A human kidney (click on image for description).
|Significant diseases||Hypertension, Kidney cancer|
|Significant tests||Kidney biopsy, Urinalysis|
|Glossary||Glossary of medicine|
Nephrology (from Greek nephros "kidney", combined with the suffix -logy, "the study of") is a specialty of medicine and pediatrics that concerns itself with the kidneys: the study of normal kidney function and kidney disease, the preservation of kidney health, and the treatment of kidney disease, from diet and medication to renal replacement therapy (dialysis and kidney transplantation).
The Ancient Greek language includes the forms of Greek used in Ancient Greece and the ancient world from around the 9th century BCE to the 6th century CE. It is often roughly divided into the Archaic period, Classical period, and Hellenistic period. It is antedated in the second millennium BCE by Mycenaean Greek and succeeded by medieval Greek.
The kidneys are two bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about 11 centimetres (4.3 in) in length. They receive blood from the paired renal arteries; blood exits into the paired renal veins. Each kidney is attached to a ureter, a tube that carries excreted urine to the bladder.
A medical speciality is a branch of medical practice that is focused on a defined group of patients, diseases, skills, or philosophy. Examples include children (paediatrics), cancer (oncology), laboratory medicine (pathology), or primary care. After completing medical school, physicians or surgeons usually further their medical education in a specific specialty of medicine by completing a multiple-year residency to become a medical specialist.
Nephrology also studies systemic conditions that affect the kidneys, such as diabetes and autoimmune disease; and systemic diseases that occur as a result of kidney disease, such as renal osteodystrophy and hypertension. A physician who has undertaken additional training and become certified in nephrology is called a nephrologist.
A systemic disease is one that affects a number of organs and tissues, or affects the body as a whole.
An autoimmune disease is a condition arising from an abnormal immune response to a normal body part. There are at least 80 types of autoimmune diseases. Nearly any body part can be involved. Common symptoms include low grade fever and feeling tired. Often symptoms come and go.
Renal osteodystrophy is currently defined as an alteration of bone morphology in patients with chronic kidney disease (CKD). It is one measure of the skeletal component of the systemic disorder of chronic kidney disease-mineral and bone disorder (CKD-MBD). The term "renal osteodystrophy" was coined in 1943, 60 years after an association was identified between bone disease and renal failure.
The term "nephrology" was first used in about 1960. Before then, the specialty was usually referred to as "kidney medicine."
Nephrology concerns the diagnosis and treatment of kidney diseases, including electrolyte disturbances and hypertension, and the care of those requiring renal replacement therapy, including dialysis and renal transplant patients. Many diseases affecting the kidney are systemic disorders not limited to the organ itself, and may require special treatment. Examples include acquired conditions such as systemic vasculitides (e.g. ANCA vasculitis) and autoimmune diseases (e.g., lupus), as well as congenital or genetic conditions such as polycystic kidney disease.
Hypertension, also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure typically does not cause symptoms. Long-term high blood pressure, however, is a major risk factor for coronary artery disease, stroke, heart failure, atrial fibrillation, peripheral vascular disease, vision loss, chronic kidney disease, and dementia.
Renal replacement therapy (RRT) is therapy that replaces the normal blood-filtering function of the kidneys. It is used when the kidneys are not working well, which is called renal failure and includes acute kidney injury and chronic kidney disease. Renal replacement therapy includes dialysis, hemofiltration, and hemodiafiltration, which are various ways of filtration of blood with or without machines. Renal replacement therapy also includes kidney transplantation, which is the ultimate form of replacement in that the old kidney is replaced by a donor kidney.
In medicine, dialysis is the process of removing excess water, solutes, and toxins from the blood in people whose kidneys can no longer perform these functions naturally. This is referred to as renal replacement therapy.
Patients are referred to nephrology specialists after a urinalysis, for various reasons, such as acute kidney failure, chronic kidney disease, hematuria, proteinuria, kidney stones, hypertension, and disorders of acid/base or electrolytes.
Chronic kidney disease (CKD) is a type of kidney disease in which there is gradual loss of kidney function over a period of months or years. Early on there are typically no symptoms. Later, leg swelling, feeling tired, vomiting, loss of appetite, or confusion may develop. Complications may include heart disease, high blood pressure, bone disease, or anemia.
Hematuria is the presence of red blood cells in the urine. Visible hematuria, also known as gross hematuria, causes visible red or brown discoloration of the urine. Microscopic hematuria is invisible to the naked eye and is often found by urinalysis or urine dipstick; it is said to be chronic or persistent if 5 or more red blood cells (RBCs) per high-power field can be seen in 3 of 3 consecutive centrifuged specimens obtained at least 1 week apart. Any part of the kidneys or urinary tract can leak blood into the urine. The causes of hematuria are broad, ranging from urinary tract infection to kidney stones to bladder cancer.
