Pathophysiology of Disease: Chapter 16 ( ) RENAL DISEASE: RENAL STONES AND UT OBSTRUCTION Pathophysiology of Disease: Chapter 16 ( ) Jack DeRuiter, PhD Dept of Pharmacal Sciences April, 2000

Urinary Tract Obstruction: Common Causes (page 402) Obstructions of Ureter, Bladder Outlet or Urethra caused by: Structural malformations (Table 16-16) Inflammation and Trauma Tumor/Cancer of renal and neighboring structures Blood clots Pregnancy Neuropathy/Spinal Cord Disease Renal stones

Clinical Presentation: ( pages ) Flank Pain (+/-): –Distention of ureter, renal pelvis or capsule –Severity: proportional to distention Hematuria Azotemia: Bilateral Obstruction Decreased urine production –Anuria: Bilateral obstruction

Etiology ( page 402) Hypercalciuria (75%): Calcium oxalate stone –Heredity (Idiopathic; most common), Neoplasm, Bowel surgery Struvite Stones (10-15%): Magnesium, Ammonium, Phosphate –UT Infections: Urease-Producing microbes (Proteus) Hyperusicosuria (5-8%): Uric acid stones –Gout, Heredity, Malignancy, Lesch-Nyhan Syndrome Cystinuria (1%): Defective amino acid transport

Pathology and Pathogenesis (page 402) Cause: Nucleation and precipitation of salts in renal structures Contributing Factors –Dehydration: Less salt “dissolved” –High protein diets: Acidosis and Inc GFR: Ca –High sodium diet: Calcium oxalate –Essential Hypertension: Hypercalciuria Dietary calcium and oxalate does not enhance likelihood of stone formation in most patients

Preventative/Protective Measures (page 402) Fluids: Enhanced dissolution of salts Citrate: chelates Ca to form soluble complex which is excreted Magnesium: Salt replacement? Dietary fiber: Indirect Effect?

Treatment and Complications: Pages Stone passage: Fluids, bed rest and analgesia Treatments (Table 16-17): –Diuretics, urine alkalinization, allopurinol, etc Complications: –Hydronephrosis/Complete obstruction –Infection or abscess behind obstruction –Renal damage due to repeated stone formation –Hypertension: increased renin production