Urolithiasis

Disease class: Urologic diseases

Physiology

• Urine flows along the urinary tract from the kidneys, down the ureters, into the bladder, then through the urethra.  
• The urinary tract is lined with smooth muscle which can contract to narrow the lumen at any point of the tract. At a contracting section the pressure on the fluid is high. The fluid moves forwards to reach a dilated section where the pressure is lower. The contractions and dilations move along the tract like a wave. This type of muscular activity is called ureteric peristalsis.

 

Pathophysiology

• This refers to formation of a solid piece of material in the urinary tract. This material may be called a stone, calculus, or a lith. 
• It may obstruct the urinary tract, causing sudden-onset symptoms, particularly acute severe pain. 
• As the smooth muscle along the urinary tract contracts, the pressure rises and but the urine cannot escape the tract. The severity of pain along the tract fluctuates as peristalsis occurs. This is called colic or colicky pain.

Subtypes

• Cystolithiasis (stone formation in the bladder)
• Nephrolithiasis (stone formation in the kidney)
• Ureterolithiasis (stone formation in the ureter)

 

Symptoms

• Colic: renal or ureteric. A cramping pain, which oscillates in severity.

Complications

• Acute kidney injury (post-renal) 

Compare with

• Cholelithiasis (formation of gallstones).