Proteinuria is the presence of excess proteins in the urine. In healthy persons, urine contains very little protein; an excess is suggestive of illness. Excess protein in the urine often causes the urine to become foamy, although foamy urine may also be caused by bilirubin in the urine (bilirubinuria), retrograde ejaculation, pneumaturia due to a fistula, or drugs such as pyridium.
A nephrologist is a physician who specializes in the care and treatment of kidney disease. Nephrology requires additional training to become an expert with advanced skills. Nephrologists may provide care to people without kidney problems and may work in general/internal medicine, transplant medicine, immunosuppression management, intensive care medicine, clinical pharmacology, perioperative medicine, or pediatric nephrology.
A physician, medical practitioner, medical doctor, or simply doctor, is a professional who practises medicine, which is concerned with promoting, maintaining, or restoring health through the study, diagnosis, prognosis and treatment of disease, injury, and other physical and mental impairments. Physicians may focus their practice on certain disease categories, types of patients, and methods of treatment—known as specialities—or they may assume responsibility for the provision of continuing and comprehensive medical care to individuals, families, and communities—known as general practice. Medical practice properly requires both a detailed knowledge of the academic disciplines, such as anatomy and physiology, underlying diseases and their treatment—the science of medicine—and also a decent competence in its applied practice—the art or craft of medicine.
An expert is someone who has a prolonged or intense experience through practice and education in a particular field. Informally, an expert is someone widely recognized as a reliable source of technique or skill whose faculty for judging or deciding rightly, justly, or wisely is accorded authority and status by peers or the public in a specific well-distinguished domain. An expert, more generally, is a person with extensive knowledge or ability based on research, experience, or occupation and in a particular area of study. Experts are called in for advice on their respective subject, but they do not always agree on the particulars of a field of study. An expert can be believed, by virtue of credential, training, education, profession, publication or experience, to have special knowledge of a subject beyond that of the average person, sufficient that others may officially rely upon the individual's opinion. Historically, an expert was referred to as a sage (Sophos). The individual was usually a profound thinker distinguished for wisdom and sound judgment.
Immunosuppression is a reduction of the activation or efficacy of the immune system. Some portions of the immune system itself have immunosuppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse reaction to treatment of other conditions.
Nephrologists may further sub-specialise in dialysis, kidney transplantation, chronic kidney disease, cancer-related kidney diseases (Onconephrology), procedural nephrology or other non-nephrology areas as described above.
Procedures a nephrologist may perform include native kidney and transplant kidney biopsy, dialysis access insertion (temporary vascular access lines, tunnelled vascular access lines, peritoneal dialysis access lines), fistula management (angiographic or surgical fistulogram and plasty), and bone biopsy.
Nephrology training in Australia and New Zealand typically includes completion of a medical degree (Bachelor of Medicine, Bachelor of Surgery: 4–6 years), internship (1 year), Basic Physician Training (3 years minimum), successful completion of the Royal Australasian College of Physicians written and clinical examinations, and Advanced Physician Training in Nephrology (2–3 years). The training pathway is overseen and accredited by the Royal Australasian College of Physicians. Increasingly, nephrologists may additionally complete of a post-graduate degree (usually a PhD) in a nephrology research interest (3–4 years). Finally, all Australian and New Zealand nephrologists participate in career-long professional and personal development through the Royal Australasian College of Physicians and other bodies such as the Australian and New Zealand Society of Nephrology and the Transplant Society of Australia and New Zealand.
In the United Kingdom, nephrology (or often renal medicine) is a subspecialty of general medicine. A nephrologist has completed medical school, foundation year posts (FY1 and FY2) and core medical training (CMT) and passed the Membership of the Royal College of Physicians (MRCP) exam before competing for a National Training Number (NTN) in renal medicine. The typical subspecialty training is five years and leads to a Certificate of Completion of Training (CCT) in both renal medicine and general (internal) medicine. Subspecialty trainees often interrupt their clinical training to obtain research degrees (MD/PhD).
