Diabetes in dogs

Diabetes mellitus strikes 1 in 500 dogs. The condition is treatable, and need not shorten the animal's life span or interfere with quality of life. If left untreated, the condition can lead to cataracts, increasingly weakness in the legs (neuropathy), malnutrition, ketoacidosis and/or dehydration, and death. Diabetes mainly affects middle-aged and older dogs, but there have also been juvenile cases. The typical canine diabetes patient is middle-aged, female and overweight at diagnosis.

The number of dogs diagnosed with diabetes mellitus has increased three-fold in thirty years. Looking back on survival rates from almost the same time period, only 50% survived the first 60 days after diagnosis and went on to be successfully treated at home. With treatment, diabetic dogs are able to survive as long as non-diabetic dogs of the same age and gender.

Diabetes mellitus is commonly divided into two types, depending on the origin of the condition: Type 1 diabetes, sometimes called "juvenile diabetes", is caused by destruction of the beta cells of the pancreas. The condition is also referred to as Insulin-Dependent diabetes, meaning the sufferer must have exogenous insulin injections to replace the insulin his/her pancreas is no longer capable of producing or able to produce in enough quantity to properly supply the body's need for it. Dogs have Insulin-Dependent, or Type 1, diabetes. Because of this, there is no possibility their permanently damaged pancreatic beta cells could "re-awaken" to engender a remission as may be possible with some feline diabetes cases (Most cats have Type 2 diabetes.)

Symptoms

Generally there's a gradual onset of the disease over a few weeks, and it may escape notice for a while. The main symptoms are:

• excessive water consumption-- Polydipsia
• frequent and/or excessive urination-- Polyuria --possible house "accidents"
• greater than average appetite-- Polyphagia --with either weight loss or maintainance of current weight
• cloudy eyes-- Cataracts

Treatment

Early diagnosis and interventive treatment can mean reduced incidence of complications such as cataracts and neuropathy. Since dogs are insulin-dependent, oral drugs are not effective for them, and must instead be placed on insulin replacement therapy.

A common form of this treatment is an intermediate-acting basal insulin (NPH/isophane, Caninsulin/Vetsulin), with a regimen of food and insulin every 12 hours. With Lantus (insulin glargine) being unreliable in dogs, it is rarely used to treat canine diabetes. Most dogs don't require basal/bolus insulin injections.

Diet

Most of the commercially available prescription diabetes foods are high in fiber, in complex carbohydrates, and have proven therapeutic results.

Of primary concern is getting the animal eating, or keeping them eating, as getting the prescribed amount of insulin is dependent on eating full meals. In that interest, it may be best to administer whichever food type the dog will readily eat, in the interest of being able to give full doses of insulin as directed, putting the diet change "on hold" for the time being, and possibly forgoing any changes at all.

These quotes from Dr. William Schall in a 2009 Diabetes presentation may be pertinent:

• "...if the diabetic dog refuses the ideal diet it is not in the patient's best interest to rigidly insist that the caregiver only feed the prescribed food. The consequences of feeding a non-prescription diabetes diet are usually minimal as the increased dose of required insulin is seldom greater that 2-4%.

• "It is also important that some latitude in feeding times be considered. Although timed feedings that correspond to insulin administration maybe ideal, some dogs (although with less frequency than cats) refuse to adhere to timed feedings, having been intermittent nibblers all of their lives. In as much as most dogs are treated with basal insulin only (no feeding associated pulse insulin administration), dogs that refuse to eat specifically at the time of intermediate acing insulin administration can usually be satisfactorily regulated. In the overall context of initial home insulin administration, efforts should be made to keep dogs eating even if the food type and feeding schedule is not textbook optimized."

• Dr. Tony Buffington of Ohio State University agrees,"Remember, it is always better for a patient to eat some of the "wrong" diet than none of the "right" diet!"

Regulation

The goal at first 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 commonly recommended method is to Start Low-Go Slow, with typical starting insulin doses at 0.25 IU/KG (2.2 lb) to 0.50 IU/KG (2.2 lb) of body weight.

