Chronic kidney disease (CKD) is a type of long-term
kidney disease
Kidney disease, or renal disease, technically referred to as nephropathy, is damage to or disease of a kidney. Nephritis is an Inflammation, inflammatory kidney disease and has several types according to the location of the inflammation. Infla ...
, defined by the sustained presence of abnormal
kidney function
Assessment of kidney function occurs in different ways, using the presence of symptoms and medical sign, signs, as well as measurements using urine tests, blood tests, and medical imaging.
Renal physiology, Functions of a healthy kidney include ...
and/or abnormal kidney structure.
To meet criteria for CKD, the abnormalities must be present for at least three months. Early in the course of CKD, patients are usually asymptomatic, but later symptoms may include
leg swelling, feeling tired,
vomiting
Vomiting (also known as emesis, puking and throwing up) is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose.
Vomiting can be the result of ailments like food poisoning, gastroenteritis, pre ...
, loss of appetite, and
confusion
In psychology, confusion is the quality or emotional state of being bewildered or unclear. The term "acute mental confusion" .
Complications can relate to hormonal dysfunction of the kidneys and include (in chronological order)
high blood pressure
Hypertension, also known as high blood pressure, is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms itself. It is, however, a major ri ...
(often related to activation of the
renin–angiotensin system
The renin–angiotensin system (RAS), or renin–angiotensin–aldosterone system (RAAS), is a hormone system that regulates blood pressure, fluid, and electrolyte balance, and systemic vascular resistance.
When renal blood flow is reduced, ...
),
bone disease
Bone disease refers to the medical conditions which affect the bone.
Terminology
A bone disease is also called an "osteopathy", but because the term osteopathy is often used to refer to an alternative health-care philosophy, use of the term can ...
, and
anemia
Anemia (also spelt anaemia in British English) is a blood disorder in which the blood has a reduced ability to carry oxygen. This can be due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin availabl ...
.
Additionally CKD patients have markedly increased
cardiovascular
In vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. It includes the cardiovascular system, or vascular system, that consists of the heart a ...
complications with increased risks of
death
Death is the end of life; the irreversible cessation of all biological functions that sustain a living organism. Death eventually and inevitably occurs in all organisms. The remains of a former organism normally begin to decompose sh ...
and hospitalization. CKD can lead to
end-stage kidney failure requiring
kidney dialysis
Kidney 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. Along with kidney transplantation, it is a type of renal replacement therapy.
...
or
kidney transplantation.
Causes of chronic kidney disease include
diabetes
Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or the cells of th ...
,
high blood pressure
Hypertension, also known as high blood pressure, is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms itself. It is, however, a major ri ...
,
glomerulonephritis, and
polycystic kidney disease.
[ Risk factors include a family history of chronic kidney disease.][ Diagnosis is by ]blood tests
A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a hypodermic needle, or via fingerprick. Multiple tests for specific blood components, such as a glucose test or a cho ...
to measure the estimated glomerular filtration rate (eGFR), and a urine test
A urine test is any medical test performed on a urine specimen. The analysis of urine is a valuable diagnostic tool because its composition reflects the functioning of many body systems, particularly the kidneys and urinary system, and specimens ...
to measure albumin
Albumin is a family of globular proteins, the most common of which are the serum albumins. All of the proteins of the albumin family are water- soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Alb ...
. Ultrasound
Ultrasound is sound with frequency, frequencies greater than 20 Hertz, kilohertz. This frequency is the approximate upper audible hearing range, limit of human hearing in healthy young adults. The physical principles of acoustic waves apply ...
or kidney biopsy may be performed to determine the underlying cause.[ Several severity-based staging systems are in use.]
Testing people with risk factors ('' case-finding'') is recommended.[ Initial treatments may include medications to lower blood pressure, blood sugar, and cholesterol.][ Angiotensin converting enzyme inhibitors (ACEIs) or ]angiotensin II receptor antagonists
Angiotensin II receptor blockers (ARBs), formally angiotensin II receptor type 1 (AT1) antagonists, also known as angiotensin receptor blockers, angiotensin II receptor antagonists, or AT1 receptor antagonists, are a group of pharmaceuticals tha ...
(ARBs) are generally first-line agents for blood pressure control, as they slow progression of the kidney disease and the risk of heart disease. Loop diuretic
Loop diuretics are pharmacological agents that primarily inhibit the Na-K-Cl cotransporter located on the luminal membrane of cells along the thick ascending limb of the loop of Henle. They are often used for the treatment of hypertension and e ...
s may be used to control edema
Edema (American English), also spelled oedema (British English), and also known as fluid retention, swelling, dropsy and hydropsy, is the build-up of fluid in the body's tissue (biology), tissue. Most commonly, the legs or arms are affected. S ...
and, if needed, to further lower blood pressure.[ NSAIDs should be avoided.] Other recommended measures include staying active, and "to adopt healthy and diverse diets with a higher consumption of plant-based foods compared to animal-based foods and a lower consumption of ultraprocessed foods."[ Plant-based diets are feasible and are associated with improved intermediate outcomes and biomarkers. An example of a general, healthy diet, suitable for people with CKD who do not require restrictions, is the Canada Food Guide Diet. People with CKD who require dietary restrictions or who have other specific nutritional problems should be referred to a dietitian.] Treatments for anemia and bone disease may also be required. Severe disease requires hemodialysis
Hemodialysis, American and British English spelling differences#ae and oe, also spelled haemodialysis, or simply ''"'dialysis'"'', is a process of filtering the blood of a person whose kidneys are not working normally. This type of Kidney dialys ...
, peritoneal dialysis, or a kidney transplant for survival.
