Kidney disease,or renal disease,technically referred to as nephropathy,is damage to or disease of a kidney. Nephritis is an inflammatory kidney disease and has several types according to the location of the inflammation. Inflammation can be diagnosed by blood tests. Nephrosis is non-inflammatory kidney disease. Nephritis and nephrosis can give rise to nephritic syndrome and nephrotic syndrome respectively. Kidney disease usually causes a loss of kidney function to some degree and can result in kidney failure,the complete loss of kidney function. Kidney failure is known as the end-stage of kidney disease,where dialysis or a kidney transplant is the only treatment option.
Vasculitis is a group of disorders that destroy blood vessels by inflammation. Both arteries and veins are affected. Lymphangitis is sometimes considered a type of vasculitis. Vasculitis is primarily caused by leukocyte migration and resultant damage. Although both occur in vasculitis,inflammation of veins (phlebitis) or arteries (arteritis) on their own are separate entities.
Granulomatosis with polyangiitis (GPA),previously known as Wegener's granulomatosis (WG),after the German physician Friedrich Wegener,is a rare long-term systemic disorder that involves the formation of granulomas and inflammation of blood vessels (vasculitis). It is an autoimmune disease and a form of vasculitis that affects small- and medium-size vessels in many organs but most commonly affects the upper respiratory tract,lungs and kidneys. The signs and symptoms of GPA are highly varied and reflect which organs are supplied by the affected blood vessels. Typical signs and symptoms include nosebleeds,stuffy nose and crustiness of nasal secretions,and inflammation of the uveal layer of the eye. Damage to the heart,lungs and kidneys can be fatal.
Henoch–Schönlein purpura (HSP),also known as IgA vasculitis,is a disease of the skin,mucous membranes,and sometimes other organs that most commonly affects children. In the skin,the disease causes palpable purpura,often with joint pain and abdominal pain. With kidney involvement,there may be a loss of small amounts of blood and protein in the urine,but this usually goes unnoticed;in a small proportion of cases,the kidney involvement proceeds to chronic kidney disease. HSP is often preceded by an infection,such as a throat infection.
Eosinophilic granulomatosis with polyangiitis (EGPA),formerly known as allergic granulomatosis, is an extremely rare autoimmune condition that causes inflammation of small and medium-sized blood vessels (vasculitis) in persons with a history of airway allergic hypersensitivity (atopy).
Myeloperoxidase (MPO) is a peroxidase enzyme that in humans is encoded by the MPO gene on chromosome 17. MPO is most abundantly expressed in neutrophils,and produces hypohalous acids to carry out their antimicrobial activity,including hypochlorous acid,the sodium salt of which is the chemical in bleach. It is a lysosomal protein stored in azurophilic granules of the neutrophil and released into the extracellular space during degranulation. Neutrophil myeloperoxidase has a heme pigment,which causes its green color in secretions rich in neutrophils,such as mucus and sputum. The green color contributed to its outdated name verdoperoxidase.
Anti-neutrophil cytoplasmic antibodies (ANCAs) are a group of autoantibodies,mainly of the IgG type,against antigens in the cytoplasm of neutrophils and monocytes. They are detected as a blood test in a number of autoimmune disorders,but are particularly associated with systemic vasculitis,so called ANCA-associated vasculitides (AAV).
Membranous glomerulonephritis(MGN) is a slowly progressive disease of the kidney affecting mostly people between ages of 30 and 50 years,usually white people.
Nephritic syndrome is a syndrome comprising signs of nephritis,which is kidney disease involving inflammation. It often occurs in the glomerulus,where it is called glomerulonephritis. Glomerulonephritis is characterized by inflammation and thinning of the glomerular basement membrane and the occurrence of small pores in the podocytes of the glomerulus. These pores become large enough to permit both proteins and red blood cells to pass into the urine. By contrast,nephrotic syndrome is characterized by proteinuria and a constellation of other symptoms that specifically do not include hematuria. Nephritic syndrome,like nephrotic syndrome,may involve low level of albumin in the blood due to the protein albumin moving from the blood to the urine.
