Chronic kidney disease (CKD) is a type of
kidney disease in which a gradual loss of
kidney function
Assessment of kidney function occurs in different ways, using the presence of symptoms and signs, as well as measurements using urine tests, blood tests, and medical imaging.
Functions of a healthy kidney include maintaining a person's fluid ...
occurs over a period of months to years.
Initially generally no symptoms are seen, but later symptoms may include
leg swelling, feeling tired,
vomiting
Vomiting (also known as emesis and throwing up) is the involuntary, 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, gastroenteri ...
, loss of appetite, and
confusion
In medicine, confusion is the quality or 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 (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, ...
system),
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 or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, t ...
.
Additionally CKD patients have markedly increased
cardiovascular
The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha ...
complications with increased risks of death and hospitalization.
Causes of chronic kidney disease include
diabetes
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...
,
high blood pressure,
glomerulonephritis
Glomerulonephritis (GN) is a term used to refer to several kidney diseases (usually affecting both kidneys). Many of the diseases are characterised by inflammation either of the glomeruli or of the small blood vessels in the kidneys, hence the ...
, and
polycystic kidney disease
Polycystic kidney disease (PKD or PCKD, also known as polycystic kidney syndrome) is a genetic disorder in which the renal tubules become structurally abnormal, resulting in the development and growth of multiple cysts within the kidney. These c ...
.
[ Risk factors include a family history of chronic kidney disease.][ Diagnosis is by blood tests to measure the estimated ]glomerular filtration rate
Renal functions include maintaining an acid–base balance; regulating fluid balance; regulating sodium, potassium, and other electrolytes; clearing toxins; absorption of glucose, amino acids, and other small molecules; regulation of blood pre ...
(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 a ...
to measure albumin
Albumin is a family of globular proteins, the most common of which are the serum albumins. All the proteins of the albumin family are water-soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Albumins ...
. Ultrasound
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...
or kidney biopsy
Renal biopsy (also kidney biopsy) is a medical procedure in which a small piece of kidney is removed from the body for examination, usually under a microscope. Microscopic examination of the tissue can provide information needed to diagnose, moni ...
may be performed to determine the underlying cause.[ Several severity-based staging systems are in use.]
Screening at-risk people is recommended.[ Initial treatments may include medications to lower blood pressure, blood sugar, and cholesterol.][ ]Angiotensin converting enzyme inhibitor
Angiotensin-converting-enzyme inhibitors (ACE inhibitors) are a class of medication used primarily for the treatment of high blood pressure and heart failure. They work by causing relaxation of blood vessels as well as a decrease in blood vol ...
s (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 diuretics that act on the Na-K-Cl cotransporter along the thick ascending limb of the loop of Henle in the kidney. They are primarily used in medicine to treat hypertension and edema often due to congestive heart failure ...
s may be used to control edema and, if needed, to further lower blood pressure.[ NSAIDs should be avoided.] Other recommended measures include staying active, and certain dietary changes such as a low-salt diet and the right amount of protein.[ Treatments for anemia and bone disease may also be required.] Severe disease requires hemodialysis
Hemodialysis, also spelled haemodialysis, or simply dialysis, is a process of purifying the blood of a person whose kidneys are not working normally. This type of dialysis achieves the extracorporeal removal of waste products such as creatinin ...
, peritoneal dialysis
Peritoneal dialysis (PD) is a type of dialysis which uses the peritoneum in a person's abdomen as the membrane through which fluid and dissolved substances are exchanged with the blood. It is used to remove excess fluid, correct electrolyte pro ...
, or a kidney transplant
Kidney transplant or renal transplant is the organ transplant of a kidney into a patient with end-stage kidney disease (ESRD). Kidney transplant is typically classified as deceased-donor (formerly known as cadaveric) or living-donor transplantati ...
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
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 importa ...
