Monday, November 10, 2014

Diabetes and your cat

Somewhere between 1 in 100 and 1 in 500 cats will develop diabetes during their lifetime. As pet obesity becomes more of a problem, these numbers are expected to increase.

What is diabetes mellitus?

There are two forms of diabetes in cats: diabetes insipidus and diabetes mellitus.  Diabetes insipidus is a very rare disorder that results in failure to regulate body water content.  The more common type of diabetes seen in cats is called diabetes mellitus.  This treatable disease is seen on a fairly regular basis, usually in cats 5 years of age or older. The highest risk categories are older cats, obese cats, and male cats. Other contributing factors can include hyperthyroid disease (elevated thyroid function), chronic pancreatitis (long term inflammation of the pancreas), Cushing's Disease (also known as hyperadrenocorticism, or excessive production of cortisol by the adrenal glands), acromegaly (excessive growth hormone production by the pituitary gland), and the use of steroid medications. In some countries, the Birman breed appears to be at higher risk for diabetes, but this is not the case in the United States.

Simply put, diabetes mellitus is a failure of the pancreas to regulate blood sugar.  The pancreas is a small but vital organ that is located near the liver and stomach.  It is shaped like an "L" and is made up of two different groups of cells.  One type of cells produces the enzymes necessary for proper digestion. These enzymes help break down or "metabolize" fats, proteins and carbohydrates. The other group, called beta cells, produces the hormone called insulin. Insulin is in charge of instructing the cells of the body to use the glucose that enters the blood stream after sugars are broken down.

Some people with diabetes take insulin shots and others take oral medication.  Is this true for cats?

In cats, two types of diabetes mellitus have been discovered.  Both types are similar in that there is a failure to regulate blood sugar, but the basic mechanisms of disease differ somewhat between the two groups. 

1.         Type I, or Insulin Dependent Diabetes Mellitus, results from total or near-complete destruction of the beta cells. This is the most common type of feline diabetes.  As the name implies, cats with this type of diabetes require insulin injections to stabilize blood sugar. 
2.         Type II, or Non-Insulin Dependent Diabetes Mellitus, is different because some insulin-producing cells remain.  However, the amount produced is insufficient, there is a delayed response in secreting it, and the tissues of the cats body are relatively resistant to it.  These cats may be treated with an oral drug that stimulates the remaining functional cells to produce or release insulin in an adequate amount to normalize blood sugar.  Alternatively, they may be treated with insulin.  Cats with NIDDM may ultimately progress to total beta-cell destruction and then require insulin injections.

Why is insulin so important?

The role of insulin is much like that of a gatekeeper: it stands at the surface of body cells and opens the door, allowing glucose to leave the blood stream and pass into the cells.  Glucose is a vital substance that provides much of the energy needed for life, and it must work inside the cells.  Without an adequate amount of insulin, glucose in unable to enter the cells.  It builds up in the blood, setting in motion a series of events, which can ultimately prove fatal.  When cells are not able to use the glucose in the blood because insulin is deficient, the cells become starved for energy.  Because cells need energy to function, and a cat's body needs functional cells to remain alive, the body starts breaking down stores of fat and protein to use as alternative energy sources.

Because the cat's cells are starving, the cat eats more, but because the diabetic cat can only get energy from stored fat and protein, and not the food that he is eating, he loses weight. Thus, we have weight loss in a cat with a ravenous appetite.  The body tries to get rid of the excess glucose by eliminating it in the urine.  However, along with the glucose, a large amount of body fluid is eliminated, too, because glucose (blood sugar) attracts water.  This results in the production of a large amount of urine.  To avoid dehydration, the cat becomes thirsty and drinks more and more water.  Thus, we have the four classical signs of diabetes:  
  • Weight loss
  • Ravenous appetite
  • Increased water consumption
  • Increased urination

How is diabetes mellitus diagnosed?

The diagnosis of diabetes mellitus is based on three criteria: the four classical clinical signs, the presence of a persistently high level of glucose in the blood stream, and the presence of glucose in the urine. 

