May | 2013 | alliedanimalhospital

Diabetes mellitus is a disease common in humans, but did you know it occurs in our pets as well?

Diabetes mellitus occurs when the pancreas doesn’t  produce enough insulin. Insulin is required for the body to efficiently digest and utilize sugars, fats and proteins. 

Diabetes most commonly occurs in middle age to older dogs and cats, but occasionally occurs in young animals.  When diabetes occurs in young animals, it is often genetic and may occur in related animals or in certain family lines.  Diabetes mellitus is seen more commonly in female dogs and in male cats. 

As in people, certain conditions predispose a dog or cat to developing diabetes. Animals that are overweight or those with inflammation of the pancreas (a condition known as pancreatitis) are predisposed to developing diabetes. Long term use of certain drugs can also predispose an animal to diabetes.  These drugs include long term use of certain steroids and certain hormone type medications.  These are commonly used drugs and side effects to this extreme are very rare.  Only a small percentage of animals receiving these drugs develop diabetes, and only after long term consecutive use.

The body needs insulin to digest sugar, fat and protein from the diet and convert it to energy.  When the body stops producing insulin, sugar accumulates in the blood and the urine.  Sugar in the urine causes the pet to pass large amounts of urine and to drink lots of water – these symptoms can be early signs of diabetes.  Blood sugar level is instrumental in stimulation of hunger in the brain.  Without insulin, the sugar does not get metabolized and thus does not reach the brain.  Because of this the animal feels constantly hungry, but may lose weight due to inability to absorb nutrients from the diet. Sugar is an excellent medium for bacterial growth, so untreated diabetic pets are more likely to develop infections and commonly get bladder, kidney, or skin infections. Diabetic dogs often develop cataracts in the eyes. Cataracts are caused by the accumulation of water in the lens and will eventually lead to blindness.  These cataracts can be treated by an ophthalmologist in a procedure called a phacoemulsification.  Less common signs of diabetes are weakness or abnormal gait due to nerve or muscle dysfunction.  There are two major forms of diabetes in the dog and cat: 1) uncomplicated diabetes and 2) diabetes with ketoacidosis. Pets with uncomplicated diabetes may have the signs just described but are not extremely ill.  Diabetic pets with ketoacidosis are very ill and may be vomiting and depressed.

The diagnosis of diabetes is made in the veterinary hospital by finding a large increase in blood sugar on bloodwork and a large amount of sugar in the urine.  Cats may be stressed by having a blood sample drawn, which can result in a temporary increase in blood sugar.  This increase tends to be much smaller than that seen in diabetes.  Your veterinarian may want to run a test called fructosamine to help differentiate stress hyperglycemia from diabetes.  A blood screen of other organs is obtained to look for changes in the liver, kidney and pancreas and urine sample may be cultured to look for infection of the kidneys or bladder. Diabetic patients with the complications of the severe form called ketoacidosis may have an elevation of waste products that are normally removed by the kidneys.

The treatment is different for patients with uncomplicated diabetes and those with ketoacidosis.  Ketoacidotic diabetics are treated with intravenous fluids and rapid acting insulin. These pets must be hospitalized under constant supervision of veterinary staff as this can be a life threatening condition. This treatment is continued until the pet is no longer vomiting and is eating, then the treatment is the same as for uncomplicated diabetes.

Diabetes is managed long term by the injection of  insulin by the owner once or twice a day. Some diabetic cats can be treated with oral medications instead of insulin injections, but the oral medications are rarely effective in the dog. There are three general types of insulin used in dogs and cats:

• short- acting insulin (regular or crystalline) is used in sick (ketoacidotic) diabetic animals until they are eating again 


• NPH and Lente are intermediate- acting insulins 


• Ultralente and PZI are long- acting insulins

The action of insulin varies in each individual and most dogs and cats will need 2 insulin shots daily.  The insulin needs of the individual animal are determined by collecting small amounts of blood for glucose (sugar) levels every 1-2 hours for 12-24 hours. This is called an insulin-glucose-response curve. When insulin treatment is first begun,  it is often  necessary to perform several insulin-glucose-response curves to determine:

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  • which insulin type to use
  
  
  • how much insulin to give
  
  
  • how often to give insulin
  
  
  • when is the best time to feed the animal
  
  
  
  

  The animal’s insulin needs may change over time requiring a change in insulin type or frequency of injection.  We monitor the animal’s utilization and changing need for insulin through a test called fructosamine which gives us an overview of the pet’s changing blood sugar level over the previous several weeks.  The pet will often need several fructosamine tests while regulating their insulin level.  They will then need a fructosamine level every 6 months to ensure they are continuing to be regulated on their current dose of insulin.

