Kidney diseases, or renal diseases, technically referred to as nephropathies, are Pathology conditions affecting the kidneys—the organs that facilitate removal of Metabolic waste and Toxin from the bloodstream, regulate the body's concentration of Electrolyte, maintain the appropriate acid-base balance of Blood plasma, and produce urine as a byproduct of metabolism.
When used colloquially, the term kidney disease may refer to chronic kidney disease (CKD), an umbrella term for any progressive loss of kidney function over at least three months, from any cause.
From a technical standpoint, the heterogenous group of kidney diseases can be broadly divided into categories based on which anatomical structures are involved: the glomeruli, the filtering capillaries of the kidney; tubules, which carry filtered blood; the renal interstitium, the fluid-filled space between these structures; and the renal Blood vessel, which deliver blood towards and away from the kidney.
All forms of kidney disease, glomerular or otherwise, have the potential to damage all four components of the kidney, culminating in Kidney failure—the stage of disease at which Kidney dialysis or a kidney transplant are necessary.
Rates for both chronic kidney disease and mortality have increased, associated with the rising prevalence of diabetes and the aging global population.
Causes
Causes of kidney disease include deposition of the
Immunoglobulin A Antibody in the glomerulus, administration of
, xanthine oxidase deficiency,
Cytotoxicity of chemotherapy agents, and a long-term exposure to
lead or its salts. Chronic conditions that can produce nephropathy include systemic lupus erythematosus, as well as diabetes mellitus and high blood pressure (hypertension), which lead to diabetic nephropathy and hypertensive nephropathy, respectively.
Autosomal dominant polycystic kidney disease
"Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic disease, affecting a half million Americans.
The clinical phenotype can result from at least two different gene defects. One gene that can cause ADPKD has been located on the short arm of chromosome 16."
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[[IgA nephropathy
IgA nephropathy is the most common glomerulonephritis throughout the world
Primary IgA nephropathy is characterized by deposition of the
IgA antibody in the glomerulus. The classic presentation (in 40–50% of the cases) is episodic frank
hematuria which usually starts within a day or two of a non-specific upper respiratory tract infection (hence
synpharyngitic) as opposed to post-streptococcal glomerulonephritis which occurs some time (weeks) after initial infection. Less commonly gastrointestinal or urinary infection can be the inciting agent. All of these infections have in common the activation of mucosal defenses and hence IgA antibody production.
Polycystic disease of the kidneys
Additional possible cause of nephropathy is due to the formation of cysts or pockets containing fluid within the kidneys. These cysts become enlarged with the progression of aging causing renal failure. Cysts may also form in other organs including the liver, brain, and ovaries. Polycystic kidney disease is a genetic disease caused by mutations in the PKD1, PKD2, and PKHD1 genes. This disease affects about half a million people in the US. Polycystic kidneys are susceptible to infections and cancer.
Xanthine oxidase deficiency
Another possible cause of Kidney disease is due to decreased function of
xanthine oxidase in the
purine degradation pathway. Xanthine oxidase will degrade
hypoxanthine to
xanthine and then to
uric acid. Xanthine is not very soluble in water; therefore, an increase in xanthine forms crystals (which can lead to
) and result in damage to the kidney.
Xanthine oxidase inhibitors, like
allopurinol, can cause nephropathy.
Diabetes
Diabetic nephropathy is a progressive kidney disease caused by
angiopathy of the
capillary in the glomeruli. It is characterized by nephrotic syndrome and diffuse scarring of the glomeruli. It is particularly associated with poorly managed diabetes mellitus and is a primary reason for
Kidney dialysis in many developed countries. It is classified as a
Microangiopathy of diabetes.
[Longo et al., Harrison's Principles of Internal Medicine, 18th ed., p. 2982]
Lupus
Despite expensive treatments,
lupus nephritis remains a major cause of morbidity and mortality in people with relapsing or refractory lupus nephritis.
COVID-19
COVID-19 is associated with kidney disease. In patients hospitalized with COVID-19, the
prevalence of acute kidney injury is estimated to be 28%, and the prevalence of renal replacement therapy is estimated to be 9%.
Analgesics
One cause of nephropathy is the long term usage of pain medications known as
analgesics. The pain medicines which can cause kidney problems include
aspirin,
acetaminophen, and nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen. This form of nephropathy is "chronic analgesic nephritis", a chronic inflammatory change characterized by loss and atrophy of tubules and interstitial fibrosis and inflammation (BRS Pathology, 2nd ed.).
Specifically, long-term use of the analgesic phenacetin has been linked to renal papillary necrosis (necrotizing papillitis).
Iodinated contrast media
Kidney disease induced by iodinated contrast media (ICM) is called contrast induced nephropathy (CIN) or contrast-induced acute kidney injury (AKI). Currently, the underlying mechanisms are unclear. But there is a body of evidence that several factors including
apoptosis-induction seem to play a role.
