A 7-year old boy began complaining of severe headaches, dizziness, and general malaise approximately 2 weeks after he had a mild "strep throat". His mother noticed puffiness of his face and darkening of the urine. She also noticed that the boy was excreting less and less urine and that he was becoming short of breath, and from time to time had an urge to vomit.

On physical examination, there was anasarca, slight elevation of blood pressure, and tachycardia. Urine was scanty and brownish red.

On microscopic examination the urine contained numerous red blood cells. Occasional red blood cells and granular casts were noticed. There was also 3+ proteinuria.

The glomerulus from the present case shows pathognomonic features of post-streptococcal glomerulonephritis. Where is the hump located? What is it composed of?

Immunofluorescence microscopy examination of the biopsy stained with fluoresceinated antibodies to human IgG. Describe the pattern of fluorescence and compare it with the electron microscopic findings. Which technique has revealed more immune deposits?

Question for Class Discussion