Nephritis is

inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...

of the

kidneys In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and right in the retro ...

and may involve the

glomeruli ''Glomerulus'' (; : glomeruli) is a common term used in anatomy to describe globular structures of entwined vessels, fibers, or neurons. ''Glomerulus'' is the diminutive of the Latin ''glomus'', meaning "ball of yarn". ''Glomerulus'' may refer to ...

tubules In biology, a tubule is a general term referring to small tube or similar type of structure. Specifically, tubule can refer to: * a small tube or fistular structure * a minute tube lined with glandular epithelium * any hollow cylindrical body stru ...

, or interstitial tissue surrounding the glomeruli and tubules. It is one of several different types of

nephropathy Kidney disease, or renal disease, technically referred to as nephropathy, is damage to or disease of a kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipap ...

Types

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 ...

is inflammation of the

. Glomerulonephritis is often implied when using the term "nephritis" without qualification. *

Interstitial nephritis Interstitial nephritis, also known as tubulointerstitial nephritis, is inflammation of the area of the kidney known as the renal interstitium, which consists of a collection of cells, extracellular matrix, and fluid surrounding the renal tubules ...

(or tubulo-interstitial nephritis) is inflammation of the spaces between

renal tubule The nephron is the minute or microscopic structural and functional unit of the kidney. It is composed of a renal corpuscle and a renal tubule. The renal corpuscle consists of a tuft of capillaries called a glomerulus and a cup-shaped structure ...

Causes

Nephritis can often be caused by infections and toxins, but it is most commonly caused by

autoimmune disorder An autoimmune disease is a condition that results from an anomalous response of the adaptive immune system, wherein it mistakenly targets and attacks healthy, functioning parts of the body as if they were foreign organisms. It is estimated tha ...

s that affect the major organs like kidneys. *

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 ...

is inflammation that results from a

urinary tract infection A urinary tract infection (UTI) is an infection that affects a part of the urinary tract. Lower urinary tract infections may involve the bladder (cystitis) or urethra (urethritis) while upper urinary tract infections affect the kidney (pyel ...

that reaches the

renal pelvis The renal pelvis or pelvis of the kidney is the funnel-like dilated part of the ureter in the kidney. It is formed by the convergence of the major calyces, acting as a funnel for urine flowing from the major calyces to the ureter. It has a mucous ...

of the kidney. *

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 ...

is inflammation of the kidney caused by

systemic lupus erythematosus Lupus, formally called systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Common ...

(SLE), a disease of the

immune system The immune system is a network of biological systems that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to bacteria, as well as Tumor immunology, cancer cells, Parasitic worm, parasitic ...

. * Athletic nephritis is nephritis resulting from strenuous exercise. Bloody urine after strenuous exercise may also result from march hemoglobinuria, which is caused by trauma to

red blood cell Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cel ...

s, causing their rupture, which leads to the release of hemoglobin into the urine.

Mechanism

Nephritis can produce glomerular injury, by disturbing the glomerular structure with inflammatory cell proliferation. This can lead to reduced glomerular blood flow, leading to reduced urine output (

oliguria Oliguria or hypouresis is the low output of urine specifically more than 80 ml/day but less than 400ml/day. The decreased output of urine may be a sign of dehydration, kidney failure, hypovolemic shock, hyperosmolar Hyperglycemic Nonketotic Syndro ...

) and retention of waste products (

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 ...

). As a result, red blood cells may leak out of damaged glomeruli, causing blood to appear in the urine (

hematuria Hematuria or haematuria is defined as the presence of blood or red blood cells in the urine. "Gross hematuria" occurs when urine appears red, brown, or tea-colored due to the presence of blood. Hematuria may also be subtle and only detectable with ...

). Low renal blood flow activates the renin–angiotensin–aldosterone system (RAAS), causing fluid retention and mild

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 ...

. As the kidneys inflame, they begin to excrete needed protein from the affected individual's body into the urine stream. This condition is called

proteinuria Proteinuria is the presence of excess proteins in the urine. In healthy persons, urine contains very little protein, less than 150 mg/day; an excess is suggestive of illness. Excess protein in the urine often causes the urine to become fo ...

. Loss of necessary protein due to nephritis can result in several life-threatening symptoms. The most serious complication of nephritis can occur if there is significant loss of the proteins that keep blood from clotting excessively. Loss of these proteins can result in blood clots, causing sudden stroke.

Diagnosis

The diagnosis depends on the cause of the nephritis, and in the case of

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 ...

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 ...

, X-rays and an ultrasound can help ascertain if the individual has the condition.

Treatment

Nephritis and nephrosis world map - DALY - WHO2004

Treatment (or management) of nephritis depends on what has provoked the inflammation of the kidney(s). In the case of lupus nephritis,

hydroxychloroquine Hydroxychloroquine, sold under the brand name Plaquenil among others, is a medication used to prevent and treat malaria in areas where malaria remains sensitive to chloroquine. Other uses include treatment of rheumatoid arthritis, lupus, an ...

could be used.

Prevalence

Nephritis represents the ninth-most-common cause of death among all women in the US (and the fifth leading cause among non-

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 ...

black women). Worldwide, the highest rates of nephritis are 50–55% for African or Asian descent followed by Hispanic at 43% and

Caucasian Caucasian may refer to: Common meanings *Anything from the Caucasus region or related to it ** Ethnic groups in the Caucasus ** ''Caucasian Exarchate'' (1917–1920), an ecclesiastical exarchate of the Russian Orthodox Church in the Caucasus re ...

at 17%. The average age of an individual diagnosed with kidney inflammation (in this case, lupus nephritis) is 28.4 years old.

References

External links

{{Authority control Inflammations Kidney diseases