Nephrology training can be accomplished through one of two routes. The first pathway is through an internal medicine pathway leading to an Internal Medicine/Nephrology specialty, and sometimes known as "adult nephrology". The second pathway is through Pediatrics leading to a speciality in Pediatric Nephrology. In the United States, after medical school adult nephrologists complete a three-year residency in internal medicine followed by a two-year (or longer) fellowship in nephrology. Complementary to an adult nephrologist, a pediatric nephrologist will complete a three-year pediatric residency after medical school or a four-year Combined Internal Medicine and Pediatrics residency. This is followed by a three-year fellowship in Pediatic Nephrology. Once training is satisfactorily completed, the physician is eligible to take the American Board of Internal Medicine (ABIM) or American Osteopathic Board of Internal Medicine (AOBIM) nephrology examination. Nephrologists must be approved by one of these boards. To be approved, the physician must fulfill the requirements for education and training in nephrology in order to qualify to take the board's examination. If a physician passes the examination, then he or she can become a nephrology specialist. Typically, nephrologists also need two to three years of training in an ACGME or AOA accredited fellowship in nephrology. Nearly all programs train nephrologists in continuous renal replacement therapy; fewer than half in the United States train in the provision of plasmapheresis.Only pediatric trained physicians are able to train in pediatric nephrology, and internal medicine (adult) trained physicians may enter general (adult) nephrology fellowships.
History and physical examination are central to the diagnostic workup in nephrology. The history typically includes the present illness, family history, general medical history, diet, medication use, drug use and occupation. The physical examination typically includes an assessment of volume state, blood pressure, heart, lungs, peripheral arteries, joints, abdomen and flank.
Examination of the urine (urinalysis) allows a direct assessment for possible kidney problems, which may be suggested by appearance of blood in the urine (haematuria), protein in the urine (proteinuria), pus cells in the urine (pyuria) or cancer cells in the urine. A 24-hour urine collection can be used to quantify daily protein loss (see proteinuria), urine output, creatinine clearance or electrolyte handling by the renal tubules.
Basic blood tests can be used to check the concentration of hemoglobin, platelets, sodium, potassium, chloride, bicarbonate, urea, creatinine, calcium, magnesium or phosphate in the blood. All of these may be affected by kidney problems. The serum creatinine concentration can be used to estimate the function of the kidney, called the creatinine clearance or estimated glomerular filtration rate (GFR). More specialized tests can be ordered to discover or link certain systemic diseases to kidney failure such as infections (hepatitis B, hepatitis C), autoimmune conditions (systemic lupus erythematosus, ANCA vasculitis), paraproteinemias (amyloidosis, multiple myeloma) and metabolic diseases (diabetes, cystinosis).
Structural abnormalities of the kidneys are identified with imaging tests. These may include Medical ultrasonography/ultrasound, computed axial tomography (CT), scintigraphy (nuclear medicine), angiography or magnetic resonance imaging (MRI).
In certain circumstances, less invasive testing may not provide a certain diagnosis. Where definitive diagnosis is required, a biopsy of the kidney (renal biopsy) may be performed. This typically involves the insertion, under local anaesthetic and ultrasound or CT guidance, of a core biopsy needle into the kidney to obtain a small sample of kidney tissue. The kidney tissue is then examined under a microscope, allowing direct visualization of the changes occurring within the kidney. Additionally, the pathology may also stage a problem affecting the kidney, allowing some degree of prognostication. In some circumstances, kidney biopsy will also be used to monitor response to treatment and identify early relapse.
Treatments in nephrology can include medications, blood products, surgical interventions (urology, vascular or surgical procedures), renal replacement therapy (dialysis or kidney transplantation) and plasma exchange. Kidney problems can have significant impact on quality and length of life, and so psychological support, health education and advanced care planning play key roles in nephrology.
Chronic kidney disease is typically managed with treatment of causative conditions (such as diabetes), avoidance of substances toxic to the kidneys (nephrotoxins like radiologic contrast and non-steroidal anti-inflammatory drugs), antihypertensives, diet and weight modification and planning for end-stage kidney failure. Impaired kidney function has systemic effects on the body. An erythropoetin stimulating agent may be required to ensure adequate production of red blood cells, activated vitamin D supplements and phosphate binders may be required to counteract the effects of kidney failure on bone metabolism, and blood volume and electrolyte disturbance may need correction.
Auto-immune and inflammatory kidney disease, such as vasculitis or transplant rejection, may be treated with immunosuppression. Commonly used agents are prednisone, mycophenolate, cyclophosphamide, ciclosporin, tacrolimus, everolimus, thymoglobulin and sirolimus. Newer, so-called "biologic drugs" or monoclonal antibodies, are also used in these conditions and include rituximab, basiliximab and eculizumab. Blood products including intravenous immunoglobulin and a process known as plasma exchange can also be employed.
