canine and feline urolithiasis. magnesium ammonium phosphate calcium oxalate urate cystine calcium...
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Canine and Feline Urolithiasis
Magnesium ammonium phosphateCalcium oxalateUrateCystineCalcium phosphateSilicateMixed stones
Canine UrolithiasisPrevalence (%)
1986 1990 1994Struvite 67.0 57.0 49.5Calcium oxalate 6.8 19.8 32.7Urate 5.1 5.5 8.0Cystine 2.4 1.6 1.0Calcium phosphate 3.0 1.6 0.6Mixed/Compound 11.9 12.6 7.4
Feline Urolithiasis Prevalence (%)
1986 1990 1996Struvite 85.0 66.0 36.4Calcium oxalate 3.0 16.0 53.4Urate 1.8 6.1 4.9Cystine 0.0 0.1 0.1Calcium phosphate 2.0 2.9 0.6Mixed/compound 5.2 5.9 3.4
Canine and Feline UrolithiasisPathogenesis
labile region
critical supersaturation
metastabile supersaturation
saturation, Ksp
undersaturation
increasingactivityproduct
Canine and Feline UrolithiasisPathogenesis
Activity ProductConcentration of crystal constituentsConcentration of other solutesUrine pHIonic strength
Feline Lower Urinary Tract DiseasePathogenesis
UrolithsUrethral plugs
Large quantity of matrix ( > 50% matrix)Mixed with crystals or without crystals
Canine and Feline UrolithiasisClinical Diagnosis
AgeGenderBreedRadiograhic findings CrystalluriaUrinary pHPresence of infection
Canine and Feline UrolithiasisClinical Diagnosis
Urinary pH Alkaline
Struvite
Calcium apatite
Acid to neutral
Calcium oxalate
Cystine
Canine and Feline UrolithiasisClinical Diagnosis
Presence of Infection
Urease producing micro-organisms
Struvite Dogs most cases UTI Cats 1-2% UTI
Canine UrolithiasisUrease producing bacteria
2NH3 + CO2 NH2 =C=NH2 + H2O
O
=
Urease
NH4++ HCO3-NH3
+ H2O + CO2
Canine and Feline UrolithiasisTreatment & Prevention
TreatmentDietary & Medical dissolutionSurgicalNon-surgical retrieval
Prevention of recurrenceDietary modificationsWater intake
Canine and Feline UrolithiasisDietary management
Undersaturate the urineExcretion of building blocks
Urine volume
Urinary pH favorable to stone dissolution
Feline Lower Urinary Tract DiseaseStruvite & calcium oxalate
No single diet for both struvite and calcium oxalate
Conflicting actions of several key nutrients
Clinical diagnosis is essential
Feline Lower Urinary Tract DiseaseStruvite
Patient profileFemale Younger cat, < 7 yearsObeseIndoor, multi-cat householdLow water intakeMore alkaline urinary pH (> 6.5)
Feline Lower Urinary Tract DiseaseCalcium oxalate
Patient profileMale (neutered)Older cat > 4 years ObesePersian, Himalayan, BurmeseIndoor, urbanMore acid urinary pH
Feline Lower Urinary Tract Disease Calcium oxalate
Medical historyHistory of calcium oxalate, documented
by quantitative urolith analysisNo response to appropriate dietary struvite
therapy Inappropriate use of urinary acidifiers
Feline Lower Urinary Tract Disease Calcium oxalate
Treatment
SurgeryPrevention
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 DiseaseCalcium oxalate
Nutrient profilePotassium citrateUrinary pH 6.6-6.8Increased moisturePyridoxine (vitamin B6)Soluble fiberModerate magnesium
Feline Lower Urinary Tract Disease Struvite
Mg - NH4 - PO4 . 6H20
MagnesiumAmmoniumAnionic phosphate
Feline Lower Urinary Tract DiseaseStruvite
Dietary managementReduced magnesium
Less than 20 mg/100 kcal ME
Less than 0.1% (dry matter) Increased diuresis
Water
Sodium
Feline Lower Urinary Tract DiseaseStruvite
Dietary managementAcid urine pHAvoid over-acidification
Metabolic acidosis
Renal diseaseDissolution - urinary pH 5.9 - 6.1Prevention - normal acid urinary pH 6.2-6.4
Canine and Feline UrolithiasisUrinary acidification
Decrease in urine pH from 8.5 to 5.5 NH4+ - 1000 x Increase
PO4 3 - - 13 000 x decrease
Moderately acid urine pH : 6.2 - 6.4
Contra-indicaties voor verzurend dieet
• Nierinsufficiëntie
• Groei (ontkalking)
• Acidose
• Ca-oxalaat stenen
• Urineverzuurders toevoegen aan verzurend dieet
Feline Lower Urinary Tract DiseaseStruvite
Dietary managementFeed calculolytic diet exclusively1 - 2 monthsLonger if UTI is present If no reduction of calculi after 2 months,
surgery should be considered
Canine UrolithiasisStruvite
Mg - NH4 - PO4 . 6H20
