Canine and Feline Urolithiasis

Magnesium ammonium phosphate Calcium oxalate Urate Cystine Calcium phosphate Silicate Mixed stones

Canine Urolithiasis Prevalence (%) Struvite Calcium oxalate Urate Cystine Calcium phosphate Mixed/Compound

Feline Urolithiasis Prevalence (%) Struvite Calcium oxalate Urate Cystine Calcium phosphate Mixed/compound

Canine and Feline Urolithiasis Pathogenesis Concentration of building blocks Urinary pH Time

Canine and Feline Urolithiasis Pathogenesis labile region critical supersaturation metastabile supersaturation saturation, Ksp undersaturation increasing activity product

Canine and Feline Urolithiasis Pathogenesis Activity Product Concentration of crystal constituents Concentration of other solutes Urine pH Ionic strength

Feline Lower Urinary Tract Disease Pathogenesis Uroliths Urethral plugs 3Large quantity of matrix ( > 50% matrix) 3Mixed with crystals or without crystals

Canine and Feline Urolithiasis Clinical Diagnosis Age Gender Breed Radiograhic findings Crystalluria Urinary pH Presence of infection

Canine and Feline Urolithiasis Clinical Diagnosis Urinary pH 3Alkaline Struvite Calcium apatite 3Acid to neutral Calcium oxalate Cystine

Canine and Feline Urolithiasis Clinical Diagnosis Presence of Infection Urease producing micro-organisms Struvite 3Dogs most cases UTI 3Cats 1-2% UTI

Canine Urolithiasis Urease producing bacteria 2NH 3 + CO 2 NH 2 = C = NH 2 + H 2 O O = Urease NH HCO3 - NH 3 + H 2 O + CO 2

Canine and Feline Urolithiasis Treatment & Prevention Treatment Dietary & Medical dissolution Surgical Non-surgical retrieval Prevention of recurrence Dietary modifications Water intake

Canine and Feline Urolithiasis Dietary management Undersaturate the urine Excretion of building blocks Urine volume Urinary pH favorable to stone dissolution

Feline Lower Urinary Tract Disease Struvite & calcium oxalate No single diet for both struvite and calcium oxalate Conflicting actions of several key nutrients Clinical diagnosis is essential

Canine and Feline Urolithiasis Struvite Ca Oxalate pH Mg PO 4 Na Lower Urinary Tract Disease

Feline Lower Urinary Tract Disease Struvite Patient profile Female Younger cat, < 7 years Obese Indoor, multi-cat household Low water intake More alkaline urinary pH (> 6.5)

Feline Lower Urinary Tract Disease Calcium oxalate Patient profile Male (neutered) Older cat > 4 years Obese Persian, Himalayan, Burmese Indoor, urban More acid urinary pH

Feline Lower Urinary Tract Disease Calcium oxalate Medical history History of calcium oxalate, documented by quantitative urolith analysis No response to appropriate dietary struvite therapy Inappropriate use of urinary acidifiers

Feline Lower Urinary Tract Disease Calcium oxalate Treatment Surgery Prevention Avoid dietary and medical risk factors

Feline Lower Urinary Tract Disease Calcium oxalate Dietary risk factors Excess vitamin C & D Acidification Ad libitum feeding Moderate protein = protective Very low protein = risk factor Low fiber Feeding dry Excessive Ca & P restriction

Feline Lower Urinary Tract Disease Calcium oxalate Nutrient profile Potassium citrate Urinary pH Increased moisture Pyridoxine (vitamin B6) Soluble fiber Moderate magnesium

Feline Lower Urinary Tract Disease Struvite Mg - NH 4 - PO 4. 6H 2 0 Magnesium Ammonium Anionic phosphate

Feline Lower Urinary Tract Disease Struvite Dietary management Reduced magnesium Less than 20 mg/100 kcal ME Less than 0.1% (dry matter) Increased diuresis Water Sodium

Feline Lower Urinary Tract Disease Struvite Dietary management Acid urine pH Avoid over-acidification Metabolic acidosis Renal disease Dissolution - urinary pH Prevention - normal acid urinary pH

Canine and Feline Urolithiasis Urinary acidification Decrease in urine pH from 8.5 to 5.5 3NH x Increase 3PO x decrease Moderately acid urine 3pH :

Contra-indicaties voor verzurend dieet Nierinsufficiëntie Groei (ontkalking) Acidose Ca-oxalaat stenen Urineverzuurders toevoegen aan verzurend dieet

Feline Lower Urinary Tract Disease Struvite Dietary management Feed calculolytic diet exclusively months Longer if UTI is present If no reduction of calculi after 2 months, surgery should be considered

Canine Urolithiasis Struvite Mg - NH 4 - PO 4. 6H 2 0 CrystalDiet MagnesiumMagnesium AmmoniumProtein Anionic phosphatePhosphorus

Canine Urolithiasis Struvite - Dissolution Nutrients Minimize protein Reduce magnesium Reduce phosphorus Stimulate water intake Increase sodium Acidify urine

