Urinary Diseases of Exotic Pets Flashcards
Basic kidney functions
Nitrogenous waste excretion
Osmotic balance
Acid-base balance
Endocrine Functions
Nitrogenous waste excretion
Ammonia (NH3) is a byproduct of amino acid metabolism
NH3 -> NH4+ (ammonium) at physiologic pH
Both NH3 and NH4+ are toxic
Animals can be classed as:
- Ammonotelic (excrete NH3 or NH4+ unchanged)
- Ureotelic (excrete Urea)
- Uricotelic (excrete Uric Acid)
Small herbivores
Rabbits and rodents Kidneys are unipapillate 1 papilla and 1 calyx enter ureter directly Ureters to bladder to urethra Urinary bladder - Flaccid in rabbits - 3x more distensible than cats Urethra - Experimental model - same size as 1 year old boy
Rabbit calcium metabolism
Absorption of dietary calcium is passive
- Independent of vit. D
Calcium homeostasis regulated by kidneys
- Urine route of Ca excretion
- 45-60% ( <2% in other SM)
- Increased dietary intake, inc urinary excretion
Total blood calcium high, variable
Herbivore urine
Alkaline (pH > 8.0) - Herbivores Precipitates - Calcium carbonate -rabbit - Calcium oxalate - GP Turbidity - Hydration, health, dietary calcium, age, repro status Color - Red, orange, yellow, brown
Calciuria
Calcium N in urine Hypercalciuria - Large amount of sand or sludge in the bladder - Cystitis, urethral irritation Urolithiasis - Calculi in the urinary system - Cystic, urethral, renal, and ureteral - Contributing factors, but the cause isn't fully understood
Urolithiasis and urinary sludging
Predisposing factors May be unrelated to calciuria Non-obstruction - Genetics - Dehydration - Inactivity - Obesity - Urine retention - Cystitis - Changes in pH - Diet - Lack of latrine - Cystitis - Strep. pyogenes (GP) Obstruction Anything that causes urine retention - Adhesions - Abscesses - Tumors - Urine sludging
Typical Hx for Urolithiasis and urinary sludging
Limited exercise, obesity
Diet of pellets and alfalfa hay free-choice
- high in digestible calcium
CS of Urolithiasis and urinary sludging
Depression Lethargy Anorexia/ Weight loss Hematuria/Polyuria/Stranguria Hunched posture Teeth grinding Urinary incontinence Perineal dermatitis Pasty urine
Dx of urolithiasis and urinary sludging
Physical Examination
Palpation UB
Nephromegaly
- Hydronephrosis
Diagnostic testing for urolithiasis and urinary sludging
Imaging - Radiography - Ultrasonography Hematology - CBC . Infection, anemia - Chemistry panel . Renal function, hepatic health, blood calcium Not terribly useful
Urinalysis - SG 1.003-1.0036 - Trace protein, glucose - Crystals, RBCs, WBCs - Bacteria . Culture - R/O reproductive origin . Cysto collection
Tx of urolithiasis and urinary sludging
ID and correct causes Supportive care - Wound management . Soothing shampoos . Dry completely . Protect skin - Fluid therapy - Antibiotics . Enrofloxacin, TMS - Analgesia . Opiods, NSAIDS
Mgmt or urinary sludging and stones
Management of Urinary Sludging (and small stones) - Manual expression of bladder . Sedation or anesthesia - Diuresis IV/SQ fluids . Re-hydration . Dilute urine . Increase volume - Urohydropropulsion
Tx of Urolithiasis
Urolithiasis Stabilization Surgery - Cystotomy . Surgical spoon . Flush/suction . Culture bladder wall/stone - Nephrectomy . Renal pelvic calculus . PX guarded . Risk post-surgical complications
Prevention
Dilute urine \+ Increase water intake . Succulent greens . Fruit juices (sugar-free) . Flavored water Bowl vs. sipper bottle Limit dietary calcium - Grass hay pellets - No supplements Body condition - Exercise - Grazing - Promotes micturition
Prevention continued
Potassium citrate - Rabbits (33 mg/kg PO q 8 h) - GPs (10-30 mg/kg PO q 12 h) - Citrate salt highly soluble - Complexes with calcium - Reduces formation of calcium oxalate - Urine alkalinizer . Increasing solubility of calcium oxalate Monitoring - UA, rads q 6 months
Ferrets
x True carnivores x Not prone to crystaluria x Urinary calculi NOT common x Bacterial cystitis occasionally seen
Urethral Obstruction in male ferrets
Secondary to adrenal
disease
Paraprostatic cysts
Prostatic hyperplasia
Diagnosis of ferret urethral obstruction
Abdominal US/radiography
+/- contrast
UA - culture and sensitivity testing
Tx of ferret urethral obstruction
Historically treated with
perineal urethrostomy
- Obstruction is proximal to perineal urethra
- Not indicated
Must manage underlying adrenal disease Medical management - GnRH analog Surgical management - Adrenalectomy - Prostatic cyst drainage/marsupialization Manage post-renal obstruction Heavy sedation/anesthesia Catheterization - 3 fr - Tomcat cath = too big - Urethra fragile - Leaking into cysts?
