Symptoms of lupus nephritis introduction

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Lupus nephritis is histologically evident in most patients with systemic lupus erythematosus (SLE), even those without clinical manifestations of renal disease. Evaluating renal function in SLE patients is important because early detection and treatment of renal involvement can significantly improve renal outcome.

Clinically, SLE usually presents with fever, weight loss (100%), arthralgias, synovitis, arthritis (95%), pleuritis, pericarditis (80%), malar facial rash, photodermatosis, alopecia (75%), anaemia, leukopaenia, thrombocytopaenia, and thromboses (50%).

About half of cases of SLE demonstrate signs of lupus nephritis at one time or another. Renal-specific signs include proteinuria (100%), nephrotic syndrome (55%), granular casts (30%), red cell casts (10%), microhematuria (80%), macrohematuria (2%), reduced renal function (60%), RPGN (30%), ARF (2%), hypertension (35%), hyperkalemia (15%) and tubular abnormalities (70%).

A diagram of the pathological changes in a glomerulus visible via electron microscopy in SLE nephritis. Black: immune complex; dark purple: basement membrane; pink: endothelium; green: visceral epithelium; light purple: mesangial cells
In histology, stage I (minimal mesangial) disease has a normal appearance under light microscopy, but mesangial deposits are visible under electron microscopy. At this stage urinalysis is typically normal.

stage II disease (mesangial proliferative) is noted by mesangial hypercellularity and matrix expansion. Microscopic haematuria with or without proteinuria may be seen. Hypertension, nephrotic syndrome, and acute renal insufficiency are rare at this stage.

stage III disease (focal lupus nephritis) is indicated by sclerotic lesions involving less than 50% of the glomeruli, which can be segmental or global, and active or chronic, with endocapillary or extracapillary proliferative lesions. Under electron microscopy, subendothelial deposits are noted, and some mesangial changes may be present. Immunofluorescence reveals the so-called "Full House" stain, staining positively for IgG, IgA, IgM, C3, and C1q. Clinically, haematuria and proteinuria is present, with or without nephrotic syndrome, hypertension, and elevated serum creatinine.

Diffuse proliferative lupus nephritis; photo shows the classic "flea-bitten" appearance of the cortical surface in the diffuse proliferative glomerulonephritides
stage IV lupus nephritis (diffuse proliferative) is both the most severe, and the most common subtype. More than 50% of glomeruli are involved. Lesions can be segmental or global, and active or chronic, with endocapillary or extracapillary proliferative lesions. Under electron microscopy, subendothelial deposits are noted, and some mesangial changes may be present. Immunofluorescence reveals the so-called "Full House" stain, staining positively for IgG, IgA, IgM, C3, and C1q. Clinically, haematuria and proteinuria are present, frequently with nephrotic syndrome, hypertension, hypocomplementemia, elevated anti-dsDNA titres and elevated serum creatinine.

Glucocorticoids plus either cyclophosphamide intravenously or mycophenolate mofetil orally should be administered to patients with class III/IV disease; patients with class I/II nephritis do not require immunosuppressive therapy

A wire-loop lesion may be present in stage III and IV. This is a glomerular capillary loop with subendothelial immune complex deposition that is circumferential around the loop. Stage V is denoted by a uniformly thickened, eosinophilic basement membrane. Stage III and IV are differentiated only by the number of glomeruli involved (which is subject to inherent sample bias), but clinically the presentation and prognosis are both expected to be more severe in stage IV versus stage III.

A final stage is usually included by most practitioners, stage VI, or advanced sclerosing lupus nephritis. It is represented by Global sclerosis involving more than 90% of glomeruli, and represents healing of prior inflammatory injury. Active glomerulonephritis is usually not present. This stage is characterised by slowly progressive renal dysfunction, with relatively bland urine sediment. Response to immunotherapy is usually poor.

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