الفهرس 
Introduction
Aim of the workOnly 14 pages are availabe for public view
 |  | from | 232 |  |  |
| | | from | 232 | | |
Abstract
Immunologic renal diseases in pediatrics encompass a broad range of clinicopathologic entities, some of which are limited to kidney disease (primary) where as in others the kidney involvement is one component of a systemic disease(secondary). The immune mechanisms underlying these diverse conditionsare equally complex and diverse.
Most glomerulonephritides result from either circulating immune complex deposition within the glomerulus or in situ immune complex formation. This activates complement, as well as cellular and humoral pathways of inflammation. Within the glomerulus, there can be endothelial, epithelial, and mesangialhy percellularity, infiltration of leukocytes, thickening or duplication of the glomerular basement membrane, and necrosis. This results in loss of capillary integrity and obstruction of blood flow through the glomerular capillary loops. This capillary injury and obstruction of glomerular blood flow leads to the fluid overload, oligoanuric renal failure, hematuria,and RBC casts.
The two most common causes of glomerulonephritis in children are acute postinfectious glomerulonephritis and IgA nephropathy. Other less common but important causes of glomerulonephritis include Henoch-Schِnlein purpura, membranoproliferative glomerulonephritis ,Goodpasteur disease, antineutrophilic cytoplasmic antibody positive vasculitis, systemic lupus erythematosus.
Acute poststreptococcal glomerulonephritis is the most common cause of aute postinfectious glomerulonephritis in children and has a higher incidence in developing countries. Acute post infectious glomerulonephritis is caused by nephritogenic forms of Lancefield group A streptococci. In most cases, there is clinical or laboratory evidence of antecedent streptococcal infection.
IgA Nephropathy is an immune complex mediated glomerulonephritis. Its course is highly variable and can range from asymptomatic microhematuria to recurrent episodes of gross hematuria to hypertension and acute and chronic renal failure.
Glomerulonephritis can be seen in systemic inflammatory diseases such as systemic vessel vasculitides, such as Henoch-Schönlein purpura, cryoglobulinemic vasculitis, microscopic polyangiitis, Wegener’s granulomatosis, or Churg-Strauss syndrome.
Henoch-Schönlein purpura is caused by vascular localization of IgA dominant immune complexes, which manifests as IgA nephropathy in the glomeruli.
Cryoglobulinemic vasculitisis caused by cryoglobulin deposition in vessels and often is associated with hepatitis C infection. In glomeruli, cryoglobulinemia usually causes type I membranoproliferative glomerulonephritis, but other phenotypes of proliferative and even membranous glomerulonephritis may develop.
The clinical presentation of acute glomerulonephritis is variable. Some children are asymptomatic and are accidentally discovered , and others present to the emergency department with hypertensive emergency, edema, and acute renal failure. On history, the child’s urine maybe cola or iced tea colored; there is usually no associated dysuria. The child’s face, abdomen, or legs may look swollen. One third of patients will complain of cough, sore throat, fever, or headache.The most common physical examination findings are any combination of hypertension, edema, and gross hematuria. Nausea, vomiting, and abdominal pain are seen less often. Presentation with anuria, seizures, pulmonary edema, and symptoms of congestive heart failure occurs infrequently.
Laboratory evaluation is required to assess renal function and serum electrolyte concentrations and determine the etiology of the glomerular inflammation.
The presence of RBC casts should be determined in a fresh urine specimen examined by microscopy. The serum C3 concentration can differentiate between many causes of glomerulonephritis. A low serum C3 concentration is present in acute post streptococcal glomerulonephritis and membranoproliferative glomerulonephritis. Patients with Systemic lupus erythematosus may have low serum concentrations of C3 and C4. In those with IgA associated nephropathy, small vessel vasculitis, and Henoch-Schönlein purpura nephritis, the serum C3 concentration is normal. The serum C3 concentration should return to normal in 6 to 8 weeks in children with acute post streptococcal glomerulonephritis. If this does not occur and the patient remains symptomatic, then a biopsy should be considered to evaluate for membranoproliferative glomerulonephritis
Renal ultrasonography shows non specific echogenicity. Chest radiograph may show fluid overload or features of vasculitis.
The most definitive way to diagnose the cause and guide therapy of glomerulonephritis is a percutaneous renal biopsy. Using a combination of light microscopy, immunofluorescence, and electron microscopy, the underlying glomerulonephritis type can be discerned.
Management of fluid balance, control of hypertension, and correction of electrolyte abnormalities are the most acute components of the treatment of glomerulonephritis.
For patients with oliguria, fluid administration should be limited to insensible fluid losses plus replacement of urine output. Insensible losses can be estimated at one third of daily maintenance requirements. Children who are volume overloaded can also be given intravenous furosemide. Over time, as the child’s urine output improves, fluid intake can be liberalized. The combination of evaluation of daily weights and physical examination looking for signs of volume overload guides total daily fluid volume requirements
Treatment of hypertension associated glomerulonephritis with Furosemide and calcium channel blockers should be used as initial therapy.
Therapies targeting the underlying glomerulonephritis such as corticosteroids, cyclophosphamide, cyclosporine, mycophenolate mofetil, rituximab,mizoribrine, azathioprine in case of nephrotic syndrome ,membranoproliferative glomerulonephritis, small vessels vasculitides and intravenous immunoglobulins and plasmapheresis in case of systemic lupus erythematosus and Henoch-Schönlein purpura are now used with good results.