Exotics Flashcards
Briefly describe avian renal anatomy
- large pair of lobulated kidneys surrounded by abdominal air sac
- Reptilian and mammalian nephrons
- No urinary bladder, empty into cloaca
- Reflux of urine into coprodeum and colon aids water reabsorption
- Ischiatic (and others) nerves run through and dorsal to kidneys
List the common causes of primary renal disease in birds
- Hypervitaminosis A
- Hypervitaminosis D3
- Dehydration
- Heavy metal toxicity
- Infection (e.g. extension of air sacculitis, systemic spread, ascending infection)
- Neoplasia
- Amyloidosis and lipidosis
What condition may lead to amyloidosis in birds?
Bumblefoot
Compare the types of nephrons found in the avian kidney
- Reptilian: no LoH, cortex only
- Mammalian: LoH, extends from cortex to medulla
Compare visceral and articular gout
- Visceral: uric acid tophi in soft tissues e.g. liver, pericardium, kidney
- Articular: uric acid tophi in and around joints, often feet and hocks
Describe the development of gout in birds and reptiles
- Decreased uric acid secretion: dehydration, renal tubular disease, hypovit A, infection/inflammation, post-renal obstruction
- Increased uric acid production: excess dietary protein
Outline the typical presentation of avian renal disease
- early signs often subtle
- Advanced signs: non-specific, fluffed up, lethargic, eyes closed
- More specific signs: PUPD, uni or bilateral HL paresis, haematuria, feather picking over kidneys, gout, leaning when standing
What factors is the level of dehydration in a bird assessed on?
- PCV/TS
- Skin elasticity
- MM moisture
- Brightness of the eye
- Ulna refill time
- Most sick birds are 5-10% dehydrated at presentation
List the diagnostic tests that may be used in the investigation of urinary tract disease in birds
- Uric acid
- Blood biochem and haematology
- Urinalysis
- Murexide test
- Radiogaphy
- Ultrasound
- Endoscopy
- (MRI/CT)
Outline the interpretation of haem and biochem in a bird with urinary tract disease
- Uric acid: elevated once >70% renal function lost, post-prandial rise in carnivores
- Urea as indicator of dehydration only
- Creatinine not useful
- Phosphorous: may be elevated in renal failure (and haemolysis)
- Calcium: reduced in renal failure
- Potassium: elevated in acute renal failure
- Sodium: hyper in dehydration, hypo in renal failure
Discuss the use of urinalysis in the investigation of urinary tract disease in birds
- Difficult to obtain pure sample
- Normal urine contains crystals and bacteria
- Look for renal casts, abnormal cells, glucose etc.
- USG species specific (aroun 1.005-1.020)
Outline the murexide test in birds
- Confirmation of gout
- Sample of material e.g. joint aspirate mixed with nitric acid and dried over flame
- Add 1 drop concentrated ammonium
- Mauve = uric acid (positive)
Outline the use of radiography in the investigation of urinary tract disease in birds
- VD and lateral, wings and legs extended
- Normal kidneys difficult to see, but have small rim of air dorsal to kidneys on lateral view (absent in renomegaly)
- May see eggs, cloacaliths, evidence of gout in rest of body
Evaluate the use of ultrasonography in the investigation of urinary tract disease in birds
Useful to look at architecture of kidney but often severely hampered by air sacs
Evaluate the use of endoscopy in the investigation of urinary tract disease in birds
- Most useful to visualise and biopsy kidneys
- Can assess most other organs at the same time
- Requires specific training and expertise
Outline the supportive care for the average sick bird
- Keep warm (29-30˚C)
- Quiet, away from predators
- Dim lighting
- Oxygen
- Nebulise saline for 20-30mins
- Fluid therapy (SC, IV, IO but not humerus or femur)
- metoclopramide 0.5-1mg/kg IM q8-12hours if ileus
Outline a basic fluid therapy plan for a bird
- Maintenance fluids ~50ml/kg/day
- Rehydrate over 48 hours
- Day 1 and 2: maintenance + half calculated rehydration fluids
- Day 3: maintenance fluids
List the treatment factors that should be considered for a bird with urinary tract disease
- General supportive care
- Assessment of dehydration
- Fluid therapy
- Food
- Antibiotics
- Allopurinol
Outline the nutrition for a bird with urinary tract disease
- High fat and carb, lower protein
- Ensure balanced diet for species
- Vitamin supplementation may be needed in some
Discuss the use of antibiotics in a bird with urinary tract disease
- Aminoglycosides nephrotoxic
- TMPS and amoxyclav can be nephrotoxic if bird is dehydrated
Discuss the use of allopurinol in a bird with urinary tract disease
- Xanthine oxidase inhibitor
- May help reduce hyperuricaemia, thereby reducing gout
- BUT may worsen gout in some species e.g. Red tail hawk
Briefly outline the reptilian renal anatomy
- Renal portal system similar to birds
- No LoH
- Urinary bladder in chelonia and some lizards
- Urine can be modified in bladder/colon
- Salt glands present in some desert and aquatic species
List the common causes of reptile renal disease
- Inadequate husbandry: humidity, temp, diet, supplements
- Chronic dehydration
- Infection e.g. bacterial, parasitic
- Neoplasia
How might chronic dehydration occur in a reptile?
