Poststreptococcal glomerulonephritis

Poststreptococcal glomerulonephritis is a nonsuppurative sequela of streptococcal infection that occasionally complicates pregnancy. Although group A beta-hemolytic streptococci are responsible for the majority of cases, multiple groups of streptococci can cause postinfectious glomerulonephritis. Infection of the skin or pharynx with streptococci typically precedes kidney involvement by 6 days to 2 weeks. The risk of developing acute nephritis after streptococcal infection ranges from 1–15%. This disorder usually affects children, and is more frequent in males. Poststreptococcal glomerulonephritis is considered an immune complex disease because interactions between antigen–antibody complexes and the complement system result in glomerular injury. Patients present with a wide range of complaints including hematuria, edema, malaise, lethargy, nausea, fever, weakness, anorexia, cough, and dyspnea. The most common exam findings include hypertension, edema, and hematuria. The differential diagnosis includes multisystem disease, other primary glomerular diseases, nonstreptococcal postinfectious glomerulonephritis, and urinary tract infection. The diagnosis is confirmed by the detection of antistreptococcal antibodies, and renal biopsy showing hypercellularity and proliferation. Treatment is supportive, and renal function tends to improve rapidly. Antibiotics are indicated if the patient is concurrently infected. Penicillin is the drug of choice, but erythromycin can be used in the penicillin-allergic patient. Immunity is lifelong, but recurrences may develop after infection with a different nephritogenic strain. If signs of irreversible kidney damage are present, the disease is considered chronic. Presentation in pregnancy may be confused with preeclampsia as hypertension, edema, and proteinuria are presenting signs in both entities. Poststreptococcal glomerulonephritis may lead to preterm delivery but typically has a successful outcome.