Feline DM

Question 1

What are the 2 most common endocrine diseases in cats?

Answer 1

Hyperthyroidism

Feline Diabetes Mellitus:

• 1:100 – 1:400 cats
• Burmese cats (1:50)
• Increased incidence with increased age

Question 2

What type of DM is more common in cats?

Answer 2

• The common pathogenesis in cats is fundamentally different to that in the dog
• Now known that type II DM (NIDDM= non insulin dependent diabetes means you have plenty of insulin but it is just not working) is much more common in cats than first thought
• Although they produce some insulin, peripheral antagonism or down regulation of receptors results in uncontrolled hyperglycaemia

Question 3

Describe the cycle of insulin resistance?

Answer 3

Question 4

Outline the types of diabetes mellitus and their pathogenesis?

Answer 4

Type I

• Immune-mediated destruction (rare)

Type II

• Impaired insulin secretion and peripheral action
• Underlying causes of diabetic state (type II)

Specific causes - pancreatitis, pancreatic neoplasia, acromegaly, hyperadrenocorticism

Question 5

Outline how type II diabetes may be caused by glucose/lipid toxicity?

Answer 5

• Chronic high levels glucose impair insulin secretion
• long-term glucose infusions -permanent diabetes
• >2wks, glycogen deposition and cell death result
• Similar high circulating lipid concentrations
• This is often termed “glucose toxicity”

Question 6

Discuss 3 parts of the pathogenesis of Type 2 DM?

Answer 6

• Peripheral insensitivity caused by:
  
  • Obesity
  • Stress
• Glucose toxicity
• Amyloid

Question 7

What can be seen here?

Answer 7

One of knock on consequences of DM is amyloid deposition in the pancreas

Question 8

Draw a schematic that shows the causes of DM and at what stage treatment may prevent development of chronic irreversible DM?

Answer 8

At the 4th box it is this point If we can sort this out at this stage we can prevent development of DM 2

Question 9

What is the pathophysiology of DM and what clinical signs does this cause?

Answer 9

• drop in tissue utilisation of glucose, amino acids and FFA
• Increase in gluconeogenesis, glycogenolysis, tissue catabolism
• Main first sign: Osmotic diuresis and secondary PD (if they arent PD suggest the glucose in blood is below renal threshold)
• Nock on effect can be dehydration
• Polyphagia
• Cataract
• Ketonaemia / Ketoacidosis

Question 10

How can DM be diagnosed on clinical history?

Answer 10

Clinical history

• Middle aged to older cats
• Neutered males over-represented in case numbers
• PU/PD
• Weight loss (despite eating loads)
• Polyphagia
• May also have a plantigrade stance caused by peripheral neuropathy (see picture)

Question 12

Based on clinical signs how can a diganosis of DM be confirmed?

Answer 12

Diagnosis in the cat is confounded by stress hyperglycaemia (Another disease process may make them look diabetic) so best to confirm with:

• Urine glucose at home
• Fructosamine (>400umol/l) Aka glycosylated albumin
• Ruling out other possible causes:

Hyper T4

Question 13

What complicatins/co-mordities should be checked for with a suspicion of DM?

Answer 13

• Up to 50% of all diabetic patients will have an active UTI on presentation
• Assessing for this in both cats and dogs is therefore vital

Question 14

What are the aims of DM treatment?

Answer 14

• Maintain adequate glycaemic control sufficient to avoid side-effects associated with hyperglycaemia e.g. ketoacidosis, cataracts, pancreatitis, nephropathy, retinopathy
• Recent evidence would suggest that a high proportion of cats (from referral institutions) will enter into diabetic remission with aggressive early treatment – note this is not cure (aggressive early treatment can get them into the pre-diabetic stage again)
  
  • 60-67% of cases
  • Primary care by comparison reported at ~26%
  • 30% of those in remission will suffer relapse
• Cats often suffer fewer overt complications and therefore regulation does not need to be as rigid as in the dog
• Although most cats are insulin-resistant diabetics (remember glucose toxicity), we use a combination of food and exogenous insulin to try to overcome the resistance and generate glycaemic control
• Some cats can be treated with diet ALONE in the long-term, so called “self-cure”

Question 15

What are the 2 licensed treatments for DM in the UK for cats?

Answer 15

• Two licensed products in UK:
• ProZinc (designed for cats but also licensed for Dogs)
• Caninsulin is also licenced for cats
• Dose
  
  • 0.25 – 0.5iu/kg BID
  • Start at 0.25iu/kg
• Aim is to use exogenous insulin to generate glycaemic control and then possibly rely on dietary treatment if possible
  
  • Type II aetiology

Question 16

How should the diabetic cat’s diet be managed?