The normal level of glucose in the blood is 80-120 mg/dl (3.9-6.1 mmol/L).  It may rise to 250-300 mg/dl 13.8-16.5 mmol/L) following a meal or when the cat is very excited.  However, diabetes is the only common disease that will cause the blood glucose level to rise above 400 mg/dl (22 mmol/L).  Some diabetic cats will have a glucose level as high as 800 mg/dl (44 mmol/L), although most will be in the range of 400-600 mg/dl (22-33 mmol/L).

To keep the body from losing its needed glucose, the kidneys do not allow glucose to be filtered out of the blood stream until an excessive level is reached.  This means that cats with a normal blood glucose level will not have glucose in the urine.  Diabetic cats, however, have excessive amounts of glucose in the blood, so it will be present in the urine.

What are the implications for my cat and me?

For the diabetic cat, one reality exists: blood glucose cannot be regulated normally without treatment. Short term, the cat can compensate by digesting body stores of fat and protein, but over time, a condition called "ketoacidosis" can occur. This is due to the body's inability to handle excessive breakdown of fat and protein for energy - the waste products, called "ketones" build up in the blood and lower the blood pH, making it more acidic. Because the diabetic cat is already dehydrated, the situation becomes more severe. The signs of diabetic ketoacidosis (DKA) are:

  • a ravenous cat that now has no appetite
  • vomiting
  • diarrhea
  • lethargy
  • weakness
  • dehydration
  • respiratory abnormalities
 If a diabetic cat is having symptoms such as these, he should see a veterinarian immediately, as DKA can often require intensive care and IV fluid therapy.

Diabetic cats may develop unhealthy skin and flaky coat, liver disease, and secondary bacterial infections. Because diabetics have very dilute and sugar-filled urine, they are at higher risk than the average cat for urinary tract infections. Untreated diabetics may become weak, developing a condition called "diabetic neuropathy". Cats with this disorder often walk with their hocks touching the ground and have trouble jumping.

Although the cat can go a day or so without treatment and not get into a crisis, treatment should be looked upon as part of the cat's daily routine.  Treatment almost always requires some dietary changes.  Whether an individual cat will require oral therapy or insulin injections will vary. 

As for the owner, there are two implications: financial commitment and personal commitment. 

When your cat is well regulated, the maintenance costs are minimal.  The oral medication, insulin, and syringes are not extremely expensive.  However, the financial commitment is significant during the initial regulation process and if complications arise. 

If applicable,  your cat will be hospitalized for a few days to deal with the immediate crisis and to begin the regulation process.  The "immediate crisis" is only great if your cat is so sick that it has quit eating and drinking for several days. Ketoacidotic cats may require a week or more of hospitalization with quite a bit of laboratory testing. 

The financial commitment may again be significant if complications arise.  We will work with you to try and achieve consistent regulation, but some cats are difficult to keep regulated.  It is important that you pay close attention to instructions related to administration of medication, to diet, and to home monitoring.  Another complication that can arise is hypoglycemia or low blood sugar. Severe hypoglycemia can be fatal.  Hypoglycemia or low blood sugar is most commonly due to inconsistencies in treatment or because some cats can have a spontaneous remission of their disease.  

Your personal commitment to treating your cat is very important in maintaining regulation and preventing crises.  Most diabetic cats require insulin injections twice daily, at about 12 hour intervals.  They must be fed the same food in the same amount on the same schedule every day.  If you are out of town, your cat must receive proper treatment while you are gone.  These factors should be considered carefully before deciding to treat a diabetic cat.

What is involved in treatment?

