Thickening of glomerular capillary walls: a guide to differential diagnosis by electron microscopy

Glomerular basement membrane abnormalities associated with apparently idiopathic hematuria: ultrastructural morphometric analysis

In a recent review of 480 renal biopsies, 41 cases were identified in which glomerular basement membrane (GBM) ultrastructural abnormalities were the major lesion. All of the patients had hematuria. None had evidence of immune-mediated glomerulonephritis. Positive family histories of renal disease were present in the majority of cases, and one case of Alport's syndrome was included. Subjectively, the GBM changes were variable but nearly always included membrane thinning. For objective characterization of this glomerular abnormality, a detailed morphometric study of GBM thickness was undertaken: 12 of these patients (study group) were compared with seven patients (control subjects) with subjectively normal glomeruli who underwent biopsy for reasons other than nonsurgical hematuria but who were also thought to have normal glomerular ultrastructure. The seven control subjects had a mean GBM thickness of 394 nm (SD, 19; range, 356 to 432 nm). Of the 12 study group patients, 11 had mean GBM thicknesses significantly different from control values (nine had mean GBM thinning: range, 235 to 327 nm; two had thickening: means, 440 and 469 nm). In the remaining case (Alport's syndrome) the overall mean was normal, but an abnormal distribution of very thin and very thick GBM regions was seen. Of the four apparently normal hematuric patients, significant mean GBM thinning (326 to 347 nm) was demonstrated in three, with an excess of thin GBM in the fourth case, although the mean thickness was normal. Thus, measurable abnormalities were defined in all of the cases of hematuria examined. The GBM measurements confirmed the subjective impression of membrane abnormality, usually attenuation, as the principal finding in this group of hematuric patients. Furthermore, morphometric analysis may reveal subtle changes of GBM thickness missed by subjective assessment.

Glomerulonephritis: approaches to classification

Glomerulonephritis has many mechanisms and may take a variety of patterns. Almost as many classifications of glomerulonephritis exist as there have been classifiers. None is perfect. Morphological classification of glomerulonephritis is inadequate alone but provides useful information about the pattern of response to the injurious mechanism and may allow accurate assessment of prognosis. In this paper some approaches to the classification of glomerulonephritis are discussed, the major categories are reviewed and a prognostic method of classification is proposed.

Microtubuloreticular structures in the cerebral vasculature of a patient with herpes simplex encephalitis

In this report we will document the presence of microtubuloreticular structure (MTRS) in the cerebral vasculature of a patient who had contracted herpes simplex (HSV) encephalitis. Twenty of twenty-one blood vessels (capillaries, arterioles, venules) contained MTRS within the cytoplasm of endothelial and/or associated cells. The use of this evidence to support a diagnosis of HSV encephalitis is discussed.