Diabetes in dogs

(see also Diabetes in cats)

, which contain insulin-producing beta cells and other endocrine related cells. Permanent damage to these beta cells results in Type 1, or insulin-dependent diabetes, for which exogenous insulin replacement therapy is the only answer.]]

Diabetes mellitus is a disease in which the beta cells of the endocrine pancreas either stop producing insulin or can no longer produce it in enough quantity for the body's needs. The body uses glucose for energy. Without insulin, cells are not able to use the glucose for its intended purpose, so it begins to build up in the blood where it can be seen as hyperglycemia or high blood glucose levels. 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 exogenous insulin injections must replace the insulin the pancreas is no longer capable of producing or able to produce in enough quantity to supply the body's need for it. Dogs have Insulin-Dependent, or Type 1, diabetes; current research finds no Type 2 diabetes in dogs. Because of this, there is no possibility the permanently damaged pancreatic beta cells could re-activate to engender a remission as may be possible with some feline diabetes cases, where the primary type of diabetes is Type 2. There is another form of diabetes, Diabetes insipidus, which is a condition of insufficient antidiuretic hormone or resistance to it.

This most common form of diabetes 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, increasing weakness in the legs (neuropathy), malnutrition, ketoacidosis, dehydration, and death. Diabetes mainly affects middle-aged and older dogs, but there are also 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. Currently, diabetic dogs receiving treatment have the same expected lifespan as non-diabetic dogs of the same age and gender.

Classification and causes

At present, there is no international standard classification of diabetes in dogs.

Insulin Resistance Diabetes or Secondary Diabetes, which describes the resistance to insulin caused by other medical conditions or by hormonal drugs. Various breed and treatment studies have been able provide some evidence of a genetic connection. Studies have also furnished evidence that canine diabetes has a seasonal connection not unlike its human Type 1 diabetes counterpart, and a "lifestyle" factor, with pancreatitis being a clear cause of diabetes in dogs. This evidence suggests that the disease in dogs also has some environmental and dietary factors involved.

Secondary diabetes may be caused by use of steroid medications, the hormones of estrus or acromegaly, (spaying can resolve the diabetes), pregnancy, or other medical conditions such as Cushing's disease. Returning to non-diabetic status would depend on the amount of damage the pancreatic insulin-producing beta cells have sustained. It is also possible for acute pancreatitis to cause a temporary, or transient diabetes, most likely due to damage to the endocrine portion's beta cells. Pancreatitis can also damage the endocrine pancreas to the point where the diabetes is permanent.

Genetic susceptibility of certain breeds

This list of risk factors for canine diabetes is taken from the genetic breed study that was published in 2007. Their "neutral risk" category should be interpreted as insufficent evidence that the dog breed genetically shows a high, moderate, or a low risk for the disease. All risk information is based only on discovered genetic factors. High risk

Cairn Terrier

Samoyed

Moderate risk

Bichon Frise

Border Collie

Border Terrier

Collie

Dachshund

English Setter

Poodle

Schnauzer

Yorkshire Terrier

Neutral risk

Cavalier King Charles Spaniel

Cocker Spaniel

Doberman

Jack Russell Terrier

Labrador Retriever

Mixed Breed

Rottweiler

West Highland Terrier

Low risk

Boxer

German Shepherd

Golden Retriever

Springer Spaniel

Staffordshire Bull Terrier

Weimaraner

Symptoms

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

Management

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. They must instead be placed on insulin replacement therapy. Unapproved so-called "natural" remedies make similar claims for their products. All of this is based on the premise of having an endocrine pancreas with beta cells capable of producing insulin. Those with Type 1, or insulin-dependent diabetes, have beta cells which are permanently damaged, thus unable to produce insulin.

The goal is to regulate the pet's blood glucose using insulin and some probable diet and daily routine changes. The process may take a few weeks or even many months. It is basically the same as in type-1 diabetic humans. The aim is to keep the blood glucose values within an acceptable range during the whole day, or most of it. The commonly recommended method is by "starting low and going slow" as indicated for people with diabetes, with typical starting insulin doses at 0.25 IU/KG (2.2 lb)

The diabetic pet is regulated when its blood glucose levels remain within an acceptable range on a regular basis. Acceptable levels for dogs are between 5 and 10 mmol/L or 90 to 180 mg/dL.

Insulin therapy

The general form of this treatment is an intermediate-acting basal insulin with a regimen of food and insulin every 12 hours, insulin following the meal. The most commonly used intermediate-acting insulins are NPH, also referred to as isophane, or Caninsulin, also known as Vetsulin, a porcine Lente insulin. While the normal diabetes routine is timed feedings with insulin shots following the meals, dogs unwilling to adhere to this pattern can still attain satisfactory regulation.

With Lantus (insulin glargine) and Protamine Zinc Insulin (PZI) being unreliable in dogs, they are rarely used to treat canine diabetes. Bovine insulin has been used as treatment for some dogs, particularly in the UK. Pfizer Animal Health discontinued of all three types of its veterinary Insuvet bovine insulins in late 2010 and suggested patients be transitioned to Caninsulin. The original owner of the insulin brand, Schering-Plough Animal Health, contracted Wockhardt UK to produce them. Wockhardt UK has produced both bovine and porcine insulins for the human pharmaceutical market for some time. Their Hypurin line of bovine insulins is comparable to that of Insuvet.