Chronic kidney disease affected 753 million people globally in 2016 (417 million females and 336 million males.) In 2015, it caused 1.2 million deaths, up from 409,000 in 1990.[ Table 2, p. 137 ] The causes that contribute to the greatest number of deaths are high blood pressure at 550,000, followed by diabetes at 418,000, and glomerulonephritis at 238,000.[
]
Signs and symptoms
CKD is initially without symptoms and is usually detected on routine screening blood work by either an increase in serum creatinine, or protein in the urine. As the kidney function decreases, more unpleasant symptoms may emerge:
* Blood pressure
Blood pressure (BP) is the pressure of Circulatory system, circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term ...
is increased due to fluid overload and the production of vasoactive hormones created by the kidney via the renin-angiotensin system, increasing the risk of developing hypertension
Hypertension, also known as high blood pressure, is a Chronic condition, long-term Disease, medical condition in which the blood pressure in the artery, arteries is persistently elevated. High blood pressure usually does not cause symptoms i ...
and heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to Cardiac cycle, fill with and pump blood.
Although symptoms vary based on which side of the heart is affected, HF ...
. People with CKD are more likely than the general population to develop atherosclerosis
Atherosclerosis is a pattern of the disease arteriosclerosis, characterized by development of abnormalities called lesions in walls of arteries. This is a chronic inflammatory disease involving many different cell types and is driven by eleva ...
with consequent cardiovascular disease
Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina, heart attack), heart failure, hypertensive heart disease, rheumati ...
, an effect that may be at least partly mediated by uremic toxins. People with both CKD and cardiovascular disease have significantly worse prognoses than those with only cardiovascular disease.
* Urea
Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest am ...
accumulates, leading to azotemia
Azotemia (), also spelled azotaemia, 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. It is ...
and ultimately uremia
Uremia is the condition of having high levels of urea in the blood. Urea is one of the primary components of urine. It can be defined as an excess in the blood of amino acid and protein metabolism end products, such as urea and creatinine, which ...
(symptoms ranging from lethargy
Lethargy is a state of tiredness, sleepiness, weariness, fatigue, sluggishness, or lack of energy. It can be accompanied by depression, decreased motivation, or apathy. Lethargy can be a normal response to inadequate sleep, overexertion, overw ...
to pericarditis
Pericarditis () is inflammation of the pericardium, the fibrous sac surrounding the heart. Symptoms typically include sudden onset of sharp chest pain, which may also be felt in the shoulders, neck, or back. The pain is typically less severe whe ...
and encephalopathy
Encephalopathy (; ) means any disorder or disease of the brain, especially chronic degenerative conditions. In modern usage, encephalopathy does not refer to a single disease, but rather to a syndrome of overall brain dysfunction; this syndrome ...
). Due to its high systemic concentration, urea is excreted in eccrine sweat at high concentrations and crystallizes on the skin as the sweat evaporates (" uremic frost").
* Potassium
Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...
accumulates in the blood (hyperkalemia
Hyperkalemia is an elevated level of potassium (K+) in the blood. Normal potassium levels are between 3.5 and 5.0 mmol/L (3.5 and 5.0 mEq/L) with levels above 5.5mmol/L defined as hyperkalemia. Typically hyperkalemia does not cause symptoms. Oc ...
with a range of symptoms including malaise
In medicine, malaise is a feeling of general discomfort, uneasiness or lack of wellbeing and often the first sign of an infection or other disease. It is considered a vague termdescribing the state of simply not feeling well. The word has exist ...
and potentially fatal cardiac arrhythmia
Arrhythmias, also known as cardiac arrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. Essentially, this is anything but normal sinus rhythm. A resting heart rate that is too fast – above 100 beat ...
s). Hyperkalemia usually does not develop until the glomerular filtration rate
Renal functions include maintaining an acid–base balance; regulating fluid balance; regulating sodium, potassium, and other electrolytes; clearance (medicine), clearing toxins; absorption of glucose, amino acids, and other small molecules; reg ...
falls to less than 20–25 mL/min/1.73 m2, when the kidneys have decreased ability to excrete potassium. Hyperkalemia in CKD can be exacerbated by acidemia (triggering the cells to release potassium into the bloodstream to neutralize the acid) and from lack of insulin
Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the insulin (''INS)'' gene. It is the main Anabolism, anabolic hormone of the body. It regulates the metabol ...
.
* Fluid overload symptoms may range from mild edema
Edema (American English), also spelled oedema (British English), and also known as fluid retention, swelling, dropsy and hydropsy, is the build-up of fluid in the body's tissue (biology), tissue. Most commonly, the legs or arms are affected. S ...
to life-threatening pulmonary edema
Pulmonary edema (British English: oedema), also known as pulmonary congestion, is excessive fluid accumulation in the tissue or air spaces (usually alveoli) of the lungs. This leads to impaired gas exchange, most often leading to shortness ...
.
* Hyperphosphatemia results from poor phosphate elimination in the kidney, and contributes to increased cardiovascular risk by causing vascular calcification. Circulating concentrations of fibroblast growth factor-23 (FGF-23) increase progressively as the kidney capacity for phosphate excretion declines, which may contribute to left ventricular hypertrophy and increased mortality in people with CKD .
* Hypocalcemia
Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L), while levels less than 2.1  ...
results from 1,25 dihydroxyvitamin D3 deficiency (caused by high FGF-23 and reduced kidney mass) and the skeletal resistance to the calcemic action of parathyroid hormone. Osteocytes are responsible for the increased production of FGF-23, which is a potent inhibitor of the enzyme 1-alpha-hydroxylase (responsible for the conversion of 25-hydroxycholecalciferol into 1,25 dihydroxyvitamin D3). Later, this progresses to secondary hyperparathyroidism, kidney osteodystrophy, and vascular calcification that further impairs cardiac function. An extreme consequence is the occurrence of the rare condition named calciphylaxis.