Toxicity of chemotherapy agents
Nephropathy can be associated with some therapies used to treat cancer. The most common form of kidney disease in cancer patients is acute kidney injury (AKI) which can usually be due to volume depletion from vomiting and diarrhea that occur following chemotherapy or occasionally due to kidney toxicities of chemotherapeutic agents. Kidney failure from break down of cancer cells, usually after chemotherapy, is unique to
onconephrology. Several chemotherapeutic agents, for example
cisplatin, are associated with acute and chronic kidney injuries.
[Portilla D, Safar AM, Shannon ML, Penson RT. "Cisplatin nephrotoxicity". In: UpToDate, Palevsky PM (Ed), UpToDate, Waltham, MA, 2013. http://www.uptodate.com/contents/cisplatin-nephrotoxicity] Newer agents such as
Anti-VEGF (anti-VEGF) are also associated with similar injuries, as well as
proteinuria,
hypertension, and thrombotic microangiopathy.
Lithium
Lithium, a medication commonly used to treat
bipolar disorder and schizoaffective disorders, can cause nephrogenic diabetes insipidus; its long-term use can lead to nephropathy.
Long term lithium treatment is known to cause chronic kidney disease after 10-20 years of treatment in 1-5% of people.
End-stage renal disease due to lithium occurs in 0.53% of people versus 0.2% in the general population.
Dosing lithium more than once per day is associated with more kidney damage.
Kidney harm can be mitigated by dosing lithium once per day at night and keeping the dose as low as possible.
Dosing lithium once per day allows for long periods where the kidney is exposed to low levels of lithium, which minimizes kidney harm.
Anabolic-androgenic steroids
Regular and long-term use of anabolic-androgenic steroids (AAS) can cause both acute and chronic kidney disease through several direct and indirect mechanisms.
Focal segmental glomerulosclerosis is the most common condition arising in such cases.
Discontinuation of AAS in the early stage of Kidney Disease can result in a reversal of the kidney damage.
Diet
Higher dietary intake of animal protein, animal fat, and cholesterol may increase risk for
microalbuminuria, a sign of kidney function decline,
and generally, diets higher in fruits, vegetables, and whole grains but lower in meat and
Candy may be protective against kidney function decline.
This may be because sources of animal protein, animal fat, and cholesterol, and sweets are more acid-producing, while fruits, vegetables, legumes, and whole grains are more base-producing.
Diagnosis
The standard diagnostic workup of suspected kidney disease includes a
medical history, physical examination, a urine test, and an ultrasound of the kidneys (renal ultrasonography). An ultrasound is essential in the diagnosis and management of kidney disease.
Treatment
Treatment approaches for kidney disease focus on managing the symptoms, controlling the progression, and also treating co-morbidities that a person may have.
Transplantation
Millions of people across the world have kidney disease. Of those millions, several thousand will need dialysis or a kidney transplant at its
kidney failure.
In the United States, as of 2008, 16,500 people needed a kidney transplant.
Of those, 5,000 died while waiting for a transplant.
Currently, there is a shortage of donors, and in 2007 there were only 64,606 kidney transplants in the world.
This shortage of donors is causing countries to place monetary value on kidneys. Countries such as Iran and Singapore are eliminating their lists by paying their citizens to donate. Also, the black market accounts for 5–10 percent of transplants that occur worldwide.
The act of buying an organ through the black market is illegal in the United States.
To be put on the waiting list for a kidney transplant, patients must first be referred by a physician, then they must choose and contact a donor hospital. Once they choose a donor hospital, patients must then receive an evaluation to make sure they are sustainable to receive a transplant. In order to be a match for a kidney transplant, patients must match blood type and human leukocyte antigen factors with their donors. They must also have no reactions to the
Antibody from the donor's kidneys.
Dialysis
Because of the shortage of kidney donors,
kidney dialysis is the most common method of renal replacement therapy for patients with
kidney failure. Usually it is started at Stage 5 of chronic kidney failure, when the glomerular filtration rate is less than 15% of the normal.
For most patients, a kidney transplant offers a significant survival advantage and improved quality of life compared to remaining on dialysis, often adding years to life expectancy, though early risks exist, especially with certain donor types or in the elderly, but long-term outcomes favor transplant. Studies consistently show better long-term survival rates for transplant recipients, with one-year survival rates often above 90-95% for transplant, while dialysis patients face higher mortality.
Prognosis
Kidney disease can have serious consequences if it cannot be controlled effectively. Generally, the progression of kidney disease is from mild to serious. Some kidney diseases can cause
kidney failure.
See also
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Hematologic Diseases Information Service
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Mesoamerican nephropathy, an enigmatic chronic kidney disease of Central America
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Protein toxicity
