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

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

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