Diabetes strikes 1 in 400 cats and
a similar number of dogs, though recent veterinary studies note that it is
becoming more common lately in cats. Symptoms in dogs and cats are similar
to those in humans. Generally, most dogs and about 5-20% of cats experience
type-1 (insulin-dependent) diabetes, rather than the type-2 that's now becoming
common in obese humans. The other 80-95% of cats experience type-2 diabetes..
The condition is definitely treatable, and need not shorten the animal's life
span or life quality. In type-2 cats, prompt effective treatment can even
lead to diabetic remission, in which the cat no longer needs injected insulin.
Untreated, the condition leads to blindness in dogs, increasingly weak legs
in cats, and eventually malnutrition, ketoacidosis and/or dehydration, and
death.
Cats and dogs will generally show a gradual onset of the disease over a few weeks, and it may escape notice for a while. The condition is unusual in cats less than seven years old, though younger dogs are more susceptible to Type-1 (juvenile) diabetes. The first obvious symptoms are a sudden weight loss or gain, accompanied by excessive drinking and urination; for example, cats can appear to develop an obsession with water and lurk around faucets or water bowls. Appetite is suddenly either ravenous (up to three-times normal) or absent. In dogs, the next symptom is vision problems and cataracts, while in cats the back legs may become weak and the gait may become stilted or wobbly. Owners should watch for noticeable thinning of the skin and apparent fragility: these are also serious and indicate that the animal is metabolizing (breaking down) its own body fat and muscle to survive. Dehydration is also common by this point and death can follow quickly.
Diabetes can be treated but is life-threatening if left alone. Early diagnosis and treatment by a qualified veterinarian can help, not only in preventing nerve damage, but in some cases, in cats, can even lead to remission. Cats usually seem to do best with long-lasting insulins and low carbohydrate diets, specifically Hill's Prescription Diet M/D or Purina D/M. Canned is always better than dry formulas for diabetic cats. Dogs have varying "best" treatments depending on the individual case. Diet is a critical component of treatment, and is in many cases effective on its own.
Humans with Type-1 diabetes are
often treated with a "basal plus bolus" method, where a long-acting
insulin is injected once or twice daily to provide a "basal" insulin
level, then shorter-acting insulin is used just before mealtimes.
For cats, a "basal" method is usually employed instead -- a single
slow-acting dose, twice daily, along with a very low carbohydrate diet, attempts
to keep the blood sugar within a recommended range for the entire day. In
this case it's important for the pet to avoid large meals, since they can
seriously affect the blood sugar. (Meals may also be timed to coincide with
peak insulin activity.) Once-daily doses are not recommended for most cats,
since insulin usually metabolizes faster in cats than in dogs or humans; an
insulin brand that lasts 24 hours in people may only be effective for about
12 in a cat.
For dogs, either of the above two methods may be used. For example, a basal-only
method combined with a high-fiber diet, or a basal-bolus method along with
a normal canine diet, can be effective.
Cats and dogs may be treated with animal insulins (pork-based is most similar
to a dog's natural insulin, beef-based for a cat), or with human synthetic
insulins. The best choice of insulin brand and type varies between pets and
may require some experimentation. One of the popular human synthetic insulins,
Humulin N /Novolin N/ NPH, is reasonable for dogs, but is usually a poor choice
for cats, since cats' metabolize (most) insulin about twice as fast. The Lente
and Ultralente versions were therefore very popular for feline use until summer
2005, when manufacturers discontinued them.
Until the early 1990s, the most recommended type for pets was beef/pork-derived
PZI, but that type was phased out over the 1990s. There are sources currently
available again in the US and UK, and many vets are now starting to recommend
them again for pets.
Vetsulin,is a brand of pork-based insulin, which is designed for dogs, and
is available through veterinarians.Vetsulin can also used for the ex-label
treatment of diabetes mellitus in cats and pet rabbits and guinea pigs.