When the kidneys are no longer able to sustain the demands of the body, end-stage kidney failure is said to have occurred. Without renal replacement therapy, death from kidney failure will eventually result. Dialysis is an artificial method of replacing some kidney function to prolong life. Renal transplantation replaces kidney function by inserting into the body a healthier kidney from an organ donor and inducing immunologic tolerance of that organ with immunosuppression. At present, renal transplantation is the most effective treatment for end-stage kidney failure although its worldwide availability is limited by lack of availability of donor organs.
Most kidney conditions are chronic conditions and so long term followup with a nephrologist is usually necessary.
The world's first society of nephrology was the French 'Societe de Pathologie Renale'. Its first president was Jean Hamburger, and its first meeting was in Paris in February 1949. In 1959, Hamburger also founded the 'Société de Néphrologie', as a continuation of the older society. The UK's Renal Association was founded in 1950; the second society of nephrologists. Its first president was Arthur Osman. Its first meeting was on 30 March 1950 in London. The Società di Nefrologia Italiana was founded in 1957 and was the first national society to incorporate the phrase nephrologia (or nephrology) into its name.
The word 'nephrology' appeared for the first time in a conference, on 1–4 September 1960 at the "Premier Congrès International de Néphrologie" in Evian and Geneva, the first meeting of the International Society of Nephrology (ISN, International Society of Nephrology). The first day (1.9.60) was in Geneva and the next three (2–4.9.60) were in Evian, France. The early history of the ISN is described by Robinson and Richet in 2005 and the later history by Barsoum in 2011. The ISN is the largest global society representing medical professionals engaged in advancing kidney care worldwide.
In the USA, founded in 1964, the National Kidney Foundation is a national organization representing patients and professionals who treat kidney diseases. Founded in 1966, the American Society of Nephrology (ASN) is the world’s largest professional society devoted to the study of kidney disease. The American Nephrology Nurses' Association (ANNA), founded in 1969, promotes excellence in and appreciation of nephrology nursing to make a positive difference for patients with kidney disease. The American Association of Kidney Patients (AAKP) is a non-profit, patient-centric group focused on improving the health and well-being of CKD and dialysis patients. The National Renal Administrators Association (NRAA), founded in 1977, is a national organization that represents and supports the independent and community-based dialysis providers. The American Kidney Fund directly provides financial support to patients in need, as well as participating in health education and prevention efforts. ASDIN (American Society of Diagnostic and Interventional Nephrology) is the main organization of interventional nephrologists. Other organizations include CIDA, VASA etc. which deal with dialysis vascular access. The Renal Support Network (RSN) is a nonprofit, patient-focused, patient-run organization that provides non-medical services to those affected by chronic kidney disease (CKD).
In the United Kingdom, the UK National Kidney Federation and British Kidney Patient Association (BKPA)represents patients, and the Renal Association represents renal physicians and works closely with the National Service Framework for kidney disease.
Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys no longer function. It is divided into acute kidney failure and chronic kidney failure. Symptoms may include leg swelling, feeling tired, vomiting, loss of appetite, or confusion. Complications of acute disease may include uremia, high blood potassium, or volume overload. Complications of chronic disease may include heart disease, high blood pressure, or anemia.
Renal function, in nephrology, is an indication of the kidney's condition and its role in renal physiology. Glomerular filtration rate (GFR) describes the flow rate of filtered fluid through the kidney. Creatinine clearance rate is the volume of blood plasma that is cleared of creatinine per unit time and is a useful measure for approximating the GFR. Creatinine clearance exceeds GFR due to creatinine secretion, which can be blocked by cimetidine. In alternative fashion, overestimation by older serum creatinine methods resulted in an underestimation of creatinine clearance, which provided a less biased estimate of GFR. Both GFR and CCr may be accurately calculated by comparative measurements of substances in the blood and urine, or estimated by formulas using just a blood test result.
Kidney disease, or renal disease, also known as nephropathy, is damage to or disease of a kidney. Nephritis is an inflammatory kidney disease and has several types according to the location of the inflammation. Inflammation can be diagnosed by blood tests. Nephrosis is non-inflammatory kidney disease. Nephritis and nephrosis can give rise to nephritic syndrome and nephrotic syndrome respectively. Kidney disease usually causes a loss of kidney function to some degree and can result in kidney failure, the complete loss of kidney function. Kidney failure is known as the end-stage of kidney disease, where dialysis or a kidney transplant is the only treatment option.
Acute kidney injury (AKI), previously called acute renal failure (ARF), is an abrupt loss of kidney function that develops within 7 days.