* Changes in mineral and bone metabolism that may cause 1) abnormalities of calcium
Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...
, phosphorus
Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...
(phosphate
Phosphates are the naturally occurring form of the element phosphorus.
In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthop ...
), parathyroid hormone, or vitamin D
Vitamin D is a group of structurally related, fat-soluble compounds responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, along with numerous other biological functions. In humans, the most important compo ...
metabolism; 2) abnormalities in bone turnover, mineralization, volume, linear growth, or strength ( kidney osteodystrophy); and 3) vascular or other soft-tissue calcification. CKD–mineral and bone disorders have been associated with poor outcomes.
* Metabolic acidosis
Metabolic acidosis is a serious electrolyte disorder characterized by an imbalance in the body's acid-base balance. Metabolic acidosis has three main root causes: increased acid production, loss of bicarbonate, and a reduced ability of the kidn ...
may result from decreased capacity to generate enough ammonia
Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...
from the cells of the proximal tubule. Acidemia affects the function of enzymes and increases the excitability of cardiac and neuronal membranes by the promotion of hyperkalemia.
* Anemia
Anemia (also spelt anaemia in British English) is a blood disorder in which the blood has a reduced ability to carry oxygen. This can be due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin availabl ...
is common and is especially prevalent in those requiring hemodialysis. It is multifactorial in cause but includes increased inflammation, reduction in erythropoietin
Erythropoietin (; EPO), also known as erythropoetin, haematopoietin, or haemopoietin, is a glycoprotein cytokine secreted mainly by the kidneys in response to cellular hypoxia; it stimulates red blood cell production ( erythropoiesis) in th ...
, and hyperuricemia leading to bone marrow suppression. Hypoproliferative anemia occurs due to inadequate production of erythropoietin by the kidneys.
* In later stages, cachexia
Cachexia () is a syndrome that happens when people have certain illnesses, causing muscle loss that cannot be fully reversed with improved nutrition. It is most common in diseases like cancer, Heart failure, congestive heart failure, chronic o ...
may develop, leading to unintentional weight loss, muscle wasting, weakness, and anorexia.
* Cognitive decline in patients experiencing CKD is an emerging symptom revealed in research literature. Research suggests that patients with CKD face a 35–40% higher likelihood of cognitive decline and or dementia. This relation is dependent on the severity of CKD in each patient; although emerging literature indicates that patients at all stages of CKD will have a higher risk of developing these cognitive issues.
* Sexual dysfunction
Sexual dysfunction is difficulty experienced by an individual or partners during any stage of normal sexual activity, including physical pleasure, desire, preference, arousal, or orgasm. The World Health Organization defines sexual dysfunction ...
is very common in both men and women with CKD. A majority of men have a reduced sex drive, difficulty obtaining an erection, and reaching orgasm, and the problems get worse with age. Most women have trouble with sexual arousal, and painful menstruation and problems with performing and enjoying sex are common.
Causes
The most common causes of CKD are diabetes mellitus
Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained hyperglycemia, high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or th ...
, hypertension
Hypertension, also known as high blood pressure, is a Chronic condition, long-term Disease, medical condition in which the blood pressure in the artery, arteries is persistently elevated. High blood pressure usually does not cause symptoms i ...
, and glomerulonephritis. About one of five adults with hypertension and one of three adults with diabetes have CKD. If the cause is unknown, it is called ''idiopathic''.
By anatomical location
* Vascular Vascular can refer to:
* blood vessels, the vascular system in animals
* vascular tissue
Vascular tissue is a complex transporting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue ...
disease includes large-vessel disease such as bilateral kidney artery stenosis and small-vessel disease such as ischemic nephropathy, hemolytic–uremic syndrome, and vasculitis
Vasculitis is a group of disorders that destroy blood vessels by inflammation. Both artery, arteries and veins are affected. Lymphangitis (inflammation of lymphatic vessels) is sometimes considered a type of vasculitis. Vasculitis is primarily c ...
.
* Glomerular disease comprises a diverse group and is classified into:
** Primary glomerular disease such as focal segmental glomerulosclerosis and IgA nephropathy (or nephritis)
** Secondary glomerular disease such as diabetic nephropathy and lupus nephritis
Lupus nephritis is an inflammation of the kidneys caused by systemic lupus erythematosus (SLE) and childhood-onset systemic lupus erythematosus which is a more severe form of SLE that develops in children up to 18 years old; both are autoimmune d ...
* Tubulointerstitial disease includes drug- and toxin-induced chronic tubulointerstitial nephritis, and reflux nephropathy
* Obstructive nephropathy, as exemplified by bilateral kidney stone
Kidney stone disease (known as nephrolithiasis, renal calculus disease, or urolithiasis) is a crystallopathy and occurs when there are too many minerals in the urine and not enough liquid or hydration. This imbalance causes tiny pieces of cr ...
s and benign prostatic hyperplasia
Benign prostatic hyperplasia (BPH), also called prostate enlargement, is a noncancerous increase in size of the prostate gland. Symptoms may include frequent urination, trouble starting to urinate, weak stream, urinary retention, inability t ...
of the prostate gland; rarely, pinworms infecting the kidney can cause obstructive nephropathy.
Other
* Genetic congenital disease such as polycystic kidney disease or 17q12 microdeletion syndrome.