Bird urinary tract
Urinary tract
- Anatomically simple
- Mammalian and reptilian function
Bird urinary system
URINARY SYSTEM
2 kidneys
- Dorsal body wall - renal fossa of synsacrum
- 3 lobes
- No demarcation between cortex and medulla
- No renal pelvis
- Collecting ducts drain lobules into ureters
- Ureters to urodeum
Bird urinary system continued
URINARY SYSTEM
Lobules
- Large area of cortical tissue
. Reptilian and mammalian nephrons
- Small area of medullary tissue
. Loops of Henle, collecting ducts, capillary network
Reptilian nephrons (90%)
- Excrete uric acid through proximal convoluted tubular
excretion
Mammalian nephrons (10%)
- Located in cortical area but loops of Henle in medullary area
- Forming and concentrating urine through glomerular
filtration
More bird urinary system
Renal portal blood undergoes tubular
secretion, clear urates
- Glomerular filtration does not clear urates
Urine product contains urine and urates
- Insoluable waste uric acid vs. ammonia
- Independent of hydration status*
Bird urinary disorders
Clinical signs - Polyuria - Polydipsia - Oliguria/anuria - Uric acid deposition in tissues -Hind limb paresis/paralysis - Systemically ill . Lethargy . Ruffled feathers . Anorexic . Dehydrated
Diagnostic testing for bird urinary disorders
Diagnostics for Urinary Disorders - Multi-modal - Hematology . CBC * Inflammation * Infection . Plasma Chemistry
Diagnostic testing for bird urinary disorders
Plasma Chemistry
- Elevated uric acid (>10 mg/dl psittacines)
. 70% of renal tissue affected
. Other causes: high protein meal, muscle catabolism, dehydration (mild elevation)
- Inc phosphorus, dec calcium (Normal - 1.5-2 Ca:l Pin)
- BUN, creatinine - non- diagnostic for renal disease
. May be indicators of
dehydration and renal
perfusion
- Potassium
. Increase in acute renal disease
. Sample processing
. Cell leakage
- Sodium and chloride
. Dehydration
- AST/CK
. Muscle wasting if chronically debilitated
More diagnostic testing for bird urine
Urinalysis Fecal contamination unavoidable Collect on wax paper - Separate urine Sediment evaluation limited to casts - granular, cellular, hyaline - uric acid crystals Specific gravity 1.005- 1.020 g/uL - Polyuria secondary to renal disease = isosthenuric - Polyuria secondary to hepatic disease = hyposthenuric pH 6.5-8.0 - protein - glucose
Other bird diagnostics
Rads
Culture
Endoscopy
Bird Tx
Renal disease - Treat etiology - Manage the renal failure . Birds often require critical care and hospitalization Goals of therapy - Dec uric acid in body . Decrease production . Enhance elimination
Bird tx continued
Fluid therapy - Little effect on uric acid level . Support patient . Perfuse kidneys Feed diet low in protein Phosphorus binders - Aluminum hydroxide Calcium carbonate Na restricted diets contraindicated - Na inc solubility of uric acid Allopurinol - 10-15 mg/kg BID - Inhibits uric acid formation Colchicine/probenicid combo - Dec inflammation, and dec uric acid Omega 3 FA
Etiologies of Bird problems
Bacterial nephritis - Ascending infections from cloaca - Reproductive activity - Hematogenous spread - Inflammatory leukogram - Antimicrobial therapy . Avoid Sulfas** - Excretion via same route as uric acid . Avoid nephrotoxic drugs - Aminoglycosides
More etiologies of bird problems