, or protein in the urine. As the kidney function decreases, more unpleasant symptoms may emerge:
* Blood pressure is increased due to fluid overload and production of vasoactive hormones created by the kidney via the renin–angiotensin system, increasing the risk of developing hypertension and heart failure. People with CKD are more likely than the general population to develop atherosclerosis
Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheromatous plaque. At onset there are usually no s ...
with consequent cardiovascular disease, 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 known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid.
Urea serves an important ...
accumulates, leading to azotemia
Azotemia (''azot'', "nitrogen" + '' -emia'', "blood condition") 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 compou ...
and ultimately uremia
Uremia is the term for high levels of urea in the blood. Urea is one of the primary components of urine. It can be defined as an excess of amino acid and protein metabolism end products, such as urea and creatinine, in the blood that would be no ...
(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, overwo ...
to pericarditis and encephalopathy
Encephalopathy (; from grc, ἐνκέφαλος "brain" + πάθος "suffering") means any disorder or disease of the brain, especially chronic degenerative conditions. In modern usage, encephalopathy does not refer to a single disease, but r ...
). Due to its high systemic concentration, urea is excreted in eccrine sweat at high concentrations and crystallizes on skin as the sweat evaporates ("uremic frost
Uremic frost is a colloquial description for crystallized urea deposits that can be found on the skin of those affected by chronic kidney disease (CKD). In states of prolonged kidney failure and subsequent uremia, the high level of urea in the bl ...
").
* Potassium
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosph ...
accumulates in the blood (hyperkalemia
Hyperkalemia is an elevated level of potassium (K+) in the blood. Normal potassium levels are between 3.5 and 5.0mmol/L (3.5 and 5.0mEq/L) with levels above 5.5mmol/L defined as hyperkalemia. Typically hyperkalemia does not cause symptoms. Occasi ...
with a range of symptoms including malaise and potentially fatal cardiac arrhythmia
Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults ...
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; clearing toxins; absorption of glucose, amino acids, and other small molecules; regulation of blood pre ...
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
Acidosis is a process causing increased acidity in the blood and other body tissues (i.e., an increase in hydrogen ion concentration). If not further qualified, it usually refers to acidity of the blood plasma.
The term ''acidemia'' describes t ...
(which leads to extracellular shift of potassium) and from lack of insulin.
* Fluid overload
Hypervolemia, also known as fluid overload, is the medical condition where there is too much fluid in the blood. The opposite condition is hypovolemia, which is too little fluid volume in the blood. Fluid volume excess in the intravascular comp ...
symptoms may range from mild edema to life-threatening pulmonary edema
Pulmonary edema, also known as pulmonary congestion, is excessive liquid accumulation in the tissue and air spaces (usually alveoli) of the lungs. It leads to impaired gas exchange and may cause hypoxemia and respiratory failure. It is due t ...
.
* Hyperphosphatemia
Hyperphosphatemia is an electrolyte disorder in which there is an elevated level of phosphate in the blood. Most people have no symptoms while others develop calcium deposits in the soft tissue. Often there is also low calcium levels which can ...
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 mm ...
results from 1,25 dihydroxyvitamin D3 deficiency (caused by high FGF-23 and reduced kidney mass) and resistance to the 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
Calcifediol, also known as calcidiol, 25-hydroxycholecalciferol, or 25-hydroxyvitamin D3 (abbreviated 25(OH)D3), is a form of vitamin D produced in the liver by hydroxylation of vitamin D3 (cholecalciferol) by the enzyme vitamin D 25-hydroxylas ...
into 1,25 dihydroxyvitamin D3). Later, this progresses to secondary hyperparathyroidism
Secondary hyperparathyroidism is the medical condition of excessive secretion of parathyroid hormone (PTH) by the parathyroid glands in response to hypocalcemia (low blood calcium levels), with resultant hyperplasia of these glands. This disorde ...
, kidney osteodystrophy, and vascular calcification that further impairs cardiac function. An extreme consequence is the occurrence of the rare condition named calciphylaxis
Calciphylaxis, also known as calcific uremic arteriolopathy (CUA) or “Grey Scale”, is a rare syndrome characterized by painful skin lesions. The pathogenesis of calciphylaxis is unclear but believed to involve calcification of the small blood ...
