PATHOLOGY - Diabetes Mellitus

Question 1

What is the pathophysiology for diabetes mellitus in dogs?

Answer 1

In dogs, there is immune-mediated destruction of the islets of Langerhans, resulting in decreased insulin production

Question 2

Which risk factors can progress diabetes mellitus in dogs?

Answer 2

Pancreatitis
Progesterone
Obesity
Cortisol
Inflammation

Progesterone, obesity, cortisol and inflammation all cause insulin resistance

Question 3

What is the pathophysiology of diabetes mellitus in cats?

Answer 3

In cats, insulin secretion is inadequte due to a combination of islets of Langerhans pathology and peripheral insulin resistance. The most common form of pathology at the islets of Langerhans in cats in amyloidosis which resuluts in insensitivity of the islet cels to changes in blood glucose concentrations

Question 4

Which factors can cause cats to develop peripheral resistance to insulin?

Answer 4

Obesity
Growth hormone
Progesterone
Cortisol
Glucose toxicity

Question 5

What is glucose toxicity?

Answer 5

Glucose toxicity is where there are very high blood glucose concentrations resulting in the inhibition of insulin receptors

Question 6

How can glucose toxicity be resolved?

Answer 6

Glucose toxicity can be resolved if the blood glucose levels are reduced for several weeks, which can allow the insulin receptors to regenerate

Question 7

What is the typical signalement for diabetes mellitus?

Answer 7

Older animals
Intact females
Breed predispositions

Question 8

Why are intact female animals at an increased risk of diabetes mellitus?

Answer 8

Intact females are at an increased risk of diabetes mellitus due to progesterone mediated insulin resistance

Question 9

Which dog breeds are predisposed to developing diabetes mellitus?

Answer 9

Samoyeds
Terriers

Question 10

Which cat breeds are predisposed to developing diabetes mellitus?

Answer 10

Bermese cats

Question 11

What are the general clinical signs of diabetes mellitus?

Answer 11

Usually BAR
PUPD
Polyphagia
Anorexia (in cats)
Weight loss
Lethargy
Blindness (in dogs)
Hindlimb weakness (in cats)

Question 12

What causes blindness in dogs with diabetes mellitus?

Answer 12

Diabetic cataracts

Question 13

What causes hindlimb weakness in cats with diabetes mellitus?

Answer 13

Diabetic neuropathies result in hindlimb weakbness and a hindlimb plantigrade stance

Question 14

Which diagnostic tests can be done to confirm a diagnosis of diabetes mellitis?

Answer 14

Urinalysis (urine dipstick)
Biochemistry

Question 15

What is a key indicator of diabetes mellitus on a urine dipstick?

Answer 15

Glucosuira
Ketones (not always)

Question 16

What is a key indicator of diabetes mellitus on biochemistry?

Answer 16

Hyperglycaemia above the renal threshold

Question 17

What is the renal threshold of glucose?

Answer 17

The renal threshold for glucose is the blood glucose concentration where the kidney’s ability to reabsorb glucose from the renal tubules is exceeded. Once the serum glucose levels rise above this threshold, the kidneys begin to excrete glucose into the urine

Question 18

What is the renal threshold of glucose in dogs?

Answer 18

10mmol/L

Question 19

What is the renal threshold of glucose in cats?

Answer 19

12mmol/L

Question 20

Which other biochemistry findings are common with diabetes mellitus?

Answer 20

Increased liver enzymes
Hypercholesterolaemia

Question 21

Why can the liver enzymes be increased with diabetes mellitus?

Answer 21

Liver enzymes can be increased due to steroid induced hepatopathies however there should be no signs of liver dysfunction

Question 22

What should you be aware of when assessing hyperglycaemia in cats?

Answer 22

Cats can have a marked stress induced hyperglycaemia that goes beyond the renal threshold so it is important to differentiate between a true diabetes mellitus and physiological stress

Question 23

What can be used to differentiate between a true diabetes mellitus and physiological stress induced hyperglycaemia?

Answer 23

Serum fructosamine levels

Question 24

What is fructosamine?

Answer 24

When glucose circulates in the blood, it can bind to serum proteins, and fructosamine is formed when glucose specifically binds to albumin. When fructosamine levels are beyond the reference range, this indicates a more chronic hyperglycaemia which indicates a true diabetes mellitus rather than a physiological stress hyperglycaemia

Question 25

How do you manage diabetes mellitus in dogs?

Answer 25

Insulin injections

Question 26

Why are insulin injections the only option for management of diabetes mellitus in dogs?

Answer 26

Insulin injections are the only treatment option for diabetes mellitus in dogs as diabetes is caused by an autoimmune response which results in no insulin being produced

Question 27

How do you manage diabetes mellitus in cats?

Answer 27

SGLT 2 inhibitors
Insulin injections

Question 28

How are SGLT 2 inhibitors used to manage diabetes mellitus in cats?

Question 29

Give an example of an SGLT 2 inhibitor

Answer 29

Velagliflozin

Question 30

Which aspects of the patient’s daily routine should be carefully planned to help manage diabetes mellitus?

Answer 30

Feeding times
Feeding amounts
Type of food
Insulin amount
Timing of insulin injection
Exercise
Environment