Why there's no increase in Hydrostatic pressure in glomerular capillaries?

Not a full answer but it's a start (in the context of an obstruction): "Obstruction of urine flow results in an increase in hydrostatic pressures proximal to the site of obstruction. It is this buildup of pressure that leads to the accompanying pain, the distention of the collecting system in the kidney, and elevated intratubular pressures that initiate tubular dysfunction. In the first days of obstruction, the dilatation of the poorly compliant collecting system may be minimal. As the increased hydrostatic pressure is expressed in the urinary space of the glomeruli, further filtration decreases or stops completely." (Harrison's, 20e, Chapter 313)