Your pet is "regulated" when its blood glucose remains within an acceptable range all day, every day. Acceptable levels vary somewhat between vets, but is roughly from between 5 and 10 mmol/L (90 to 180 mg/dL) for dogs. (The range is wider for diabetic animals than non-diabetic, because 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.

Buying an inexpensive glucometer and learning how to test at home will save many expensive trips to the vet, avoid dangerous overdoses, and give you a better handle on the pet's ongoing condition. Urine strips are not accurate enough for this. Glucometers made for humans are generally accurate using canine and feline blood except when reading lower ranges of blood glucose (<80 mg/dl--4.44 mmol/L). It is at this point where the size difference in human vs animal red blood cells can create inaccurate readings.

Blood sugar guidelines

Absolute numbers vary between pets, and with meter calibrations. The numbers below are as shown on a typical home glucometer.

For general guidelines only, the levels to watch are approximately:

mmol/L	mg/dL(US)	Blood Glucose Guidelines
<2.77	<50	Readings below this level are usually considered hypoglycemic when giving insulin, even if you see no symptoms of it. Treat immediately.
3.44-6	62-108	Non-diabetic glucose values for dogs who don't have diabetes.
5	90	A commonly cited minimum safe value for the lowest target blood sugar of the day when insulin-controlled.
7.8	140	According to the American Association of Clinical Endocrinologists (AACE), threshold above which organ and pancreatic dysfunction may begin in hospitalized humans and the maximum target for post-meal blood glucose in humans.
5.5-10	100-180	Commonly used target range for diabetics, for as much of the time as possible.
10	180	"Renal threshold" for dogs-when excess glucose from the kidneys spills into the urine and roughly when the dog begins to show diabetic symptoms.
14	250	Approximate maximum safe value for the highest blood sugar of the day. Dogs can form cataracts at this level. Check for ketones using urine strips.
16.7	300	Check for ketones.
>20	>360	Check for ketones frequently, be sure you are giving insulin. The dog can feel any of numerous ill effects both short and long-term, see hyperglycemia for details.

Seeing ketone values above trace/small is an indication to contact your vet or local emergency treatment center.

Ketones/ketoacidosis

Ketones in the urine or blood, as detected by urine strips or a blood ketone testing meter, may indicate the beginning of diabetic ketoacidosis (DKA), a dangerous and often quickly fatal condition caused by high glucose levels (hyperglycemia) and low insulin levels combined with certain other systemic stresses. DKA can be fixed if caught quickly.

Ketones are produced by the liver as part of fat metabolism and are normally not found in sufficient quantity to be able to be measured in urine or blood (non-diabetics or well-controlled diabetics). Since the body is set up to normally burn glucose as its fuel, when glucose isn't available as an energy source, (untreated/poorly treated diabetes and some other unrelated medical conditions), it begins to burn fat for energy instead. The result of the body turning to burning fat instead of glucose means more ketone production which is able to be measured when testing either urine or blood for them.

At present, there is only one glucometer available for home use that tests blood for ketones using special strips for that purpose--Abbott's Precision Xtra (known by brand names Precision/Optima/Xceed outside of the US). The blood ketone test strips are very expensive-prices start at about $50 for 10 strips, so it's most likely urine test strips--either ones that test only for ketones (brand name example Ketostix) or ones that test for both glucose and ketones in urine (brand name example Ketodiastix) would be used.

Ketone Monitoring Needed:
High blood sugar	over 14 mmol/L or 250 mg/dL
Dehydration	(skin doesn't jump back after pulling a bit gums are tacky or dry)
Not eating for over 12 hours
Vomiting
Lethargy
Infection or illness
High stress levels
Breath smells like acetone (nail-polish remover) or fruit.

When testing urine for ketones, the sample needs to be as fresh as possible. Ketones evaporate quickly, so there's a chance of getting a false negative test result if you're testing older urine.

The urine testing stix bottle has instructions and color charts to show you how the color on the stix will change given the level of ketones/glucose in the urine over 15 (ketones-Ketostix) or 30 (glucose-Ketodiastix) seconds. Be sure to read the colors at those time intervals because the colors will continue to darken and a later reading will be an incorrect result. Timing with a clock or watch second hand instead of counting is said to be more accurate.