Canine Urolithiasis Struvite - Dissolution % DM Normal Calculolytic FoodsDiet Protein Magnesium Phosphorus Sodium Urinary pH

Canine Urolithiasis Struvite - Dissolution Feed calculolytic diet exclusively Treat urinary tract infection Continue treatment till 4 weeks after radiographic dissolution

Canine Urolithiasis Struvite - Dissolution Monthly evaluation Radiography Serum urea nitrogen (SUN) Urinalysis: crystals, culture bacteria Owner compliance Struvite crystalluria SUN > 10 mg/dl

Canine Urolithiasis Struvite - Dissolution Reasons for failure Insufficient time Non-compliance by owner Urinary tract infection Non-Struvite urolith

Canine Urolithiasis Struvite - Treatment Indications for surgery Obstruction Anatomical defects No response to medical treatment Diet is contraindicated

Canine Urolithiasis Struvite - Treatment Diet contra-indications Sodium retention Heart failure, hypertension, liver disease, nephrotic syndrome Increased protein requirements Pregnancy, lactation, growth, cats Acidifing diet Renal insuff., metabolic acidosis, growth, Ca-ox.

Canine Urolithiasis Struvite - Prevention Prevention of recurrence Urinary acidification Moderate reduction of protein, Mg, P Moderate sodium level

Canine Urolithiasis Calcium oxalate Treatment Surgery Hydropropulsion

Canine Urolithiasis Calcium oxalate Verminderen uitscheiding bouwstenen Calcium Ca-opname + Calciurie Vitamine D3: Ca aborptie + indirect calciurie P: te laag: stimulatie Vit D3 Na: stimulatie calciurie Zure urine: stimulatie calciurie Oxalaat: spinazie, rubarber, chocolade

Canine Urolithiasis Calcium oxalate Verhogen inhibitoren Magnesium pH urine: Alkalinserend: vb. K-citraat Dierlijke eiwitten verzuren: hoge eiwitopname vermijden Andere: wateropname

Canine Urolithiasis Calcium oxalate - Prevention Prevention of recurrence Avoid excessive intake of protein Low calcium intake Low oxalate intake Low sodium intake Avoid urinary acidification Potassium citrate

Canine Urolithiasis Calcium oxalate Prevention of recurrence Advanced renal failure diet

Canine Urolithiasis Ammonium urate - Treatment Dissolution Dietary management Allopurinol Urinary tract infection

Canine Urolithiasis Ammonium urate - Treatment Allantoin Meat diets Xanthine Uric acid Uricase (Defect in Dalmatians) Xanthine oxidase Allopurinol  + + Purine / Pyrimidine (Nucleic acids & Cell nuclei)

Canine Urolithiasis Ammonium urate - Treatment Dietary management Ammonium - Low protein Urate - Low purine Muscle & organ tissue = high in purines Egg & casein = low in purines Alkalinize urine

Canine Urolithiasis Alkalinize urine NH 3 NH 4 + H+H+ Decreases NH 4 + concentration

Canine Urolithiasis Ammonium urate - Treatment Advanced renal failure diet weeks required for dissolution Monitor for urethral obstruction

Canine Urolithiasis Ammonium urate - Prevention Prevention of recurrence Advanced renal failure diet Low in protein & purines Alkalinizing the urine Allopurinol

Canine Urolithiasis Cystine - Composition = Cysteïne - Cysteïne Genetische afwijking: gestoorde reabsorptie van Cystine: weinig oplosbaar Ornithine Lysine wateroplosbaar Alanine

Canine Urolithiasis Cystine - Treatment Surgery Dissolution

Canine Urolithiasis Cystine - Treatment Dissolution Dietary management D-Penicillamine 2-MPG (Thiola) Urinary tract infection

Canine Urolithiasis Cystine - Treatment Dietary management Low Protein Low in cystine, cysteine Low sodium Alkalinize urine Advanced renal failure diet

Canine Urolithiasis Cystine - Treatment Dissolution Cystine + D-Penicillamine or 2-MPG  D-Penicillamine-Cysteine 2-MPG - Cysteine Solubility x 50

Canine Urolithiasis Cystine - Treatment Urine pH SolubilityUrine pH 1.0 x x x8.0

Canine Urolithiasis Cystine - Prevention Prevention of recurrence Inborn error do not breed Advanced renal failure diet 2-MPG 15 mg/kg BID or D-Penicillamine 10 mg/kg BID

Gemengde stenen Ca-oxalaat & struvietPrimair vs. secundair irritatie - ontsteking Ca-oxalaat secundaire infectie ureasevorming pH  & NH 4 +  Struvite

Canine and Feline Urolithiasis Conclusion Correct differential diagnosis is important for success of treatment Urolithiasis has an underlying cause which should be further investigated Dietary versus surgical treatment is decided based on stone type, location and medical factors.

Canine and Feline Urolithiasis Conclusion One diet can not work for all types of uroliths Preventive diets should provide balanced nutrition Avoid over-acidification of the urine