.
* Changes in mineral and bone metabolism that may cause 1) abnormalities of calcium
Calcium is a chemical element with the 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 t ...
, phosphorus
Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...
(phosphate
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 orthophosphoric acid .
The phosphate or orthophosphate ion is derived from phosph ...
), parathyroid hormone
Parathyroid hormone (PTH), also called parathormone or parathyrin, is a peptide hormone secreted by the parathyroid glands that regulates the serum calcium concentration through its effects on bone, kidney, and intestine.
PTH influences bone ...
, or vitamin D
Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects. In humans, the most important compounds in this group are vitamin D3 (c ...
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 kidneys ...
may result from decreased capacity to generate enough ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...
from the cells of the proximal tubule. Acidemia affects the function of enzymes and increases excitability of cardiac and neuronal membranes by the promotion of hyperkalemia.
* Anemia
Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, t ...
is common and is especially prevalent in those requiring haemodialysis. It is multifactorial in cause, but includes increased inflammation, reduction in erythropoietin, 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 complex syndrome associated with an underlying illness, causing ongoing muscle loss that is not entirely reversed with nutritional supplementation. A range of diseases can cause cachexia, most commonly cancer, congestive heart ...
may develop, leading to unintentional weight loss, muscle wasting, weakness, and anorexia.
* 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 a ...
is very common in both men and women with CKD. A majority of men have a reduced sex drive
Libido (; colloquial: sex drive) is a person's overall sexual drive or desire for sexual activity. Libido is influenced by biological, psychological, and social factors. Biologically, the sex hormones and associated neurotransmitters that act up ...
, difficulty obtaining an erection, and reaching orgasm, and the problems get worse with age. Most women have trouble with sexual arousal, and painful menstruation
Dysmenorrhea, also known as period pain, painful periods or menstrual cramps, is pain during menstruation. Its usual onset occurs around the time that menstruation begins. Symptoms typically last less than three days. The pain is usually in the ...
and problems with performing and enjoying sex are common.
Causes
The three most common causes of CKD in order of frequency as of 2015 are diabetes mellitus
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...
, hypertension, and glomerulonephritis
Glomerulonephritis (GN) is a term used to refer to several kidney diseases (usually affecting both kidneys). Many of the diseases are characterised by inflammation either of the glomeruli or of the small blood vessels in the kidneys, hence the ...
. 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
The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away f ...
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 arteries and veins are affected. Lymphangitis (inflammation of lymphatic vessels) is sometimes considered a type of vasculitis. Vasculitis is primarily caused ...
.
* Glomerular disease comprises a diverse group and is classified into:
** Primary glomerular disease such as focal segmental glomerulosclerosis
Focal segmental glomerulosclerosis (FSGS) is a histopathologic finding of scarring (sclerosis) of glomeruli and damage to renal podocytes.Rosenberg, Avi Z.; Kopp, Jeffrey B. (2017-03-07). "Focal Segmental Glomerulosclerosis". ''Clinical Journal o ...
and IgA nephropathy
IgA nephropathy (IgAN), also known as Berger's disease () (and variations), or synpharyngitic glomerulonephritis, is a disease of the kidney (or nephropathy) and the immune system; specifically it is a form of glomerulonephritis or an inflammati ...
(or nephritis)
** Secondary glomerular disease such as diabetic nephropathy
Diabetic nephropathy, also known as diabetic kidney disease, is the chronic loss of kidney function occurring in those with diabetes mellitus. Diabetic nephropathy is the leading causes of chronic kidney disease (CKD) and end-stage renal disease ...
and lupus nephritis
Lupus nephritis is an inflammation of the kidneys caused by systemic lupus erythematosus (SLE), an autoimmune disease. It is a type of glomerulonephritis in which the glomeruli become inflamed. Since it is a result of SLE, this type of glomerulo ...