It's important to time the test accurately and not take into account any color changes on the Ketostix strip which occur after 15 seconds or the Ketodiastix strip color changes occurring after 30 seconds.

In general, ketone problems that are more serious than the "trace/slight" range need immediate medical attention; they can't be treated at home. Veterinary care for ketosis/ketoacidosis can involve intravenous (IV) fluids to counter dehydration and flush the animal's system of the ketones and when necessary, to replace depleted electrolytes, such as bicarbonate; intravenous or intramuscular short-acting insulin to bring the blood glucose levels down; measured amounts of glucose or force feeding, sometimes by feeding tube, to force the metabolism back from fat-burning to glucose-burning.

Dr. Michael Herrtage describes the situation well in his WSAVA presentation, "In diabetic ketoacidosis, there are serious derangements in fluid, electrolyte and acid-base status.."

Hypoglycemia

Hypoglycemia, or low blood glucose, can happen even if you are careful, since pets' insulin requirements sometimes change without warning. Vomiting and diarrhea episodes can bring on a hypoglycemia reaction, due to dehydration or simply a case of too much insulin and not enough properly digested food.

Symptoms of hypoglycemia should always be taken seriously and addressed promptly. Better to risk treating a "non-legal" hypo than to fail to respond quickly to the signs of actual hypoglycemia.

From the DVM 360 2007 article by Dr. Audrey Cook:

"Hypoglycemia is deadly; hyperglycemia is not. Owners must clearly understand that too much insulin can kill, and that they should call a veterinarian or halve the dose if they have any concerns about a pet's well-being or appetite. Tell owners to offer food immediately if the pet is weak or is behaving strangely."

Symptoms

The symptoms are:

• depression/lethargy
• confusion/dizziness
• trembling
• ataxia (loss of coordination and/or balance)
• 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, with a feeding syringe or dropper, if the animal is in seizures!

Don't try to make an seizing or unconsicous animal swallow. The food or liquid could possibly choke him/her. There is also a chance that the materials could be aspirated (wind up in the lungs instead of being swallowed).

Treatment

• If the pet has hypoglycemia according to the blood glucose meter (<2.2mmol/L or 40mg/dL), but no symptoms, give treats or food if possible. If they won't eat, try putting food in their mouth.

• If that doesn't work, some honey or syrup followed by food or treats can be administered, and continued until the blood glucose rises, and the latest insulin shot's peak action is past.

• The honey, syrup or "fast-acting" sugar (simple carbohydrates) will make the blood glucose rise, but the rise will not last very long.

• Feeding something with complex carbohydrates in it when the pet is able to take it will make sure hypoglycemia doesn't overtake the "quick" sugar fix.

• According to BD Diabetes Diabetes in Pets website, the amount of syrup for dogs is: for small dogs-one teaspoon; for larger dogs- one tablespoon. Intervet sugggests one tablespoon of a sugar solution (Karo syrup, pancake syrup., etc) rubbed onto the gums, regardless of the size of the dog.

• Intervet suggests 1 gram of glucose for every kilogram (2.2 lb) of the animal's body weight and extra food every 1-2 hours to counter the insulin's effects.

Possible cures

In cases of secondary or transient diabetes where the condition may be caused by use of steroid medications, the hormones of heat (spaying can resolve the diabetes) / pregnancy, or other medical conditions such as Cushing's disease, it may be possible to treat the primary medical problem and revert the animal to non-diabetic status. Returning to non-diabetic status would depend on the amount of damage the pancreatic insulin-producing beta cells have sustained.

It happens rarely, but it is possible for a pancreatitis attack to "jolt" the endocrine portion of the organ back into being capable of producing insulin once again in dogs.

External links

• Dogs and Diabetes - Signs, Treatment, Complexities

• Management of Insulin Overdose (Hypoglycemia-low blood sugar) Schermerhorn pages 1-6/Persistent Hyperglycemia (high blood sugar) Schermerhorn pages 7-16-Veterinary Learning Systems Compendium Standards of Care 2001

• Veterinary Emergency & Critical Care Society-list of emergency facilities world-wide
• Blood glucose converter-mg/dl to mmol/L and vice-versa-Children With Diabetes