Chronic Glomerulonephritis

Schema of the renal corpuscle structure: A - Renal corpuscle B - Proximal tubule C - Distal convoluted tubule D - Juxtaglomerular apparatus 1. Basal lamina 2. Bowman's capsule - parietal layer 3. Bowman's capsule - visceral layer 3a. Pedicels 3b. Podocyte 4. Bowman's space 5a. Mesangium - Intraglomerular mesangial cell 5b. Mesangium - Extraglomerular mesangial cell 6. Granular cells (Juxtaglomerular cells) 7. Macula densa 8. Myocytes (smooth muscle) 9. Arteriola afferens 10. Capillaries of the glomerulus 11. Arteriola efferens.

The most common chronic glomerulonephritis in children include:

• IgA nephropathy (Berger's glomerulonephritis) - most common;
• Mesangioproliferative glomerulonephritis without IgA deposits;
• Membranoproliferative glomerulonephritis;
• Glomerulonephritis in systemic diseases accompanied by nephrotic syndrome.

IgA nephropathy

• IgA-mesangioproliferative glomerulonephritis, IgA nephropathy
• immunocomplex nephritis - IgA globulin deposits (demonstrated by immunofluorescence assay of renal biopsy);
• in school children and adolescents, more often in boys;
• pathogenesis: impaired immunoregulation with increased IgA production → mesangial deposits of IgA immunocomplexes;
• clinical picture: incidental findings of microscopic haematuria or episodes of macroscopic haematuria in upper respiratory tract infections;
  • mild proteinuria (0.5-1 g/day), nephrotic syndrome is not typical; about half of cases have elevated serum IgA;
• diagnosis: biopsy - mesangioproliferative glomerulonephritis, immunofluorescence testing for IgA deposits (+IgG and C3C); focal and segmental glomerular involvement;
• therapy: no causal treatment; eradication of sources of bacterial infection, in proteinuria ACE inhibitors or angiotensin receptor blockers;
• prognosis: some have a benign course, some are at risk of progression to chronic kidney disease - dispensary required.

Membranoproliferative glomerulonephritis

• mesangiocapillary GN, persistent hypocomplementary GN
• chronic mesangioproliferative glomerulonephritis with dense deposits within the basement membrane;
• uncommon in children, pathogenesis is unclear;
• clinical picture: development of hematuria and proteinuria, nephrotic syndrome; decreased complement levels;
• diagnosis: biopsy - intramembranous deposits on electron microscopy;
• therapy: no causal treatment; corticosteroids for rapid progression;
• prognosis: poor - progression to terminal chronic renal failure within 5-8 years.

Membranous nephropathy

• in adults the most common cause of nephrotic syndrome; rare in children;
• pathogenesis: immunocomplex disease - diffusely thickened glomerular membrane, inclusions from immune complexes (IgG and C3);
• clinical picture: nephrotic syndrome (manifestation mostly in the 2nd decade); microhematuria, proteinuria, hypoalbuminemia;
• diagnosis: biopsy (histology and immunofluorescence);
• therapy: salt restriction, diuretics, possibly immunosuppressants.

Glomerulonephritis in Henoch-Schonlein purpura

• Henoch-Schönlein purpura is a vasculitis that affects small blood vessels of the skin and gastrointestinal tract; in 25-50%, the kidneys and, rarely, the CNS are also affected;
• renal involvement is focally segmental and resembles IgA nephropathy;
• clinical picture: 1-2 weeks after seeding of petechiae, microscopic haematuria and proteinuria, rarely nephrotic; rarely in the form of rapidly progressive glomerulonephritis;
• therapy: corticosteroids - controversial;
• prognosis: good, microscopic haematuria often persists.

Glomerulonephritis in SLE

• severe and frequent complication of SLE;
• systemic lupus erythematosus (SLE) is a chronic inflammatory autoimmune disease caused by B-cell hyperactivity, autoantibody production against components of the cell nucleus, and immune complex deposition;
• clinical picture: hematuria and proteinuria, nephrotic syndrome, early glomerular filtration disorder, rapidly progressive severe glomerulonephritis;
• diagnosis: biopsy (histology, immunofluorescence - positive Ig, complement, fibrinogen)
• therapy: corticosteroids, cyclophosphamide, possibly immunosuppressants.

Goodpasture syndrome

• a combination of pulmonary hemorrhage and glomerulonephritis due to the production of antibodies against the pulmonary alveoli and glomerular basement membrane;
• very rare in children;
• biopsy picture of rapidly progressive glomerulonephritis; evidence of anti-GBM antibodies in serum; poor prognosis.

References

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