* Tubulointerstitial disease includes drug- and toxin-induced chronic tubulointerstitial nephritis, and reflux nephropathy
Reflux nephropathy is kidney damage (nephropathy) due to urine flowing backward (reflux) from the bladder toward the kidneys; the latter is called vesicoureteral reflux (VUR). Longstanding VUR can result in small and scarred kidneys during the firs ...
* Obstructive nephropathy, as exemplified by bilateral kidney stone
Kidney stone disease, also known as nephrolithiasis or urolithiasis, is a crystallopathy where a solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine s ...
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, inability to urinate, or loss o ...
of the prostate gland; rarely, pinworms
Pinworm infection (threadworm infection in the UK), also known as enterobiasis, is a human parasitic disease caused by the pinworm. The most common symptom is itching in the anal area. The period of time from swallowing eggs to the appearanc ...
infecting the kidney can cause obstructive nephropathy.
Other
* Genetic congenital disease such as polycystic kidney disease
Polycystic kidney disease (PKD or PCKD, also known as polycystic kidney syndrome) is a genetic disorder in which the renal tubules become structurally abnormal, resulting in the development and growth of multiple cysts within the kidney. These c ...
or 17q12 microdeletion syndrome
17q12 microdeletion syndrome, also known as 17q12 deletion syndrome, is a rare chromosomal anomaly caused by the deletion of a small amount of material from a region in the long arm of chromosome 17. It is typified by deletion of the HNF1B gen ...
.
* Mesoamerican nephropathy
Mesoamerican nephropathy (MeN) is an endemic, non-diabetic, non-hypertensive chronic kidney disease (CKD) characterized by reduced glomerular filtration rate (GFR) with mild or no proteinuria and no features of known primary glomerular diseases. M ...
, 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
Mesoamerican nephropathy (MeN) is an endemic, non-diabetic, non-hypertensive chronic kidney disease (CKD) characterized by reduced glomerular filtration rate (GFR) with mild or no proteinuria and no features of known primary glomerular diseases. M ...
, has been noted among male workers in Central America, mainly in sugarcane fields in the lowlands of El Salvador and Nicaragua
Nicaragua (; ), officially the Republic of Nicaragua (), is the largest country in Central America, bordered by Honduras to the north, the Caribbean to the east, Costa Rica to the south, and the Pacific Ocean to the west. Managua is the countr ...
. 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
Diagnosis
Diagnosis of CKD is largely based on history
History (derived ) is the systematic study and the documentation of the human activity. The time period of event before the invention of writing systems is considered prehistory. "History" is an umbrella term comprising past events as well ...
, examination, and urine dipstick
A urine test strip or dipstick is a basic diagnostic tool used to determine pathological changes in a patient's urine in standard urinalysis.
A standard urine test strip may comprise up to 10 different chemical pads or reagents which react (chang ...
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 importa ...
level (see above). Differentiating CKD from acute kidney injury
Acute kidney injury (AKI), previously called acute renal failure (ARF), is a sudden decrease in kidney function that develops within 7 days, as shown by an increase in serum creatinine or a decrease in urine output, or both.
Causes of AKI are c ...
(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 GFRis 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. Normal GFR is 90-120 ml/min. The units of creatinine vary from country to country, but since the glomeruli make up <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 either the liver or the spleen (Figure 22 and Figure 23). Moreover, decreased kidney size and cortical thinning are also often seen and especially when disease progresses (Figure 24 and Figure 25). However, kidney size correlates to height, and short persons tend to have small kidneys; thus, kidney size as the only parameter is not reliable.[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
Glomerulonephritis (GN) is a term used to refer to several kidney diseases (usually affecting both kidneys). Many of the diseases are characterised by inflammation either of the glomeruli or of the small blood vessels in the kidneys, hence the ...
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. Hyperechoic kidney without demarcation of cortex and medulla.][
File:Ultrasonography of chronic pyelonephritis with reduced kidney size and focal cortical thinning.jpg, ]Chronic pyelonephritis
Pyelonephritis is inflammation of the kidney, typically due to a bacterial infection. Symptoms most often include fever and flank tenderness. Other symptoms may include nausea, burning with urination, and frequent urination. Complications may ...
