Renal biopsy: Difference between revisions

'''Renal biopsy''' (also '''kidney biopsy''') is a [[medical procedure]] in which a small piece of [[kidney]] is removed from the body for examination, usually under a [[microscope]].<ref>{{Citation |last=Young |first=Michael |title=Renal Biopsy |date=2022 |url=https://www.ncbi.nlm.nih.gov/books/NBK470275/ |work=StatPearls |access-date=2023-11-24 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=29262196 |last2=Leslie |first2=Stephen}}</ref> Microscopic examination of the tissue can provide information needed to diagnose, monitor or treat problems of the kidney.

A renal biopsy can be targeted to a particular [[lesion]], for example a [[tumour]] arising from the kidney ('''targeted renal biopsy'''). More commonly, however, the biopsy is non-targeted as medical conditions affecting the kidney typically involve all kidney tissue indiscriminately. In the latter situation, any sufficiently- sized piece of kidney tissue can be used.{{citation needed|date=April 2022}}

A '''native renal biopsy''' is one in which the patient's own kidneys are biopsied. In a '''transplant renal biopsy''', the kidney of another person that has been [[Organ transplant|transplanttransplanted]]ed into the patient is biopsied. Transplant kidney biopsy can be performed when nothing is apparently wrong with the transplant kidney for the purposes of surveillance for hidden disease ('''protocol transplant biopsy'''). This is typically done at 0, 3 and 12 months post-transplant according to a transplant unit protocol. Biopsy of the transplanted kidney taken during the transplant operation is termed '''implantation transplant biopsy''' or '''post-perfusion transplant biopsy''' depending on the timing of the biopsy with respect to key stages of the operation. When the transplanted kidney is not working properly, biopsy may be undertaken to identify the cause of dysfunction. This is referred to as an '''indication transplant biopsy''', because something has prompted the performance of the biopsy.

Before 1951, the only way of obtaining kidney tissue from a live person was through an open operation.{{cn|date=March 2023}}

In 1951, Danish physicians Poul Iversen and Claus Brun described a method involving needle biopsy which has become the new standard.<ref>{{cite journal |authorvauthors=Iversen P, Brun C |title=Aspiration biopsy of the kidney |journal=Am. J. Med. |volume=11 |issue=3 |pages=324–30 |date=September 1951 |pmid=14877837 |doi=10.1016/0002-9343(51)90169-6}}</ref>

RenalKidney biopsy is performed on selected patients with [[Nephrology|kidney disease]]. It is most commonly used when less invasive tests are insufficient. The decision on whether or not to proceed to a renalkidney biopsy is usually made by a [[nephrologist]].{{cn|date=March 2023}}

* [[Haematuria]] (or blood in the urine) can occur with a number of conditions that affect the kidneys and urinary tract. While renal biopsy is not indicated in all cases of haematuria, it may be performed in those with [[hematuria|glomerular haematuria]] (blood that is thought to come from damage to the [[Glomerulus (kidney)|glomerulus]]) or when combined with features of progressive renal disease (e.g. increasing [[proteinuria]], elevated blood pressure and [[kidney failure]]). One example is the [[nephritic syndrome]].

* [[Proteinuria]] (or protein in the urine) occurs in many renal conditions. Renal biopsy is usually reserved for patients with high or increasing levels of proteinuria, or for patients who have proteinuria along with other signs of renal dysfunction. One example is the [[nephrotic syndrome]].

* [[RenalKidney failure]] (or impaired [[Renal physiology|kidney function]] due to kidney injury) can occur abruptly ([[acute renalkidney failure]]) or progress over a period of time ([[chronic renalkidney failuredisease]]). The cause of [[acute renalkidney failure]] can usually be determined without renalkidney biopsy. Biopsy is performed in those instances where the cause is uncertain.

* Targeted renalkidney biopsy can be used to obtain tissue from a [[tumour]] arising from or adjacent the kidney.

* For [[surveillance]] of hidden disease involving the transplant kidney, so-called protocol renal biopsy undertaken at fixed intervals post-transplantation.

* When the transplant kidney is not working as well as expected, or when there is a deterioration in function. In these instances, biopsy is performed to exclude [[Transplant rejection|rejection]], [[polyoma virus|BK nephropathy]], drug-toxicity or recurrence of the disease that caused [[kidney failure]] in the first place.