Crystal DietMagnesium MagnesiumAmmonium ProteinAnionic phosphate Phosphorus
Canine UrolithiasisStruvite - Dissolution
NutrientsMinimize proteinReduce magnesiumReduce phosphorusStimulate water intakeIncrease sodium
Acidify urine
Canine UrolithiasisStruvite - Dissolution
% DM Normal Calculolytic Foods
DietProtein 15 - 60 7.6Magnesium 0.03 - 0.27 0.02Phosphorus 0.41 - 2.43 0.10Sodium 0.11 - 2.22 1.28Urinary pH 6.7 - 8.3 5.9 - 6.1
Canine UrolithiasisStruvite - Dissolution
Feed calculolytic diet exclusivelyTreat urinary tract infectionContinue treatment till 4 weeks after
radiographic dissolution
Canine UrolithiasisStruvite - Dissolution
Monthly evaluation Radiography Serum urea nitrogen (SUN) Urinalysis: crystals, culture bacteria
Owner compliance Struvite crystalluria SUN > 10 mg/dl
Canine UrolithiasisStruvite - Dissolution
Reasons for failureInsufficient timeNon-compliance by ownerUrinary tract infectionNon-Struvite urolith
Canine UrolithiasisStruvite - Treatment
Indications for surgeryObstructionAnatomical defectsNo response to medical treatmentDiet is contraindicated
Canine UrolithiasisStruvite - Treatment
Diet contra-indicationsSodium retention
Heart failure, hypertension, liver disease, nephrotic syndrome
Increased protein requirements
Pregnancy, lactation, growth, cats
Acidifing dietRenal insuff., metabolic acidosis, growth, Ca-ox.
Canine UrolithiasisStruvite - Prevention
Prevention of recurrenceUrinary acidificationModerate reduction of protein, Mg, PModerate sodium level
Canine UrolithiasisCalcium oxalate
Verminderen uitscheiding bouwstenen• CalciumCa-opname + CalciurieVitamine D3: Ca aborptie + indirect calciurieP: te laag: stimulatie Vit D3Na: stimulatie calciurieZure urine: stimulatie calciurie
• Oxalaat: spinazie, rubarber, chocolade
Canine UrolithiasisCalcium oxalate
Verhogen inhibitoren• Magnesium• pH urine:Alkalinserend: vb. K-citraatDierlijke eiwitten verzuren: hoge eiwitopname
vermijden
Andere: wateropname
Canine UrolithiasisCalcium oxalate - Prevention
Prevention of recurrenceAvoid excessive intake of proteinLow calcium intakeLow oxalate intakeLow sodium intakeAvoid urinary acidificationPotassium citrate
Canine Urolithiasis Ammonium urate - Treatment
DissolutionDietary managementAllopurinolUrinary tract infection
Canine UrolithiasisAmmonium urate - Treatment
Allantoin
Meat diets Xanthine
Uric acid
Uricase
(Defect in Dalmatians)
Xanthine oxidase
Allopurinol
+
+
Purine / Pyrimidine
(Nucleic acids &
Cell nuclei)
Canine UrolithiasisAmmonium urate - Treatment
Dietary managementAmmonium - Low protein Urate - Low purine
Muscle & organ tissue = high in purines
Egg & casein = low in purines
Alkalinize urine
Canine UrolithiasisAmmonium urate - Treatment
Advanced renal failure diet8 - 11 weeks required for dissolutionMonitor for urethral obstruction
Canine UrolithiasisAmmonium urate - Prevention
Prevention of recurrenceAdvanced renal failure diet
Low in protein & purines
Alkalinizing the urine
Allopurinol
Canine Urolithiasis Cystine - Composition = Cysteïne - Cysteïne
Genetische afwijking: gestoorde reabsorptie van
Cystine: weinig oplosbaarOrnithineLysine wateroplosbaarAlanine
Canine Urolithiasis Cystine - Treatment
DissolutionDietary managementD-Penicillamine2-MPG (Thiola)Urinary tract infection
Canine Urolithiasis Cystine - Treatment
Dietary managementLow Protein
Low in cystine, cysteine
Low sodiumAlkalinize urineAdvanced renal failure diet
Canine Urolithiasis Cystine - Treatment
DissolutionCystine + D-Penicillamine or 2-MPG
D-Penicillamine-Cysteine
2-MPG - Cysteine
Solubility x 50
Canine Urolithiasis Cystine - Prevention
Prevention of recurrenceInborn error do not breedAdvanced renal failure diet2-MPG 15 mg/kg BID
orD-Penicillamine 10 mg/kg BID
Gemengde stenen
Ca-oxalaat & struviet Primair vs. secundair
irritatie - ontsteking
Ca-oxalaat
secundaire infectie
ureasevorming
pH & NH4+
Struvite
Canine and Feline UrolithiasisConclusionCorrect differential diagnosis is
important for success of treatmentUrolithiasis has an underlying cause
which should be further investigatedDietary versus surgical treatment is
decided based on stone type, location and medical factors.