Objective 8: Explain Pathophysiologic Changes in Urolithiasis and Hydronephrosis

Urolithiasis

Formation or presence of stones, also called calculi, anywhere in the urinary tract.

Urinary Calculi

Stones that form when dissolved substances in urine crystallize and accumulate.

Stone Formation

Occurs when urinary solute concentrations become high enough for substances to precipitate into crystals.

Dehydration and Stone Formation

Low urine volume increases solute concentration, making crystal formation more likely.

Urolithiasis Risk Factors

Excess urinary solutes, insufficient fluid intake, urinary tract infections, and high animal protein intake.

Renal Colic

Severe spasmodic pain caused when a stone obstructs the ureter.

Ureteral Spasms

Muscular contractions of the ureter against an obstruction, contributing to intense renal colic.

Hematuria with Urolithiasis

Can occur when a stone irritates or damages the urinary tract lining.

Hydronephrosis from Urolithiasis

Occurs when a stone obstructs urine drainage and causes urine to back up into the renal pelvis and calyces.

Hydronephrosis

Distention of the renal pelvis and calyces due to retained urine.

Effects of Increased Renal Pressure

Compresses kidney tissue, reduces renal blood flow and filtration, and can damage nephrons.

Persistent Hydronephrosis

Can cause permanent renal tissue injury and loss of kidney function.

What is urolithiasis?

The formation or presence of stones anywhere within the urinary tract.

What are urinary calculi?

Stones formed from crystals that accumulate in the urinary tract.

How do urinary stones form?

Dissolved substances become concentrated, precipitate into crystals, and gradually accumulate.

What factors increase the risk of urolithiasis?

Excess urinary solutes, dehydration, UTIs, and high animal protein intake.

Why does dehydration increase stone formation?

Low urine volume concentrates dissolved substances, encouraging crystal formation.

What happens when a stone becomes lodged in the ureter?

It can partially or completely obstruct urine drainage.

What is renal colic?

Severe spasmodic pain caused by a stone obstructing the ureter.

Why does a ureteral stone cause intense pain?

The ureter contracts against the obstruction while trying to move urine and the stone forward.

Why can hematuria occur with urinary stones?

The stone irritates or damages the urinary tract lining.

How can urolithiasis lead to hydronephrosis?

A stone can obstruct urine flow, causing urine to back up into the renal pelvis and calyces.

What happens to the renal pelvis and calyces during hydronephrosis?

They become distended or enlarged from accumulated urine.

How does increased pressure affect kidney tissue?

It compresses renal tissue and interferes with blood flow and filtration.

What can prolonged hydronephrosis cause?

Permanent renal tissue damage and loss of kidney function.

What is the relationship between urinary stones and hydronephrosis?

A stone may obstruct urine flow, causing urine backup that produces hydronephrosis.