* Mesoamerican nephropathy, is "a new form of kidney disease that could be called agricultural nephropathy". A high and so-far unexplained number of new cases of CKD, referred to as the Mesoamerican nephropathy, has been noted among male workers in Central America, mainly in sugarcane fields in the lowlands of El Salvador
El Salvador, officially the Republic of El Salvador, is a country in Central America. It is bordered on the northeast by Honduras, on the northwest by Guatemala, and on the south by the Pacific Ocean. El Salvador's capital and largest city is S ...
and Nicaragua
Nicaragua, officially the Republic of Nicaragua, is the geographically largest Sovereign state, country in Central America, comprising . With a population of 7,142,529 as of 2024, it is the third-most populous country in Central America aft ...
. Heat stress from long hours of piece-rate work at high average temperatures
of about 36 °C (96 °F) is suspected, as are agricultural chemicals
An agrochemical or agrichemical, a contraction of ''agricultural chemical'', is a chemical product used in industrial agriculture. Agrichemical typically refers to biocides (pesticides including insecticides, herbicides, fungicides and nematicid ...
* Chronic lead
Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...
exposure
Diagnosis
Diagnosis of CKD is largely based on history
History is the systematic study of the past, focusing primarily on the Human history, human past. As an academic discipline, it analyses and interprets evidence to construct narratives about what happened and explain why it happened. Some t ...
, examination, and urine dipstick combined with the measurement of the serum creatinine
Creatinine (; ) is a breakdown product of creatine phosphate from muscle and protein metabolism. It is released at a constant rate by the body (depending on muscle mass).
Biological relevance
Serum creatinine (a blood measurement) is an impor ...
level. Differentiating CKD from acute kidney injury
Acute kidney injury (AKI), previously called acute renal failure (ARF), is a sudden decrease in renal function, kidney function that develops within seven days, as shown by an increase in serum creatinine or a decrease in urine output, or both.
...
(AKI) is important because AKI can be reversible. One diagnostic clue that helps differentiate CKD from AKI is a gradual rise in serum creatinine (over several months or years) as opposed to a sudden increase in the serum creatinine (several days to weeks). In many people with CKD, previous kidney disease or other underlying diseases are already known. A significant number present with CKD of unknown cause.
Screening
Screening those who have neither symptoms nor risk factors for CKD is not recommended. Those who should be screened include: those with hypertension or history of cardiovascular disease, those with diabetes or marked obesity, those aged > 60 years, subjects with African American ancestry, those with a history of kidney disease in the past, and subjects who have relatives who had kidney disease requiring dialysis.
Screening should include calculation of the estimated GFR (eGFR) from the serum creatinine level, and measurement of urine albumin-to-creatinine ratio (ACR) in a first-morning urine specimen (this reflects the amount of a protein called albumin in the urine), as well as a urine dipstick screen for hematuria.
The GFR is derived from the serum creatinine and is proportional to 1/creatinine, i.e. it is a reciprocal relationship; the higher the creatinine, the lower the GFR. It reflects one aspect of kidney function, how efficiently the glomeruli – the filtering units – work. The normal GFR is >90 ml/min. The units of creatinine vary from country to country, but since the glomeruli comprise <5% of the mass of the kidney, the GFR does not indicate all aspects of kidney health and function. This can be done by combining the GFR level with the clinical assessment of the person, including fluid status, and measuring the levels of hemoglobin, potassium, phosphate, and parathyroid hormone.
Ultrasound
Kidney ultrasonography is useful for diagnostic and prognostic purposes in chronic kidney disease. Whether the underlying pathologic change is glomerular sclerosis, tubular atrophy, interstitial fibrosis, or inflammation, the result is often increased echogenicity of the cortex. The echogenicity of the kidney should be related to the echogenicity of the liver or the spleen. Moreover, decreased kidney size and cortical thinning are often seen especially when the disease progresses. However, kidney size correlates to height, and short persons tend to have small kidneys; thus, kidney size as the only parameter is unreliable.[Content initially copied from:]
(CC-BY 4.0)
/ref>
File:Ultrasonography of chronic renal disease caused by glomerulonephritis.jpg, Chronic renal disease caused by glomerulonephritis with increased echogenicity and reduced cortical thickness. Measurement of kidney length on the US image is illustrated by '+' and a dashed line.[
File:Ultrasonography of kidney with nephrotic syndrome.jpg, ]Nephrotic syndrome
Nephrotic syndrome is a collection of symptoms due to kidney damage. This includes proteinuria, protein in the urine, hypoalbuminemia, low blood albumin levels, hyperlipidemia, high blood lipids, and significant edema, swelling. Other symptoms ...
. Hyperechoic kidney without demarcation of cortex and medulla.[
File:Ultrasonography of chronic pyelonephritis with reduced kidney size and focal cortical thinning.jpg, Chronic pyelonephritis with reduced kidney size and focal cortical thinning. Measurement of kidney length on the US image is illustrated by '+' and a dashed line.][
File:Ultrasonography of end-stage chronic kidney disease.jpg, End-stage chronic kidney disease with increased echogenicity, homogenous architecture without visible differentiation between parenchyma and renal sinus, and reduced kidney size. Measurement of kidney length on the US image is illustrated by '+' and a dashed line.][
]
Additional imaging
Additional tests may include nuclear medicine
Nuclear medicine (nuclear radiology, nucleology), is a medical specialty involving the application of radioactivity, radioactive substances in the diagnosis and treatment of disease. Nuclear imaging is, in a sense, ''radiology done inside out'', ...
MAG3 scan to confirm blood flow and establish the differential function between the two kidneys. Dimercaptosuccinic acid (DMSA) scans are also used in kidney imaging; with both MAG3 and DMSA being used chelated with the radioactive element technetium-99.