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 or nucleology is a medical specialty involving the application of radioactive substances in the diagnosis and treatment of disease. Nuclear imaging, in a sense, is " radiology done inside out" because it records radiation emi ...
MAG3 scan
Radioisotope renography is a form of medical imaging of the kidneys that uses radiolabelling. A renogram, which may also be known as a MAG3 scan, allows a nuclear medicine physician or a radiologist to visualize the kidneys and learn more about how ...
to confirm blood flow and establish the differential function between the two kidneys. Dimercaptosuccinic acid
Succimer, sold under the brand name Chemet among others, is a medication used to treat lead, mercury, and arsenic poisoning. When radiolabeled with technetium-99m, it is used in a number of types of diagnostic testing. A full course is 19 days ...
(DMSA) scans are also used in kidney imaging; with both MAG3 and DMSA being used chelated
Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These ligands are ...
with the radioactive element technetium-99
Technetium-99 (99Tc) is an isotope of technetium which decays with a half-life of 211,000 years to stable ruthenium-99, emitting beta particles, but no gamma rays. It is the most significant long-lived fission product of uranium fission, produci ...
.
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 signs of damage seen in blood, urine, or imaging studies which includes 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 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 end-stage kidney disease, 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 failure is classified as eit ...
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 the 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 stage of CKD (stage 5), who have not yet started kidney replacement therapy, are also referred to as NDD-CKD.
Management
Apart from controlling other risk factors, the goal of therapy is to slow down or halt the progression of CKD. Control of blood pressure and treatment of the original disease are the broad principles of management.
Blood pressure
Angiotensin converting enzyme inhibitor
Angiotensin-converting-enzyme inhibitors (ACE inhibitors) are a class of medication used primarily for the treatment of high blood pressure and heart failure. They work by causing relaxation of blood vessels as well as a decrease in blood vol ...
s (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 blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may ...
, stroke, heart failure, 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 9–12 g/dL is recommended; raising hemoglobin levels to the normal range has not been found to be of benefit.
** Guidelines recommend treatment with parenteral iron
Iron supplements, also known as iron salts and iron pills, are a number of iron formulations used to treat and prevent iron deficiency including iron deficiency anemia. For prevention they are only recommended in those with poor absorption, ...
prior to treatment with erythropoietin.
** 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 "man") is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This in ...
s improve anemia.
* Calcitriol
Calcitriol is the active form of vitamin D, normally made in the kidney. It is also known as 1,25-dihydroxycholecalciferol. It is a hormone which binds to and activates the vitamin D receptor in the nucleus of the cell, which then increases the ...
is recommended for vitamin D deficiency
Vitamin D deficiency or hypovitaminosis D is a vitamin D level that is below normal. It most commonly occurs in people when they have inadequate exposure to sunlight, particularly sunlight with adequate ultraviolet B rays (UVB). Vitamin D defic ...
and control of metabolic bone disease
Metabolic bone disease is an abnormality of bones caused by a broad spectrum of disorders. Most commonly these disorders are caused by deficiencies of minerals such as calcium, phosphorus, magnesium or vitamin D leading to dramatic clinical disord ...
.
* Phosphate binders Phosphate binders are medications used to reduce the absorption of dietary phosphate; they are taken along with meals and snacks. They are frequently used in people with chronic kidney failure (CKF), who are less able to excrete phosphate, resulting ...
are used to control the serum phosphate
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 orthophosphoric acid .
The phosphate or orthophosphate ion is derived from phosph ...
levels, which are usually elevated in advanced chronic kidney disease.
* Phosphodiesterase-5 inhibitors and zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc 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 periodi ...
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 a ...
in men.
Lifestyle Interventions
Obesity
Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's ...
may have a negative impact in CKD, increasing the risk of disease progression to ESKD or kidney failure
Kidney failure, also known as end-stage kidney disease, 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 failure is classified as eit ...
