Pediatric tubulointerstitial nephritis

Abstract

Involvement of the tubulointerstitial compartment in renal diseases can be either primary or even more commonly secondary to glomerular, vascular, or structural disease (Table 1). However, even in the latter disorders, the magnitude of involvement and damage to the tubulointerstitium can have a significant effect on the outcome of the primary disease [1, 2]. This chapter addresses primary tubulointerstitial nephritis (TIN) which is a syndrome in which there is a spectrum of diseases ranging from acute to chronic. TIN is characterized histologically by inflammation and damage of tubulointerstitial structures, with relative sparing of glomerular and vascular elements [3, 4]. Acute TIN is typically associated with marked tubulointerstitial inflammation, varying degrees of edema and tubular epithelial cell damage, and mononuclear cell infiltration [5]. In contrast, chronic lesions generally are characterized by evidence of tubular epithelial cell damage and atrophy, with tubulointerstitial fibrosis [5]. Although there are important clinical and pathophysiologic distinctions between acute and chronic TIN, they are best viewed as a continuum of manifestations of renal injury [6, 7]. Acute TIN is often reversible; however, progression to chronic renal disease can occur [8–10].