Stages
A glomerular filtration rate (GFR) ≥ 60 mL/min/1.73 m2 is considered normal without chronic kidney disease if there is no kidney damage present.
Kidney damage is defined as signs of damage seen in blood, urine, or imaging studies which include lab albumin/creatinine ratio (ACR) ≥ 30.[ All people with a GFR <60 mL/min/1.73 m2 for 3 months are defined as having chronic kidney disease.][
Protein in the urine is regarded as an independent marker for the worsening of kidney function and cardiovascular disease. Hence, British guidelines append the letter "P" to the stage of chronic kidney disease if protein loss is significant.]
# Stage 1: Slightly diminished function; kidney damage with normal or relatively high GFR (≥90 mL/min/1.73 m2) and persistent albuminuria. Kidney damage is defined as pathological abnormalities or markers of damage, including abnormalities in blood or urine tests or imaging studies.
# Stage 2: Mild reduction in GFR (60–89 mL/min/1.73 m2) with kidney damage. Kidney damage is defined as pathological abnormalities or markers of damage, including abnormalities in blood or urine tests or imaging studies.[
# Stage 3: Moderate reduction in GFR (30–59 mL/min/1.73 m2):.][ British guidelines distinguish between stage 3A (GFR 45–59) and stage 3B (GFR 30–44) for purposes of screening and referral.][
# Stage 4: Severe reduction in GFR (15–29 mL/min/1.73 m2)][ Preparation for kidney replacement therapy.
# Stage 5: Established kidney failure (GFR <15 mL/min/1.73 m2), permanent kidney replacement therapy,][ or end-stage kidney disease.
The term "non-dialysis-dependent chronic kidney disease" (NDD-CKD) is a designation used to encompass the status of those persons with an established CKD who do not yet require the life-supporting treatments for ]kidney failure
Kidney failure, also known as renal failure or end-stage renal disease (ESRD), is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney fa ...
known as kidney replacement therapy (RRT, including maintenance dialysis or kidney transplantation). The condition of individuals with CKD, who require either of the two types of kidney replacement therapy ( dialysis or transplant), is referred to as end-stage kidney disease (ESKD). Hence, the start of the ESKD is practically the irreversible conclusion of the NDD-CKD. Even though the NDD-CKD status refers to the status of persons with earlier stages of CKD (stages 1 to 4), people with advanced stages of CKD (stage 5), who have not yet started kidney replacement therapy, are also referred to as NDD-CKD.
Management
Chronic kidney disease (CKD) is a serious condition often linked to diabetes and high blood pressure. There is no cure, but a combination of lifestyle changes and medications can help slow its progression. This might include a plant-dominant diet with less protein and salt, medications to control blood pressure and sugar, and potentially newer anti-inflammatory drugs. Doctors may also focus on managing heart disease risk, preventing infections, and avoiding further kidney damage. While dialysis may eventually be needed, a gradual transition can help preserve remaining kidney function. More research is ongoing to improve CKD management and patient outcomes.
Blood pressure
Angiotensin converting enzyme inhibitors (ACEIs) or angiotensin II receptor antagonists
Angiotensin II receptor blockers (ARBs), formally angiotensin II receptor type 1 (AT1) antagonists, also known as angiotensin receptor blockers, angiotensin II receptor antagonists, or AT1 receptor antagonists, are a group of pharmaceuticals tha ...
(ARBs) are recommended as first-line agents since they have been found to slow the decline of kidney function, relative to a more rapid decline in those not on one of these agents.[ They have also been found to reduce the risk of major cardiovascular events such as ]myocardial infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when Ischemia, blood flow decreases or stops in one of the coronary arteries of the heart, causing infarction (tissue death) to the heart muscle. The most common symptom ...
, stroke
Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...
, heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to Cardiac cycle, fill with and pump blood.
Although symptoms vary based on which side of the heart is affected, HF ...
, and death from cardiovascular disease when compared to placebo in individuals with CKD.[ ACEIs may be superior to ARBs for protection against progression to kidney failure and death from any cause in those with CKD.][ Aggressive blood pressure lowering decreases people's risk of death.
]
Other measures
* Aggressive treatment of high blood lipids is recommended.
* A low-protein, low-salt diet may result in slower progression of CKD and reduction in proteinuria as well as controlling symptoms of advanced CKD to delay dialysis start. A tailored low-protein diet, designed for low acidity, may help prevent damage to kidneys for people with CKD. Additionally, controlling salt ingestion helps to decrease the incidence of coronary heart disease, lowering blood pressure and reducing albuminuria.
* Anemia – A target hemoglobin level of 100–120 g/L is recommended; raising hemoglobin levels to the normal range has not been found to be of benefit.
** Guidelines recommend treatment with parenteral iron prior to treatment with erythropoietin
Erythropoietin (; EPO), also known as erythropoetin, haematopoietin, or haemopoietin, is a glycoprotein cytokine secreted mainly by the kidneys in response to cellular hypoxia; it stimulates red blood cell production ( erythropoiesis) in th ...
.
** Replacement of erythropoietin is often necessary in people with advanced disease.
** It is unclear if androgen
An androgen (from Greek ''andr-'', the stem of the word meaning ) is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This includes ...
s improve anemia.
* Calcitriol
Calcitriol is a hormone and the active form of vitamin D, normally made in the kidney. It is also known as 1,25-dihydroxycholecalciferol. It binds to and activates the vitamin D receptor in the nucleus of the cell, which then increases the exp ...
is recommended for vitamin D deficiency and control of metabolic bone disease.
* Phosphate binders are used to control the serum phosphate
Phosphates are the naturally occurring form of the element phosphorus.
