Renal disease in birds and reptiles

• Urinary differences in birds and reptiles overview

  They gave limited ability to concentrate their urine.

  All birds and most reptiles lack a urinary bladder (exceptions are Chelonia, chameleons).

  Urine may be modified in bladder in colon. So urine is not a goof indication of the kidneys function.

  Renal portal system exists.

  Nitrogen is excreted as uric acid.
• Clinical signs of renal disease in birds - non-specific

  Early signs of disease aer often sublet.

  Signs of advanced are often non-specific e.g. fluffed-up, lethargic, anorexic, dehydration.
• Clinical signs of renal disease in birds - specific

  PUPD

  Unilateral or bilateral hindlimb paresis/paralysis, could show as the bird not perching properly.

  Hameaturia

  Feather plucking over kidneys.

  Articular (affecting joints) and visceral (internal) gout.
• Clinical signs of renal disease in reptiles - non-specific

  Early signs of disease are often subtle and non-specific:

  • Lethargy
  • Anorexia
  • Weight loss
  • Dysecdysis
  • Abnormal thermoregulation/behaviour.
• Clinical signs of renal disease in reptiles - specific

  Hindlimb weakness

  Constipation (renomegaly in pelvic canal)

  Gout

  Oedema (nephrotic syndrome)

  PUPD are usually not a feature of renal disease.
• Clinical exam of reptiles and birds with renal disease

  Asses the patient from a far.

  Ensure you have every thing to hand.

  Inspect cage, dropping, food ect.

  Thorough history from owner.

  Birds - may need to place in warm, humidified oxygen cage first.

  Reptiles - ensure patient is kept warm.
• Clinical signs of dehydration in birds

  Mouth = mucus membranes are hard to, but they may look dry

  SKin= skin tent elasticity is not a reliable indicator in birds.

  Eyes = dull and sunken (skin around the eye wrinkled)

  Circulation = Basilic wing vein refill time is a good indicator.

  Weight loss - especially if sudden
• Clinical signs of dehydration in reptiles

  Skin = dry, wrinkled or puckered skin. Loss of skin elasticity and flexibilaity. Dysecdysis.

  Eyes = sunken, receded eyes.

  Musculoskeletal = generalised weakness and lethargy.

  Mouth = tacky or dry mucous membranes. Thick saliva.

  Celomic = doughy on palpation, constipation or infrequent defecation.

  Weight loss - especially if sudden.

  Appearance of urates and urine.
• Common causes of primary renal diseases in birds

  Inadequate diet

  Hypovitaminosis A

  Hypervitaminosis D3

  Lipidosis

  Heavy metal toxicity

  Infection (Primary or secondary from a systemic infection causing nephritis)

  Neoplasia

  Amyliodosis
• Common causes of primary renal disease in reptiles

  Inadequate husbandry:

  • Low humidity
  • Temperature
  • Diet (high protein)
  • Hypovitaminosis A
  • Hypervitaminosis D3

  Chronic dehydration

  Bacterial infection (primary or secondary from a systemic infection causing nephritis)

  Neoplasia
• Gout in birds and reptiles - overview

  Gout is a sign of renal failure in birds and reptiles.

  Visceral gout = accumulation of urate (uric acid) deposits in soft tissues e.g. liver, pericardium and kidney.

  Articular gout = accumulation of urate (uric acid) deposits in and around joints e.g. often feet and hocks.

  Gout occurs when uric acid secretion is decreased and/or uric acid production is increased.
• In gout in birds and reptiles increased Uric acid production is caused by?

  Excess dietary protein
• In gout in birds and reptiles decreased Uric acid secretion is caused by?

  Dehydration

  Renal tubular disease

  Hypovitaminosis A

  Infection/ inflammation

  Post-renal obstruction e.g. uroliths, egg binding.
• Biochemistry tests for renal dysfunction in birds and reptiles - urea

  Birds - May help assess dehydration but not kidney function.

  Reptiles - may be elevated in dehydration or anorexia. Renal disease likely if uric acid also raised
• Biochemistry tests for renal dysfunction in birds and reptiles - creatine

  Not very useful in birds or reptiles.
• Biochemistry tests for renal dysfunction in birds and reptiles - uric acid

  Elevated only when >70% kidney function is lost.

  Mild to no elevation in dehydration.

  Post-prandial rise in carnivorous birds and reptiles.

  • Fast carnivorous birds for 24 hours before sample.
  • Fast carnivorous reptiles for 24-36 hours before sample (most presented anorexic).
• Biochemistry tests for renal dysfunction in birds and reptiles - phosphorous

  Birds - may be elevated in renal failure (and haemolysis).

  Reptiles - may be elevated, renal failure more likely if phosphorous higher than total calcium. Hyperphosphataemia is often the first biochemistry abnormality.
• Biochemistry tests for renal dysfunction in birds and reptiles - calcium

  Birds - may be reduced in renal failure.

  Reptiles - may be reduced in chronic renal failure but normal or increased in acute renal failure.

