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
Source:DR.NS.MANI.MD Associate Professor in Pediatrics