Gout - Articular . Uric acid tophi deposited in joints - Chronic renal failure . Very painful . Analgesia . Consider euthanasia - Visceral . Uric acid deposited in viscera - Acute renal failure - Difficult to diagnose and treat
Renal neoplasia of birds
Neoplasia, budgies over-represented Avian kidney has 3 lobes, ischiatic nerve between cranial and middle lobes Presenting signs include: lameness, abdominal distension Biopsy and histopathology diagnostic Radiography - must differentiate between gonad and cranial pole of kidney
Reptiles
Kidneys: - Paired - Lobulated, Elongated . Squamates - Location . Pelvic canal . Coelomic cavity
Reptile Urinary system
Ureters Urodeum Urinary bladder - Absent in crocodilians and snakes - Chelonians water resorption Urine flow
Reptilian urinary disorders
Clinical signs - Muscle tremors - Dehydration - Wasting (CRF) . Anorexia - Weak and depressed - Palpable kidneys . Digital- cloaca . Externally . Constipation - Edema
Diagnostic testing of reptiles
Similar to birds Hematology - CBC * PCV - Dehydration * Leukocytosis - Reference ranges?
Diagnostic testing of reptiles
Urinalysis Cystocentesis or catheter Sample not sterile - Culture: + or - Color- clear to straw - Green- biliverdin (liver) Specific gravity - 1.003-1.014 (low normally) - Increased with renal disease pH: herbivore- alkaline; carnivore- acidic Bilirubin, ketones: negative Glucose, protein: none to low Bacteria- common Crystals- amorphous urates normal; calcium oxalates: renal disease Cells- few RBC, few renal tubular, squamous, transitional Casts- renal compromise**
Other diagnostic tests of reptiles
Radiographs - Cranial extension of kidney from pelvic canal - Negative contrast . Air into coelomic cavity . (10ml/kg) Ultrasound - Scales . Ultrasound gel or water bath Biopsy - Transcutaneous tru-cut - Exploratory coeliotomy: cranial
Tx goals in reptiles
Stabilize patient
Correct problems
Protect remaining functional kidney
Tx of reptiles
Correct environment and diet Fluid therapy - Support, not diuresis . Assess dehydration: maintenance plus deficit . Maintenance: 25-40 ml/kg/day . Route: PO, SQ, 10, IV - Shock: up to 5 ml/kg/hr - Acute renal failure . May cause cardiac overload b/c delayed return to function
Tx of reptiles continued
Hypocalcemia
- Treatment for secondary Hyperparathyroidism
. IO/IV: calcium gluconate (400 mg/kg/day)
. Oral preferred when stabile
- Calcium glubionate
Phosphate binders Allopurinol (Reduce uric acid)
Colchicine/Probenecid
Reduce protein catabolism
Lower protein diet
Therapy for reptiles
Vitamin D - Controversial - Humans used to reduce PTH . Reduce renal toxicity without hypercalcemia Antimicrobials - Culture and Sensitivity Omega 3 FA - Anti-inflammatory effect
Suspected etiologies of reptiles
Gout - Limit uric acid secretion - Overwhelming production - Severe dehydration Bacterial diseases - Gram-negative opportunists . Microthrombi Other infectious - Fungal - Parasitic . Protozoa - Cryptosporidiosis . Trematodes . Nematodes Viral - IBD- snakes Neoplasia
More suspected etiologies of reptiles
Nutritional - High protein diets - Limited water, humidity - Hypervitaminosis D Toxic compounds (e.g., aminoglycosides) Amyloidosis - Low molecular weight amyloid - Chronic antigenic stimulation Trauma