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 and obese
Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's we ...
adults with CKD (of various stages) have been studied to assess its safety and efficacy. A recent systematic review collected evidence from 17 studies which evaluated lifestyle (including dietary, physical activity
Physical activity is defined as any voluntary bodily movement produced by skeletal muscles that requires energy expenditure.Global Recommendations on Physical Activity for Health, 2009. World Health Organization. Geneva, Switzerland. Accessed 13/ ...
/ exercise, or behavioural strategies used in isolation or in combination), pharmacological (used to reduce absorption or suppress appetite) and surgical interventions. The review concluded that lifestyle interventions may provide some health benefits, namely improving body weight, low density lipoprotein (LDL) cholesterol
Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...
and diastolic blood pressure (DBP), when compared to usual care or controls. Whether these benefits extend to help reducing cardiovascular events, kidney function and risk of death is uncertain. These conclusions were based on very low quality of evidence, so future robust studies are needed. Thus, it is recommended that weight management interventions should be individualised, according to a thorough patients' assessment regarding clinical condition, motivations and preferences.
Sleep
People with CKD experience sleep disorders, thus not being able to get quality sleep. There are several strategies that could help, such as relaxation techniques, exercise, acupressure and medication:
* Exercise: weak evidence demonstrates that exercise may be helpful with sleep regulation. Nevertheless, exercise possibly decreases fatigue and depression in people with CKD.
* Acupressure: evidence suggests that this technique may have slight effects on latency and sleep duration, as well as on fatigue reduction, although these results are not reliable due to the diversity of conclusions in several articles.
Despite all the available options studied so far, evidence shows that none of them is effective in the treatment of sleep disorders. This means that we are not able to conclude which is the best guidance to improve sleep quality in this type of population.
eHealth interventions
There is currently limited evidence suggesting that eHealth
eHealth (also written e-health) is a relatively recent healthcare practice supported by electronic processes and communication, dating back to at least 1999. Usage of the term varies as it covers not just "Internet medicine" as it was conceived ...
interventions may improve dietary sodium intake and fluid management for people with chronic kidney disease (CKD). The findings are based on low certainty evidence of 43 studies. So, more large and higher quality research studies are needed to understand the impact of eHealth on the health of people with CKD.
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 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
Home hemodialysis (HHD) is the provision of hemodialysis to purify the blood of a person whose kidneys are not working normally, in their own home. One advantage to doing dialysis at home is that it can be done more frequently and slowly, which r ...
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
Peritoneal dialysis (PD) is a type of dialysis which uses the peritoneum in a person's abdomen as the membrane through which fluid and dissolved substances are exchanged with the blood. It is used to remove excess fluid, correct electrolyte pro ...
.
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
A professional association (also called a professional body, professional organization, or professional society) usually seeks to further a particular profession, the interests of individuals and organisations engaged in that profession, and th ...
recommend that physicians do not perform routine cancer screening in people with limited life expectancies due to ESKD because evidence does not show that such tests lead to improved outcomes.
In children, growth failure is a common complication from 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 h ...
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 16.8% of U.S. adults aged 20 years and older in the period from 1999 to 2004. 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 in some cases not known; 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
Mesoamerican nephropathy (MeN) is an endemic, non-diabetic, non-hypertensive chronic kidney disease (CKD) characterized by reduced glomerular filtration rate (GFR) with mild or no proteinuria and no features of known primary glomerular diseases. M ...
(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 where it is the eighth largest cause of in-hospital mortality.
Although CKDu was first documented among sugar cane workers in Costa Rica in the 1970s, it may well have affected plantation labourers since the introduction of sugar cane farming to the Caribbean in the 1600s. In colonial times the death records of slaves on sugar plantations was much higher than for slaves forced into other labour.[
]
Race
African, Hispanic
The term ''Hispanic'' ( es, hispano) refers to people, cultures, or countries related to Spain, the Spanish language, or Hispanidad.
The term commonly applies to countries with a cultural and historical link to Spain and to viceroyalties forme ...
s, and South Asians, particularly those from Pakistan, Sri Lanka, Bangladesh, and India, 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.