A newer ultra-slow time-release synthetic human insulin, called Lantus (or
Glargine) is an extremely popular first choice for feline diabetics. It usually
requires twice a day administration. When combined with a low carbohydrate
diet, Lantus insulin has a 50% remission rate (meaning the cat no longer needs
daily insulin).
The weak legs syndrome found in many diabetic cats is a form of neuropathy, in particular caused by damage to the myelin sheath of the peripheral nerves caused by glucose toxication and cell starvation. (There are other conditions that can cause weak legs too, consult your vet before assuming neuropathy.) Most common in cats, the back legs become weaker until the cat displays "Plantigrade stance", standing on its hocks instead of on its toes as usual. The cat may also have trouble walking and jumping, and may need to sit down after a few steps. Some recommend a specific form of Vitamin B12 to heal the nerve damage. Neuropathy often heals on its own within 1 to 3 months once blood sugar is regulated.
Dogs' eyes are highly sensitive to high blood sugar, and will have blurred vision, cataracts, or even total blindness after as little as a few days at blood glucose concentration above 14 mmol/L (250 mg/mL). Cataracts may be treated later, but blindness is permanent in most cases. Fortunately, as dogs rely considerably on their senses of smell and hearing, blindness is less of a disability than might otherwise be expected.
Cats and dogs may in some cases
have their mealtimes strictly scheduled and planned to match with injection
times, especially when on insulins with a pronounced peak action like Vetsulin
or Humulin N. In other cases where the pet free-feeds and normally eats little
bits all day or night, it may be best to remain on this schedule and try to
use a very slow-acting insulin to keep a constant level of blood glucose.
Consult your Glendale Animal Hospital veterinarian. Regulation of your diabetic
is NOT possible without regular vists to check the blood sugar, and some testing
can be done at home. The first goal of therapy is to "regulate"
the pet's blood glucose, which may take a few weeks or even many months. This
process is basically the same as in type-1 diabetic humans. The goal is to
keep the blood glucose values in a comfortable range for the pet during the
whole day, or most of it.
The recommended method is to"Start Low and Go Slow". The initial
dosage will be very conservative (low) (usually between 0.5 and 2 units daily,
split into 12-hour dosages) and may not affect the pet's symptoms noticeably
at first. This is necessary because although high blood sugar can kill within
weeks, low blood sugar can kill in minutes. Dosage must be increased gradually
and carefully. The usual recommended method is to increase the dose by 1/2
to 1 unit every 7 to 14 days.
Buying a blood glucose meter and testing strips is an option for home monitoring
of your diabetic. It is imperitive that the instrument be approved and callibrated
for dogs or cats. The equipment may seem like a heavy investment but it can
pay for itself in a matter of months. It will do no good if testing is not
performed at the specific times requested by your veterinarian and the information
shared with your vet in a timely fashion. Following your veterinarian's recommendations
is vital to successful home monitoring. Adjusting dosages of insulin yourself
can lead to complications and possibly death of your diabetic. Urine strips
are not accurate enough for home monitoring.
Your pet is "regulated" when its blood glucose remains within an
acceptable range all day, every day. Acceptable varies somewhat between cats,
and dogs, usually between 80 to 200for cats, and between 90 to 250 for dogs.
(The range is wider for diabetic animals than non-diabetic, since shots cannot
replicate the accuracy of a working pancreas.) It's important, though,
that the glucose level be in the lower half of that range for as much of the
day as possible.
