Hypocomplementaemia is seen -

RPGN may occur either during or following an infection. In both cases, circulating immune complexes are present and activation of the complement system promotes consumption of complement factors, resulting in low serum C3 and C4 concentration, as observed in many causes of glomerulonephritis . Post-infectious glomerulonephritis is observed most commonly in children and young adults, and typically presents 10 days after a streptococcal throat infection or longer after a skin infection. The clinical presentation ranges from mild abnormalities on urinalysis to RPGN with severe AKI. The anti-streptolysin (ASO) test is positive in up to 95% of patients with streptococcal throat infections. Treatment is suppoive, with control of blood pressure and fluid overload with salt restriction, diuretics and dialysis if required. Antibiotic therapy is rarely needed, as the renal disease occurs after the infection has subsided. The medium-term prognosis for children and most adults is good, with recovery of renal function typical even in those requiring dialysis therapy. Some patients may develop CKD 20-30 years after the original presentation, however. An immune complex-mediated disease may also be observed during an infection, typically a staphylococcal infection such as endocarditis, skin infection or pneumonia, but also with subacute endocarditis due to Streptococcus viridans. This occurs more commonly in older adults and the presentation tends not to be as fulminant as with post-streptococcal disease. In addition to suppoive measures, antibiotic therapy is required, as infection is usually concurrent with renal disease . Ref Harrison20th edition pg 233