In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthop ...
levels, which are usually elevated in advanced chronic kidney disease.
* Phosphodiesterase-5 inhibitors and zinc
Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...
may improve sexual dysfunction
Sexual dysfunction is difficulty experienced by an individual or partners during any stage of normal sexual activity, including physical pleasure, desire, preference, arousal, or orgasm. The World Health Organization defines sexual dysfunction ...
in men.
Lifestyle interventions
Weight loss
Obesity
Obesity is a medical condition, considered by multiple organizations to be a disease, in which excess Adipose tissue, body fat has accumulated to such an extent that it can potentially have negative effects on health. People are classifi ...
may have a negative impact in CKD, increasing the risk of disease progression to ESKD or kidney failure
Kidney failure, also known as renal failure or end-stage renal disease (ESRD), is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney fa ...
compared to controls with healthy weight, and when in advanced stages also may hinder people's eligibility to kidney transplantation. For example, the consumption of high calorie and high fructose beverages can make an individual "60% more likely to develop CKD".
Weight management interventions in overweight
Being overweight is having more body fat than is optimally healthy. Being overweight is especially common where food supplies are plentiful and lifestyles are sedentary.
, excess weight reached epidemic proportions globally, with more than ...
and obese adults with CKD include lifestyle interventions (dietary changes, physical activity
Physical activity is defined as any voluntary movement produced by skeletal muscles that requires energy expenditure.Global Recommendations on Physical Activity for Health, 2009. World Health Organization. Geneva, Switzerland. Accessed 13/07/2018 ...
/exercise
Exercise or workout is physical activity that enhances or maintains fitness and overall health. It is performed for various reasons, including weight loss or maintenance, to aid growth and improve strength, develop muscles and the cardio ...
, or behavioural strategies), pharmacological (used to reduce absorption or suppress appetite) and surgical interventions. Any of these can help people with CKD lose weight, however, it is not known if they can also prevent death or cardiovascular events like heart complications or stroke. It is recommended that weight management interventions should be individualised, according to a thorough patients' assessment regarding clinical condition, motivations, and preferences.
Dietary salt intake
High dietary sodium intake may increase the risk of hypertension and cardiovascular disease. The effect of dietary restriction of salt in foods has been investigated in people with chronic kidney disease. For people with CKD, including those on dialysis, reduced salt intake may help to lower both systolic and diastolic blood pressure, as well as albuminuria. Some people may experience low blood pressure and associated symptoms, such as dizziness, with lower salt intake. The effect of salt restriction on extracellular fluid, oedema, and total body weight reduction is unknown.
EHealth interventions may improve dietary sodium intake and fluid management for people with CKD.
Omega-3 supplementation
In people with CKD who require hemodialysis, there is a risk that vascular blockage due to clotting, may prevent dialysis therapy from being possible. Even though Omega-3 fatty acid
Omega−3 fatty acids, also called omega−3 oils, ω−3 fatty acids or ''n''−3 fatty acids, are polyunsaturated fatty acids (PUFAs) characterized by the presence of a double bond three atoms away from the terminal methyl group in their ...
s contribute to the production of eicosanoid
Eicosanoids are lipid signaling, signaling molecules made by the enzymatic or non-enzymatic oxidation of arachidonic acid or other polyunsaturated fatty acids (PUFAs) that are, similar to arachidonic acid, around 20 carbon units in length. Eicosa ...
molecules that reduce clotting, it does not have any impact on the prevention of vascular blockage in people with CKD.
Protein supplementation
Regular consumption of oral protein-based nutritional supplements may increase serum albumin levels slightly in people with CKD, especially among those requiring hemodialysis or who are malnourished. Prealbumin level and mid-arm muscle circumference may also be increased following supplementation. Despite possible improvement in these indicators of nutritional status, it is not certain that protein supplements affect the quality of life, life expectancy, inflammation, or body composition.
Iron supplementation
Intravenous (IV) iron therapy may help more than oral iron supplements in reaching target hemoglobin
Hemoglobin (haemoglobin, Hb or Hgb) is a protein containing iron that facilitates the transportation of oxygen in red blood cells. Almost all vertebrates contain hemoglobin, with the sole exception of the fish family Channichthyidae. Hemoglobin ...
levels. However, allergic reactions may also be more likely following IV-iron therapy.
Sleep
Individuals with CKD have an increased prevalence of sleep apnea
Sleep apnea (sleep apnoea or sleep apnœa in British English) is a sleep-related breathing disorder in which repetitive Apnea, pauses in breathing, periods of shallow breathing, or collapse of the upper airway during sleep results in poor vent ...
compared to the general population (both obstructive sleep apnea
Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial airway obstruction, obstruction of the respiratory tract#Upper respiratory tract, upper airway lea ...
and central sleep apnea
Central sleep apnea (CSA) or central sleep apnea syndrome (CSAS) is a sleep-related Disorder (medicine)#Disorder, disorder in which the effort to Breathing, breathe is diminished or absent, typically for 10 to 30 seconds either intermittently o ...
). The presence of sleep apnea in CKD has been associated with an increased risk of cardiovascular events and mortality.
People with CKD also experience sleep disorders, thus unable to get quality sleep. There are several strategies that could help, such as relaxation techniques, exercise, and medication. Exercise may be helpful with sleep regulation and may decrease fatigue and depression in people with CKD. However, none of these options have been proven to be effective in the treatment of sleep disorders. This means that it is unknown what is the best guidance to improve sleep quality in this population.
Referral to a nephrologist
Guidelines for referral to a nephrologist vary between countries. Most agree that nephrology referral is required by Stage 4 CKD (when eGFR/1.73m2 is less than 30 mL/min; or decreasing by more than 3 mL/min/year).