The best one word answer to that question is "consistency".  Your cat needs consistent administration of medication, consistent feeding, and a stable, stress-free lifestyle.  To best achieve this, it is preferred that your cat lives indoors.  Although that is not essential, indoor living removes many uncontrollable variables that can disrupt regulation.
Drawing a dose of Lantus insulin from an insulin pen

Your cat's feeding routine is also important.  The average cat prefers to eat about 10-15 times per day, one mouthful at a time.  This means that food is left in the bowl at all times for free choice feeding.  However, this is not the best way to feed a diabetic cat.  The preferred way is to feed twice daily, just before each insulin injection.  If your cat is currently eating on a free choice basis, please try to make the change.  However, if your cat will not change or if you have several cats that eat in a free choice fashion, you may find that this change is not practical.  If a two-meals-per-day feeding routine will not work for you, it is still very important that you find some way to accurately measure the amount of food that is consumed.

Fortunately, there are more and more advanced feeding options available to help monitor your cat's food intake. Some new products on the market that may be helpful are the MeowSpace Feeding and Litterbox Solution, or the soon-to-be-available Sure Feed microchip or collar tag activated pet feeder. An exciting prospect that is on the horizon is the Bistro Facial Recognition Smart Feeder. All these feeding options help multi-cat households control food access among their multiple cats to ensure that they have a better idea how well their diabetic is eating.

Since obesity is one of the predisposing factors for diabetes, making sure that your cat maintains a healthy, active lifestyle is important. Encouraging diabetic cats to eat a healthy, low carbohydrate, high protein diet, including 3-6oz canned food daily, may help encourage healthy weight loss.

                About Insulin

Insulin comes in an airtight bottle that is labeled with the insulin type and the concentration.  Before using, mix the contents.  It says on the label to roll it gently, not shake it.  The reason for this is to prevent foam formation, which will make accurate measuring difficult.  If it is not shaken properly, it will not mix well, and dosing will not be accurate.  Therefore, the trick is to shake it vigorously enough to mix it without creating foam.  Since bubbles can be removed (as described later), it is more important to mix it well than to worry about foam formation. 

Insulin is a hormone that will lose its effectiveness if exposed to direct sunlight or high temperatures.  It should be kept in the refrigerator, but it should not be frozen.  It is not ruined if left out of the refrigerator for a day or two, although this is not advisable.  Insulin is safe as long as it is used as directed, but it should be kept out of reach of children.

** You should replace your bottle of insulin every 6 months, regardless if the entire content has been used.  Studies have found that insulin loses its effectiveness over a long period of time. **

                Drawing up the Insulin

Have the syringe and needle, insulin bottle, and cat ready.  Then, follow these steps:

1)        Remove the guard from the needle, and draw back the plunger to the appropriate dose level.
2)        Carefully insert the needle into the insulin bottle. 
3)        Inject air into the bottle; this prevents a vacuum from forming within the bottle. 
4)        Withdraw the correct amount of insulin into the syringe.

Various brands of U-100 insulin syringes
Before injecting your cat with the insulin, check that there are no air bubbles in the syringe.  If you get an air bubble, draw twice as much insulin into the syringe as you need.  Then withdraw the needle from the insulin bottle and tap the barrel of the syringe with your finger to make the air bubble rise to the nozzle of the syringe.  Gently and slowly expel the air bubble by moving the plunger upward.

When this has been done, check that you have the correct amount of insulin in the syringe.  The correct dose of insulin can be assured if you measure from the needle end, or "0" on the syringe barrel, to the end of the plunger nearest the needle.

                Injecting the Insulin

The steps to follow for injecting insulin are:

1)       Hold the syringe in your right hand (switch hands if you are left-handed).
2)       Have someone hold your cat while you pick up a fold of skin from somewhere along your cat's back with your free hand (pick up a different spot each day).
3)       Quickly push the very sharp, very thin needle through your cat's skin.  This should be easy and painless.  However, take care to push the needle through only one layer of skin and not into your finger or through two layers of skin.  The latter will result in injecting the insulin onto your cat's haircoat or onto the floor.
Proper subcutaneous injection techniques
4)       To inject the insulin, place your thumb on the plunger and push it all the way into the syringe barrel.
5)       Withdraw the needle from your cat's skin.  Immediately place the needle/syringe into the sharp’s container.  Stroke your cat to reward it for sitting quietly.

