CANINE
CUSHINGS SYNDROME
‘Hyperadrenocorticism’
by Marian Godwin Clifford
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What
is Cushings Syndrome? Cushings Syndrome or hyperadrenocorticism
is a common clinical syndrome in dogs, especially in older dogs. It occurs
when the hormone Cortisol is produced to excess.
This is usually caused by an ACTH (adreno-corticotrophic hormone) secreting
pituitary tumour (85% cases ), which then over stimulates the adrenal gland
which produces too much cortisol. The pituitary gland is a mass of specialised
cells at the base of the brain. The adrenal glands are small pockets of
specialised cells sitting behind each kidney.
Sometimes, however, Cushings is caused by an adrenal gland tumour, which
starts to produce cortisol independently of the pituitary gland.
The third cause of Cushings is over-prescribed medications, specifically
those corticosteroids to treat itching skin. This third cause is reversible
by slowly withdrawing the steroid medication which will allow the adrenal
glands to resume functioning.
It is not yet known whether Cushings in Scottish Terriers is an inherited
predisposition .
What are the Symptoms? It is important for the Scottie owner to be familiar with the symptoms, as they are sometimes mistaken for the aging process. No dog will present with all of the symptoms, and some symptoms are more common than others. Symptoms also depend on the duration of the disease.
| - | Increased
thirst (polydipsia) with associated increased urination (polyuria)
Most common symptom, may be viewed by the owner as incontinence or a
behavioural issue. Some owners wrongly believe that the problem will
be resolved by withholding water. Never withhold water from a dog that
is drinking excessively until your dog has been examined by a veterinary
surgeon. In Cushings, the increase in thirst is directly related to
the increase in urine production. When water is withheld, the same volume
or urine is produced and dehydration and kidney failure can result; |
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| - | Increased
hunger (polyphagia) Common symptom, occurs in most dogs. Not a
normal hearty appetite, but a voracious appetite which can lead to bad
behaviour such as food stealing, raiding bins; |
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| - | Pot
belly Common symptom, due to enlarged liver, distribution of
fat, muscle atrophy in the abdominal wall; |
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| - | Muscle
atrophy Or wasting which can also affect the limbs and the head,
resulting in a thin-legged dog with a bony, skull-like appearance of
the head; |
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| - | Panting; |
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| - | Coat
changes (dry, thin, brittle coat or baldness) Begins with symmetrical
hair loss on the flanks (alopecia); |
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| - | Weakness
Could be due to muscle weakness. Dog less willing to exercise,
tires easily; |
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| - | Skin
changes There are a number of these and any or none can be present
at any one time: Thinning, loss of elasticity, slow wound healing, bruising,
hair loss, lacklustre coat, dandruff, comedones (blackheads), calcinosis
cutis (calcium deposits in the skin); |
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| - | Reproductive
problems (unaltered dogs) Where, in bitches, they stop cycling
and in dogs, they may undergo a reduction on the size and firmness of
the testicles; |
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| - | Myotonia
Rigidity of the muscles (rare); |
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| - | Neurological
Problems Affects the nervous system due to the presence of a mass
pressing on the brain in the case of a pituitary gland tumour. Symptoms
include: Dullness, depression, head pressing, walking in circles, ataxia,
behavioural changes, loss of appetite, blindness, seizures (epilepsy),
and unequal pupils. (Rare); |
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| - | Diabetes Mellitus Occurs in about 10% of affected dogs. |
How is Cushings Diagnosed? On the basis of the history, diagnosis is made by examining the clinical symptoms and confirmed with selective blood and urine tests. There is no single test to diagnose Cushings, and this syndrome is often difficult to diagnose .
How
is Cushings Treated? Considering that most Cushingoid dogs are
elderly, they could have concurrent health problems making treatment difficult.
Surgery is rarely recommended and most dogs are medically managed.
Until recently, there were no licensed medicines available in the UK and
special importation licences had to be obtained for drugs with potentially
harmful side effects. A new product, ‘Vetoryl' (Trilostane) developed
in the UK, is now available. Medication is easy by administering an oral
capsule, which is then given daily for life.
According to the literature , the early results are extremely promising
in controlling what has been, until now, a difficult disease to treat.
Monitoring and Checkups Cushingoid dogs should be regularly monitored. My
vet suggests a check-up every 4 months to evaluate the progress of the therapy.