  Measure ionised and total calcium in conjunction with albumin
• Biochemistry tests for renal dysfunction in birds and reptiles - potassium

  Elevated in renal failure (and haemolysis)
• Biochemistry tests for renal dysfunction in birds and reptiles - sodium

  Birds - hypernatraemia in dehydration and hyponatraemia in renal failure.
• Urinalysis in birds and reptiles - overview

  Difficult to obtain ‘pure/sterile’ sample. Hard to avoid faecal contamination.

  Normal urine contains crystals and bacteria.

  Look for renal casts, abnormal cells, glucose (birds), Hexamita parasite (reptiles).

  Urine can be modified after the kidneys in many exotic species.
• Urinalysis in birds and reptiles - Birds

  Specific gravity range 1.005-1.020 but is species specific.

  USG not very helpful in most cases.
• Urinalysis in birds and reptiles - reptiles


  pH may change from normal alkaline to acidic in anorexic herbivores and post hibernation.

  Specific gravity range 1.003-1.014 may elevate slightly in dehydration.

  USG not very helpful in most cases.
• Diagnostic tests in birds and reptiles - murexide test

  Test used to confirm gout.

  Sample of material (e.g. joint aspirate) is mixed with nitric acid and dried over flame.

  Add 1 drop concentrated ammonia.

  If turns mauve = uric acid.
• Radiography for renal problems in birds

  Two views - ventraldorsal and lateral (wings and legs extended).

  Normal kidneys difficult to see especially on VD view.

  Gonad and pelvis may obscure lateral view.

  Small rim of air dorsal to the kidneys on lateral view. This is absent in renomegaly.

  Look for changes in size, density and contour. Eggs, cloacaliths, evidence of gout and whole of body.

  
• Normal avian radiographs

  1 = lungs

  2 = heart

  3 = liver

  4 = ventriculus

  5 = intestinal loops

  6 = proventriculus

  7 = spleen

  8 = kidney

  9 = gonad

  
• radiograph diagnostic tests for reptiles

  2 or 3 views: ventrodorsal, horizontal-beam lateral +/- horizontal-beam craniocaudal (Chelonia).

  Kidneys often difficult to see unless enlarged or increased density.

  Look for changes in size, density and contour. Eggs, uroliths, gout and bone density (MBD).
• Treatment of renal disease in birds - over view

  Keep warm, quiet and away from predators.

  Fluid therapy:

  • SC, IV, IO depending on the severity of dehydration, the birds demeanour and whether the GI tract is functional.
  • Use clinical exam, PCV and TP to determine dehydration %.

  Commence oral fluids once the bird is more stable.

  Crop feed once bird tolerates oral fluids (build up)./
• Treatment of renal disease in birds - antibiotics

  Take care with antibiotics!!;

  • Aminoglycosides are nephrotoxic.
  • TMPS can potentially be nephrotoxic if a bird is severely dehydrated.

  Allopurinol (xanthine oxidase inhibitor):

  • May help reduce hyperuricaemia (take care in red tail hawks).

  Metoclopramide:

  • 0.5-1mg/kg IM q 8-12 hours if crop stasis.
• Renal treatment in reptiles - overview

  Heat: patient should be kept at preferred body temperature.

  Light: appropriate UV-B light for the species.

  Ensure correct humidity and appropriate access to water e.g. bath, spray.
• Renal treatment in reptiles - fluid therapy

  SC, IV, IO depending on hydration status.

  Use clinical exam, urates/urine, also PCV and TP to determine dehydration %.

  10-30ml/kg/day for maintenance + 25% of the fluid deficit daily.

  Rehydration. may take 10-14 days in severe cases.

  Overzealous fluid therapy can cause pulmoanry/ tissue oedema, hypokalaemia and death.

  All fluids should be warmed to the upper level of the preferred optimal temperature zone. Can add an electrolyte/ amino acid.
• Renal treatment in reptiles - bathing

  Should be performed daily in all inpatients.

  Encourage drinking, voiding urine/ faeces and some can suck fluid into the cloaca/ bladder.

  Can add medication or supplements to the bath e.g. Reptoboost.

  Close monitoring is essential to prevent drowning even in aquatic species.
• Renal treatment in reptiles - antibiotics

  Take care:

  • Mos infections are caused by gram negative bacteria.
  • Aminoglycosides are nephrotoxic.
  • Ceftazadime is commonly used.

  Allopurinol (Xanthine oxidase inhibitor):

  • May help to reduce hyperuricaemia.
• Prevention of renal disease in birds and reptiles - husbandry

  Correct husbandry (temperatures, humidity, lighting).

  Fed the correct, balanced diet.

  Correct use of supplements in insectivore reptiles to correct the Ca:P imbalance.

  Keep hydrated by offering daily fresh water correctly.

  Bathe reptiles regularly.
• Prevention of renal disease in birds and reptiles - hypovitaminosis A

  Prevent by giving a balanced diet with multivitamins, such as Nutrobal by Vetark (calcium, A, C, E, D3, K3 and group B vitamins).

  Herbivores can covert vitamin A from plant material.

  Typically an issue in omnivore or carnivore species. Carnivores have to get vitamin A from animals sources (e.g. liver).

  Only use injectable Vitamin A to treat hypovitaminosis A if severe, due to risks of over-dosing (toxicity).

  Will generally have other nutritional deficiencies as well due to imbalanced diet - so diet always needs correcting.