HCP. All the medications taken by the individual should be informed to the HCP, along with the history of any previous diseases, infections, surgeries, and allergies. Based on the medications taken, sometimes some medicines are advised to stop depending on the health condition and risk vs. benefits. These include over-the-counter medications, blood thinners, and opioid painkillers. Sometimes, other medicines may be prescribed by the HCP before undergoing a biopsy.

Specific routine blood and urine investigations are carried out to rule out any infections or other conditions unknown to the individual. These are also done to understand that other factors are stable in the body. Biopsy is done on an empty stomach. Hence, stopping eating or drinking 8 hours before the procedure is advisable. 

During the biopsy procedure

The procedure is generally done in a hospital, and one has to be admitted for the same. Patients will typically be awake and lie on the abdomen so that it can give the best access to the kidney to be biopsied. One will be awake if the procedure is done under sedation or asleep when done under general anesthesia. 

After locating the kidney using a sonogram or x-ray images, the skin is marked and cleaned once the biopsy site is found for inserting the needle. A numbing local anesthetic gel is applied, and a needle is pushed through the skin to obtain the samples. One has to hold the breath while inserting the needle. After receiving enough samples, either using one or two needles, the biopsied area is covered with a bandage. 

In some patients where the above procedure cannot be done, open surgery is done to obtain the samples. The tissue sample collected is sent to a pathology lab and is examined by a pathologist who studies it and writes a detailed report. The duration of results depends on the lab but generally takes 3 – 5 days. 

Recovery after the biopsy

Patients are advised to rest in bed for a day after the biopsy. Healing can be faster, and bleeding will be less if one does not move to the side and stays still. Vitals are often checked for signs of bleeding or distress, and necessary blood tests are also performed. Patients are discharged the next day after their vitals are stable. It is advised not to be involved for at least two weeks in strenuous activities like heavy lifting, strenuous exercise, including contact sports, and sexual intercourse after the biopsy.

Risks and complications of biopsy

The possible risks associated with this procedure include bleeding from the operated site or blood in the urine. Mild pain will be present, which will subside in a few days. The development of abnormal connections between an artery and vein, which can lead to fistula formation, can occur sometimes. The development of infections or the accumulation of blood around the kidneys are other complications. 

Conclusion

A kidney biopsy, whether percutaneous or open, is an essential diagnostic tool for detecting and evaluating kidney diseases. It provides valuable insights into the extent of tissue damage, helps in treatment planning, and facilitates monitoring of kidney health, including post-transplant assessment. Though there are potential risks, kidney biopsy is essential in diagnosing and managing renal conditions.