It is neither necessary nor desirable to swab the skin with alcohol to "sterilize" it.  There are four reasons:

1)       Due to the nature of the thick hair coat and the type of bacteria that live near the skin of cats, brief swabbing with alcohol or any other antiseptic is not effective. 
2)       Because a small amount of alcohol can be carried through the skin by the needle, it may actually carry bacteria with it into the skin. 
3)       The sting caused by the alcohol can make your cat dislike the injections. 
4)       If you have accidentally injected the insulin on the surface of the skin, you will not know it.  If you do not use alcohol and the skin or hair is wet following an injection, the injection was not done properly.

Many people are initially fearful of giving insulin injections.  If this is your initial reaction, consider these points. 
1)        Insulin does not cause pain when it is injected. 
2)        The injections are made with very tiny needles that your cat hardly feels. 
3)        The injections are given just under the skin in areas in which it is almost impossible to cause damage to any vital organ.  Please do not decide whether to treat your cat with insulin until we have demonstrated the injection technique.  You will be pleasantly surprised at how easy it is.

Although the above procedures may at first seem complicated and somewhat overwhelming, they will very quickly become second nature.  Your cat will soon learn that once or twice each day it has to sit still for a few minutes.  In most cases, a reward of stroking results in a fully cooperative cat that eventually may not even need to be held.

Is continual or periodic monitoring needed?

Because a cat's need for insulin can change over time, and because some cats may experience "spontaneous remission", it is extremely important that your cat's progress be checked on a regular basis.  Monitoring is a joint project on which owners and veterinarians must work together. Cats that have experienced a remission are at increased risk for becoming diabetic again, so monitoring in these cats is also important, despite the fact that they no longer require insulin therapy.

               Home Monitoring

First, you need to be constantly aware of your cat's appetite, weight, water consumption, and urine output.  You should be feeding a constant amount of food each day, which will allow you to be aware of days that your cat does not eat, all of it or is unusually hungry after the feeding.  You should weigh your cat at least once monthly.  It is best to use the same scales each time.  A baby scale works well for this. 

You should develop a way to measure water consumption.  The average 10-pound (4.5-kg) cat should drink no more than 7 1/2 oz. (225 ml) of water per 24 hours.  Since this is highly variable from one cat to another, keeping a record of your cat's water consumption for a few weeks will allow you to establish what is normal for your cat.  Another way to measure water consumption is based on the number of times it drinks each day.  When properly regulated, it should drink no more than four times per day.  If this is exceeded, you should take steps to make an actual measurement.

Urine output can be measured by determining the amount of litter that is scooped out of the litter box.  This is a little less accurate if you have more than one cat that uses the litter box, but it can still be meaningful.  The best way to measure litter is to use a clumping litter and scoop it into a sealable container.  After a few weeks you will be able to know the normal rate at which the jar fills.  Too rapid filling will indicate that your cat's urine production has increased.

Keeping a daily diary, calendar or spreadsheet of your cat's weight, food intake, water intake, urine output and the timing of each insulin injection will help you feel comfortable and confident in your pet's progress, and will be very helpful for the veterinarian to assess at each checkup. Any significant change in your cat's food intake, weight, water intake, or urine output is an indicator that the diabetes is not well controlled.  We should see the cat at that time for blood testing

               Monitoring of Blood Glucose

Determining the level of glucose in the blood is the most accurate means of monitoring.  This should be done about every 3-4 months if your cat seems to be well regulated.  It should also be done at any time the clinical signs of diabetes are present.

Timing is important when the blood glucose is determined.  Since eating will elevate the blood sugar for several hours, it is best to test the blood at least 6 hours after eating.  When testing the blood we want to know the highest and lowest glucose readings for the day.  The highest reading should occur just before an injection of insulin is given.  The lowest should occur at the time of peak insulin effect.  This is usually 5-8 hours after an insulin injection, but it should have been determined during the initial regulation process.  Therefore, the proper procedure is as follows:

1)       Feed your cat its normal morning meal then bring it to hospital immediately.  If you cannot get it to the hospital within 30 minutes, do not feed it.  In that situation, bring its food with you.
2)       Bring your cat to the hospital early in the morning without giving it insulin.
3)       A blood sample will be taken immediately, then we will give insulin and feed your cat if it did not eat at home.
4)       A second blood sample will be taken at the time of peak insulin effect.