Society and culture
The International Society of Nephrology
The International Society of Nephrology (ISN) is an organization concerned with kidney health.
Introduction
The ISN has over 9,000 professional members from more than 156 countries. In addition, the ISN closely collaborates with over 100 nation ...
is an international body representing specialists in kidney diseases.
United States
* The National Kidney Foundation
The National Kidney Foundation, Inc. (NKF) is a voluntary health organization in the United States, headquartered in New York City, with over 30 local offices across the country. Its mission is to prevent kidney and urinary tract diseases, impr ...
is a national organization representing people with chronic kidney diseases and professionals who treat kidney diseases.
* The American Kidney Fund
The American Kidney Fund (AKF) is a publicly supported non-profit organization founded in 1971.
The AKF provides comprehensive programs of kidney health awareness, education, and prevention. It provides financial assistance that helps 1 out of ...
is a national nonprofit organization providing treatment-related financial assistance to one of every five people undergoing dialysis each year.
* The Renal Support Network
The Renal Support Network (RSN) is an American nonprofit, kidney patient-focused, kidney patient-run organization that works to benefit individuals affected by chronic kidney disease (CKD). RSN's mission is to help patients develop their personal ...
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
The Renal Physicians Association (RPA) is an association representing nephrology professionals in the United States. RPA was founded in 1973 and headquartered in Rockville, Maryland. Their members are committed to improving the care of patient ...
is an association representing nephrology professionals.
United Kingdom
It was said to be costing the National Health Service
The National Health Service (NHS) is the umbrella term for the publicly funded healthcare systems of the United Kingdom (UK). Since 1948, they have been funded out of general taxation. There are three systems which are referred to using the " ...
about £1.5 billion a year in 2020.
Kidney Care UK
The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...
and The UK National Kidney Federation represent people with chronic kidney disease. The Renal Association The Renal Association, now the UK Kidney Association (UKKA), is the second oldest nephrology society in the world. It is the leading professional body for the UK renal community, dedicated to improving lives by supporting all professionals in the de ...
represents Kidney physicians and works closely with the National Service Framework
A National Service Framework (NSF) was any of several policies set by the National Health Service (NHS) in England to define standards of care for major medical issues such as cancer, coronary heart disease, chronic obstructive pulmonary disease, d ...
for kidney disease.
Australia
Kidney Health Australia serves that country.
Other animals
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 and boxer. The Swedish elkhound, Siberian husky and Finnish spitz were the breeds with the lowest rates.
Research
Currently, several compounds are in development for the treatment of CKD. These include the angiotensin receptor blocker (ARB) olmesartan medoxomil; and sulodexide
Sulodexide, traded as Aterina, is a highly purified mixture of glycosaminoglycans composed of low molecular weight heparin (80%) and dermatan sulfate (20%).
Pharmacology
The low molecular weight of both sulodexide fractions allows for extensive o ...
, a mixture of low molecular weight heparin and dermatan sulfate.
Unbiased research with complete reporting is required to determine the safety and effectiveness of acupuncture
Acupuncture is a form of alternative medicine and a component of traditional Chinese medicine (TCM) in which thin needles are inserted into the body. Acupuncture is a pseudoscience; the theories and practices of TCM are not based on scientif ...
to treat depression, pain, sleep problems
A sleep disorder, or somnipathy, is a medical disorder of an individual's sleep patterns. Some sleep disorders are severe enough to interfere with normal physical, mental, social and emotional functioning. Polysomnography and actigraphy are tests ...
, and uraemic pruritus in people who are undergoing dialysis treatments on a regular basis.
References
External links
*
Chronic Renal Failure Information
from Great Ormond Street Hospital
* /Https://www.mybestpdf.com/world-diabetes-day-2022/ How to Prevent Chronic Kidney Disease n World Diabetes Day 2022
{{DEFAULTSORT:Chronic Kidney Disease
Kidney diseases
Organ failure
Wikipedia medicine articles ready to translate