The safety of renal biopsy is affected by the following conditions:<ref>{{cite journal |authorvauthors=Mendelssohn D, Cole E |title=Outcomes of percutaneous kidney biopsy, including those of solitary native kidneys. |journal=Am J Kidney Dis |volume=26 |issue=4 |pages=580–585 |date=October 1995 |pmid=7573010 |doi=10.1016/0272-6386(95)90592-8}}</ref><ref>{{cite journal |authorvauthors=Whittier L, Korbet S |title=Renal biopsy: update |journal=Current Opinion in Nephrology and Hypertension |volume=13 |issue=6 |pages=661–665 |date=November 2004 |pmid=15483458 |doi=10.1097/00041552-200411000-00013|s2cid=40898162 }}</ref>

* [[bleeding diathesis]]

* uncontrolled severe [[hypertension|high blood pressure]]

* uncooperative patient

* presence of a solitary native kidney

* [[azotemia]] or [[uraemia]]

* certain anatomical abnormalities of the kidney

* skin infection at the biopsy site

* medications that interfere with clotting (e.g. [[warfarin]] or [[heparin]])

* [[pregnancy]]

* [[urinary tract infection]]

* [[obesity]]

===Before Biopsybiopsy===

Like most invasive medical procedures, a renal biopsy is not without risk (see [[Renal biopsy#Complications|Complications]]). A [[nephrologist]] will have to satisfy themselves that a renal biopsy is of appropriate benefit to justify the risks of the procedure before proceeding. This will include careful consideration of patient characteristics and other clinical information obtained from history, examination and other less-invasive investigations.{{cn|date=March 2023}}

Prior to the procedure, [[informed consent]] is usually taken. Arrangements will also be made to ensure that appropriate post-biopsy care and supervision is in place. Fasting is usually not required,. howeverHowever, this will depend on centre preference.

===During Biopsybiopsy===

Renal biopsy is typically performed by a [[nephrologist]] or [[interventional radiologist]]. The biopsy is planned with the assistance of [[medical ultrasonography|ultrasound]] or [[X-ray computed tomography|CT scanning]] to visualise the location and depth of the kidneys immediately before the biopsy.{{cn|date=March 2023}}

In the case of a native kidney biopsy, the procedure will be performed with the patient lying on their stomach ([[Prone position|prone]]) or on their side ([[lateral decubitus]] position). For transplant renal biopsy, the patient lies on their back ([[supine]]). The biopsy procedure usually takes about 15 minutes.{{cn|date=March 2023}}

The site of biopsy is prepared antiseptic solution and sterile drapes are applied. If real-time imaging is used, sterile coverings will be placed on the equipment. The person performing the procedure ([[proceduralist]]) will wash their hands and don a sterile gown and gloves. A mask may or may not be worn.

After the site is prepared, the proceduralist injects [[local anaesthetic]] into the skin, through the subcutaneous tissue and down to and around the kidney. There may be a sharp sting as the local anaesthetic is injected. After a few seconds, the site will be numb and only a sensation of pressure should be felt. A small 1-2mm1–2&nbsp;mm incision is made to allow insertion of the biopsy needle. In most cases, real-time imaging will be used to guide positioning of the local anaesthetic and biopsy needles. In the case of blind biopsy, this will not be used. A loud click may be heard as the spring -loaded biopsy needle is fired into the kidney to obtain a tissue sample. The resulting core of kidney tissue is usually less than 1mm1&nbsp;mm in diameter and up to 1&nbsp;cm long. This may be done more than once to obtain sufficient kidney tissue.

===After Biopsybiopsy===

Post-biopsy care will differ from centre to centre. Most hospitals will observe patients who have had renal biopsy for 4–6 hours andto allowminimise dischargethe homerisk ifof therebleeding. Blood pressure and urine are nofrequently observedmonitored to ensure the patient does not have any bleeding complications. duringMild-moderate thispain periodis managed with simple [[analgesic]]s such as [[paracetamol]] or [[acetaminophen]]. OtherSevere centrespain willis admitusually patientsan whoindication haveof hadbleeding renalcomplication, biopsyand overnightmay prompt a longer hospital stay and forfurther observationtests.