Microscopic polyangiitis is an autoimmune disease characterized by a systemic,pauci-immune,necrotizing,small-vessel vasculitis without clinical or pathological evidence of granulomatous inflammation.
Proteinase 3,also known as PRTN3,is an enzyme that in humans is encoded by the PRTN3 gene.
p-ANCA,or MPO-ANCA,or perinuclear anti-neutrophil cytoplasmic antibodies,are antibodies that stain the material around the nucleus of a neutrophil. They are a special class of anti-neutrophil cytoplasmic antibodies.
Rapidly progressive glomerulonephritis (RPGN) is a syndrome of the kidney that is characterized by a rapid loss of kidney function,with glomerular crescent formation seen in at least 50% or 75% of glomeruli seen on kidney biopsies. If left untreated,it rapidly progresses into acute kidney failure and death within months. In 50% of cases,RPGN is associated with an underlying disease such as Goodpasture syndrome,systemic lupus erythematosus or granulomatosis with polyangiitis;the remaining cases are idiopathic. Regardless of the underlying cause,RPGN involves severe injury to the kidneys' glomeruli,with many of the glomeruli containing characteristic glomerular crescents.
Glomerulopathy is diseases that impact the glomeruli in the nephron,either inflammatory or noninflammatory. Glomerulopathy includes collapsing glomerulopathy,glomerulocystic kidney disease,glomerulomegaly,membranous nephropathy,and tip lesion glomerulopathy.
Pauci-immune vasculitis is a form of vasculitis that is associated with minimal evidence of hypersensitivity upon immunofluorescent staining for IgG. Often,this is discovered in the setting of the kidney.
Necrotizing vasculitis,also called systemic necrotizing vasculitis,is a general term for the inflammation of veins and arteries that develops into necrosis and narrows the vessels.
Focal proliferative nephritis is a type of glomerulonephritis seen in 20% to 35% of cases of lupus nephritis,classified as type III. As the name suggests,lesions are seen in less than half of the glomeruli. Typically,one or two foci within an otherwise normal glomerulus show swelling and proliferation of endothelial and mesangial cells,infiltration by neutrophils,and/or fibrinoid deposits with capillary thrombi. Focal glomerulonephritis is usually associated with only mild microscopic hematuria and proteinuria;a transition to a more diffuse form of renal involvement is associated with more severe disease.
Ronald Jonathan Falk,MD,FACP,FASN is the Nan and Hugh Cullman Eminent Professor and Chair of the Department of Medicine at the University of North Carolina-Chapel Hill (UNC). He is a clinical nephrologist and internationally recognized expert in anti-neutrophil cytoplasmic autoantibody (ANCA)-induced vasculitis and autoimmune kidney disease. His career as a translational physician-scientist spans more than three decades. His clinical practice and translational research focus on characterizing the cell,tissue and physiologic changes in the development of specific autoimmune kidney diseases and developing new approaches for studying autoimmunity,inflammation and basic neutrophil/monocyte biology. He was Chief of the UNC Division of Nephrology and Hypertension from 1993-2015. He co-founded the UNC Kidney Center in 2005 and continues as Co-Director. Falk is a Past-President of the American Society of Nephrology (ASN). Since 2015,he has served as Chair of the Department of Medicine at UNC.
Avacopan,sold under the brand name Tavneos,is a medication used to treat anti-neutrophil cytoplasmic autoantibody-associated vasculitis. Avacopan is a complement 5a receptor antagonist and a cytochrome P450 3A4 inhibitor.
IgM nephropathy or immunoglobulin M nephropathy (IgMN) is a kind of idiopathic glomerulonephritis that is marked by IgM diffuse deposits in the glomerular mesangium. IgM nephropathy was initially documented in 1978 by two separate teams of researchers.