Alport syndrome is a genetic disorder affecting around 1 in 5,000-10,000 children, characterized by glomerulonephritis, end-stage kidney disease, and hearing loss. Alport syndrome can also affect the eyes, though the changes do not usually affect sight, except when changes to the lens occur in later life. Blood in urine is universal. Proteinuria is a feature as kidney disease progresses.
Hepatorenal syndrome is a life-threatening medical condition that consists of rapid deterioration in kidney function in individuals with cirrhosis or fulminant liver failure. HRS is usually fatal unless a liver transplant is performed, although various treatments, such as dialysis, can prevent advancement of the condition.
Interstitial nephritis, also known as tubulointerstitial nephritis, is inflammation of the area of the kidney known as the interstitium, which consists of a collection of cells, extracellular matrix, and fluid surrounding the renal tubules. In addition to providing a scaffolding support for the tubular architecture, the interstitium has been shown to participate in the fluid and electrolyte exchange as well as endocrine functions of the kidney. There are a variety of known factors that can provoke the inflammatory process within the renal interstitium, including pharmacologic, environmental, infectious and systemic disease contributors. The spectrum of disease presentation can range from an acute process to a chronic condition with progressive tubular cell damage and renal dysfunction.
Congenital nephrotic syndrome is a rare kidney disease which manifests in infants during the first 3 months of life, and is characterized by high levels of protein in the urine (proteinuria), low levels of protein in the blood, and swelling. This disease is primarily caused by genetic mutations which result in damage to components of the glomerular filtration barrier and allow for leakage of plasma proteins into the urinary space.
Rapidly progressive glomerulonephritis (RPGN) is a syndrome of the kidney that is characterized by a rapid loss of renal function, with glomerular crescent formation seen in at least 50% or 75% of glomeruli seen on kidney biopsies. If left untreated, it rapidly progresses into acute renal failure and death within months. In 50% of cases, RPGN is associated with an underlying disease such as Goodpasture syndrome, systemic lupus erythematosus or granulomatosis with polyangiitis; the remaining cases are idiopathic. Regardless of the underlying cause, RPGN involves severe injury to the kidneys' glomeruli, with many of the glomeruli containing characteristic glomerular crescents.
Glomerulosclerosis is hardening of the glomeruli in the kidney. It is a general term to describe scarring of the kidneys' tiny blood vessels, the glomeruli, the functional units in the kidney that filter urea from the blood.
Robert Provenzano is an American nephrologist. Provenzano is Chief of the Division of Nephrology, Hypertension & Transplantation, Director of Nephrology Research, and Director of Acute Dialysis Services at St John Hospital & Medical Center in Detroit, MI. He is also an Associate Clinical Professor of Medicine at Wayne State University School of Medicine He is the Chief Operating Officer of St Clair Specialty Physicians in Detroit, and the Vice President of Medical Affairs for DaVita, Inc. He is also the lead physician at Colorado Springs Nephrology in Colorado Springs, Colorado.
Amin J. Barakat is a Lebanese-American physician known for the diagnosis Barakat syndrome.
Renal biopsy is a medical procedure in which a small piece of kidney is removed from the body for examination, usually under a microscope. Microscopic examination of the tissue can provide information needed to diagnose, monitor or treat problems of the kidney.
Nathan W. Levin is an American physician and founder of the Renal Research Institute, LLC., a research institute dedicated to improving the outcomes of patients with kidney disease, particularly those requiring dialysis. Levin is one of the most prominent and renowned figures in clinical nephrology as well as nephrology research. He has authored multiple book chapters and over 350 peer-reviewed publications, including articles in leading journals such as Nature, the New England Journal of Medicine, and The Lancet.
Ronald Jonathan Falk, MD, FASN is the Allen Brewster Distinguished Professor of Medicine at the University of North Carolina-Chapel Hill. Since 1993, he has been chief of the UNC Division of Nephrology and Hypertension, and is also the co-founder and director of the UNC Kidney Center. He is currently the chair of UNC's department of Internal Medicine. Dr. Falk is a Past-President of the American Society of Nephrology (ASN).
Ramesh Kumar MRCP, FRCP is the first Indian Member of Royal College of Physicians (MRCP in Kidney diseases and a pioneer of nephrology in India and South Asia. He was awarded the Padma Shri in 1992 and the Padma Bhushan in 2003 by the President of India for his pioneering, notable and continued contributions to Nephrology.
Professor David Johnson is an Australian nephrologist known for kidney treatments and transplants in Australia. In 2009 he was a Queensland State Finalist for Australian of the Year, for his work in the early recognition and care of people with chronic kidney disease and specifically for his work in detection of chronic kidney disease.