Renal biopsy
Encyclopedia
A renal biopsy
is a procedure in which a sample of kidney
(also called renal) tissue is obtained. Microscopic examination of the tissue can provide information needed to diagnose, monitor or treat a renal disorder
.
. It is most commonly performed when less invasive measures are insufficient. The following are examples of the most common reasons for biopsy:
Hematuria with renal disease — Hematuria (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 hematuria, it may be performed in those with hematuria as well as progressive renal disease (such as increasing proteinuria or blood pressure).
Proteinuria — Proteinuria (protein in the urine) occurs in many patients with renal conditions. Renal biopsy is usually reserved for patients with relatively high or increasing levels of proteinuria or for patients who have proteinuria along with other signs of renal dysfunction.
A patient with nephrotic syndrome
(significant proteinuria, low blood albumin level, and oedema (swelling) of the arms and legs) may need a renal biopsy, especially if the patient has systemic lupus erythematosus
(SLE). Other patients with nephrotic syndrome may require a renal biopsy, depending upon the suspected cause of the nephrotic syndrome.
Acute renal failure
— renal failure
refers to kidney injury that impairs kidney function
. It can occur abruptly (called acute renal failure) or progress over a period of time (called chronic renal failure
). The cause of acute renal failure can usually be determined without renal biopsy. Biopsy is performed in those instances when the cause is uncertain.
Acute nephritic syndrome
— Patients with acute nephritic syndrome have hematuria, proteinuria, high blood pressure
, and impaired renal function
. Renal biopsy may be recommended to determine the cause of nephritic syndrome unless it can be determined through blood test
ing.
, uncontrolled severe hypertension
, uncooperative patient, and presence of a solitary native kidney (although the last has been challenged with the advent of more advanced guidance imaging technologies). Relative contraindications include severe azotemia
, certain anatomical abnormalities of the kidney, skin infection at the desired biopsy site, hemostasis
-altering drugs (e.g. warfarin
or heparin
), pregnancy
, urinary tract infections, and obesity
.
abnormality. The biopsy is usually performed while the patient is awake, after receiving an injection of local anaesthesia
(numbing medicine) to minimize pain.
To decrease the risk of bleeding, patients are usually advised to avoid medicines that increase the risk of bleeding (such as aspirin or nonsteroidal anti-inflammatory drugs
(ibuprofen, naproxen)) for one to two weeks before the biopsy. If the patient takes warfarin or heparin (drugs that impair clotting and increase the risk of bleeding), the physician will give specific instructions about the dose and time to take these medications before surgery.
Biopsy procedure — In most cases, an ultrasound is done to guide the physician inserting the needle. Less commonly, computed tomography
(CT scan) guidance is used. The needle is inserted through the skin in the back and into the kidney. Once the needle is in contact with the kidney, a sample of renal tissue is withdrawn.
In some patients, a different approach may be used to perform the biopsy. In this case, the patient is sedated and a small skin incision is made to obtain the sample of kidney tissue; this procedure is called open renal biopsy.
Following the biopsy, the patient made to lie flat on their back for six hours to minimize any risk of bleeding, blood pressure and urine are frequently monitored to ensure the patient is not suffering any complications.
Bleeding is the most common complication of renal biopsy. Rarely, bleeding is severe enough to require a blood transfusion
or surgery. Most patients who undergo renal biopsy notice blood in the urine
for several days after the procedure. Patients with urine that is bright red or brown for longer than one week should consult with their healthcare provider.
Pain is a common problem, although it is usually mild to moderate and resolves within a few hours. Medications can be given to reduce pain after the procedure. Patients who experience severe or prolonged pain should notify their healthcare provider; this can be a sign of a blood clot
that is obstructing the ureter (tube that leads to the bladder) or a large hematoma (a mass of clotted blood) that stretches the kidney.
Arteriovenous fistula
is also a possible complication. Damage caused by the biopsy needle to the walls of an adjacent artery and vein can lead to a fistula (a connection between the two blood vessel
s). Fistulas generally do not cause problems and usually close on their own over time.
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
is a procedure in which a sample of kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
(also called renal) tissue is obtained. Microscopic examination of the tissue can provide information needed to diagnose, monitor or treat a renal disorder
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
.
Indications
Renal biopsy is recommended for selected patients with kidney diseaseNephrology
Nephrology is a branch of internal medicine and pediatrics dealing with the study of the function and diseases of the kidney.-Scope of the specialty:...
