This chapter deals with nephritis associated with bacterial infections. A variety of bacterial infections are associated with renal disease, among which are Streptococcus (group A and C), Staphylococcus (aureus and epidermidis), Salmonella (typhi and paratyphi), Treponema pallidum, and Brucella abortus sui. We will limit our considerations to three specific disease entities: Poststreptococcal glomerulonephritis, glomerulonephritis associated with infective endocarditis, and glomerulonephritis associated with infected atrioventricular shunts.
- Acute nephritic syndrome (hematuria, edema, hypertension, ± oliguria), occasionally nephrotic syndrome, and rarely rapidly progressive azotemia.
- No evidence of systemic disease.
- Recent streptococcal infection (serology or culture).
- Reduced serum complement (CH50 and C3).
The incidence of acute poststreptococcal glomerulonephritis (APSGN) has decreased dramatically in most industrialized countries. The association with alcoholism in adult patients has been noticed in central Europe. Nevertheless, in other countries, such as Singapore, Trinidad, and Venezuela, a poststreptococcal etiology is the causative factor in more than 70% of the children admitted to the hospital with glomerulonephritis. The reason for these geographic variations in epidemiology may be the accessibility to early medical care and antibiotic treatment resulting from improvements in living standards. In addition, a lack of hygiene and sanitation prevalent in underdeveloped countries may predispose to a Th1 type of response (characteristic of APSGN) in contrast to the Th2 response that tends to favor minimal change disease in the industrialized countries with higher standards of hygiene. APSGN presents as sporadic cases, clusters of cases, or epidemics that follow streptococcal infections of the throat or the skin. The original epidemics were all due to group A streptococci, but the most recent large epidemic was due to the consumption of unpasteurized milk and cheese from cows with mastitis caused by Streptococcus zooepidemicus.
Streptococci of M types 47, 49, 55, and 57 are frequently the etiologic agents of pyodermitis-associated nephritis while types 1, 2, 4, and 12 correspond to upper respiratory streptococcal infections causing nephritis. There is a wide variability in the incidence of nephritis following a nephritogenic streptococcal infection, but the incidence among siblings is close to 40%, which indicates a familial predisposition to the disease; however, a genetic marker of susceptibility for APSGN has not been found.
APSGN is an immune complex-mediated disease. Humoral and cellular immune mechanisms are involved. Immune complexes formed in the circulation or in situ induce the local activation of the complement (preferentially by an alternative pathway) and coagulation systems (platelet consumption and activation) and the recruitment of inflammatory cells. Infiltration of helper T lymphocytes is an early feature and increased levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α, and platelet-derived growth factor (PDGF) have been demonstrated. In addition, there is evidence of autoimmune reactivity attributed in part to neuraminidase-induced desialization of normal components. Antineutrophil cytoplasmic antibody (ANCA), cryglobulins, serum rheumatoid factor titers, C3eNef, and antiimmunoglobulin (Ig) G ...