Absolute numbers vary between pets, and with meter calibrations. The numbers below are as shown on a typical home glucometer while hometesting blood glucose, not necessarily the more accurate numbers a vet would see. For general guidelines only, the levels to watch are approximately:
|
mmol/L
|
mg/dL(US)
|
|
|
<2.2
|
<40
|
Readings below this level are usually considered hypoglycemic when giving insulin, even if you see no symptoms of it. Treat immediately |
|
2.2-7.5
|
40-130
|
Non-diabetic range. These numbers, when not giving insulin, are very good news. It is unsafe to aim for this level when on insulin, unless your control is very good. |
|
3.2-4.4
|
57-79
|
The average non-diabetic pet's blood glucose level. This level provides no safety margin for a diabetic on insulin. Don't aim for this range, but don't panic if you see it, either. If the number is not falling, it's healthy. |
|
5
|
90
|
The commonly cited minimum safe value for the lowest blood sugar of the day. |
|
5.5-10
|
100-180
|
The commonly used target range for diabetics. |
|
7.8
|
140
|
The threshold above which organ and pancreatic damage may begin, according to the American Association of Clinical Endocrinologists (AACE). |
|
<10-15
|
<180-270
|
The renal threshold for glucose, when excess glucose from the kidneys spills into the urine. This is usually when the pet begins to show diabetic symptoms. |
|
14
|
250
|
The approximate maximum safe value for the highest blood sugar of the day in dogs. Dogs can go blind at this level. Dogs are more sensitive to high blood sugar than cats, but cats should try to stay below this level as well. Check for ketones. |
|
16.7
|
300
|
The approximate maximum safe value for the highest blood sugar of the day, in cats, to avoid neuropathy and complications. Some cats can go on long-term at this level or higher, but there will eventially be side effects. Check for ketones. |
|
>20
|
>360
|
Cats are much more resilient than dogs or humans at these high levels; nevertheless, the blood sugar should be lowered. The cat or dog could suffer from many ill effects both short and long term. Check for ketones frequently, be sure you are giving insulin. |
An acute hypoglycemic episode (very
low blood sugar) can happen even if you are careful, since pets' insulin requirements
sometimes change without warning. The symptoms are depression/lethargy, confusion/dizziness,
loss of excretory/bladder control, vomiting, and then loss of consciousness
and/or seizures. As soon as possible, administer honey or corn syrup by rubbing
it on the gums (even if unconscious, but not if in seizures), and rush it
to the vet. Carry more honey or corn syrup with you on the way and keep rubbing
it on the gums, where it can be absorbed -- it could save the pet's life.
Every minute without blood sugar causes brain damage. (Some recommend administering
syrup anally if the animal is in seizures!)
If the pet has hypoglycemia according to the blood glucose meter (<2.2
mmol/L or 40 mg/dL), but has no symptoms, give treats or food if possible.
If they won't eat, try putting food in their mouth. If that doesn't work,
administer some honey followed by food or cat treats, and continue to do so
until the blood glucose is rising, and the latest insulin shot's peak action
is past.
Sometimes a mild hypoglycemic episode will go unnoticed, or leave evidence
such as an "accident" where kitty fails to make it to the litterbox.
In these cases the blood sugar will probably appear paradoxically high upon
the next test hours later, since the pet's body will react to the low blood
sugar by stimulating the liver to release storedglycogen. This condition is
known as Somogyi rebound and requires a lowered insulin dosage
for the next few days. The Somogyi rebound may also occur when the pet's blood
glucose drops too rapidly, even if it never actually reaches a low reading.
It is in many cases possible to
induce remission (a temporary or permanent freedom from insulin-dependence)
in type-2 diabetic cats. (This appears to be unique to cats, unfortunately
for dogs and humans.) There is growing agreement among experts that a combination
of low carbohydrate healthy diet, well-chosen insulin, and well-chosen dosage
plans can in many cases partially heal a damaged pancreas and allow the cat's
blood sugar to be controlled entirely by diet thereafter. (A low carbohydrate
diet is usually required for the remainder of the cat's life.)
Remission is a realistic goal for treatment of type-2 diabetic cats (that
is, 80-95% of all diabetic cats) who are properly regulated quickly. Chances
of success are highest in the first few months after initial diagnosis, due
to ongoing damage from glucose toxicity caused by hyperglycemia. This limited
time window is a good reason to start with low carbohydrate diet and very
slow-acting insulins, the most successful known combination, right away.