Renal disease in a child: Acute glomerulonephritis Flashcards
Define acute glomerulonephritis.
Bilateral inflammation of renal glomeruli with proliferation of cellular elements secondary to an immunological mechanism.
Explain the aetiology of acute glomerulonephritis.
Post-infectious: Secondary to group A B-haemolytic streptococcus; glomerular inflammation secondary to streptococcal proteins derivatives. Serotype 12 (post-URTI) and serotype 49 (post-skin infection).
Other causative organisms: Diplococcal, staphylococcal, mycobacterial, CMV, coxsackie virus, EBV.
Haemolytic uraemic syndrome: Haemolytic anaemia, thrombocytopenia, and endothelial damage to glomerular capilalries secondary to infection to E.coli 0157, shigella or salmonella.
Henoch-schonlein purpura (HSP): Hypersensitivity vasculitis and inflammatory or response within the glomerular capillaries.
Berger disease: Diffuse mesangial deposition of IgA and IgG.
Systemic lupus erythematosus (SLE) nephritis: The immune system produces antinuclear antibodies. Antibodies and complement complexes accumulate in the kidneys resulting in an inflammatory response.
What are risk factors for acute glomerulonephritis?
Preceding sore throat/impetigo (post-infectious GN), URTI (HSP) or GI infection (HUS). Hepatitis and diabetes.
What is the pathophysiology of acute glomerulonephritis?
Histopathology: Swelling of the glomerular tufts and infiltration with polymorphonucelocytes.
Immunoflurescence: Immunoglobulins and complement deposition
Summarise the epidemiology of acute glomerulonephritis.
Typically, 2-12 years old, although may be any age. M:F = 2:1.
Incidence depends on underlying cause but generally rare. SLE is uncommon in children.
What are signs and symptoms of acute glomerulonephritis?
General: Characterised by the sudden onset of haematuria, proteinuria, and red cell casts. Often associated with hypertension, oedema (faces, ankles, and ascites) and impaired renal function. Flank pain may be present secondary to renal capsule swelling.
HSP: Characteristic petechial/purpuric rash on buttock and extensor surfaces, arthralgia commonly at the ankles, symptoms of nephritis, abdominal pain.
What are appropriate investigations for acute glomerulonephritis?
Urine: Microscopy; RBC +/- casts and culture, 24-hour collection; protein and creatinine clearance.
Bloods: Decrease Hb, increase WCC, decrease platelets (HUS), increased urea, increased ESR/CRP, metabolic acidosis, GFR
Specific: Increase Antistreptolysin titre, (increased in 1-3/52 and peaks at 3-5/52), RBC fragmentation, stool culture (HUS), IgA antibodies, antinuclear antibodies (SLE)
Imaging: Renal USS
Surgical: Renal biopsy may be necessary.
What is the management for acute glomerulonephritis?
General: Correction of any electrolyte abnormalities/acid-base imbalances. Fluid restriction if severe oedema present.
Medical: PO antibiotcs for post-infective causes (penicillin for streptococcus), antihypertensive therapy, treatment of pulmonary oedema, possible use of steroids +/- cytotoxic/immunosuprresive agents (HSP, vasculitis)
What are complications associated with acute glomerulonephritis?
Hypertension: Encephalopathy, convulsions, end-organ damage, cerebral haemorrhage.
Renal Failure: Uraemia, metabolic acidosis, electrolyte abnormalities, fluid overload.
What is the prognosis of acute glomerulonephritis?
10% develop chronic glomerulonephritis.
Mortality depends on cause.