. It is most commonly performed when less invasive measures are insufficient. The following are examples of the most common reasons for biopsy:
Hematuria with renal disease — Hematuria (blood in the urine) can occur with a number of conditions that affect the kidneys and urinary tract
Urinary system
The urinary system is the organ system that produces, stores, and eliminates urine. In humans it includes two kidneys, two ureters, the bladder and the urethra.-Kidney:...
. While renal biopsy is not indicated in all cases of hematuria, it may be performed in those with hematuria as well as progressive renal disease (such as increasing proteinuria or blood pressure).
Proteinuria — Proteinuria (protein in the urine) occurs in many patients with renal conditions. Renal biopsy is usually reserved for patients with relatively high or increasing levels of proteinuria or for patients who have proteinuria along with other signs of renal dysfunction.
A patient with nephrotic syndrome
Nephrotic syndrome
Nephrotic syndrome is a nonspecific disorder in which the kidneys are damaged, causing them to leak large amounts of protein from the blood into the urine....
(significant proteinuria, low blood albumin level, and oedema (swelling) of the arms and legs) may need a renal biopsy, especially if the patient has systemic lupus erythematosus
Lupus erythematosus
Lupus erythematosus is a category for a collection of diseases with similar underlying problems with immunity . Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs...
(SLE). Other patients with nephrotic syndrome may require a renal biopsy, depending upon the suspected cause of the nephrotic syndrome.
Acute renal failure
Acute renal failure
Acute kidney injury , previously called acute renal failure , is a rapid loss of kidney function. Its causes are numerous and include low blood volume from any cause, exposure to substances harmful to the kidney, and obstruction of the urinary tract...
— renal failure
Renal failure
Renal failure or kidney failure describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood...
refers to kidney injury that impairs kidney function
Renal physiology
Renal physiology is the study of the physiology of the kidney. This encompasses all functions of the kidney, including reabsorption of glucose, amino acids, and other small molecules; regulation of sodium, potassium, and other electrolytes; regulation of fluid balance and blood pressure;...
. It can occur abruptly (called acute renal failure) or progress over a period of time (called chronic renal failure
Chronic renal failure
Chronic kidney disease , also known as chronic renal disease, is a progressive loss in renal function over a period of months or years. The symptoms of worsening kidney function are unspecific, and might include feeling generally unwell and experiencing a reduced appetite...
). The cause of acute renal failure can usually be determined without renal biopsy. Biopsy is performed in those instances when the cause is uncertain.
Acute nephritic syndrome
Nephritic syndrome
Nephritic syndrome is a collection of signs associated with disorders affecting the kidneys, more specifically glomerular disorders. It is characterized by having small pores in the podocytes of the glomerulus, large enough to permit proteins and red blood cells to pass into the urine...
— Patients with acute nephritic syndrome have hematuria, proteinuria, high blood pressure
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
, and impaired renal function
Renal function
Renal function, in nephrology, is an indication of the state of the kidney and its role in renal physiology. Glomerular filtration rate describes the flow rate of filtered fluid through the kidney...
. Renal biopsy may be recommended to determine the cause of nephritic syndrome unless it can be determined through blood test
Blood test
A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a needle, or via fingerprick....
ing.
Contraindications
Absolute contraindications to a percutaneous approach traditionally include bleeding diathesisBleeding diathesis
In medicine , bleeding diathesis is an unusual susceptibility to bleeding mostly due to hypocoagulability, in turn caused by a coagulopathy . Several types are distinguished, ranging from mild to lethal...
, uncontrolled severe hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
, uncooperative patient, and presence of a solitary native kidney (although the last has been challenged with the advent of more advanced guidance imaging technologies). Relative contraindications include severe azotemia
Azotemia
Azotemia is a medical condition characterized by abnormally high levels of nitrogen-containing compounds, such as urea, creatinine, various body waste compounds, and other nitrogen-rich compounds in the blood...
, certain anatomical abnormalities of the kidney, skin infection at the desired biopsy site, hemostasis
Hemostasis
Hemostasis or haemostasis is a process which causes bleeding to stop, meaning to keep blood within a damaged blood vessel . Most of the time this includes blood changing from a liquid to a solid state. Intact blood vessels are central to moderating blood's tendency to clot...
