出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/09/09 22:15:41」(JST)
| Rapidly progressive glomerulonephritis | |
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Histopathological image of crescentic glomerulonephritis in a patient with MPO-ANCA positive rapid progressive glomerulonephritis. Hematoxylin & eosin stain.
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| Classification and external resources | |
| Specialty | urology |
| ICD-10 | N00-N08 with .7 suffix |
| DiseasesDB | 3165 |
| eMedicine | med/881 med/890 |
Rapidly progressive glomerulonephritis (RPGN) is a syndrome of the kidney that is characterized by a rapid loss of renal function,[1][2] (usually a 50% decline in the glomerular filtration rate (GFR) within 3 months)[2] with glomerular crescent formation seen in at least 50%[2] or 75%[1] of glomeruli seen on kidney biopsies. If left untreated, it rapidly progresses into acute renal failure[3] 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 (crescent-shaped scars).[4] Because of this microscopic feature, RPGN is also called crescentic glomerulonephritis.[4][5]
Most types of RPGN are characterized by severe and rapid loss of kidney function featuring severe hematuria (blood in the urine), red blood cell casts in the urine, and proteinuria (protein in the urine), sometimes exceeding 3 g protein/24 h, a range associated with nephrotic syndrome. Some patients also experience hypertension (high blood pressure) and edema. Severe disease is characterized by pronounced oliguria or anuria, which portends a poor prognosis.[6]
The clinical picture is consistent with nephritic syndrome, although the degree of proteinuria may occasionally exceed 3 g/24 h, a range associated with nephrotic syndrome. Untreated disease may progress to decreased urinary volume (oliguria), which is associated with poor kidney function.
Serum analysis often aids in the diagnosis of a specific underlying disease. The presence of anti-Glomerular basement membrane (GBM) antibodies suggests type I RPGN; antinuclear antibodies (ANA) may support a diagnosis of systemic lupus erythematosus and type II RPGN; and type III and idiopathic RPGN are frequently associated with anti-neutrophil cytoplasmic antibodies (ANCA)-positive serum.[6]
Treatment depends on the underlying disease process. For example, plasmapheresis, corticosteroids, and cytotoxic drugs may promote recovery in Goodpasture syndrome, a cause of type I RPGN. Despite even early treatment, however, many patients with RPGN may ultimately require dialysis and possibly renal transplant.
RPGN can be classified into three types, based upon the immunofluorescence patterns.[7]
Accounting for approximately 20% of RPGN, type I RPGN is characterized by the presence of autoantibodies directed against the glomerular basement membrane (GBM). It is also called anti-GBM glomerulonephritis. The antibodies are directed against a particular protein found in the GBM, type IV collagen, specifically the noncollagenous region of its α3 chain.[6]
In addition to the anti-GBM antibodies, some cases of type I RPGN are also associated with antibodies directed against the basement membrane of lung alveoli, producing Goodpasture syndrome. The majority of type I disease, however, features anti-GBM antibodies alone; these cases are considered idiopathic.[6]
RPGN caused by the deposition of immune complexes accounts for 25% of RPGN and is classified as type II. Thus any immune complex disease that involves the glomerulus may progress to RPGN if severe enough. These diseases include systemic lupus erythematosus, acute proliferative glomerulonephritis, Henoch-Schönlein purpura, and IgA nephropathy.[6] While polyarteritis nodosa also involves vasculitis associated immune complex deposition that can lead to renal failure, it is not considered part of type-II RPGN because it mainly affects medium sized vessels and does not necessarily involve the kidneys.
Also known as pauci-immune RPGN, type III RPGN accounts for 55% of RPGN and features neither immune complex deposition nor anti-GBM antibodies. Instead, the glomeruli are damaged in an undefined manner, perhaps through the activation of neutrophils in response to ANCA. Type III RPGN may be isolated to the glomerulus (primary, or idiopathic) or associated with a systemic disease (secondary). In most cases of the latter, the systemic disease is an ANCA-associated vasculitis such as Wegener granulomatosis, microscopic polyangiitis, or Churg-Strauss syndrome.[6]
Classification of type III RPGN into primary or secondary may be unnecessary, as primary type III RPGN and secondary type III RPGN may represent a spectrum of the same disease process.[6]
The ANCA form may have a more favorable response to treatment than other forms.[8]
Type IV has features of both types I and III. This is also called "double-antibody" positive disease.
Despite the wide variety of diseases that cause RPGN, all types of RPGN are characterized by glomeruluar injury and the formation of crescents. Severe injury and GBM rupture leads to the leakage of plasma proteins through the GBM. Of these proteins, fibrin is thought to contribute most strongly to crescent formation. Epithelial cells lining the Bowman capsule respond to the leaked fibrin and proliferate. Infiltrating white blood cells such as monocytes and macrophages may also proliferate. These proliferating cells surround and compress the glomerulus, forming a crescent-shaped scar that is readily visible on light microscopy of a renal biopsy.[6]
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| リンク元 | 「急速進行性糸球体腎炎」「RPGN」 |
| 拡張検索 | 「immune complex rapidly progressive glomerulonephritis」「idiopathic rapidly progressive glomerulonephritis」 |
| 関連記事 | 「rapid」「rapidly」「progressive」「glomerulonephritis」 |
臨床的に数週から数ヶ月の経過で急速に腎機能が低下して腎不全に至る予後不良の疾患であり、病理的には半月体形成がみられる(半月体形成性糸球体腎炎)ことが特徴の疾患である。小児には稀であり、30-60歳に多く、また男性に多い(男女比=2:1)。血清学的に半月体形成性糸球体腎炎は3つの病型に分類され、それぞれ原因が異なる。type Iは抗基底膜抗体の存在が特徴的であり、特発性のものとグッドパスチャー症候群によるものがある。typeIIは免疫複合体型であり、免疫複合体の沈着が特徴的であり、特発性、感染症(溶連菌感染後急性糸球体腎炎、紫斑病性腎炎、敗血症、感染性心膜炎、B型肝炎、C型肝炎)、悪性腫瘍、自己免疫性(全身性エリテマトーデス、結節性多発性動脈炎、クリオグロブリン血症)、糸球体疾患の続発(IgA腎症、膜性増殖性糸球体腎炎)などよるものがある。type IIIはpauci-immune型(つまり蛍光顕微鏡上、免疫複合体が乏しい)でありANCAが関連しているとされ、特発性の他、ウェゲナー肉芽腫症、顕微鏡多発血管炎などが原因となる。初発症状は全身倦怠感、食欲不振、嘔気などの非特異的症状で潜行性に発症するが、急性腎炎症状やネフローゼ症候群で発症することがある。約50%の例に上気道感染症、インフルエンザ、発熱などの潜行性感染が認められる。進行すれば腎炎症状を呈し、浮腫、乏尿、腎不全、血尿・肉眼的血尿、高血圧をきたす。診断は腎生検により行う。治療は半月体が線維化する以前に(つまり細胞性)、できるだけ早期に開始する。ステロイドパルス療法、カクテル療法(副腎皮質ステロイド、免疫抑制薬、抗凝固療法、抗血小板療法)、血漿交換法を行う。予後は極めて不良であり、発症後数週から数ヶ月、遅くとも1年で腎不全に至る。(YN.E-44 PED.1247)
[★] 急速進行性糸球体腎炎 rapidly progressive glomerulonephritis