  
  

    Before you give insulin injections to your pet, your veterinarian will show you how to:

  
  
  
  
  • handle insulin
  
  
  • use a syringe
  
  
  • draw insulin from the bottle in the correct amount
  
  
  • give your pet the insulin shot
  
  
  • The insulin molecule is fragile and will become less effective (or even inactive) if it becomes too hot or cold or is shaken vigorously.  Insulin is mixed by gently rolling the bottle between the hands, never by shaking. Pay attention to the expiration date on the bottle and discard insulin that is outdated.
    It is a good idea to practice using water and giving the “shot” to an object such as a piece of fruit until you are comfortable using needles, syringes and drawing accurate amounts of fluid into a syringe.  Ask your veterinarian for assistance in learning to draw and inject the insulin properly.
    Syringes and needles used to give insulin should not be discarded in the trash but should be placed in a puncture-proof container (an old laundry detergent container works well) and taken to your veterinarian for disposal. 
    Insulin injections are not as perfect as the insulin produced by the pancreas. Blood sugar levels will not always be normal in diabetic pets. The goal of treatment is to reduce the  signs of diabetes. When diabetes is well controlled with insulin, the pet should drink, eat and urinate normal amounts.  They should have a good appetite and have normal activity.
  
  
  • Just as in humans, insulin needs are closely related to the type of food eaten by the pet. Your veterinarian will recommend a specific diet and feeding regimen that will enhance the effectiveness of insulin. If your pet is overweight, s(he) will be placed on a weight-reducing diet. As the pet loses weight, less insulin will be needed.  It is very important to feed only the recommended diet..NO table scraps or treats that are not part of the recommended diet.
    Heavy exercise will reduce the amount of insulin needed. It is important  to talk to your veterinarian before making changes in diet or exercise.
    There is always some risk that a diabetic patient on insulin will develop low blood sugar.  For this reason, it is important that your pet eat a good meal at the time of insulin administration.  If there is a day that your pet will not eat well, your veterinarian should be contacted prior to administering insulin.  Signs of low blood sugar include weakness, staggering, seizures, or just being more quiet than usual. You should keep corn syrup on hand to rub on the animals gums if they have signs suggestive of low blood sugar.  Don’t pour large amounts of corn syrup in the mouth of an animal that is not fully conscious as the syrup may be inhaled into the lungs.  Simply rub a small amount on the gums. 
  
  
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    Because insulin needs vary with the activity and lifestyle of your pet, you may want to keep a written daily log of:

    
    
    
    
    • the dose of insulin
    
    
    • location in which the insulin is injected
    
    
    • any changes in the pet’s activity or appetite
    
    
    
    

    Your veterinarian may ask you to check your pet’s urine for sugar using a test strip. If your pet is well regulated on insulin, the sugar readings in most urine samples will be negative or trace. The strips may have color pads only for glucose or for glucose and ketones.

    
    

    Diabetes is rarely reversible in dogs, but diabetic cats will sometimes regain the ability to produce their own insulin in the pancreas (remission). Cats that developed diabetes after receiving long term glucocorticoids or hormones are more likely to stop needing insulin after a while compared to cats that developed diabetes without a known cause.  As in people, weight is a big factor in the development of diabetes in cats.  Cats that are placed on an appropriate diet and reach their target weight have a better chance of having a remission than dogs.

    
    

    You should have your diabetic pet evaluated by a veterinarian at 2-4 month intervals or anytime another health problem develops. The development of other health problems will often interfere with insulin regulation.