Urinary tract obstruction

Know the causes, gross appearance and microscopic features of hydronephrosis

• Cause

• Obstruction at any level from urethra up to pelvis
• Unilateral / Bilateral
• Complete / Incomplete

• Gross appearance

• Slight to massive enlargement of kidney
• Cup-shaped depression of papillae and thinning of cortex
• Progressive blunting of pyramid apices

• Microscopic features

• Cortical tubular atrophy with marked diffuse interstitial fibrosis in the case of chronic disease
• Significant interstitial inflammation even in the absence of infection

Know the clinical manifestations of partial and bilateral complete obstruction of urinary flow.

• Unilateral obstruction is often asymptomatic for long periods of time as unaffected kidney can provide adequate function

• Sudden and complete obstruction

• Reduction of GFR  azotemia

• Mild dilation of pelvis and calyces

• Patient often dies w/in a week or so from renal failure, so there is not usually enough time for substantial dilation to take place

• Subtotal and intermittent obstruction

• GFR not suppressed
• Progressive dilation of pelvis and calyces

Category: Pathology Notes