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 or keeping the animal eating, as use of the prescribed amount of insulin is dependent on eating full meals. When no meal at all is eaten, there is still a need for a basal dosage of insulin, which supplies the body's needs without taking food into consideration. Eating a partial meal would mean a reduction in insulin dose. Basal and reduced insulin dose information should be part of initial doctor–client diabetes discussions in case of need. If the animal will not eat a prescribed diet, it is not in the dog's best interest to insist on it; the amount of additional insulin required because a non-prescription diet is being fed is generally between 2–4%. Since dogs with diabetes are prone to pancreatitis and hyperlipidemia, feeding a low-fat food may help limit or avoid these complications. Prescription foods are fixed formulas, while most non-prescription ones are open formula unless the manufacturer states otherwise.

Glucometers and urine test strips

The use of an inexpensive glucometer and blood glucose testing at home can help avoid dangerous insulin overdoses and can provide a better picture of how well the condition is managed. A 2003 study of canine diabetes caregivers who were new to testing blood glucose at home found 85% of them were able to both succeed at testing and to continue it on a long-term basis. Using only one blood glucose reading as the reason for an insulin dose increase is to be avoided; while the results may be higher than desired, further information, such as the lowest blood glucose reading or nadir, should be available to prevent possible hypoglycemia. Urine strips are not accurate enough for this and are not recommended to be used as the sole factor for insulin adjustments. Urine glucose testing strips have a negative result until the renal threshold of 10 mmol/L or 180 mg/dL is reached or exceeded for a period of time. The range of negative reading values is quite wide-covering euglycemia (normal or close to normal blood glucose values with no danger of hypoglycemia) to hypoglycemia (low blood glucose values) where treatment would be necessary.

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. Glucometers for humans were successfully used with pets long before animal-oriented meters were produced. A 2009 study directly compared readings from both types of glucometers to those of a chemistry analyzer. Neither glucometer's readings exactly matched those of the analyzer, but the differences of both were not clinically significant when compared to analyzer results. All glucometer readings need to be compared to same sample laboratory values to determine accuracy.

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, or Xceed outside of the US). The blood ketone test strips are very expensive; prices start at about $50 for ten strips. It is 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. The table at left is a guide to when ketones may be present.

Ketone problems that are more serious than the "trace or slight" range need immediate medical attention; they cannot be treated at home. Veterinary care for ketosis/ketoacidosis can involve intravenous (IV) fluids to counter dehydration such as bicarbonate; intravenous or intramuscular measured amounts of glucose or force feeding, sometimes by feeding tube, to force the metabolism back from fat-burning to glucose-burning. When testing urine for ketones, the sample needs to be as fresh as possible. Ketones evaporate quickly, so there is a chance of getting a false negative test result if testing older urine. The urine testing strip bottle has instructions and color charts to illustrate how the color on the strip will change given the level of ketones or glucose in the urine over 15 (ketones–Ketostix) or 30 (glucose–Ketodiastix) seconds. Reading the colors at those time intervals is important because the colors will continue to darken and a later reading will be an incorrect result. Seizures and coma are possible. Treatment is similar to that of ketoacidosis, with the exceptions being that NHS requires that the blood glucose levels and rehydration be normalized at a slower rate than for DKA; cerebral edema is possible if the treatment progresses too rapidly. With a condition like fever, it is possible to measure the amount of fluid losses from it with a formula that increases by 7% for each degree of above normal body temperature, so it would be classed as a sensible loss.

Hyperglycemia means more of a risk for dehydration. Dehydration can change the way exogenous insulin is absorbed, so either hyperglycemia or hypoglycemia are possible; dehydration can also cause false (negative or positive) urine ketone test results.

A check of the pet's gums and skin can indicate dehydration; gums are tacky and dry and skin does not snap back quickly when pinched if dehydration is present.

Treatment complications

Hypoglycemia

Hypoglycemia, or low blood glucose, can happen even with care, since insulin requirements can sometimes change without warning. Some common reasons for hypoglycemia include increased or unplanned exercise, illness, or medication interactions, where another medication the effects of the insulin. Symptoms of hypoglycemia need to always be taken seriously and addressed promptly. Since serious hypoglycemia can be fatal, it is better to treat a suspected incident than to fail to respond quickly to the signs of actual hypoglycemia. Dr. Audrey Cook addressed the issue in her 2007 article on diabetes mellitus: "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

Some common symptoms are: weakness

ataxia (loss of coordination or balance)

loss of excretory or bladder control (sudden house accident)

vomiting, and then loss of consciousness and possible seizures

Successful home treatment of a hypoglycemia event depends on being able to recognize the symptoms early and responding quickly with treatment. Seizures or loss of consciousness because of low blood glucose levels are medical emergencies.

Treatment

Food should be offered at the first signs of possible hypoglycemia. If the animal refuses it, a sugar solution (corn syrup, honey, pancake syrup, etc.) should be poured on the finger and rubbed on its gums or under the tongue (sublingually). Intervet suggests one tablespoon of a sugar solution rubbed onto the gums, regardless of the size of the dog. act rapidly and will make the blood glucose rise, but the rise will not last very long, as they are broken down quickly by the body. when the pet is able to eat will make sure another hypoglycemia event does not overtake the rapid rise in blood glucose levels from the sugar solution. Complex carbohydrates take longer to be broken down by the body, so they do not raise blood glucose levels until some time after being eaten. A small meal should be fed and the animal taken for medical evaluation to determine if further treatment is needed.

References

External links

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

Pounds to Kilograms/Kilograms to Pounds online Converter-Open Toronto

Shortage of Vetsulin in the Critical Need Program and Discontinuation of Program FDA February 4, 2011

Discontinuation of Program Intervet February 7, 2011

Intervet: Vetsulin Will Return Intervet February 11, 2011

Dogs and Diabetes - Signs, Treatment, Complexities

Vet-approved recipes for diabetic dog food

Category:Diabetes Category:Dog diseases Category:Dog health