What is the Long-term Prognosis for a Cushingoid dog? Although
Cushings is incurable, frustrating to diagnose and expensive to treat, it
is treatable. Fortunately, it is not painful and many dogs live for some
years with excellent quality of life after having being diagnosed and receiving
treatment. There is anecdotal evidence of dogs living many years after diagnosis,
but it is practical to expect that the dog will live out its natural lifespan.
It can, however, lead to suffering in an untreated dog. It will progress
and can leave the dog prone to various infections, as excess cortisol is
immunosuppressive.
Ultimately, a dog with Cushings can have improved quality of life following
diagnosis and treatment, and their lives may be extended. It is possible
for this disease to be managed by the vigilant and committed owner for many
years.
Personal Experience My 11-year old Scottish Terrier bitch, Ailish, was diagnosed with Cushings in June 2002, having 18 months previously been tested as borderline-Cushingoid. This is the basis for my interest and the reason for this article.
Ailish
presented with the first six symptoms. The vet asked me to try and measure
her intake of water, and it came to a combined intake of about three litres
per day for two Scottish Terriers (one drinking normally). It was this that
brought us to take her to the vet in the first place.
One of her most difficult symptoms to manage is the huge appetite and the
lengths to which she will go to to steal food. A gift hamper was once left
on the floor, and she gnawed through the corrugated cardboard in order to
get to some biscuits inside. She has even stolen a box of tea from shopping
bags, which had not yet been put away. We have to be patient and very aware
of where we leave anything edible (or even inedible-but-smells-good i.e.
sachet of Persil Aloe Vera inwash tabs).
She initially lost hair in the typical fashion i.e., two symmetrical patches
on her flanks, but it has since grown back – but grey! In the manner
of all elderly dogs, she is going grey, but in this case, from the bottom
up! She had a bald patch at the base of her tail, which is also now growing
back since diagnosis and medication.
The ‘dandruff’ has been controlled through a combination of
the medication and medicated shampoo, Malaseb.
Ailish had several vet visits for blood and urine tests. She had to spend several hours at the vet on two separate occasions, and had to return once as the sample had degenerated by the time it got to the lab. And I am sure that the neighbours were very amused seeing me trying to catch a “morning sample” from my squatting Scottie. I found that fashioning a ladle or scoop from tinfoil, which I slid down under and behind her as she squatted, was the most effective way to get an ample amount for the urine test.
She
was eventually prescribed one 60mg capsule of Vetoryl per day (£61.10
for 30 capsules). The most upsetting part about the medication, which I
know is ultimately saving her life, is the fact that I have to handle the
capsules with gloves (the precautions include not handling the capsules
at all if pregnant or trying to become pregnant).
I am loathe to put these on my precious dog's tongue. So I coat them in
peanut butter so that she doesn't have to have direct contact with them.
Foolish, I know, but it helps us both as she is a difficult patient to administer
capsules to.
The
one thing that we struggle with constantly – even post-medication
- is her “goopy eyes”. She needs her eyes cleaned daily and
bathed several times a week in a mild saline solution. The vet says that
there is no ulcer present, but it is simply conjunctivitis affecting an
immuno-suppressed dog. We have decided against medicating, as this will
only cause chemical conjunctivitis and perpetuate the cycle.
Although we have just recently made contact with a homeopathic vet, we are
not yet under his care. In the mean time, I am supplementing her with a
homeopathic canine geriatric supplement, colostrums, milk thistle and Echinacea.
It is now six months since her diagnosis and the start of her therapy and she has improved greatly. Her water intake has reduced considerably and I was heartened to see her start to hide food once again – under rugs, under her blanket, under cushions. This can only mean that her voracious appetite is abating.
I am hoping for her immune system to recover sufficiently for her eyes to return to normal. She has just turned 11 and I am hoping for at least another 12 – 18 months with her sweet presence.
Sources Consulted
Axiom Endocrine Fact Sheet No. 2.0
Axiom Endocrine Fact Sheet No. 2.1
clubs.akc.org/stca/geneticissues.htm#CS www.onlineveterinarypractice.com/ezines/ezine5.htm
www.supervet.co.uk/dog/cushings.html
www.kateconnick.com/library/cushingsdisease.html
www.arnolds.co.uk/newspage/articles/vetorylfaq.pdf
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