Some need to drink from droplets coming down, water bowl useless, will get dehydrated
Outline the clinical signs of renal disease in reptiles
- Early signs often subtle
- Advanced signs: non-specific, lethargy, anorexia, weight loss, dysecdysis, abnormal thermoregulation
- Other signs: HL weakness, constipation, gout, oedema
List the diagnostic tests that can be used in the investigation of renal disease in reptiles
- Blood biochem and haematology
- Urinalysis
- Murexide test
- Iohexol excretion test
- Radiography
- Ultrasound
- Endoscopy
- (MRI/CT_
Outline the interpretation of blood biochem and haematology in reptiles with renal disease
- Uric acid elevated once >70% function lost, post-prandial rise with carnivores, little to no effect of dehydration
- Urea: elevated in dehydration or anorexia, renal disease if uric acid also elevated, more useful in desert tortoises
- Creatinine not very useful
- Phos: may be elevated, renal disease more likely if phos > total calcium , may be elevated as a result of haemolysis
- Calcium: reduced in CRF, normal or increased in ARF
- Potassium elevated in ARF and haemolysis
Outline urinalysis in the investigation of renal disease in reptiles
- Try to avoid faecal contamination
- Normal urine contains crystals and bacteria
- Look for renal casts, cells, parasites e.g. Hexamita
- pH may change from normal alkaline to acidic in anorexic herbivores and post hibernation
- Normal USG: 1.003-1.014
Describe the iohexol test used in the investigation of renal disease in reptiles
- Excreted solely by glomerular filtration, good indicator of renal function
- Inject iohexol IV, take blood 4, 8 and 24 hours later
- Not routinely used
Outline the use of radiogaphy in the investigation of renal disease in reptiles
- 2-3 views, VD, horizontal beam lateral +/- horizontal beam craniocaudal (chelonia)
- Kidneys often difficult to see unless enlarged or increased density
- look for changes in size, density, contour
- Eggs, uroliths, bone density also assessed
Outline the basic treatment of all sick reptiles
- Heat: keep at preferred body temp
- Fluid: ensure correct humidity and appropriate access to water e.g. bath, spray
- Light: appropriate supplementation for the species
How can dehydration be assessed in reptiles
- PCV/TS
- Skin elasticity
- MM moisture
- Brightness of eye
- Appearance of urine and urates
- Assume most are 5-10% dehydrated or more at dehydration
What fluids are used in reptiles?
- Hartmann’s
- 0.9% saline/electrolyte + amino acid at ratio 4:1
- 2.5% dextrose in 0.45% saline OR 4% dextrose in 0.18% saline
- 9:1 ratio of 5% glucose with 0.9% saline (9 parts) to sterile water (1 part)
Outline the adminstration of fluids to reptiles
- Warm fluids to upper level of POTZ
- Rehydration may take up to 10-14 days
- 10-30ml/kg/day for maintenance + 25% of fluid deficit
- Lizards: cephalic, jugular, ventral tail vein
- Chelonians: jugular
- Snakes: jugular, intra-cardiac
- All species: intracoelomic, subcut, oral routes
- Intraosseous other than snakes
- Daily bathing
Discuss the nutritional managment of reptiles with renal disease
- Oesophagostomy tube routine procedure, can be with local, sedation or GA but all need analgesia, can be left in place for years
- Amount via O tube: Lizards: 10-20ml/kg, snakes 15-30ml/kg, tortoises 5-15ml/kg
- Balanced diet for that species, generally high fat and carb, lower protein
Discuss the use of antibiotics in the treatment of renal disease in reptiles
- Most infections due to G-ve bacteria
- Aminoglycosides are nephrotoxic
- Fluoroquinolones and ceftazadime commonly used
List adjunctive treatments that may be used for reptiles with renal disease
- Allopurinol (may help reduce hyperuricaemia)
- Anabolic steroids
- B vitamins
- Phosphate binders
