Oxalate nephrosis and its management in a captive environment Dr. Mel Burford-Pettigrew | Senior Koala Keeper
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Koalas in South Australia
1923: Professor Wood Jones releasing the first Koala introduced onto Kangaroo island.
Photo: State Library of South Australia, B49818
Threats to Koalas in South Australia
• Low genetic diversity
• Habitat Loss/over population
• Kidney Disease
• Sarcoptic Mange
• Urbansiation Source: Byron Manning
Source:
http://hancockwatch.nfshost.com/docs/koala2005a.ht
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Oxalate Nephrosis
• Not a common cause of mortality
in koalas in the eastern states
• The Mount Lofty Ranges koala
population in SA has a high
occurrence of renal dysfunction
and oxalate nephrosis continues
to be one of the predominant
issues facing the population Source:
https://www.vettails.com/vettails/2015/9/30
/calcium-oxalate-nephrosis-what-does-that-
mean
Source: Byron Manning
What Causes Oxalate Nephrosis?
Possible Theories
- Genetics
- Diet
- Liver function
More Research Required!
How to determine a healthy koala
from a renal compromised koala?
• Demeanour
• Position sitting in or
sleeping
• Hydration
• Body Condition
• Faeces
• Gut Fill
• Coat, skin, nails
• Urine (USG, Oxalates)
• Drinking
• Eyes
• Gum/Nasal Colour
• Body Temperature
• Breathing
• Feeding
• Pain (Kidney Pain)
• Movement
Urine Analysis
Dip stick
- pH
- Protein
- Blood
- Leukocytes
Refractometer
-Healthy =
>1.050
Microscope
- Oxalate crystals
Categories of Renal Compromised Koalas
LOW DEPENDENCY
CARE Mild dehydration
+1 protein
No sediment
USG 1.040
Attitude is becoming altered. Still
bright, alert and responsive
Ears and head are up – in a normal
sitting and sleeping position
Normal capillary refill
Reduced eating and decreased
faecal output (<100 pellets per day)
Low gut fill
Minimal treatment
supplementary feeding,
ongoing drug and short
term fluid therapy
HIGH DEPENDENCY
CARE Moderately dehydrated
+2 protein
≥+1 sediment
SG 1.030
Depressed but responsive to noise
and movement
Tires quickly and appears lethargic
Ears starting to droop but sitting
and sleeping in a normal position
Normal capillary refill or may
becoming pale
Minimal eating
Poor gut fill
Minimal faecal output, possible
dry
Long term treatment
Drug and fluid therapy for
life of the koala, without
which the disease will
advance
END STAGE RENAL
FAILURE Severely dehydrated
+4 protein
≥+4 sediment
USG 1.020
Non responsive to touch, noise. May
be in a semi-coma
Curled in ball; minimal response to
handling
Blueish grey or red gums
Not eating
No gut fill – high probability of
torsion if tube feed
Almost no faecal output; Gut has
likely gone into ileus
May be grinding teeth
Emaciated
Euthanasia
Due to advanced
stages of disease no
drug or fluid therapy
will alter reverse the
damage
Ongoing Assessment
Gut fill
Demeanour
Behavioural assessment
Faecal output
Sedimentation in enclosure
Feeding behaviour and amount
Mouth, gum and chin colour
Weight
Urine analysis (when required)
Mrs B
• Showed no signs of kidney
dysfunction until she was 8
years old
• She had a 6 month old joey
when she showed her first
symptoms:
• Drinking
• USG 1.030
• Oxalate crystals in urine
Issac
• Orphan from a severe weather
event and was handraised
from 385gms
• His first symptoms appeared
when he was 800gms:
• Flat in attitude
• Reduce faecal output
• Thirsty
• USG 1.020 (was also
receiving a bottle)
• Oxalate crystals in urine.
Management of Renal
Compromised Koalas
• Administered upon
diagnosis of kidney
dysfunction
• Patient remains on
this treatment for
their lifetime to
assist with
management
Mrs B High Dependency
Patient
- Now 10 years old
- Maintained on B6 and
Vivitonin
- Fluid therapy when required
- Isolated if lost more than
1kg
- Gum consumption and
faecal output monitored
- Anabolic steroid used to
stimulate appetite
- Gum Smoothie when
weight has dropped and
faecal output low.
“Gum Smoothie” Recipe
- Critical Care
- Divetelact
- Soaked MATURE leaves
- Blended to a ‘chunky sand’
texture
Triggers that can lead to
Stress in Koalas Wild koalas coming into captivity
Illness
Capture and Restraint
Release back to the wild
Competition for habitat
Separation anxiety from carer
Over handling
Intense treatment
Unfamiliar noise
Changes in feeding routine
Breeding
Incorrect housing
Travel
Abnormal gut activity
Medical Procedures
Exposure to unfamiliar animals
Change in living conditions
Seasonal preferences
Amount and quality of feed
Supplementary feeding
Housing with multiple koalas
Human contact time with the koala
Temperature change
Drought
Cleland's Collection
• 60% of the population have been diagnosed with oxalate nephrosis
• Most are in the low-dependency category and are maintained on B6 and Vivitonin as part of their treatment plan
• 5% are in the high-dependency category and are considered to be chronic kidney candidates which will involve high-dependency treatment throughout periods of their life.
Captive vs Wild
Treatment
• Once diagnosed with Oxalate
Nephrosis the individual will
require long-term, ongoing
treatment to help maintain their
kidney function.
• This is NOT a viable option for a
wild koala and unfortunately
once diagnosed the disease will
inevitably progress.