Pathology of the Kidney in Preeclampsia

Abstract

The inability to identify properly the underlying condition resulting in gestational hypertension and other renal dysfunctions during pregnancy using clinical criteria alone has led to a great deal of confusion in the literature [1–3]. An evolution in the pathologic nomenclature and the now widespread use of electron and immunofluorescent microscopy in addition to light microscopy has allowed for a more precise distinction of lesions of true preeclampsia from others that mimic preeclampsia clinically. In the 1950s, one of the authors (B.H.S.) recalls the frustration of Dieckmann not only in the inability to clinically distinguish preeclampsia from other causes of hypertension in pregnancy, but also by the discrepancy between his clinical impression and the pathologist’s report and the irreproducibil-ity of the pathologic interpretation [4]. The scope of this problem of clinical variability has been more recently revealed in several studies in which postpartum renal biopsy in women, diagnosed to have preeclampsia clinically, revealed renal lesions other than those ascribed to preeclampsia in as many as 45% of the patients [2, 5]. These other renal lesions include primary renal diseases such as glomerulonephritis, membranous nephropathy, “minimal change” nephropathy, tubulointerstitial lesions, and nephrosclerosis, in addition to lesions associated with systemic disease such as sickle cell and diabetic nephropathies [5]. These conditions were not infrequently found superimposed on the renal changes felt to be characteristic of preeclamptic toxemia (PET).