It may also be useful at an earlier stage (e.g. CKD3) when urine albumin-to-creatinine ratio is more than 30 mg/mmol, when blood pressure is difficult to control, or when hematuria or other findings suggest either a primarily glomerular disorder or secondary disease amenable to a specific treatment. Other benefits of early nephrology referral include proper education regarding options for kidney replacement therapy as well as pre-emptive transplantation, and timely workup and placement of an arteriovenous fistula in those people with chronic kidney disease opting for future hemodialysis.
Renal replacement therapy
At stage 5 CKD, kidney replacement therapy is usually required, in the form of either dialysis or a kidney transplant.
In CKD numerous uremic toxins accumulate in the blood. Even when ESKD (largely synonymous with CKD5) is treated with dialysis, the toxin levels do not go back to normal as dialysis is not that efficient. Similarly, after a kidney transplant, the levels may not go back to normal as the transplanted kidney may not work 100%. If it does, the creatinine level is often normal. The toxins show various cytotoxic activities in the serum and have different molecular weights, and some of them are bound to other proteins, primarily to albumin. Uremic toxins are classified into three groups as small water-soluble solutes, middle molecular-weight solutes, and protein-bound solutes. Hemodialysis with high-flux dialysis membrane, long or frequent treatment, and increased blood/dialysate flow has improved removal of water-soluble small molecular weight uremic toxins. Middle molecular weight molecules are removed more effectively with hemodialysis using a high-flux membrane, hemodiafiltration, and hemofiltration. However, conventional dialysis treatment is limited in its ability to remove protein-bound uremic toxins.
Prognosis
CKD increases the risk of cardiovascular disease, and people with CKD often have other risk factors for heart disease, such as high blood lipids. The most common cause of death in people with CKD is cardiovascular disease rather than kidney failure.
Chronic kidney disease results in worse all-cause mortality (the overall death rate) which increases as kidney function decreases. The leading cause of death in chronic kidney disease is cardiovascular disease, regardless of whether there is progression to stage 5.[
While kidney replacement therapies can maintain people indefinitely and prolong life, the ]quality of life
Quality of life (QOL) is defined by the World Health Organization as "an individual's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards ...
is negatively affected. Kidney transplantation increases the survival of people with stage 5 CKD when compared to other options; however, it is associated with an increased short-term mortality due to complications of the surgery. Transplantation aside, high-intensity home hemodialysis appears to be associated with improved survival and a greater quality of life, when compared to the conventional three-times-a-week hemodialysis and peritoneal dialysis.
People with ESKD are at increased overall risk for cancer. This risk is particularly high in younger people and gradually diminishes with age. Medical specialty professional organizations recommend that physicians do not perform routine cancer screening in people with limited life expectancies due to ESKD because the evidence does not show that such tests lead to improved outcomes.
In children, growth failure is a common complication of CKD. Children with CKD will be shorter than 97% of children the same age and sex. This can be treated with additional nutritional support or medication such as growth hormone
Growth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in ...
.
Survival without dialysis
Survival rates of CKD are generally longer with dialysis than without (having only conservative kidney management). However, from the age of 80 and in elderly patients with comorbidities there is no difference in survival between the two groups. Quality of life might be better for people without dialysis.
People who had decided against dialysis treatment when reaching end-stage chronic kidney disease could survive several years and experience improvements in their mental well-being in addition to sustained physical well-being and overall quality of life until late in their illness course. However, use of acute care services in these cases is common, and the intensity of end-of-life care is highly variable among people opting out of dialysis.[C. K. Liu, M. Kurella Tamura: ''Conservative Care for Kidney Failure-The Other Side of the Coin.'' In: ''JAMA network open.'' Band 5, Nummer 3, März 2022, S. e222252, , PMID 35285925.]
Epidemiology
About one in ten people have chronic kidney disease. In Canada 1.9 to 2.3 million people were estimated to have CKD in 2008. CKD affected an estimated 13.9% of U.S. adults aged 18 years and older in the period from 2017 to 2020. In 2007 8.8% of the population of Great Britain and Northern Ireland had symptomatic CKD.
Chronic kidney disease was the cause of 956,000 deaths globally in 2013, up from 409,000 deaths in 1990.
Chronic kidney disease of unknown aetiology
The cause of chronic kidney disease is sometimes unknown; it is referred to as chronic kidney disease of unknown aetiology (CKDu). a rapidly progressive chronic kidney disease, unexplained by diabetes and hypertension, had increased dramatically in prevalence over a few decades in several regions in Central America and Mexico, a CKDu referred to as the Mesoamerican nephropathy (MeN). It was estimated in 2013 that at least 20,000 men had died prematurely, some in their 20s and 30s; a figure of 40,000 per year was estimated in 2020. In some affected areas CKD mortality was five times the national rate. MeN primarily affects men working as sugarcane labourers.[ The cause is unknown, but in 2020 the science found a clearer connection between heavy labour in high temperatures and incidence of CKDu; improvements such as regular access to water, rest and shade, can significantly decrease the potential CKDu incidence.] CKDu also affects people in Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...
where it is the eighth largest cause of in-hospital mortality.
Race
African, Hispanic
The term Hispanic () are people, Spanish culture, cultures, or countries related to Spain, the Spanish language, or broadly. In some contexts, Hispanic and Latino Americans, especially within the United States, "Hispanic" is used as an Ethnici ...