-altering drugs (e.g. warfarin
Warfarin
Warfarin is an anticoagulant. It is most likely to be the drug popularly referred to as a "blood thinner," yet this is a misnomer, since it does not affect the thickness or viscosity of blood...
or heparin
Heparin
Heparin , also known as unfractionated heparin, a highly sulfated glycosaminoglycan, is widely used as an injectable anticoagulant, and has the highest negative charge density of any known biological molecule...
), pregnancy
Pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
, urinary tract infections, and obesity
Obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
.
Procedure
Preparation — Testing may be done before the biopsy to ensure that there is no evidence of infection or a blood clottingCoagulation
Coagulation is a complex process by which blood forms clots. It is an important part of hemostasis, the cessation of blood loss from a damaged vessel, wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop bleeding and begin repair of the damaged vessel...
abnormality. The biopsy is usually performed while the patient is awake, after receiving an injection of local anaesthesia
Local anesthesia
Local anesthesia is any technique to induce the absence of sensation in part of the body, generally for the aim of inducing local analgesia, that is, local insensitivity to pain, although other local senses may be affected as well. It allows patients to undergo surgical and dental procedures with...
(numbing medicine) to minimize pain.
To decrease the risk of bleeding, patients are usually advised to avoid medicines that increase the risk of bleeding (such as aspirin or nonsteroidal anti-inflammatory drugs
Non-steroidal anti-inflammatory drug
Nonsteroidal anti-inflammatory drugs, usually abbreviated to NSAIDs or NAIDs, but also referred to as nonsteroidal anti-inflammatory agents/analgesics or nonsteroidal Anti-inflammatory medicines , are drugs with analgesic and antipyretic effects and which have, in higher doses, anti-inflammatory...
(ibuprofen, naproxen)) for one to two weeks before the biopsy. If the patient takes warfarin or heparin (drugs that impair clotting and increase the risk of bleeding), the physician will give specific instructions about the dose and time to take these medications before surgery.
Biopsy procedure — In most cases, an ultrasound is done to guide the physician inserting the needle. Less commonly, computed tomography
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
(CT scan) guidance is used. The needle is inserted through the skin in the back and into the kidney. Once the needle is in contact with the kidney, a sample of renal tissue is withdrawn.
In some patients, a different approach may be used to perform the biopsy. In this case, the patient is sedated and a small skin incision is made to obtain the sample of kidney tissue; this procedure is called open renal biopsy.
Following the biopsy, the patient made to lie flat on their back for six hours to minimize any risk of bleeding, blood pressure and urine are frequently monitored to ensure the patient is not suffering any complications.
Complications
Serious complications of renal biopsy are rare.Bleeding is the most common complication of renal biopsy. Rarely, bleeding is severe enough to require a blood transfusion
Blood transfusion
Blood transfusion is the process of receiving blood products into one's circulation intravenously. Transfusions are used in a variety of medical conditions to replace lost components of the blood...
or surgery. Most patients who undergo renal biopsy notice blood in the urine
Hematuria
In medicine, hematuria, or haematuria, is the presence of red blood cells in the urine. It may be idiopathic and/or benign, or it can be a sign that there is a kidney stone or a tumor in the urinary tract , ranging from trivial to lethal...
for several days after the procedure. Patients with urine that is bright red or brown for longer than one week should consult with their healthcare provider.
Pain is a common problem, although it is usually mild to moderate and resolves within a few hours. Medications can be given to reduce pain after the procedure. Patients who experience severe or prolonged pain should notify their healthcare provider; this can be a sign of a blood clot
Thrombus
A thrombus , or blood clot, is the final product of the blood coagulation step in hemostasis. It is achieved via the aggregation of platelets that form a platelet plug, and the activation of the humoral coagulation system...
that is obstructing the ureter (tube that leads to the bladder) or a large hematoma (a mass of clotted blood) that stretches the kidney.
Arteriovenous fistula
Arteriovenous fistula
An arteriovenous fistula is an abnormal connection or passageway between an artery and a vein. It may be congenital, surgically created for hemodialysis treatments, or acquired due to pathologic process, such as trauma or erosion of an arterial aneurysm....
is also a possible complication. Damage caused by the biopsy needle to the walls of an adjacent artery and vein can lead to a fistula (a connection between the two blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
s). Fistulas generally do not cause problems and usually close on their own over time.