Nephritis

Nephritis is inflammation of the kidneys and may involve the glomeruli, tubules, or interstitial tissue surrounding the glomeruli and tubules.^[1]

Associated medical conditions

Enlarged kidney

Type

• Glomerulonephritis is inflammation of the glomeruli. Glomerulonephritis is often implied when using the term "nephritis" without qualification.^[2]
• Interstitial nephritis or tubulo-interstitial nephritis is inflammation of the spaces between renal tubules.^[3]

Causes

Nephritis is often caused by infections, and toxins, but is most commonly caused by autoimmune disorders that affect the major organs like kidneys.^[4]

• Pyelonephritis is inflammation that results from a urinary tract infection that reaches the renal pelvis of the kidney.^[5]
• Lupus nephritis is inflammation of the kidney caused by systemic lupus erythematosus (SLE), a disease of the immune system.^[6]
• 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 cells, causing their rupture, which leads to the release of hemoglobin into the blood.^[7]

Mechanism

Renin-angiotensin system

Nephritis can produce glomerular injury, by disturbing the glomerular structure with inflammatory cell proliferation.^[8] This can lead to reduced glomerular blood flow, leading to reduced urine output (oliguria)^[9] and retention of waste products (uremia). ^[10] As a result, red blood cells may leak out of damaged glomeruli, causing blood to appear in the urine (hematuria).^[11] Low renal blood flow activates the renin-angiotensin-aldosterone system (RAAS), causing fluid retention and mild hypertension.^[12]

As the kidneys inflame, they begin to excrete needed protein from the body into the urine stream. This condition is called proteinuria.^[13] 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.^[14]

Epidemiology

Nephritis represents the ninth most common cause of death among all women in the US (and the fifth leading cause among non-Hispanic black women).^[15] Worldwide the highest rates of nephritis are 50-55% for African or Asian descent, then Hispanic at 43% and Caucasian at 17%.^[16]

Disease burden of nephritis/nephrosis worldwide in 2004, depicted in terms of years lost due to ill-health, disability or early death (disability-adjusted life years per 100,000 inhabitants).^[17]

  no data

  less than 40

  40–120

  120–200

  200–280

  280–360

  360–440

  440–520

  520–600

  600–680

  680–760

  760–840

  more than 840

See also

• Nephrotic syndrome
• Bright's Disease
• Goodpasture's syndrome

References