Answer 16

Similarly to dogs, the diet should be consistent and not contain a large proportion of simple carbohydrates. In cats with suspected non-insulin dependent diabetes mellitus, obesity should be corrected as a priority to reduce insulin resistance. Emaciated cats should be fed a diet with high caloric density.

Recently, diets with high protein content have become popular in the management of diabetes mellitus in cats. These diets are used because their carbohydrate content can be reduced accordingly and because cats do not develop high peaks in post-prandial blood glucose concentration when they are fed on high protein diets. It is not clear whether supplementation of dietary fibre has any beneficial effect in cats

Question 17

It is recommended you use exogenous insulin and an appropriate diabetic diet first in treating DM but what other products are available?

Answer 17

Insulin glargine (not licensed in cats but given to cats that don’t respond to the licensed treatments also is used widely abroad):

• “Lantus”
• Human insulin analogue

Oral hypoglycaemic agents can also sometimes be used in cats with NIDDM

Question 18

How should i diabetic patient be monitored?

Answer 18

• Glucose level is hard to take in practice as the stress can induce in practice a hyperglycaemia
• Ideal monitoring would be serial blood glucose measurements
• Home blood glucose monitoring
• Measuring urine / ketone levels once/twice daily can be of use as part of routine monitoring but insulin doses should not be changed on the basis of urine glucose

Question 19

What should owners of diabetic cats be made aware of?

Answer 19

• Owners should be made aware of the signs of hypoglycaemia
• If an owner finds their diabetic cat collapsed / weak etc they should be instructed to give glucose / jam etc before telephoning for advice
  
  • Must follow this up with normal food due to short duration of the increase in blood glucose
  • This must trigger a review of the management

Question 20

How can diabetes be monitored?

Answer 20

• Usually best done firstly by general clinical examination and owners report of clinical signs
• Fructosamine can be useful in cats but again, interpret the results in light of the clinical picture!
• Blood glucose curves can be performed in well behaved cats, either from jugular or an ear tip (caution with calibration)
• Aim of BGC in cats the same as for dogs
• Home blood glucose monitoring increasingly used….

Question 21

How frequently should BGC be monitored?

Answer 21

• Remember diabetic remission
  
  • Usually within 3months
• Careful monitoring over this period
  
  • Weekly for the first 3-4 weeks
  • Then every ~2-3 weeks till 4 months
  • Then every 4 months
  • Note this must be tailored to the owners ability to carry out the testing

Question 22

What is GLIPIZIDE and how can it be used to treat DM?

Answer 22

• Sulphonylurea drug that stimulates insulin secretion from functional beta cell
  
  • Start at 2.5mg/cat BID
• Adverse reactions include hypoglycaemia, vomiting, icterus, elevated liver enzymes
  
  • Seen in < 15% of treated cats
• Can double dose to 5mg/cat after 2 weeks
  
  • Approx 25% of cats will respond

Question 23

What is METFORMIN and how can it be used to treat DM?

Answer 23

• Biguanide drug that has no direct on beta cells, but increases the sensitivity of peripheral tissues and the liver to insulin
• Also inhibits gluconeogenesis and glycogenolysis
• Doses 25-50mg cat
• Side-effects: vomiting, diarrhoea, anorexia
  
  • Really only seen at doses > 75 mg
• < 25% of cats respond

Question 24

What is ACARBOSE and how can it be used to treat DM?

Answer 24

• Alpha glucosidase inhibitor which slows intestinal absorption of glucose (inhibits sucrase, maltase, isomaltase)
• May be of some use in the dog?
• Doses 12.5-25mg/dog
• Side-effects include diarrhoea and weight loss
• Recent work indicates this is effective in some cats
  
  • Mazzaferro et.al, JFMS, (2003) 5, 183 – 189
  • 18 cats on trial (all fed high fibre food as well)
  • 11 stopped requiring insulin
  • 7 still required insulin, but the mean dose was reduced and glycaemic parameters improved

Question 25

What is CHROMIUM and how can it be used to treat DM?

Answer 25

• Naturally occurring trace element
• Increases insulin sensitivity
• Recent studies have shown little clinical benefit in dogs (n = 13)
  
  • Schachter et.al., JVIM (2001), 15, 379 - 384
• Small studies also published in cats
  
  • Appleton et.al., (2002) JFMS, 4, 13 – 25
  • 32 healthy cats fed four different concentration of Cr
  • Supplementation with 300 and 600 ppb Cr showed better response to a glucose tolerance test.