, and South Asian (particularly those from Pakistan, Sri Lanka, Bangladesh, and India) populations are at high risk of developing CKD. Africans are at greater risk due to the number of people affected with hypertension among them. As an example, 37% of ESKD cases in African Americans can be attributed to high blood pressure, compared with 19% among Caucasians. Treatment efficacy also differs between racial groups. Administration of antihypertensive drugs generally halts disease progression in white populations but has little effect in slowing kidney disease among black people, and additional treatment such as bicarbonate therapy is often required. While lower socioeconomic status contributes to the number of people affected with CKD, differences in the number of people affected by CKD are still evident between Africans and Whites when controlling for environmental factors.
Although CKD of unknown etiology was first documented among sugar cane workers in Costa Rica in the 1970s, it may well have affected plantation laborers since the introduction of sugar cane farming to the Caribbean in the 1600s. In colonial times the death records of slaves on sugar plantations were much higher than for slaves forced into other labor.[
]
Denial of care
Denial of care in chronic kidney disease treatment and management is a significant issue for minority populations. This can be due to healthcare provider prejudice, structural barriers, and health insurance coverage disparities. Healthcare provider biases can lead to under-treatment, misdiagnosis, or delayed diagnosis. Structural barriers, such as lack of insurance and limited healthcare facilities, hinder access to timely care. Furthermore, health insurance coverage disparities, with minority populations lacking adequate coverage, contribute to these disparities. Denial of care worsens health outcomes and perpetuates existing health inequities.
Race-based kidney function metric
Race-based kidney function metrics, particularly normalizing creatinine, pose ethical challenges in diagnosing and managing chronic kidney disease (CKD). While certain racial and ethnic groups are at higher risk, using race as a reference range may reinforce stereotypes and perpetuate health disparities. This approach fails to account for the complex interplay of genetic, environmental, and social factors influencing kidney function. Depending solely on race-based metrics may lead to misdiagnosis or underdiagnosis in minority populations. Alternative approaches that consider socioeconomic status, environmental exposures, and genetic vulnerability, are needed to accurately assess kidney function and address CKD care disparities.
Society and culture
Organisations
The International Society of Nephrology
The International Society of Nephrology (ISN) is an organization concerned with kidney health, founded in 1960.
In 1992 the society formed a task force to provide emergency kidney dialysis services in areas struck by disasters (usually earthquak ...
is an international body representing specialists in kidney diseases.
United States
* The National Kidney Foundation is a national organization representing people with chronic kidney diseases and professionals who treat kidney diseases.
* The American Kidney Fund is a national nonprofit organization providing treatment-related financial assistance to one of every five people undergoing dialysis each year.
* The Renal Support Network is a nonprofit, patient-focused, patient-run organization that provides non-medical services to those affected by CKD.
* Th
American Association of Kidney Patients
is a nonprofit, patient-centric group focused on improving the health and well-being of CKD and people undergoing dialysis .
* The Renal Physicians Association is an association representing nephrology
Nephrology is a specialty for both adult internal medicine and pediatric medicine that concerns the study of the kidneys, specifically normal kidney function (renal physiology) and kidney disease (renal pathophysiology), the preservation of kid ...
professionals.
United Kingdom
It was said to be costing the National Health Service
The National Health Service (NHS) is the term for the publicly funded health care, publicly funded healthcare systems of the United Kingdom: the National Health Service (England), NHS Scotland, NHS Wales, and Health and Social Care (Northern ...
about £1.5 billion a year in 2020.
Kidney Care UK and The UK National Kidney Federation represent people with chronic kidney disease. The Renal Association represents Kidney physicians and works closely with the National Service Framework for kidney disease.
Australia
Kidney Health Australia serves that country.
Other animals
Dogs
The incidence rate of CKD in dogs was 15.8 cases per 10,000 dog years at risk. The mortality rate of CKD was 9.7 deaths per 10,000 dog years at risk. (Rates developed from a population of 600,000 insured Swedish dogs; one dog year at risk is one dog at risk for one year). The breeds with the highest rates were the Bernese mountain dog, miniature schnauzer
The Miniature Schnauzer is a dog breed, breed of small dog of the Schnauzer type that originated in Germany in the mid-to-late 19th century. Miniature Schnauzers may have been developed from the smallest specimens of the Standard Schnauzer, or c ...
, and boxer. The Swedish elkhound, Siberian husky
The Siberian Husky is a dog breed, breed of medium-sized Working dog, working sled dog. The breed belongs to the Spitz genetic family. It is recognizable by its thickly furred Coat (dog), double coat, erect triangular ears, and distinctive mark ...
and Finnish spitz
Finnish may refer to:
* Something or someone from, or related to Finland
* Culture of Finland
* Finnish people or Finns, the primary ethnic group in Finland
* Finnish language, the national language of the Finnish people
* Finnish cuisine
See also ...
were the breeds with the lowest rates.
Cats
Cats with chronic kidney disease may have a buildup of waste products usually removed by the kidneys. They may appear lethargic, unkempt, and lose weight, and may have hypertension. The disease can prevent appropriate concentration of urine, causing cats to urinate in greater volumes and drink more water to compensate. Loss of important proteins and vitamins through urine may cause abnormal metabolism and loss of appetite. The buildup of acids within the blood can result in acidosis, which can lead to anemia (which can sometimes be indicated by pink or whitish gums, but by no means does the presence of normal colored gums guarantee that anemia is not present or developing), and lethargy.
Research
several compounds are in development for the treatment of CKD. These include the angiotensin receptor blocker (ARB) olmesartan medoxomil; and sulodexide, a mixture of low molecular weight heparin and dermatan sulfate.
References
External links
*
Chronic Renal Failure Information
from Great Ormond Street Hospital
* Note also the External resources links in the table below.
{{DEFAULTSORT:Chronic Kidney Disease
Kidney diseases
Organ failure
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