Lecture Notes: Urinary Calculi - Genitourinary Disorders

Overview

• Urinary Calculi: Solid particles within the urinary system.
• Symptoms: Pain, nausea, vomiting, hematuria, and chills/fever due to infection.
• Diagnosis: Primarily through noncontrast CT scans.
• Treatment: Includes analgesics, antibiotics, medical expulsive therapy, and sometimes surgical procedures.

Epidemiology

• Annual incidence in the US: 1-2% among adults.
• Hospitalization due to urinary calculi: 1 in 1000 adults annually.
• By age 70, 19% of men and 10% of women may develop a calculus.

Etiology

• Risk Factors: Metabolic disorders (e.g., hyperparathyroidism, renal tubular acidosis), dietary factors (high sodium, low fluid intake).
• Composition: 85% calcium (mainly calcium oxalate), 5-10% uric acid, 1-2% cystine, 5-15% magnesium ammonium phosphate.

Types of Urinary Calculi

• Calcium Calculi: Linked to hypercalciuria; common in those with family history.
• Uric Acid Calculi: Develop due to increased urine acidity.
• Cystine Calculi: Associated with cystinuria.
• Magnesium Ammonium Phosphate Calculi: Result from infections by urea-splitting bacteria.

Pathophysiology

• Calculi can obstruct the urinary tract, causing hydroureter and hydronephrosis.
• Obstruction sites include ureteropelvic junction, distal ureter, and ureterovesical junction.

Symptoms and Signs

• Asymptomatic in renal parenchyma unless obstructed or infected.
• Severe pain, nausea, vomiting, and gross hematuria when passing through ureter.
• Pain location indicates specific obstruction site.

Diagnosis

• Methods: Urinalysis, imaging (CT preferred), calculus composition testing.
• Differential diagnoses include peritonitis, cholecystitis, bowel obstruction, and pancreatitis.

Treatment

• Pain Relief: Opioids, ketorolac.
• Facilitate Passage: Alpha-receptor blockers like tamsulosin.
• Surgical Options: Shock wave lithotripsy, endoscopic removal.

Prevention

• Fluid Intake: At least 2.5 liters of urine daily.
• Medication: Thiazide diuretics, potassium citrate.
• Diet: Reduce animal protein, manage sodium and potassium intake.

Key Points

• The majority (85%) of stones are calcium-based.
• Even small calculi (2-5 mm) can cause obstruction.
• Treatments focus on pain relief and facilitating stone passage.
• Prevent future occurrences with dietary changes and medication based on stone composition.