Question 26

What is VANADIUM and how can it be used to treat DM?

Answer 26

• Trace element
• Acts at post-receptor site to stimulate glucose metabolism
• 0.2mg vanadium/kg/day given in water has been shown to decrease water intake and improve glycaemic control in cats
• Side-effects include anorexia, vomiting, renal toxicity

Question 27

How do you deal with difficult diabetes cases?

Answer 27

As with dogs, you cannot say that a cat is resistant to his/her insulin until they are receiving > 2.2 iu/kg each dose

If this is the case, firstly rule out owner compliance

If this is good however then there is peripheral resistance and you need to investigate the cause

• Infection (eg: UTI)
• Concurrent endocrinopathy (eg: acromegaly)
• Neoplasia
• Stress
• True insulin resistance
• acromegaly

Question 29

Today, you have diagnosed diabetes mellitus in “Oscar”, an 8yr old 6kg MN DSH belonging to Mr Brown. Mr Brown has previously owned a diabetic dog “Millie” which he successfully managed with your clinic’s help for 3yrs. He feels confident that he can manage another diabetic pet. It is important that he understands that diabetic cats are different from diabetic dogs. Outline your explanation of the differences between managing a cat versus managing a dog with diabetes mellitus:

Are there alternative therapeutic options to consider?

Answer 29

Type II DM in cats offers the possibility of treating with oral medication if injections will be impossible. Diet alone has been successful in some cases.

Question 30

Today, you have diagnosed diabetes mellitus in “Oscar”, an 8yr old 6kg MN DSH belonging to Mr Brown. Mr Brown has previously owned a diabetic dog “Millie” which he successfully managed with your clinic’s help for 3yrs. He feels confident that he can manage another diabetic pet. It is important that he understands that diabetic cats are different from diabetic dogs. Outline your explanation of the differences between managing a cat versus managing a dog with diabetes mellitus:

Will diet be less, as or more important than for his dog?

Answer 30

Diet is important in the pathogenesis of feline DM and if remission is a therapeutic goal then low CHO are likely to improve the chance of success

Question 31

Today, you have diagnosed diabetes mellitus in “Oscar”, an 8yr old 6kg MN DSH belonging to Mr Brown. Mr Brown has previously owned a diabetic dog “Millie” which he successfully managed with your clinic’s help for 3yrs. He feels confident that he can manage another diabetic pet. It is important that he understands that diabetic cats are different from diabetic dogs. Outline your explanation of the differences between managing a cat versus managing a dog with diabetes mellitus:

Will treatment be lifelong?

Answer 31

Diabetic cats may go into remission for variable periods

Question 32

Today, you have diagnosed diabetes mellitus in “Oscar”, an 8yr old 6kg MN DSH belonging to Mr Brown. Mr Brown has previously owned a diabetic dog “Millie” which he successfully managed with your clinic’s help for 3yrs. He feels confident that he can manage another diabetic pet. It is important that he understands that diabetic cats are different from diabetic dogs. Outline your explanation of the differences between managing a cat versus managing a dog with diabetes mellitus:

What long-term complications of DM can he expect?

Answer 32

Cats don’t get cataracts as easily/often as dogs. They may get neuropathy (plantigrade stance)

Question 33

Today, you have diagnosed diabetes mellitus in “Oscar”, an 8yr old 6kg MN DSH belonging to Mr Brown. Mr Brown has previously owned a diabetic dog “Millie” which he successfully managed with your clinic’s help for 3yrs. He feels confident that he can manage another diabetic pet. It is important that he understands that diabetic cats are different from diabetic dogs. Outline your explanation of the differences between managing a cat versus managing a dog with diabetes mellitus:

What problems will he need to look out for?

Answer 33

Because of the possibility of remission, signs of subclinical and clinical hypoglycaemia are important e.g., increased appetite, wobbliness etc.

Question 34

Today, you have diagnosed diabetes mellitus in “Oscar”, an 8yr old 6kg MN DSH belonging to Mr Brown. Mr Brown has previously owned a diabetic dog “Millie” which he successfully managed with your clinic’s help for 3yrs. He feels confident that he can manage another diabetic pet. It is important that he understands that diabetic cats are different from diabetic dogs. Outline your explanation of the differences between managing a cat versus managing a dog with diabetes mellitus:

What underlying conditions should you make the owner aware of in cats with DM that don’t really occur in dogs?

Answer 34

It is increasingly recognised that cats can suffer with acromegaly which leads to the development of DM. This often causes overgrowth of soft tissues and facial features and cats often have clear differences in their appearance. The diagnosis is typically made by measuring IGF-1 concentrations in the blood.