Objective Eight: Explain Pathophysiologic Changes in Urolithiasis and Hydronephrosis

Urolithiasis

Formation or presence of stones (calculi) anywhere in the urinary tract.

Urinary stone formation

Excessive solute concentration or insufficient fluid allows dissolved substances to precipitate, crystallize, and accumulate.

Urolithiasis risk factors

Excess solutes in filtrate, inadequate fluid intake, UTIs, and high animal-protein intake.

Renal colic

Severe spasmodic pain caused when a stone obstructs the ureter.

Stone-related hematuria

Stone movement can irritate or injure the urinary tract lining, causing blood in urine.

Urolithiasis-to-hydronephrosis sequence

Stone lodges and obstructs urine flow; urine backs up; renal pelvis and calyces distend; pressure damages kidney tissue.

How is hydronephrosis harmful?

Urine backup distends the renal pelvis and calyces; pressure can impair blood flow/filtration and permanently damage nephrons.

How do urinary stones form?

When solute concentrations become excessive or fluid is insufficient, substances precipitate, crystallize, and accumulate.

What factors predispose a person to urolithiasis?

Excess solutes, insufficient fluid intake, UTIs, and high animal-protein consumption.

Why does a ureteral stone cause renal colic?

The ureter contracts against the obstruction while trying to move urine and the stone, producing intense spasmodic flank pain.

How can a stone cause hydronephrosis?

A lodged stone blocks urine drainage, causing urine to back up and distend the renal pelvis and calyces.