If your cat gets excited or very nervous when riding in the car or being in the hospital, the glucose readings will be falsely elevated.  If this occurs, it is best to admit your cat to the hospital the morning (or afternoon) before testing so it can settle down for testing the next day.  Otherwise, the tests give us limited information.

Does hypoglycemia occur in cats?

Hypoglycemia means low blood sugar.  If it is below 40 mg/dl (2.2 mmol/L), it can be life-threatening.  Hypoglycemia occurs under three conditions:

1) If the insulin dose is too high.  Although most cats will require the same dose of insulin for long periods of time, it is possible for the cat's insulin requirements to change.  However, the most common causes for change are a reduction in food intake and an increase in exercise or activity.  The reason for feeding before the insulin injection is so you can know when the appetite changes.  If your cat does not eat, skip that dose of insulin.  If only half of the food is eaten just give a half dose of insulin.  Always remember that it is better for the blood sugar to be too high than too low.

2) If too much insulin is given.  This can occur because the insulin was not properly measured in the syringe or because two doses were given.  You may forget that you gave it and repeat it, or two people in the family may each give a dose.  A chart to record insulin administration will help to prevent the cat being treated twice.

3) If your cat has a spontaneous remission of the diabetes.  This is a poorly understood phenomenon, but it definitely occurs in many cats.  They can be diabetic and on treatment for many months, then suddenly no longer be diabetic.  Since this is not predictable and happens quite suddenly, a hypoglycemic crisis ("insulin shock") is usually the first indication. 

The most likely time that a cat will become hypoglycemic is the time of peak insulin effect (5-8 hours after an insulin injection).  When the blood glucose is only mildly low, the cat will be very tired and unresponsive.  You may call it and get no response.  Within a few hours, the blood glucose will rise, and your cat will return to normal.  Since many cats sleep a lot during the day, this important sign is easily missed.  Watch for it; it is the first sign of impending problems.  If you see it, please bring in your cat for blood testing.

If your cat is slow to recover from this period of lethargy, you should give it corn syrup (1 tablespoon by mouth) or feed one packet of a semi-moist cat food.  If there is no response in 15 minutes, repeat the corn syrup or the semi-moist food.  If there is still no response, contact us immediately for further instructions.  (Note: Diabetic cats should not be fed semi-moist foods except for this situation.)

If severe hypoglycemia occurs, a cat will have seizures or lose consciousness.  This is an emergency that can only be reversed with intravenous administration of glucose.  If it occurs during office hours, come in immediately.  If it occurs at night or on the weekend, call our emergency phone number for instructions.

Tell me more about spontaneous remission.

This is a poorly understood phenomenon that only happens in a few cats.  Unfortunately, it can happen rather suddenly so a hypoglycemic crisis may be created when the normal amount of insulin is given.  When it occurs, the cat may be normal for a few weeks or for many months.  However, diabetes will almost always return.  Therefore, you should watch for the typical signs of diabetes then contact us for insulin instructions.

Cats whose glucose levels are difficult to regulate or who require progressively large doses of insulin may require additional diagnostics to eliminate other concurrent or underlying diseases. Overall, cats with diabetes can be medically managed, and if they are stabilized, can live very happy and rewarding lives for years.

For after hours emergencies, please call the Oakland Veterinary Emergency/Critical Care at 248-334-6877. 

Additional resources:

AAFP Health Series: Diabetes
Caring For Your Diabetic Cat Video Series
International Cat Care Cat Health Series: Diabetes mellitus
My Cat Has Diabetes

1 comment:

  1. Blogs are so informative where we get lots of information on any topic. Nice job keep it up!!
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