Acute Poststreptococcal Glomerulonephritis

Acute Poststreptococcal Glomerulonephritis It is acute nephritic syndrome: the sudden onset of gross hematuria, edema, hypertension, and renal insufficiency. Most common cause of gross hematuria in children next is IgA nephropathy ETIOLOGY AND EPIDEMIOLOGY. Acute poststreptococcal glomerulonephritis follows infection of the throat or skin with certain “nephritogenic” strains of group A b-hemolytic streptococci. In cold weather, poststreptococcal glomerulonephritis commonly follows streptococcal pharyngitis, In warm weather glomerulonephritis follows streptococcal skin infections. PATHOLOGY. Kidneys - symmetrically enlarged. Light microscopy - all glomeruli appear enlarged diffuse mesangial cell proliferation Polymorphonuclear leukocytes are common in glomeruli Crescents and interstitial inflammation may be seen in severe cases. Immunofluorescence microscopy - deposits of immunoglobulin and complement on the glomerular basement membranes (GBMs) and in the mesangium. Electron microscopy - electron-dense deposits are observed on the epithelial side of the GBM PATHOGENESIS. depression in the serum complement (C3) level suggest that poststreptococcal glomerulonephritis is mediated by immune complexes, complement activation is primarily through the alternative (immune complex activated) pathway. CLINICAL MANIFESTATIONS. rare before the age of 3 yr. Onset 1–2 wk after an antecedent streptococcal infection. asymptomatic microscopic hematuria with normal renal function acute renal failure. Depending on the severity of renal involvement, edema, hypertension, oliguria. Encephalopathy or heart failure due to hypertension or both  The edema is usually a result of salt and water retention, nephrotic syndrome may also occur. Nonspecific symptoms such as malaise, lethargy, abdominal or flank pain, and fever are common. The acute phase generally resolves within 2 mo after onset, but urinary abnormalities may persist for more than 1 yr. DIAGNOSIS. Urine - red blood cells (RBCs), with RBC casts and proteinuria +, ++ Blood - Polymorphonuclear leukocytosis Normochromic anemia due to hemodilution and low-grade hemolysis. The serum C3 level is usually reduced. Renal function tests –Urea and creatinine Throat culture may be positive Elevated antibody titer to streptococcal antigen(s) - ASO titer may not rise after streptococcal skin infections. Best single antibody titer to measure is that to the deoxyribonuclease (DNase) B antigen. An alternative is the Streptozyme test -a slide agglutination procedure - detects antibodies to streptolysin O, DNase B, hyaluronidase, streptokinase, and nicotinamide-adenine dinucleotidase. Rrenal biopsy ordinarily is indicated. To exclude systemic lupus erythematosus and an acute exacerbation of chronic glomerulonephritis. DD - Acute glomerulonephritis may also follow infection with coagulase-positive and -negative staphylococci, Streptococcus pneumoniae, gram-negative bacteria, and certain fungal, rickettsial, and viral diseases. Bacterial endocarditis may also produce a hypocomplementemic glomerulonephritis with renal failure. COMPLICATIONS. - Are due to ARF volume overload heart failure hypertension Hyperkalemia Hyperphosphatemia hypocalcemia acidosis seizures uremia PREVENTION. Systemic antibiotic therapy of streptococcal throat and skin infections does not eliminate the risk of glomerulonephritis. Family members of patients with acute glomerulonephritis should be cultured for group A b-hemolytic streptococci and treated if culture positive. TREATMENT. Management is that of acute renal failure 10-day course of systemic antibiotic therapy, with penicillin therapy may be given but it does not change the natural history of glomerulonephritis. Bed rest if there is complication Antihypertensive medications (diuretics, Angiotensin-converting enzyme inhibitors) are indicated to treat hypertension and to avoid hypertensive complications. PROGNOSIS. Complete recovery occurs in more than 95% of children with acute post streptococcal glomerulonephritis. Acute phase may be severe and lead to chronic renal insufficiency. Appropriate management of the acute renal or cardiac failure and hypertension can avoid mortality in the acute stage. Recurrences are extremely rare. Hence no penicillin prophylaxis like Rheumatic fever

Compiled by Dr.N.S.Mani,Assistant Professor in Paediatrics,Medical College,Trichur.